birth

detection/mmdet_custom/models/dense_heads/__init__.py

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+# --------------------------------------------------------
+# DCNv4
+# Copyright (c) 2024 OpenGVLab
+# Licensed under The MIT License [see LICENSE for details]
+# --------------------------------------------------------
+
+from .deformable_detr_head import DeformableDETRHead
+from .detr_head import DETRHead
+from .dino_head import DINOHead
+from .msda import  FlashMultiScaleDeformableAttention
+from .bbox_head import DCNv4FCBBoxHead
+from .mask_rcnn import MaskRCNN_
+__all__ = ['DeformableDETRHead', 'DETRHead', 'DINOHead']

detection/mmdet_custom/models/dense_heads/bbox_head.py

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+# Copyright (c) OpenMMLab. All rights reserved.
+import torch.nn as nn
+from mmcv.cnn import ConvModule
+
+from mmdet.models.builder import HEADS
+from mmdet.models.utils import build_linear_layer
+from mmdet.models.roi_heads.bbox_heads.bbox_head import BBoxHead
+import DCNv4
+
+
+
+
+
+
+@HEADS.register_module()
+class DCNv4FCBBoxHead(BBoxHead):
+    r"""More general bbox head, with shared conv and fc layers and two optional
+    separated branches.
+
+    .. code-block:: none
+
+                                    /-> cls convs -> cls fcs -> cls
+        shared convs -> shared fcs
+                                    \-> reg convs -> reg fcs -> reg
+    """  # noqa: W605
+
+    def __init__(self,
+                 num_shared_convs=0,
+                 num_shared_fcs=0,
+                 num_cls_convs=0,
+                 num_cls_fcs=0,
+                 num_reg_convs=0,
+                 num_reg_fcs=0,
+                 conv_out_channels=256,
+                 fc_out_channels=1024,
+                 conv_cfg=None,
+                 norm_cfg=None,
+                 init_cfg=None,
+                 with_dcn=True,
+                 short_cut=False,
+                 *args,
+                 **kwargs):
+        super(DCNv4FCBBoxHead, self).__init__(
+            *args, init_cfg=init_cfg, **kwargs)
+        assert (num_shared_convs + num_shared_fcs + num_cls_convs +
+                num_cls_fcs + num_reg_convs + num_reg_fcs > 0)
+        if num_cls_convs > 0 or num_reg_convs > 0:
+            assert num_shared_fcs == 0
+        if not self.with_cls:
+            assert num_cls_convs == 0 and num_cls_fcs == 0
+        if not self.with_reg:
+            assert num_reg_convs == 0 and num_reg_fcs == 0
+        self.num_shared_convs = num_shared_convs
+        self.num_shared_fcs = num_shared_fcs
+        self.num_cls_convs = num_cls_convs
+        self.num_cls_fcs = num_cls_fcs
+        self.num_reg_convs = num_reg_convs
+        self.num_reg_fcs = num_reg_fcs
+        self.conv_out_channels = conv_out_channels
+        self.fc_out_channels = fc_out_channels
+        self.conv_cfg = conv_cfg
+        self.norm_cfg = norm_cfg
+        self.with_dcn = with_dcn
+        self.short_cut = short_cut
+
+        # add shared convs and fcs
+        self.shared_convs, self.shared_fcs, last_layer_dim = \
+            self._add_conv_fc_branch(
+                self.num_shared_convs, self.num_shared_fcs, self.in_channels,
+                True)
+        self.shared_out_channels = last_layer_dim
+
+        # add cls specific branch
+        self.cls_convs, self.cls_fcs, self.cls_last_dim = \
+            self._add_conv_fc_branch(
+                self.num_cls_convs, self.num_cls_fcs, self.shared_out_channels)
+
+        # add reg specific branch
+        self.reg_convs, self.reg_fcs, self.reg_last_dim = \
+            self._add_conv_fc_branch(
+                self.num_reg_convs, self.num_reg_fcs, self.shared_out_channels)
+
+        if self.num_shared_fcs == 0 and not self.with_avg_pool:
+            if self.num_cls_fcs == 0:
+                self.cls_last_dim *= self.roi_feat_area
+            if self.num_reg_fcs == 0:
+                self.reg_last_dim *= self.roi_feat_area
+
+        self.relu = nn.ReLU(inplace=True)
+        # reconstruct fc_cls and fc_reg since input channels are changed
+        if self.with_cls:
+            if self.custom_cls_channels:
+                cls_channels = self.loss_cls.get_cls_channels(self.num_classes)
+            else:
+                cls_channels = self.num_classes + 1
+            self.fc_cls = build_linear_layer(
+                self.cls_predictor_cfg,
+                in_features=self.cls_last_dim,
+                out_features=cls_channels)
+        if self.with_reg:
+            out_dim_reg = (4 if self.reg_class_agnostic else 4 *
+                           self.num_classes)
+            self.fc_reg = build_linear_layer(
+                self.reg_predictor_cfg,
+                in_features=self.reg_last_dim,
+                out_features=out_dim_reg)
+
+        if init_cfg is None:
+            # when init_cfg is None,
+            # It has been set to
+            # [[dict(type='Normal', std=0.01, override=dict(name='fc_cls'))],
+            #  [dict(type='Normal', std=0.001, override=dict(name='fc_reg'))]
+            # after `super(ConvFCBBoxHead, self).__init__()`
+            # we only need to append additional configuration
+            # for `shared_fcs`, `cls_fcs` and `reg_fcs`
+            self.init_cfg += [
+                dict(
+                    type='Xavier',
+                    distribution='uniform',
+                    override=[
+                        dict(name='shared_fcs'),
+                        dict(name='cls_fcs'),
+                        dict(name='reg_fcs')
+                    ])
+            ]
+
+    def _add_conv_fc_branch(self,
+                            num_branch_convs,
+                            num_branch_fcs,
+                            in_channels,
+                            is_shared=False):
+        """Add shared or separable branch.
+
+        convs -> avg pool (optional) -> fcs
+        """
+        last_layer_dim = in_channels
+        # add branch specific conv layers
+        branch_convs = nn.ModuleList()
+        if num_branch_convs > 0:
+            for i in range(num_branch_convs):
+                conv_in_channels = (
+                    last_layer_dim if i == 0 else self.conv_out_channels)
+                if self.with_dcn:
+                    assert False, 'TODO: support DCNv4 in the task head'
+                    conv =  DCNv4.DCNv4(
+                        conv_in_channels,
+                        self.conv_out_channels,
+                    )
+                else:
+                    conv = ConvModule(
+                        conv_in_channels,
+                        self.conv_out_channels,
+                        3,
+                        padding=1,
+                        conv_cfg=self.conv_cfg,
+                        norm_cfg=self.norm_cfg)
+
+                branch_convs.append(conv)
+            last_layer_dim = self.conv_out_channels
+        # add branch specific fc layers
+        branch_fcs = nn.ModuleList()
+        if num_branch_fcs > 0:
+            # for shared branch, only consider self.with_avg_pool
+            # for separated branches, also consider self.num_shared_fcs
+            if (is_shared
+                    or self.num_shared_fcs == 0) and not self.with_avg_pool:
+                last_layer_dim *= self.roi_feat_area
+            for i in range(num_branch_fcs):
+                fc_in_channels = (
+                    last_layer_dim if i == 0 else self.fc_out_channels)
+                branch_fcs.append(
+                    nn.Linear(fc_in_channels, self.fc_out_channels))
+            last_layer_dim = self.fc_out_channels
+        return branch_convs, branch_fcs, last_layer_dim
+
+    def forward(self, x):
+        # shared part
+        if self.with_dcn:
+            N, C, H, W = x.shape
+            x = x.permute(0, 2, 3, 1).view(N, H*W, C)
+            if self.num_shared_convs > 0:
+                for conv in self.shared_convs:
+                    if self.short_cut:
+                        x = x + conv(x, shape=(H, W))
+                    else:
+                        x = conv(x, shape=(H, W))
+        else:
+            if self.num_shared_convs > 0:
+                for conv in self.shared_convs:
+                    x = conv(x)
+        if self.num_shared_fcs > 0:
+            if self.with_avg_pool:
+                x = self.avg_pool(x)
+            x = x.flatten(1)
+
+            for fc in self.shared_fcs:
+                x = self.relu(fc(x))
+        # separate branches
+        x_cls = x
+        x_reg = x
+
+        for conv in self.cls_convs:
+            x_cls = conv(x_cls)
+        if x_cls.dim() > 2:
+            if self.with_avg_pool:
+                x_cls = self.avg_pool(x_cls)
+            x_cls = x_cls.flatten(1)
+        for fc in self.cls_fcs:
+            x_cls = self.relu(fc(x_cls))
+
+        for conv in self.reg_convs:
+            x_reg = conv(x_reg)
+        if x_reg.dim() > 2:
+            if self.with_avg_pool:
+                x_reg = self.avg_pool(x_reg)
+            x_reg = x_reg.flatten(1)
+        for fc in self.reg_fcs:
+            x_reg = self.relu(fc(x_reg))
+
+        cls_score = self.fc_cls(x_cls) if self.with_cls else None
+        bbox_pred = self.fc_reg(x_reg) if self.with_reg else None
+        return cls_score, bbox_pred

detection/mmdet_custom/models/dense_heads/deformable_detr_head.py

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+# Copyright (c) OpenMMLab. All rights reserved.
+import copy
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from mmcv.cnn import Linear, bias_init_with_prob, constant_init
+from mmcv.runner import force_fp32
+
+from mmdet.core import multi_apply
+from mmdet.models.utils.transformer import inverse_sigmoid
+from mmdet.models.builder import HEADS
+from .detr_head import DETRHead
+
+
+@HEADS.register_module(force=True)
+class DeformableDETRHead(DETRHead):
+    """Head of DeformDETR: Deformable DETR: Deformable Transformers for End-to-
+    End Object Detection.
+
+    Code is modified from the `official github repo
+    <https://github.com/fundamentalvision/Deformable-DETR>`_.
+
+    More details can be found in the `paper
+    <https://arxiv.org/abs/2010.04159>`_ .
+
+    Args:
+        with_box_refine (bool): Whether to refine the reference points
+            in the decoder. Defaults to False.
+        as_two_stage (bool) : Whether to generate the proposal from
+            the outputs of encoder.
+        transformer (obj:`ConfigDict`): ConfigDict is used for building
+            the Encoder and Decoder.
+    """
+
+    def __init__(self,
+                 *args,
+                 with_box_refine=False,
+                 as_two_stage=False,
+                 transformer=None,
+                 use_2fc_cls_branch=False,
+                 **kwargs):
+        self.with_box_refine = with_box_refine
+        self.as_two_stage = as_two_stage
+        self.use_2fc_cls_branch = use_2fc_cls_branch
+        if self.as_two_stage:
+            transformer['as_two_stage'] = self.as_two_stage
+
+        super(DeformableDETRHead, self).__init__(
+            *args, transformer=transformer, **kwargs)
+
+    def _init_layers(self):
+        """Initialize classification branch and regression branch of head."""
+        
+        if not self.use_2fc_cls_branch:
+            fc_cls = Linear(self.embed_dims, self.cls_out_channels)
+        else:
+            fc_cls = nn.Sequential(*[
+                Linear(self.embed_dims, int(self.embed_dims * 1.5)),
+                nn.LayerNorm(int(self.embed_dims * 1.5)),
+                nn.GELU(),
+                Linear(int(self.embed_dims * 1.5), self.cls_out_channels),
+            ])
+            fc_cls.out_features = self.cls_out_channels
+
+        reg_branch = []
+        for _ in range(self.num_reg_fcs):
+            reg_branch.append(Linear(self.embed_dims, self.embed_dims))
+            reg_branch.append(nn.ReLU())
+        reg_branch.append(Linear(self.embed_dims, 4))
+        reg_branch = nn.Sequential(*reg_branch)
+
+        def _get_clones(module, N):
+            return nn.ModuleList([copy.deepcopy(module) for i in range(N)])
+
+        # last reg_branch is used to generate proposal from
+        # encode feature map when as_two_stage is True.
+        num_pred = (self.transformer.decoder.num_layers + 1) if \
+            self.as_two_stage else self.transformer.decoder.num_layers
+
+        if self.with_box_refine:
+            self.cls_branches = _get_clones(fc_cls, num_pred)
+            self.reg_branches = _get_clones(reg_branch, num_pred)
+        else:
+
+            self.cls_branches = nn.ModuleList(
+                [fc_cls for _ in range(num_pred)])
+            self.reg_branches = nn.ModuleList(
+                [reg_branch for _ in range(num_pred)])
+
+        if not self.as_two_stage:
+            self.query_embedding = nn.Embedding(
+                self.num_query,
+                self.embed_dims * 2)
+
+    def init_weights(self):
+        """Initialize weights of the DeformDETR head."""
+        self.transformer.init_weights()
+        if self.loss_cls.use_sigmoid:
+            bias_init = bias_init_with_prob(0.01)
+            if not self.use_2fc_cls_branch:
+                for m in self.cls_branches:
+                    nn.init.constant_(m.bias, bias_init)
+        for m in self.reg_branches:
+            constant_init(m[-1], 0, bias=0)
+        nn.init.constant_(self.reg_branches[0][-1].bias.data[2:], -2.0)
+        if self.as_two_stage:
+            for m in self.reg_branches:
+                nn.init.constant_(m[-1].bias.data[2:], 0.0)
+
+    def forward(self, mlvl_feats, img_metas):
+        """Forward function.
+
+        Args:
+            mlvl_feats (tuple[Tensor]): Features from the upstream
+                network, each is a 4D-tensor with shape
+                (N, C, H, W).
+            img_metas (list[dict]): List of image information.
+
+        Returns:
+            all_cls_scores (Tensor): Outputs from the classification head, \
+                shape [nb_dec, bs, num_query, cls_out_channels]. Note \
+                cls_out_channels should includes background.
+            all_bbox_preds (Tensor): Sigmoid outputs from the regression \
+                head with normalized coordinate format (cx, cy, w, h). \
+                Shape [nb_dec, bs, num_query, 4].
+            enc_outputs_class (Tensor): The score of each point on encode \
+                feature map, has shape (N, h*w, num_class). Only when \
+                as_two_stage is True it would be returned, otherwise \
+                `None` would be returned.
+            enc_outputs_coord (Tensor): The proposal generate from the \
+                encode feature map, has shape (N, h*w, 4). Only when \
+                as_two_stage is True it would be returned, otherwise \
+                `None` would be returned.
+        """
+
+        batch_size = mlvl_feats[0].size(0)
+        input_img_h, input_img_w = img_metas[0]['batch_input_shape']
+        img_masks = mlvl_feats[0].new_ones(
+            (batch_size, input_img_h, input_img_w))
+        for img_id in range(batch_size):
+            img_h, img_w, _ = img_metas[img_id]['img_shape']
+            img_masks[img_id, :img_h, :img_w] = 0
+
+        mlvl_masks = []
+        mlvl_positional_encodings = []
+        for feat in mlvl_feats:
+            mlvl_masks.append(
+                F.interpolate(img_masks[None],
+                              size=feat.shape[-2:]).to(torch.bool).squeeze(0))
+            mlvl_positional_encodings.append(
+                self.positional_encoding(mlvl_masks[-1]))
+
+        query_embeds = None
+        if not self.as_two_stage:
+            query_embeds = self.query_embedding.weight
+        hs, init_reference, inter_references, \
+            enc_outputs_class, enc_outputs_coord = self.transformer(
+                    mlvl_feats,
+                    mlvl_masks,
+                    query_embeds,
+                    mlvl_positional_encodings,
+                    reg_branches=self.reg_branches if self.with_box_refine else None,  # noqa:E501
+                    cls_branches=self.cls_branches if self.as_two_stage else None  # noqa:E501
+            )
+        hs = hs.permute(0, 2, 1, 3)
+        outputs_classes = []
+        outputs_coords = []
+
+        for lvl in range(hs.shape[0]):
+            if lvl == 0:
+                reference = init_reference
+            else:
+                reference = inter_references[lvl - 1]
+            reference = inverse_sigmoid(reference)
+            outputs_class = self.cls_branches[lvl](hs[lvl])
+            tmp = self.reg_branches[lvl](hs[lvl])
+            if reference.shape[-1] == 4:
+                tmp += reference
+            else:
+                assert reference.shape[-1] == 2
+                tmp[..., :2] += reference
+            outputs_coord = tmp.sigmoid()
+            outputs_classes.append(outputs_class)
+            outputs_coords.append(outputs_coord)
+
+        outputs_classes = torch.stack(outputs_classes)
+        outputs_coords = torch.stack(outputs_coords)
+        if self.as_two_stage:
+            return outputs_classes, outputs_coords, \
+                enc_outputs_class, \
+                enc_outputs_coord.sigmoid()
+        else:
+            return outputs_classes, outputs_coords, \
+                None, None
+
+    @force_fp32(apply_to=('all_cls_scores_list', 'all_bbox_preds_list'))
+    def loss(self,
+             all_cls_scores,
+             all_bbox_preds,
+             enc_cls_scores,
+             enc_bbox_preds,
+             gt_bboxes_list,
+             gt_labels_list,
+             img_metas,
+             gt_bboxes_ignore=None):
+        """"Loss function.
+
+        Args:
+            all_cls_scores (Tensor): Classification score of all
+                decoder layers, has shape
+                [nb_dec, bs, num_query, cls_out_channels].
+            all_bbox_preds (Tensor): Sigmoid regression
+                outputs of all decode layers. Each is a 4D-tensor with
+                normalized coordinate format (cx, cy, w, h) and shape
+                [nb_dec, bs, num_query, 4].
+            enc_cls_scores (Tensor): Classification scores of
+                points on encode feature map , has shape
+                (N, h*w, num_classes). Only be passed when as_two_stage is
+                True, otherwise is None.
+            enc_bbox_preds (Tensor): Regression results of each points
+                on the encode feature map, has shape (N, h*w, 4). Only be
+                passed when as_two_stage is True, otherwise is None.
+            gt_bboxes_list (list[Tensor]): Ground truth bboxes for each image
+                with shape (num_gts, 4) in [tl_x, tl_y, br_x, br_y] format.
+            gt_labels_list (list[Tensor]): Ground truth class indices for each
+                image with shape (num_gts, ).
+            img_metas (list[dict]): List of image meta information.
+            gt_bboxes_ignore (list[Tensor], optional): Bounding boxes
+                which can be ignored for each image. Default None.
+
+        Returns:
+            dict[str, Tensor]: A dictionary of loss components.
+        """
+        assert gt_bboxes_ignore is None, \
+            f'{self.__class__.__name__} only supports ' \
+            f'for gt_bboxes_ignore setting to None.'
+
+        num_dec_layers = len(all_cls_scores)
+        all_gt_bboxes_list = [gt_bboxes_list for _ in range(num_dec_layers)]
+        all_gt_labels_list = [gt_labels_list for _ in range(num_dec_layers)]
+        all_gt_bboxes_ignore_list = [
+            gt_bboxes_ignore for _ in range(num_dec_layers)
+        ]
+        img_metas_list = [img_metas for _ in range(num_dec_layers)]
+
+        losses_cls, losses_bbox, losses_iou = multi_apply(
+            self.loss_single, all_cls_scores, all_bbox_preds,
+            all_gt_bboxes_list, all_gt_labels_list, img_metas_list,
+            all_gt_bboxes_ignore_list)
+
+        loss_dict = dict()
+        # loss of proposal generated from encode feature map.
+        if enc_cls_scores is not None:
+            binary_labels_list = [
+                torch.zeros_like(gt_labels_list[i])
+                for i in range(len(img_metas))
+            ]
+            enc_loss_cls, enc_losses_bbox, enc_losses_iou = \
+                self.loss_single(enc_cls_scores, enc_bbox_preds,
+                                 gt_bboxes_list, binary_labels_list,
+                                 img_metas, gt_bboxes_ignore)
+            loss_dict['enc_loss_cls'] = enc_loss_cls
+            loss_dict['enc_loss_bbox'] = enc_losses_bbox
+            loss_dict['enc_loss_iou'] = enc_losses_iou
+
+        # loss from the last decoder layer
+        loss_dict['loss_cls'] = losses_cls[-1]
+        loss_dict['loss_bbox'] = losses_bbox[-1]
+        loss_dict['loss_iou'] = losses_iou[-1]
+        # loss from other decoder layers
+        num_dec_layer = 0
+        for loss_cls_i, loss_bbox_i, loss_iou_i in zip(losses_cls[:-1],
+                                                       losses_bbox[:-1],
+                                                       losses_iou[:-1]):
+            loss_dict[f'd{num_dec_layer}.loss_cls'] = loss_cls_i
+            loss_dict[f'd{num_dec_layer}.loss_bbox'] = loss_bbox_i
+            loss_dict[f'd{num_dec_layer}.loss_iou'] = loss_iou_i
+            num_dec_layer += 1
+        return loss_dict
+
+    @force_fp32(apply_to=('all_cls_scores_list', 'all_bbox_preds_list'))
+    def get_bboxes(self,
+                   all_cls_scores,
+                   all_bbox_preds,
+                   enc_cls_scores,
+                   enc_bbox_preds,
+                   img_metas,
+                   rescale=False):
+        """Transform network outputs for a batch into bbox predictions.
+
+        Args:
+            all_cls_scores (Tensor): Classification score of all
+                decoder layers, has shape
+                [nb_dec, bs, num_query, cls_out_channels].
+            all_bbox_preds (Tensor): Sigmoid regression
+                outputs of all decode layers. Each is a 4D-tensor with
+                normalized coordinate format (cx, cy, w, h) and shape
+                [nb_dec, bs, num_query, 4].
+            enc_cls_scores (Tensor): Classification scores of
+                points on encode feature map , has shape
+                (N, h*w, num_classes). Only be passed when as_two_stage is
+                True, otherwise is None.
+            enc_bbox_preds (Tensor): Regression results of each points
+                on the encode feature map, has shape (N, h*w, 4). Only be
+                passed when as_two_stage is True, otherwise is None.
+            img_metas (list[dict]): Meta information of each image.
+            rescale (bool, optional): If True, return boxes in original
+                image space. Default False.
+
+        Returns:
+            list[list[Tensor, Tensor]]: Each item in result_list is 2-tuple. \
+                The first item is an (n, 5) tensor, where the first 4 columns \
+                are bounding box positions (tl_x, tl_y, br_x, br_y) and the \
+                5-th column is a score between 0 and 1. The second item is a \
+                (n,) tensor where each item is the predicted class label of \
+                the corresponding box.
+        """
+        cls_scores = all_cls_scores[-1]
+        bbox_preds = all_bbox_preds[-1]
+
+        result_list = []
+        for img_id in range(len(img_metas)):
+            cls_score = cls_scores[img_id]
+            bbox_pred = bbox_preds[img_id]
+            img_shape = img_metas[img_id]['img_shape']
+            scale_factor = img_metas[img_id]['scale_factor']
+            proposals = self._get_bboxes_single(cls_score, bbox_pred,
+                                                img_shape, scale_factor,
+                                                rescale)
+            result_list.append(proposals)
+        return result_list

detection/mmdet_custom/models/dense_heads/detr_head.py

@@ -0,0 +1,954 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from mmcv.cnn import Conv2d, Linear, build_activation_layer
+from mmcv.cnn.bricks.transformer import FFN, build_positional_encoding
+from mmcv.runner import force_fp32
+
+from mmdet.core import (bbox_cxcywh_to_xyxy, bbox_xyxy_to_cxcywh,
+                        build_assigner, build_sampler, multi_apply,
+                        reduce_mean)
+from mmdet.models.utils import build_transformer
+from mmdet.models.builder import HEADS, build_loss
+from mmdet.models.dense_heads.anchor_free_head import AnchorFreeHead
+import numpy as np
+
+
+@HEADS.register_module(force=True)
+class DETRHead(AnchorFreeHead):
+    """Implements the DETR transformer head.
+
+    See `paper: End-to-End Object Detection with Transformers
+    <https://arxiv.org/pdf/2005.12872>`_ for details.
+
+    Args:
+        num_classes (int): Number of categories excluding the background.
+        in_channels (int): Number of channels in the input feature map.
+        num_query (int): Number of query in Transformer.
+        num_reg_fcs (int, optional): Number of fully-connected layers used in
+            `FFN`, which is then used for the regression head. Default 2.
+        transformer (obj:`mmcv.ConfigDict`|dict): Config for transformer.
+            Default: None.
+        sync_cls_avg_factor (bool): Whether to sync the avg_factor of
+            all ranks. Default to False.
+        positional_encoding (obj:`mmcv.ConfigDict`|dict):
+            Config for position encoding.
+        loss_cls (obj:`mmcv.ConfigDict`|dict): Config of the
+            classification loss. Default `CrossEntropyLoss`.
+        loss_bbox (obj:`mmcv.ConfigDict`|dict): Config of the
+            regression loss. Default `L1Loss`.
+        loss_iou (obj:`mmcv.ConfigDict`|dict): Config of the
+            regression iou loss. Default `GIoULoss`.
+        tran_cfg (obj:`mmcv.ConfigDict`|dict): Training config of
+            transformer head.
+        test_cfg (obj:`mmcv.ConfigDict`|dict): Testing config of
+            transformer head.
+        init_cfg (dict or list[dict], optional): Initialization config dict.
+            Default: None
+    """
+
+    _version = 2
+
+    def __init__(self,
+                 num_classes,
+                 in_channels,
+                 num_query=100,
+                 num_reg_fcs=2,
+                 transformer=None,
+                 sync_cls_avg_factor=False,
+                 positional_encoding=dict(
+                     type='SinePositionalEncoding',
+                     num_feats=128,
+                     normalize=True),
+                 loss_cls=dict(
+                     type='CrossEntropyLoss',
+                     bg_cls_weight=0.1,
+                     use_sigmoid=False,
+                     loss_weight=1.0,
+                     class_weight=1.0),
+                 loss_bbox=dict(type='L1Loss', loss_weight=5.0),
+                 loss_iou=dict(type='GIoULoss', loss_weight=2.0),
+                 train_cfg=dict(
+                     assigner=dict(
+                         type='HungarianAssigner',
+                         cls_cost=dict(type='ClassificationCost', weight=1.),
+                         reg_cost=dict(type='BBoxL1Cost', weight=5.0),
+                         iou_cost=dict(
+                             type='IoUCost', iou_mode='giou', weight=2.0))),
+                 test_cfg=dict(max_per_img=100),
+                 init_cfg=None,
+                 **kwargs):
+        # NOTE here use `AnchorFreeHead` instead of `TransformerHead`,
+        # since it brings inconvenience when the initialization of
+        # `AnchorFreeHead` is called.
+        super(AnchorFreeHead, self).__init__(init_cfg)
+
+        self.bg_cls_weight = 0
+        self.sync_cls_avg_factor = sync_cls_avg_factor
+        class_weight = loss_cls.get('class_weight', None)
+        if class_weight is not None and (self.__class__ is DETRHead):
+            # assert isinstance(class_weight, float), 'Expected ' \
+            #     'class_weight to have type float. Found ' \
+            #     f'{type(class_weight)}.'
+           
+            # NOTE following the official DETR rep0, bg_cls_weight means
+            # relative classification weight of the no-object class.
+            bg_cls_weight = loss_cls.get('bg_cls_weight', class_weight)
+            
+            assert isinstance(bg_cls_weight, float), 'Expected ' \
+                'bg_cls_weight to have type float. Found ' \
+                f'{type(bg_cls_weight)}.'
+            if isinstance(class_weight, list):
+                class_weight.append(bg_cls_weight)
+                class_weight = np.array(class_weight)
+                class_weight = torch.from_numpy(class_weight)
+                class_weight = torch.ones(num_classes + 1) * class_weight
+            elif isinstance(class_weight, float):
+                class_weight = torch.ones(num_classes + 1) * class_weight
+                # set background class as the last indice
+                class_weight[num_classes] = bg_cls_weight
+            loss_cls.update({'class_weight': class_weight})
+            if 'bg_cls_weight' in loss_cls:
+                loss_cls.pop('bg_cls_weight')
+            self.bg_cls_weight = bg_cls_weight
+
+        if train_cfg:
+            assert 'assigner' in train_cfg, 'assigner should be provided ' \
+                'when train_cfg is set.'
+            assigner = train_cfg['assigner']
+            # assert loss_cls['loss_weight'] == assigner['cls_cost']['weight'],
+            #     'The classification weight for loss and matcher should be' \
+            #     'exactly the same.'
+            # assert loss_bbox['loss_weight'] == assigner['reg_cost'][
+            #     'weight'], 'The regression L1 weight for loss and matcher '\
+            #     'should be exactly the same.'
+            # assert loss_iou['loss_weight'] == assigner['iou_cost']['weight'],
+            #     'The regression iou weight for loss and matcher should be' \
+            #     'exactly the same.'
+            self.assigner = build_assigner(assigner)
+            # DETR sampling=False, so use PseudoSampler
+            sampler_cfg = dict(type='PseudoSampler')
+            self.sampler = build_sampler(sampler_cfg, context=self)
+            
+        self.num_query = num_query
+        self.num_classes = num_classes
+        self.in_channels = in_channels
+        self.num_reg_fcs = num_reg_fcs
+        self.train_cfg = train_cfg
+        self.test_cfg = test_cfg
+        self.fp16_enabled = False
+        self.loss_cls = build_loss(loss_cls)
+        self.loss_bbox = build_loss(loss_bbox)
+        self.loss_iou = build_loss(loss_iou)
+
+        if self.loss_cls.use_sigmoid:
+            self.cls_out_channels = num_classes
+        else:
+            self.cls_out_channels = num_classes + 1
+        self.act_cfg = transformer.get('act_cfg',
+                                       dict(type='ReLU', inplace=True))
+        self.activate = build_activation_layer(self.act_cfg)
+        self.positional_encoding = build_positional_encoding(
+            positional_encoding)
+        self.transformer = build_transformer(transformer)
+        self.embed_dims = self.transformer.embed_dims
+        assert 'num_feats' in positional_encoding
+        num_feats = positional_encoding['num_feats']
+        assert num_feats * 2 == self.embed_dims, 'embed_dims should' \
+            f' be exactly 2 times of num_feats. Found {self.embed_dims}' \
+            f' and {num_feats}.'
+
+        self._init_layers()
+
+    def _init_layers(self):
+        """Initialize layers of the transformer head."""
+        self.input_proj = Conv2d(
+            self.in_channels, self.embed_dims, kernel_size=1)
+        self.fc_cls = Linear(self.embed_dims, self.cls_out_channels)
+        self.reg_ffn = FFN(
+            self.embed_dims,
+            self.embed_dims,
+            self.num_reg_fcs,
+            self.act_cfg,
+            dropout=0.0,
+            add_residual=False)
+        self.fc_reg = Linear(self.embed_dims, 4)
+        self.query_embedding = nn.Embedding(self.num_query, self.embed_dims)
+
+    def init_weights(self):
+        """Initialize weights of the transformer head."""
+        # The initialization for transformer is important
+        self.transformer.init_weights()
+
+    def _load_from_state_dict(self, state_dict, prefix, local_metadata, strict,
+                              missing_keys, unexpected_keys, error_msgs):
+        """load checkpoints."""
+        # NOTE here use `AnchorFreeHead` instead of `TransformerHead`,
+        # since `AnchorFreeHead._load_from_state_dict` should not be
+        # called here. Invoking the default `Module._load_from_state_dict`
+        # is enough.
+
+        # Names of some parameters in has been changed.
+        version = local_metadata.get('version', None)
+        if (version is None or version < 2) and self.__class__ is DETRHead:
+            convert_dict = {
+                '.self_attn.': '.attentions.0.',
+                '.ffn.': '.ffns.0.',
+                '.multihead_attn.': '.attentions.1.',
+                '.decoder.norm.': '.decoder.post_norm.'
+            }
+            state_dict_keys = list(state_dict.keys())
+            for k in state_dict_keys:
+                for ori_key, convert_key in convert_dict.items():
+                    if ori_key in k:
+                        convert_key = k.replace(ori_key, convert_key)
+                        state_dict[convert_key] = state_dict[k]
+                        del state_dict[k]
+
+        super(AnchorFreeHead,
+              self)._load_from_state_dict(state_dict, prefix, local_metadata,
+                                          strict, missing_keys,
+                                          unexpected_keys, error_msgs)
+
+    def forward(self, feats, img_metas):
+        """Forward function.
+
+        Args:
+            feats (tuple[Tensor]): Features from the upstream network, each is
+                a 4D-tensor.
+            img_metas (list[dict]): List of image information.
+
+        Returns:
+            tuple[list[Tensor], list[Tensor]]: Outputs for all scale levels.
+
+                - all_cls_scores_list (list[Tensor]): Classification scores \
+                    for each scale level. Each is a 4D-tensor with shape \
+                    [nb_dec, bs, num_query, cls_out_channels]. Note \
+                    `cls_out_channels` should includes background.
+                - all_bbox_preds_list (list[Tensor]): Sigmoid regression \
+                    outputs for each scale level. Each is a 4D-tensor with \
+                    normalized coordinate format (cx, cy, w, h) and shape \
+                    [nb_dec, bs, num_query, 4].
+        """
+        num_levels = len(feats)
+        img_metas_list = [img_metas for _ in range(num_levels)]
+        return multi_apply(self.forward_single, feats, img_metas_list)
+
+    def forward_single(self, x, img_metas):
+        """"Forward function for a single feature level.
+
+        Args:
+            x (Tensor): Input feature from backbone's single stage, shape
+                [bs, c, h, w].
+            img_metas (list[dict]): List of image information.
+
+        Returns:
+            all_cls_scores (Tensor): Outputs from the classification head,
+                shape [nb_dec, bs, num_query, cls_out_channels]. Note
+                cls_out_channels should includes background.
+            all_bbox_preds (Tensor): Sigmoid outputs from the regression
+                head with normalized coordinate format (cx, cy, w, h).
+                Shape [nb_dec, bs, num_query, 4].
+        """
+        # construct binary masks which used for the transformer.
+        # NOTE following the official DETR repo, non-zero values representing
+        # ignored positions, while zero values means valid positions.
+        batch_size = x.size(0)
+        input_img_h, input_img_w = img_metas[0]['batch_input_shape']
+        masks = x.new_ones((batch_size, input_img_h, input_img_w))
+        for img_id in range(batch_size):
+            img_h, img_w, _ = img_metas[img_id]['img_shape']
+            masks[img_id, :img_h, :img_w] = 0
+
+        x = self.input_proj(x)
+        # interpolate masks to have the same spatial shape with x
+        masks = F.interpolate(
+            masks.unsqueeze(1), size=x.shape[-2:]).to(torch.bool).squeeze(1)
+        # position encoding
+        pos_embed = self.positional_encoding(masks)  # [bs, embed_dim, h, w]
+        # outs_dec: [nb_dec, bs, num_query, embed_dim]
+        outs_dec, _ = self.transformer(x, masks, self.query_embedding.weight,
+                                       pos_embed)
+
+        all_cls_scores = self.fc_cls(outs_dec)
+        all_bbox_preds = self.fc_reg(self.activate(
+            self.reg_ffn(outs_dec))).sigmoid()
+        return all_cls_scores, all_bbox_preds
+
+    @force_fp32(apply_to=('all_cls_scores_list', 'all_bbox_preds_list'))
+    def loss(self,
+             all_cls_scores_list,
+             all_bbox_preds_list,
+             gt_bboxes_list,
+             gt_labels_list,
+             img_metas,
+             gt_bboxes_ignore=None):
+        """"Loss function.
+
+        Only outputs from the last feature level are used for computing
+        losses by default.
+
+        Args:
+            all_cls_scores_list (list[Tensor]): Classification outputs
+                for each feature level. Each is a 4D-tensor with shape
+                [nb_dec, bs, num_query, cls_out_channels].
+            all_bbox_preds_list (list[Tensor]): Sigmoid regression
+                outputs for each feature level. Each is a 4D-tensor with
+                normalized coordinate format (cx, cy, w, h) and shape
+                [nb_dec, bs, num_query, 4].
+            gt_bboxes_list (list[Tensor]): Ground truth bboxes for each image
+                with shape (num_gts, 4) in [tl_x, tl_y, br_x, br_y] format.
+            gt_labels_list (list[Tensor]): Ground truth class indices for each
+                image with shape (num_gts, ).
+            img_metas (list[dict]): List of image meta information.
+            gt_bboxes_ignore (list[Tensor], optional): Bounding boxes
+                which can be ignored for each image. Default None.
+
+        Returns:
+            dict[str, Tensor]: A dictionary of loss components.
+        """
+        # NOTE defaultly only the outputs from the last feature scale is used.
+        all_cls_scores = all_cls_scores_list[-1]
+        all_bbox_preds = all_bbox_preds_list[-1]
+        assert gt_bboxes_ignore is None, \
+            'Only supports for gt_bboxes_ignore setting to None.'
+
+        num_dec_layers = len(all_cls_scores)
+        all_gt_bboxes_list = [gt_bboxes_list for _ in range(num_dec_layers)]
+        all_gt_labels_list = [gt_labels_list for _ in range(num_dec_layers)]
+        all_gt_bboxes_ignore_list = [
+            gt_bboxes_ignore for _ in range(num_dec_layers)
+        ]
+        img_metas_list = [img_metas for _ in range(num_dec_layers)]
+
+        losses_cls, losses_bbox, losses_iou = multi_apply(
+            self.loss_single, all_cls_scores, all_bbox_preds,
+            all_gt_bboxes_list, all_gt_labels_list, img_metas_list,
+            all_gt_bboxes_ignore_list)
+
+        loss_dict = dict()
+        # loss from the last decoder layer
+        loss_dict['loss_cls'] = losses_cls[-1]
+        loss_dict['loss_bbox'] = losses_bbox[-1]
+        loss_dict['loss_iou'] = losses_iou[-1]
+        # loss from other decoder layers
+        num_dec_layer = 0
+        for loss_cls_i, loss_bbox_i, loss_iou_i in zip(losses_cls[:-1],
+                                                       losses_bbox[:-1],
+                                                       losses_iou[:-1]):
+            loss_dict[f'd{num_dec_layer}.loss_cls'] = loss_cls_i
+            loss_dict[f'd{num_dec_layer}.loss_bbox'] = loss_bbox_i
+            loss_dict[f'd{num_dec_layer}.loss_iou'] = loss_iou_i
+            num_dec_layer += 1
+        return loss_dict
+
+    def get_fed_loss_classes(self, gt_classes, num_fed_loss_classes, num_classes, weight):
+        """
+        Args:
+            gt_classes: a long tensor of shape R that contains the gt class label of each proposal.
+            num_fed_loss_classes: minimum number of classes to keep when calculating federated loss.
+            Will sample negative classes if number of unique gt_classes is smaller than this value.
+            num_classes: number of foreground classes
+            weight: probabilities used to sample negative classes
+        Returns:
+            Tensor:
+                classes to keep when calculating the federated loss, including both unique gt
+                classes and sampled negative classes.
+        """
+        unique_gt_classes = torch.unique(gt_classes)
+        prob = unique_gt_classes.new_ones(num_classes + 1).float()
+        prob[-1] = 0
+        if len(unique_gt_classes) < num_fed_loss_classes:
+            prob[:num_classes] = weight.float().clone()
+            prob[unique_gt_classes] = 0
+            sampled_negative_classes = torch.multinomial(
+                prob, num_fed_loss_classes - len(unique_gt_classes), replacement=False
+            )
+            fed_loss_classes = torch.cat([unique_gt_classes, sampled_negative_classes])
+        else:
+            fed_loss_classes = unique_gt_classes
+        return fed_loss_classes
+    
+    def loss_single(self,
+                    cls_scores,
+                    bbox_preds,
+                    gt_bboxes_list,
+                    gt_labels_list,
+                    img_metas,
+                    gt_bboxes_ignore_list=None):
+        """"Loss function for outputs from a single decoder layer of a single
+        feature level.
+
+        Args:
+            cls_scores (Tensor): Box score logits from a single decoder layer
+                for all images. Shape [bs, num_query, cls_out_channels].
+            bbox_preds (Tensor): Sigmoid outputs from a single decoder layer
+                for all images, with normalized coordinate (cx, cy, w, h) and
+                shape [bs, num_query, 4].
+            gt_bboxes_list (list[Tensor]): Ground truth bboxes for each image
+                with shape (num_gts, 4) in [tl_x, tl_y, br_x, br_y] format.
+            gt_labels_list (list[Tensor]): Ground truth class indices for each
+                image with shape (num_gts, ).
+            img_metas (list[dict]): List of image meta information.
+            gt_bboxes_ignore_list (list[Tensor], optional): Bounding
+                boxes which can be ignored for each image. Default None.
+
+        Returns:
+            dict[str, Tensor]: A dictionary of loss components for outputs from
+                a single decoder layer.
+        """
+        num_imgs = cls_scores.size(0)
+        cls_scores_list = [cls_scores[i] for i in range(num_imgs)]
+        bbox_preds_list = [bbox_preds[i] for i in range(num_imgs)]
+        cls_reg_targets = self.get_targets(cls_scores_list, bbox_preds_list,
+                                           gt_bboxes_list, gt_labels_list,
+                                           img_metas, gt_bboxes_ignore_list)
+        (labels_list, label_weights_list, bbox_targets_list, bbox_weights_list,
+         num_total_pos, num_total_neg) = cls_reg_targets
+
+        labels = torch.cat(labels_list, 0)
+        label_weights = torch.cat(label_weights_list, 0)
+        bbox_targets = torch.cat(bbox_targets_list, 0)
+        bbox_weights = torch.cat(bbox_weights_list, 0)
+
+        # classification loss
+        cls_scores = cls_scores.reshape(-1, self.cls_out_channels)
+        # construct weighted avg_factor to match with the official DETR repo
+        cls_avg_factor = num_total_pos * 1.0 + \
+            num_total_neg * self.bg_cls_weight
+        if self.sync_cls_avg_factor:
+            cls_avg_factor = reduce_mean(
+                cls_scores.new_tensor([cls_avg_factor]))
+        cls_avg_factor = max(cls_avg_factor, 1)
+
+        loss_cls = self.loss_cls(
+            cls_scores, labels, label_weights, avg_factor=cls_avg_factor)
+
+        # Compute the average number of gt boxes across all gpus, for
+        # normalization purposes
+        num_total_pos = loss_cls.new_tensor([num_total_pos])
+        num_total_pos = torch.clamp(reduce_mean(num_total_pos), min=1).item()
+
+        # construct factors used for rescale bboxes
+        factors = []
+        for img_meta, bbox_pred in zip(img_metas, bbox_preds):
+            img_h, img_w, _ = img_meta['img_shape']
+            factor = bbox_pred.new_tensor([img_w, img_h, img_w,
+                                           img_h]).unsqueeze(0).repeat(
+                                               bbox_pred.size(0), 1)
+            factors.append(factor)
+        factors = torch.cat(factors, 0)
+
+        # DETR regress the relative position of boxes (cxcywh) in the image,
+        # thus the learning target is normalized by the image size. So here
+        # we need to re-scale them for calculating IoU loss
+        bbox_preds = bbox_preds.reshape(-1, 4)
+        bboxes = bbox_cxcywh_to_xyxy(bbox_preds) * factors
+        bboxes_gt = bbox_cxcywh_to_xyxy(bbox_targets) * factors
+
+        # regression IoU loss, defaultly GIoU loss
+        loss_iou = self.loss_iou(
+            bboxes, bboxes_gt, bbox_weights, avg_factor=num_total_pos)
+
+        # regression L1 loss
+        loss_bbox = self.loss_bbox(
+            bbox_preds, bbox_targets, bbox_weights, avg_factor=num_total_pos)
+        return loss_cls, loss_bbox, loss_iou
+
+    def get_targets(self,
+                    cls_scores_list,
+                    bbox_preds_list,
+                    gt_bboxes_list,
+                    gt_labels_list,
+                    img_metas,
+                    gt_bboxes_ignore_list=None):
+        """"Compute regression and classification targets for a batch image.
+
+        Outputs from a single decoder layer of a single feature level are used.
+
+        Args:
+            cls_scores_list (list[Tensor]): Box score logits from a single
+                decoder layer for each image with shape [num_query,
+                cls_out_channels].
+            bbox_preds_list (list[Tensor]): Sigmoid outputs from a single
+                decoder layer for each image, with normalized coordinate
+                (cx, cy, w, h) and shape [num_query, 4].
+            gt_bboxes_list (list[Tensor]): Ground truth bboxes for each image
+                with shape (num_gts, 4) in [tl_x, tl_y, br_x, br_y] format.
+            gt_labels_list (list[Tensor]): Ground truth class indices for each
+                image with shape (num_gts, ).
+            img_metas (list[dict]): List of image meta information.
+            gt_bboxes_ignore_list (list[Tensor], optional): Bounding
+                boxes which can be ignored for each image. Default None.
+
+        Returns:
+            tuple: a tuple containing the following targets.
+
+                - labels_list (list[Tensor]): Labels for all images.
+                - label_weights_list (list[Tensor]): Label weights for all \
+                    images.
+                - bbox_targets_list (list[Tensor]): BBox targets for all \
+                    images.
+                - bbox_weights_list (list[Tensor]): BBox weights for all \
+                    images.
+                - num_total_pos (int): Number of positive samples in all \
+                    images.
+                - num_total_neg (int): Number of negative samples in all \
+                    images.
+        """
+        assert gt_bboxes_ignore_list is None, \
+            'Only supports for gt_bboxes_ignore setting to None.'
+        num_imgs = len(cls_scores_list)
+        gt_bboxes_ignore_list = [
+            gt_bboxes_ignore_list for _ in range(num_imgs)
+        ]
+
+        (labels_list, label_weights_list, bbox_targets_list,
+         bbox_weights_list, pos_inds_list, neg_inds_list) = multi_apply(
+             self._get_target_single, cls_scores_list, bbox_preds_list,
+             gt_bboxes_list, gt_labels_list, img_metas, gt_bboxes_ignore_list)
+        num_total_pos = sum((inds.numel() for inds in pos_inds_list))
+        num_total_neg = sum((inds.numel() for inds in neg_inds_list))
+        return (labels_list, label_weights_list, bbox_targets_list,
+                bbox_weights_list, num_total_pos, num_total_neg)
+
+    def _get_area_thr(self, img_shape, type):
+        MIN_V = 0
+        MAX_V = 1e10
+        short_edge = min(img_shape[0], img_shape[1])
+        if type == 'v1':
+            DELTA = 4
+            if short_edge <= 600:
+                min_edge = 128 - DELTA
+                max_edge = MAX_V
+            elif 600 < short_edge <= 800:
+                min_edge = 96 - DELTA
+                max_edge = MAX_V
+            elif 800 < short_edge <= 1000:
+                min_edge = 64 - DELTA
+                max_edge = MAX_V
+            elif 1000 < short_edge <= 1200:
+                min_edge = 32 - DELTA
+                max_edge = MAX_V
+            elif 1200 < short_edge <= 1400:
+                min_edge = MIN_V
+                max_edge = MAX_V
+            else:
+                min_edge = MIN_V
+                max_edge = 2 + DELTA
+        elif type == 'v2':
+            if short_edge <= 1000:
+                min_edge = 112
+                max_edge = MAX_V
+            elif 1000 < short_edge <= 1400:
+                min_edge = 32
+                max_edge = 160
+            elif short_edge > 1400:
+                min_edge = 0
+                max_edge = 80
+        elif type == 'v3':
+            if short_edge <= 800:
+                min_edge = 96
+                max_edge = MAX_V
+            elif 800 < short_edge <= 1000:
+                min_edge = 64
+                max_edge = MAX_V
+            elif 1000 < short_edge <= 1400:
+                min_edge = MIN_V
+                max_edge = MAX_V
+            elif 1400 < short_edge <= 1600:
+                min_edge = MIN_V
+                max_edge = 96
+            elif short_edge > 1600:
+                min_edge = MIN_V
+                max_edge = 64
+        elif type == 'v4':
+            DELTA = 4
+            if short_edge <= 800:
+                min_edge = 96 - DELTA
+                max_edge = MAX_V
+            elif 800 < short_edge <= 1000:
+                min_edge = 64 - DELTA
+                max_edge = MAX_V
+            elif 1000 < short_edge <= 1400:
+                min_edge = MIN_V
+                max_edge = MAX_V
+            elif 1400 < short_edge <= 1600:
+                min_edge = MIN_V
+                max_edge = 64 + DELTA
+            elif short_edge > 1600:
+                min_edge = MIN_V
+                max_edge = 32 + DELTA
+
+        return min_edge ** 2, max_edge ** 2
+
+    def _get_target_single(self,
+                           cls_score,
+                           bbox_pred,
+                           gt_bboxes,
+                           gt_labels,
+                           img_meta,
+                           gt_bboxes_ignore=None):
+        """"Compute regression and classification targets for one image.
+
+        Outputs from a single decoder layer of a single feature level are used.
+
+        Args:
+            cls_score (Tensor): Box score logits from a single decoder layer
+                for one image. Shape [num_query, cls_out_channels].
+            bbox_pred (Tensor): Sigmoid outputs from a single decoder layer
+                for one image, with normalized coordinate (cx, cy, w, h) and
+                shape [num_query, 4].
+            gt_bboxes (Tensor): Ground truth bboxes for one image with
+                shape (num_gts, 4) in [tl_x, tl_y, br_x, br_y] format.
+            gt_labels (Tensor): Ground truth class indices for one image
+                with shape (num_gts, ).
+            img_meta (dict): Meta information for one image.
+            gt_bboxes_ignore (Tensor, optional): Bounding boxes
+                which can be ignored. Default None.
+
+        Returns:
+            tuple[Tensor]: a tuple containing the following for one image.
+
+                - labels (Tensor): Labels of each image.
+                - label_weights (Tensor]): Label weights of each image.
+                - bbox_targets (Tensor): BBox targets of each image.
+                - bbox_weights (Tensor): BBox weights of each image.
+                - pos_inds (Tensor): Sampled positive indices for each image.
+                - neg_inds (Tensor): Sampled negative indices for each image.
+        """
+
+        num_bboxes = bbox_pred.size(0)
+        # assigner and sampler
+        assign_result = self.assigner.assign(bbox_pred, cls_score, gt_bboxes,
+                                             gt_labels, img_meta,
+                                             gt_bboxes_ignore)
+        sampling_result = self.sampler.sample(assign_result, bbox_pred,
+                                              gt_bboxes)
+        pos_inds = sampling_result.pos_inds
+        neg_inds = sampling_result.neg_inds
+
+        # label targets
+        labels = gt_bboxes.new_full((num_bboxes, ),
+                                    self.num_classes,
+                                    dtype=torch.long)
+        labels[pos_inds] = gt_labels[sampling_result.pos_assigned_gt_inds]
+        label_weights = gt_bboxes.new_ones(num_bboxes)
+
+        # bbox targets
+        bbox_targets = torch.zeros_like(bbox_pred)
+        bbox_weights = torch.zeros_like(bbox_pred)
+        bbox_weights[pos_inds] = 1.0
+        img_h, img_w, _ = img_meta['img_shape']
+
+        # DETR regress the relative position of boxes (cxcywh) in the image.
+        # Thus the learning target should be normalized by the image size, also
+        # the box format should be converted from defaultly x1y1x2y2 to cxcywh.
+        factor = bbox_pred.new_tensor([img_w, img_h, img_w,
+                                       img_h]).unsqueeze(0)
+        pos_gt_bboxes_normalized = sampling_result.pos_gt_bboxes / factor
+        pos_gt_bboxes_targets = bbox_xyxy_to_cxcywh(pos_gt_bboxes_normalized)
+        bbox_targets[pos_inds] = pos_gt_bboxes_targets
+        return (labels, label_weights, bbox_targets, bbox_weights, pos_inds,
+                neg_inds)
+
+    # over-write because img_metas are needed as inputs for bbox_head.
+    def forward_train(self,
+                      x,
+                      img_metas,
+                      gt_bboxes,
+                      gt_labels=None,
+                      gt_bboxes_ignore=None,
+                      proposal_cfg=None,
+                      **kwargs):
+        """Forward function for training mode.
+
+        Args:
+            x (list[Tensor]): Features from backbone.
+            img_metas (list[dict]): Meta information of each image, e.g.,
+                image size, scaling factor, etc.
+            gt_bboxes (Tensor): Ground truth bboxes of the image,
+                shape (num_gts, 4).
+            gt_labels (Tensor): Ground truth labels of each box,
+                shape (num_gts,).
+            gt_bboxes_ignore (Tensor): Ground truth bboxes to be
+                ignored, shape (num_ignored_gts, 4).
+            proposal_cfg (mmcv.Config): Test / postprocessing configuration,
+                if None, test_cfg would be used.
+
+        Returns:
+            dict[str, Tensor]: A dictionary of loss components.
+        """
+        assert proposal_cfg is None, '"proposal_cfg" must be None'
+        outs = self(x, img_metas)
+        if gt_labels is None:
+            loss_inputs = outs + (gt_bboxes, img_metas)
+        else:
+            loss_inputs = outs + (gt_bboxes, gt_labels, img_metas)
+        losses = self.loss(*loss_inputs, gt_bboxes_ignore=gt_bboxes_ignore)
+        return losses
+
+    @force_fp32(apply_to=('all_cls_scores_list', 'all_bbox_preds_list'))
+    def get_bboxes(self,
+                   all_cls_scores_list,
+                   all_bbox_preds_list,
+                   img_metas,
+                   rescale=False):
+        """Transform network outputs for a batch into bbox predictions.
+
+        Args:
+            all_cls_scores_list (list[Tensor]): Classification outputs
+                for each feature level. Each is a 4D-tensor with shape
+                [nb_dec, bs, num_query, cls_out_channels].
+            all_bbox_preds_list (list[Tensor]): Sigmoid regression
+                outputs for each feature level. Each is a 4D-tensor with
+                normalized coordinate format (cx, cy, w, h) and shape
+                [nb_dec, bs, num_query, 4].
+            img_metas (list[dict]): Meta information of each image.
+            rescale (bool, optional): If True, return boxes in original
+                image space. Default False.
+
+        Returns:
+            list[list[Tensor, Tensor]]: Each item in result_list is 2-tuple. \
+                The first item is an (n, 5) tensor, where the first 4 columns \
+                are bounding box positions (tl_x, tl_y, br_x, br_y) and the \
+                5-th column is a score between 0 and 1. The second item is a \
+                (n,) tensor where each item is the predicted class label of \
+                the corresponding box.
+        """
+        # NOTE defaultly only using outputs from the last feature level,
+        # and only the outputs from the last decoder layer is used.
+        cls_scores = all_cls_scores_list[-1][-1]
+        bbox_preds = all_bbox_preds_list[-1][-1]
+
+        result_list = []
+        for img_id in range(len(img_metas)):
+            cls_score = cls_scores[img_id]
+            bbox_pred = bbox_preds[img_id]
+            img_shape = img_metas[img_id]['img_shape']
+            scale_factor = img_metas[img_id]['scale_factor']
+            proposals = self._get_bboxes_single(cls_score, bbox_pred,
+                                                img_shape, scale_factor,
+                                                rescale)
+            result_list.append(proposals)
+
+        return result_list
+
+    def _get_bboxes_single(self,
+                           cls_score,
+                           bbox_pred,
+                           img_shape,
+                           scale_factor,
+                           rescale=False):
+        """Transform outputs from the last decoder layer into bbox predictions
+        for each image.
+
+        Args:
+            cls_score (Tensor): Box score logits from the last decoder layer
+                for each image. Shape [num_query, cls_out_channels].
+            bbox_pred (Tensor): Sigmoid outputs from the last decoder layer
+                for each image, with coordinate format (cx, cy, w, h) and
+                shape [num_query, 4].
+            img_shape (tuple[int]): Shape of input image, (height, width, 3).
+            scale_factor (ndarray, optional): Scale factor of the image arange
+                as (w_scale, h_scale, w_scale, h_scale).
+            rescale (bool, optional): If True, return boxes in original image
+                space. Default False.
+
+        Returns:
+            tuple[Tensor]: Results of detected bboxes and labels.
+
+                - det_bboxes: Predicted bboxes with shape [num_query, 5], \
+                    where the first 4 columns are bounding box positions \
+                    (tl_x, tl_y, br_x, br_y) and the 5-th column are scores \
+                    between 0 and 1.
+                - det_labels: Predicted labels of the corresponding box with \
+                    shape [num_query].
+        """
+        assert len(cls_score) == len(bbox_pred)
+        max_per_img = self.test_cfg.get('max_per_img', self.num_query)
+        # exclude background
+        if self.loss_cls.use_sigmoid:
+            cls_score = cls_score.sigmoid()
+            scores, indexes = cls_score.view(-1).topk(max_per_img)
+            det_labels = indexes % self.num_classes
+            bbox_index = indexes // self.num_classes
+            bbox_pred = bbox_pred[bbox_index]
+        else:
+            scores, det_labels = F.softmax(cls_score, dim=-1)[..., :-1].max(-1)
+            scores, bbox_index = scores.topk(max_per_img)
+            bbox_pred = bbox_pred[bbox_index]
+            det_labels = det_labels[bbox_index]
+
+        det_bboxes = bbox_cxcywh_to_xyxy(bbox_pred)
+        det_bboxes[:, 0::2] = det_bboxes[:, 0::2] * img_shape[1]
+        det_bboxes[:, 1::2] = det_bboxes[:, 1::2] * img_shape[0]
+        det_bboxes[:, 0::2].clamp_(min=0, max=img_shape[1])
+        det_bboxes[:, 1::2].clamp_(min=0, max=img_shape[0])
+        if rescale:
+            det_bboxes /= det_bboxes.new_tensor(scale_factor)
+        det_bboxes = torch.cat((det_bboxes, scores.unsqueeze(1)), -1)
+
+        return det_bboxes, det_labels
+
+    def simple_test_bboxes(self, feats, img_metas, rescale=False):
+        """Test det bboxes without test-time augmentation.
+
+        Args:
+            feats (tuple[torch.Tensor]): Multi-level features from the
+                upstream network, each is a 4D-tensor.
+            img_metas (list[dict]): List of image information.
+            rescale (bool, optional): Whether to rescale the results.
+                Defaults to False.
+
+        Returns:
+            list[tuple[Tensor, Tensor]]: Each item in result_list is 2-tuple.
+                The first item is ``bboxes`` with shape (n, 5),
+                where 5 represent (tl_x, tl_y, br_x, br_y, score).
+                The shape of the second tensor in the tuple is ``labels``
+                with shape (n,)
+        """
+        # forward of this head requires img_metas
+        outs = self.forward(feats, img_metas)
+        results_list = self.get_bboxes(*outs, img_metas, rescale=rescale)
+        return results_list
+
+    def forward_onnx(self, feats, img_metas):
+        """Forward function for exporting to ONNX.
+
+        Over-write `forward` because: `masks` is directly created with
+        zero (valid position tag) and has the same spatial size as `x`.
+        Thus the construction of `masks` is different from that in `forward`.
+
+        Args:
+            feats (tuple[Tensor]): Features from the upstream network, each is
+                a 4D-tensor.
+            img_metas (list[dict]): List of image information.
+
+        Returns:
+            tuple[list[Tensor], list[Tensor]]: Outputs for all scale levels.
+
+                - all_cls_scores_list (list[Tensor]): Classification scores \
+                    for each scale level. Each is a 4D-tensor with shape \
+                    [nb_dec, bs, num_query, cls_out_channels]. Note \
+                    `cls_out_channels` should includes background.
+                - all_bbox_preds_list (list[Tensor]): Sigmoid regression \
+                    outputs for each scale level. Each is a 4D-tensor with \
+                    normalized coordinate format (cx, cy, w, h) and shape \
+                    [nb_dec, bs, num_query, 4].
+        """
+        num_levels = len(feats)
+        img_metas_list = [img_metas for _ in range(num_levels)]
+        return multi_apply(self.forward_single_onnx, feats, img_metas_list)
+
+    def forward_single_onnx(self, x, img_metas):
+        """"Forward function for a single feature level with ONNX exportation.
+
+        Args:
+            x (Tensor): Input feature from backbone's single stage, shape
+                [bs, c, h, w].
+            img_metas (list[dict]): List of image information.
+
+        Returns:
+            all_cls_scores (Tensor): Outputs from the classification head,
+                shape [nb_dec, bs, num_query, cls_out_channels]. Note
+                cls_out_channels should includes background.
+            all_bbox_preds (Tensor): Sigmoid outputs from the regression
+                head with normalized coordinate format (cx, cy, w, h).
+                Shape [nb_dec, bs, num_query, 4].
+        """
+        # Note `img_shape` is not dynamically traceable to ONNX,
+        # since the related augmentation was done with numpy under
+        # CPU. Thus `masks` is directly created with zeros (valid tag)
+        # and the same spatial shape as `x`.
+        # The difference between torch and exported ONNX model may be
+        # ignored, since the same performance is achieved (e.g.
+        # 40.1 vs 40.1 for DETR)
+        batch_size = x.size(0)
+        h, w = x.size()[-2:]
+        masks = x.new_zeros((batch_size, h, w))  # [B,h,w]
+
+        x = self.input_proj(x)
+        # interpolate masks to have the same spatial shape with x
+        masks = F.interpolate(
+            masks.unsqueeze(1), size=x.shape[-2:]).to(torch.bool).squeeze(1)
+        pos_embed = self.positional_encoding(masks)
+        outs_dec, _ = self.transformer(x, masks, self.query_embedding.weight,
+                                       pos_embed)
+
+        all_cls_scores = self.fc_cls(outs_dec)
+        all_bbox_preds = self.fc_reg(self.activate(
+            self.reg_ffn(outs_dec))).sigmoid()
+        return all_cls_scores, all_bbox_preds
+
+    def onnx_export(self, all_cls_scores_list, all_bbox_preds_list, img_metas):
+        """Transform network outputs into bbox predictions, with ONNX
+        exportation.
+
+        Args:
+            all_cls_scores_list (list[Tensor]): Classification outputs
+                for each feature level. Each is a 4D-tensor with shape
+                [nb_dec, bs, num_query, cls_out_channels].
+            all_bbox_preds_list (list[Tensor]): Sigmoid regression
+                outputs for each feature level. Each is a 4D-tensor with
+                normalized coordinate format (cx, cy, w, h) and shape
+                [nb_dec, bs, num_query, 4].
+            img_metas (list[dict]): Meta information of each image.
+
+        Returns:
+            tuple[Tensor, Tensor]: dets of shape [N, num_det, 5]
+                and class labels of shape [N, num_det].
+        """
+        assert len(img_metas) == 1, \
+            'Only support one input image while in exporting to ONNX'
+
+        cls_scores = all_cls_scores_list[-1][-1]
+        bbox_preds = all_bbox_preds_list[-1][-1]
+
+        # Note `img_shape` is not dynamically traceable to ONNX,
+        # here `img_shape_for_onnx` (padded shape of image tensor)
+        # is used.
+        img_shape = img_metas[0]['img_shape_for_onnx']
+        max_per_img = self.test_cfg.get('max_per_img', self.num_query)
+        batch_size = cls_scores.size(0)
+        # `batch_index_offset` is used for the gather of concatenated tensor
+        batch_index_offset = torch.arange(batch_size).to(
+            cls_scores.device) * max_per_img
+        batch_index_offset = batch_index_offset.unsqueeze(1).expand(
+            batch_size, max_per_img)
+
+        # supports dynamical batch inference
+        if self.loss_cls.use_sigmoid:
+            cls_scores = cls_scores.sigmoid()
+            scores, indexes = cls_scores.view(batch_size, -1).topk(
+                max_per_img, dim=1)
+            det_labels = indexes % self.num_classes
+            bbox_index = indexes // self.num_classes
+            bbox_index = (bbox_index + batch_index_offset).view(-1)
+            bbox_preds = bbox_preds.view(-1, 4)[bbox_index]
+            bbox_preds = bbox_preds.view(batch_size, -1, 4)
+        else:
+            scores, det_labels = F.softmax(
+                cls_scores, dim=-1)[..., :-1].max(-1)
+            scores, bbox_index = scores.topk(max_per_img, dim=1)
+            bbox_index = (bbox_index + batch_index_offset).view(-1)
+            bbox_preds = bbox_preds.view(-1, 4)[bbox_index]
+            det_labels = det_labels.view(-1)[bbox_index]
+            bbox_preds = bbox_preds.view(batch_size, -1, 4)
+            det_labels = det_labels.view(batch_size, -1)
+
+        det_bboxes = bbox_cxcywh_to_xyxy(bbox_preds)
+        # use `img_shape_tensor` for dynamically exporting to ONNX
+        img_shape_tensor = img_shape.flip(0).repeat(2)  # [w,h,w,h]
+        img_shape_tensor = img_shape_tensor.unsqueeze(0).unsqueeze(0).expand(
+            batch_size, det_bboxes.size(1), 4)
+        det_bboxes = det_bboxes * img_shape_tensor
+        # dynamically clip bboxes
+        x1, y1, x2, y2 = det_bboxes.split((1, 1, 1, 1), dim=-1)
+        from mmdet.core.export import dynamic_clip_for_onnx
+        x1, y1, x2, y2 = dynamic_clip_for_onnx(x1, y1, x2, y2, img_shape)
+        det_bboxes = torch.cat([x1, y1, x2, y2], dim=-1)
+        det_bboxes = torch.cat((det_bboxes, scores.unsqueeze(-1)), -1)
+
+        return det_bboxes, det_labels

detection/mmdet_custom/models/dense_heads/dino_head.py

@@ -0,0 +1,365 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+from mmdet.core import (bbox_cxcywh_to_xyxy, bbox_xyxy_to_cxcywh, multi_apply,
+                        reduce_mean)
+from ..utils import build_dn_generator
+from mmdet.models.utils.transformer import inverse_sigmoid
+from mmdet.models.builder import HEADS
+from .deformable_detr_head import DeformableDETRHead
+from mmcv.runner import force_fp32
+
+
+@HEADS.register_module()
+class DINOHead(DeformableDETRHead):
+
+    def __init__(self, *args, dn_cfg=None, **kwargs):
+        super(DINOHead, self).__init__(*args, **kwargs)
+        self._init_layers()
+        self.init_denoising(dn_cfg)
+        assert self.as_two_stage, \
+            'as_two_stage must be True for DINO'
+        assert self.with_box_refine, \
+            'with_box_refine must be True for DINO'
+
+    def _init_layers(self):
+        super()._init_layers()
+        # NOTE The original repo of DINO set the num_embeddings 92 for coco,
+        # 91 (0~90) of which represents target classes and the 92 (91)
+        # indicates [Unknown] class. However, the embedding of unknown class
+        # is not used in the original DINO
+        self.label_embedding = nn.Embedding(self.cls_out_channels,
+                                            self.embed_dims)
+
+    def init_denoising(self, dn_cfg):
+        if dn_cfg is not None:
+            dn_cfg['num_classes'] = self.num_classes
+            dn_cfg['num_queries'] = self.num_query
+            dn_cfg['hidden_dim'] = self.embed_dims
+        self.dn_generator = build_dn_generator(dn_cfg)
+
+    def forward_train(self,
+                      x,
+                      img_metas,
+                      gt_bboxes,
+                      gt_labels=None,
+                      gt_bboxes_ignore=None,
+                      proposal_cfg=None,
+                      **kwargs):
+        assert proposal_cfg is None, '"proposal_cfg" must be None'
+        assert self.dn_generator is not None, '"dn_cfg" must be set'
+        dn_label_query, dn_bbox_query, attn_mask, dn_meta = \
+            self.dn_generator(gt_bboxes, gt_labels,
+                              self.label_embedding, img_metas)
+        outs = self(x, img_metas, dn_label_query, dn_bbox_query, attn_mask)
+        if gt_labels is None:
+            loss_inputs = outs + (gt_bboxes, img_metas, dn_meta)
+        else:
+            loss_inputs = outs + (gt_bboxes, gt_labels, img_metas, dn_meta)
+        losses = self.loss(*loss_inputs, gt_bboxes_ignore=gt_bboxes_ignore)
+        return losses
+
+    def forward(self,
+                mlvl_feats,
+                img_metas,
+                dn_label_query=None,
+                dn_bbox_query=None,
+                attn_mask=None):
+        batch_size = mlvl_feats[0].size(0)
+        input_img_h, input_img_w = img_metas[0]['batch_input_shape']
+        img_masks = mlvl_feats[0].new_ones(
+            (batch_size, input_img_h, input_img_w))
+        for img_id in range(batch_size):
+            if img_id >= len(img_metas): img_id = 0
+            img_h, img_w, _ = img_metas[img_id]['img_shape']
+            img_masks[img_id, :img_h, :img_w] = 0
+
+        mlvl_masks = []
+        mlvl_positional_encodings = []
+        for feat in mlvl_feats:
+            mlvl_masks.append(
+                F.interpolate(
+                    img_masks[None],
+                    size=feat.shape[-2:]).to(torch.bool).squeeze(0))
+            mlvl_positional_encodings.append(
+                self.positional_encoding(mlvl_masks[-1]))
+
+        query_embeds = None
+        hs, inter_references, topk_score, topk_anchor = \
+            self.transformer(
+                mlvl_feats,
+                mlvl_masks,
+                query_embeds,
+                mlvl_positional_encodings,
+                dn_label_query,
+                dn_bbox_query,
+                attn_mask,
+                reg_branches=self.reg_branches if self.with_box_refine else None,  # noqa:E501
+                cls_branches=self.cls_branches if self.as_two_stage else None  # noqa:E501
+            )
+        hs = hs.permute(0, 2, 1, 3)
+
+        if dn_label_query is not None and dn_label_query.size(1) == 0:
+            # NOTE: If there is no target in the image, the parameters of
+            # label_embedding won't be used in producing loss, which raises
+            # RuntimeError when using distributed mode.
+            hs[0] += self.label_embedding.weight[0, 0] * 0.0
+            
+        outputs_classes = []
+        outputs_coords = []
+
+        for lvl in range(hs.shape[0]):
+            reference = inter_references[lvl]
+            reference = inverse_sigmoid(reference, eps=1e-3)
+            outputs_class = self.cls_branches[lvl](hs[lvl])
+            tmp = self.reg_branches[lvl](hs[lvl])
+            if reference.shape[-1] == 4:
+                tmp += reference
+            else:
+                assert reference.shape[-1] == 2
+                tmp[..., :2] += reference
+            outputs_coord = tmp.sigmoid()
+            outputs_classes.append(outputs_class)
+            outputs_coords.append(outputs_coord)
+
+        outputs_classes = torch.stack(outputs_classes)
+        outputs_coords = torch.stack(outputs_coords)
+
+        return outputs_classes, outputs_coords, topk_score, topk_anchor
+
+    @force_fp32(apply_to=('all_cls_scores', 'all_bbox_preds'))
+    def loss(self,
+             all_cls_scores,
+             all_bbox_preds,
+             enc_topk_scores,
+             enc_topk_anchors,
+             gt_bboxes_list,
+             gt_labels_list,
+             img_metas,
+             dn_meta=None,
+             gt_bboxes_ignore=None):
+        assert gt_bboxes_ignore is None, \
+            f'{self.__class__.__name__} only supports ' \
+            f'for gt_bboxes_ignore setting to None.'
+
+        loss_dict = dict()
+
+        # extract denoising and matching part of outputs
+        all_cls_scores, all_bbox_preds, dn_cls_scores, dn_bbox_preds = \
+            self.extract_dn_outputs(all_cls_scores, all_bbox_preds, dn_meta)
+
+        if enc_topk_scores is not None:
+            # calculate loss from encode feature maps
+            # NOTE The DeformDETR calculate binary cls loss
+            # for all encoder embeddings, while DINO calculate
+            # multi-class loss for topk embeddings.
+            enc_loss_cls, enc_losses_bbox, enc_losses_iou = \
+                self.loss_single(enc_topk_scores, enc_topk_anchors,
+                                 gt_bboxes_list, gt_labels_list,
+                                 img_metas, gt_bboxes_ignore)
+
+            # collate loss from encode feature maps
+            loss_dict['interm_loss_cls'] = enc_loss_cls
+            loss_dict['interm_loss_bbox'] = enc_losses_bbox
+            loss_dict['interm_loss_iou'] = enc_losses_iou
+
+        # calculate loss from all decoder layers
+        num_dec_layers = len(all_cls_scores)
+        all_gt_bboxes_list = [gt_bboxes_list for _ in range(num_dec_layers)]
+        all_gt_labels_list = [gt_labels_list for _ in range(num_dec_layers)]
+        all_gt_bboxes_ignore_list = [
+            gt_bboxes_ignore for _ in range(num_dec_layers)
+        ]
+        img_metas_list = [img_metas for _ in range(num_dec_layers)]
+        losses_cls, losses_bbox, losses_iou = multi_apply(
+            self.loss_single, all_cls_scores, all_bbox_preds,
+            all_gt_bboxes_list, all_gt_labels_list, img_metas_list,
+            all_gt_bboxes_ignore_list)
+
+        # collate loss from the last decoder layer
+        loss_dict['loss_cls'] = losses_cls[-1]
+        loss_dict['loss_bbox'] = losses_bbox[-1]
+        loss_dict['loss_iou'] = losses_iou[-1]
+
+        # collate loss from other decoder layers
+        num_dec_layer = 0
+        for loss_cls_i, loss_bbox_i, loss_iou_i in zip(losses_cls[:-1],
+                                                       losses_bbox[:-1],
+                                                       losses_iou[:-1]):
+            loss_dict[f'd{num_dec_layer}.loss_cls'] = loss_cls_i
+            loss_dict[f'd{num_dec_layer}.loss_bbox'] = loss_bbox_i
+            loss_dict[f'd{num_dec_layer}.loss_iou'] = loss_iou_i
+            num_dec_layer += 1
+
+        if dn_cls_scores is not None:
+            # calculate denoising loss from all decoder layers
+            dn_meta = [dn_meta for _ in img_metas]
+            dn_losses_cls, dn_losses_bbox, dn_losses_iou = self.loss_dn(
+                dn_cls_scores, dn_bbox_preds, gt_bboxes_list, gt_labels_list,
+                img_metas, dn_meta)
+    
+            # collate denoising loss
+            loss_dict['dn_loss_cls'] = dn_losses_cls[-1]
+            loss_dict['dn_loss_bbox'] = dn_losses_bbox[-1]
+            loss_dict['dn_loss_iou'] = dn_losses_iou[-1]
+            num_dec_layer = 0
+            for loss_cls_i, loss_bbox_i, loss_iou_i in zip(
+                    dn_losses_cls[:-1], dn_losses_bbox[:-1],
+                    dn_losses_iou[:-1]):
+                loss_dict[f'd{num_dec_layer}.dn_loss_cls'] = loss_cls_i
+                loss_dict[f'd{num_dec_layer}.dn_loss_bbox'] = loss_bbox_i
+                loss_dict[f'd{num_dec_layer}.dn_loss_iou'] = loss_iou_i
+                num_dec_layer += 1
+                
+            return loss_dict
+
+    def loss_dn(self, dn_cls_scores, dn_bbox_preds, gt_bboxes_list,
+                gt_labels_list, img_metas, dn_meta):
+        num_dec_layers = len(dn_cls_scores)
+        all_gt_bboxes_list = [gt_bboxes_list for _ in range(num_dec_layers)]
+        all_gt_labels_list = [gt_labels_list for _ in range(num_dec_layers)]
+        img_metas_list = [img_metas for _ in range(num_dec_layers)]
+        dn_meta_list = [dn_meta for _ in range(num_dec_layers)]
+        return multi_apply(self.loss_dn_single, dn_cls_scores, dn_bbox_preds,
+                           all_gt_bboxes_list, all_gt_labels_list,
+                           img_metas_list, dn_meta_list)
+
+    def loss_dn_single(self, dn_cls_scores, dn_bbox_preds, gt_bboxes_list,
+                       gt_labels_list, img_metas, dn_meta):
+        num_imgs = dn_cls_scores.size(0)
+        bbox_preds_list = [dn_bbox_preds[i] for i in range(num_imgs)]
+        cls_reg_targets = self.get_dn_target(bbox_preds_list, gt_bboxes_list,
+                                             gt_labels_list, img_metas,
+                                             dn_meta)
+        (labels_list, label_weights_list, bbox_targets_list, bbox_weights_list,
+         num_total_pos, num_total_neg) = cls_reg_targets
+        labels = torch.cat(labels_list, 0)
+        label_weights = torch.cat(label_weights_list, 0)
+        bbox_targets = torch.cat(bbox_targets_list, 0)
+        bbox_weights = torch.cat(bbox_weights_list, 0)
+
+        # classification loss
+        cls_scores = dn_cls_scores.reshape(-1, self.cls_out_channels)
+        # construct weighted avg_factor to match with the official DETR repo
+        cls_avg_factor = \
+            num_total_pos * 1.0 + num_total_neg * self.bg_cls_weight
+        if self.sync_cls_avg_factor:
+            cls_avg_factor = reduce_mean(
+                cls_scores.new_tensor([cls_avg_factor]))
+        cls_avg_factor = max(cls_avg_factor, 1)
+
+        if len(cls_scores) > 0:
+            loss_cls = self.loss_cls(
+                cls_scores, labels, label_weights, avg_factor=cls_avg_factor)
+        else:
+            loss_cls = torch.zeros(  # TODO: How to better return zero loss
+                1,
+                dtype=cls_scores.dtype,
+                device=cls_scores.device)
+            
+        # Compute the average number of gt boxes across all gpus, for
+        # normalization purposes
+        num_total_pos = loss_cls.new_tensor([num_total_pos])
+        num_total_pos = torch.clamp(reduce_mean(num_total_pos), min=1).item()
+
+        # construct factors used for rescale bboxes
+        factors = []
+        for img_meta, bbox_pred in zip(img_metas, dn_bbox_preds):
+            img_h, img_w, _ = img_meta['img_shape']
+            factor = bbox_pred.new_tensor([img_w, img_h, img_w,
+                                           img_h]).unsqueeze(0).repeat(
+                                               bbox_pred.size(0), 1)
+            factors.append(factor)
+        factors = torch.cat(factors, 0)
+
+        # DETR regress the relative position of boxes (cxcywh) in the image,
+        # thus the learning target is normalized by the image size. So here
+        # we need to re-scale them for calculating IoU loss
+        bbox_preds = dn_bbox_preds.reshape(-1, 4)
+        bboxes = bbox_cxcywh_to_xyxy(bbox_preds) * factors
+        bboxes_gt = bbox_cxcywh_to_xyxy(bbox_targets) * factors
+
+        # regression IoU loss, defaultly GIoU loss
+        loss_iou = self.loss_iou(
+            bboxes, bboxes_gt, bbox_weights, avg_factor=num_total_pos)
+
+        # regression L1 loss
+        loss_bbox = self.loss_bbox(
+            bbox_preds, bbox_targets, bbox_weights, avg_factor=num_total_pos)
+        return loss_cls, loss_bbox, loss_iou
+
+    def get_dn_target(self, dn_bbox_preds_list, gt_bboxes_list, gt_labels_list,
+                      img_metas, dn_meta):
+        (labels_list, label_weights_list, bbox_targets_list, bbox_weights_list,
+         pos_inds_list,
+         neg_inds_list) = multi_apply(self._get_dn_target_single,
+                                      dn_bbox_preds_list, gt_bboxes_list,
+                                      gt_labels_list, img_metas, dn_meta)
+        num_total_pos = sum((inds.numel() for inds in pos_inds_list))
+        num_total_neg = sum((inds.numel() for inds in neg_inds_list))
+        return (labels_list, label_weights_list, bbox_targets_list,
+                bbox_weights_list, num_total_pos, num_total_neg)
+
+    def _get_dn_target_single(self, dn_bbox_pred, gt_bboxes, gt_labels,
+                              img_meta, dn_meta):
+        num_groups = dn_meta['num_dn_group']
+        pad_size = dn_meta['pad_size']
+        assert pad_size % num_groups == 0
+        single_pad = pad_size // num_groups
+        num_bboxes = dn_bbox_pred.size(0)
+
+        if len(gt_labels) > 0:
+            t = torch.range(0, len(gt_labels) - 1).long().cuda()
+            t = t.unsqueeze(0).repeat(num_groups, 1)
+            pos_assigned_gt_inds = t.flatten()
+            pos_inds = (torch.tensor(range(num_groups)) *
+                        single_pad).long().cuda().unsqueeze(1) + t
+            pos_inds = pos_inds.flatten()
+        else:
+            pos_inds = pos_assigned_gt_inds = torch.tensor([]).long().cuda()
+        neg_inds = pos_inds + single_pad // 2
+
+        # label targets
+        labels = gt_bboxes.new_full((num_bboxes, ),
+                                    self.num_classes,
+                                    dtype=torch.long)
+        labels[pos_inds] = gt_labels[pos_assigned_gt_inds]
+        label_weights = gt_bboxes.new_ones(num_bboxes)
+
+        # bbox targets
+        bbox_targets = torch.zeros_like(dn_bbox_pred)
+        bbox_weights = torch.zeros_like(dn_bbox_pred)
+        bbox_weights[pos_inds] = 1.0
+        img_h, img_w, _ = img_meta['img_shape']
+
+        # DETR regress the relative position of boxes (cxcywh) in the image.
+        # Thus the learning target should be normalized by the image size, also
+        # the box format should be converted from defaultly x1y1x2y2 to cxcywh.
+        factor = dn_bbox_pred.new_tensor([img_w, img_h, img_w,
+                                          img_h]).unsqueeze(0)
+        gt_bboxes_normalized = gt_bboxes / factor
+        gt_bboxes_targets = bbox_xyxy_to_cxcywh(gt_bboxes_normalized)
+        bbox_targets[pos_inds] = gt_bboxes_targets.repeat([num_groups, 1])
+
+        return (labels, label_weights, bbox_targets, bbox_weights, pos_inds,
+                neg_inds)
+
+    @staticmethod
+    def extract_dn_outputs(all_cls_scores, all_bbox_preds, dn_meta):
+        # if dn_meta and dn_meta['pad_size'] > 0:
+        if dn_meta is not None:
+            denoising_cls_scores = all_cls_scores[:, :, :
+                                                  dn_meta['pad_size'], :]
+            denoising_bbox_preds = all_bbox_preds[:, :, :
+                                                  dn_meta['pad_size'], :]
+            matching_cls_scores = all_cls_scores[:, :, dn_meta['pad_size']:, :]
+            matching_bbox_preds = all_bbox_preds[:, :, dn_meta['pad_size']:, :]
+        else:
+            denoising_cls_scores = None
+            denoising_bbox_preds = None
+            matching_cls_scores = all_cls_scores
+            matching_bbox_preds = all_bbox_preds
+        return (matching_cls_scores, matching_bbox_preds, denoising_cls_scores,
+                denoising_bbox_preds)

detection/mmdet_custom/models/dense_heads/mask_rcnn.py

@@ -0,0 +1,27 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+from mmdet.models.builder import DETECTORS
+from .two_stage import TwoStageDetector
+
+
+@DETECTORS.register_module()
+class MaskRCNN_(TwoStageDetector):
+    """Implementation of `Mask R-CNN <https://arxiv.org/abs/1703.06870>`_"""
+
+    def __init__(self,
+                 backbone,
+                 rpn_head,
+                 roi_head,
+                 train_cfg,
+                 test_cfg,
+                 neck=None,
+                 pretrained=None,
+                 init_cfg=None):
+        super(MaskRCNN_, self).__init__(
+            backbone=backbone,
+            neck=neck,
+            rpn_head=rpn_head,
+            roi_head=roi_head,
+            train_cfg=train_cfg,
+            test_cfg=test_cfg,
+            pretrained=pretrained,
+            init_cfg=init_cfg)

detection/mmdet_custom/models/dense_heads/msda.py

@@ -0,0 +1,369 @@
+# --------------------------------------------------------
+# DCNv4
+# Copyright (c) 2024 OpenGVLab
+# Licensed under The MIT License [see LICENSE for details]
+# --------------------------------------------------------
+
+import torch
+from torch.cuda.amp import custom_bwd, custom_fwd
+from torch.autograd.function import Function, once_differentiable
+from mmcv.utils import ext_loader
+ext_module = ext_loader.load_ext(
+    '_ext', ['ms_deform_attn_backward', 'ms_deform_attn_forward'])
+
+class MultiScaleDeformableAttnFunction_fp16(Function):
+
+    @staticmethod
+    @custom_fwd(cast_inputs=torch.float16)
+    def forward(ctx, value, value_spatial_shapes, value_level_start_index,
+                sampling_locations, attention_weights, im2col_step):
+        """GPU version of multi-scale deformable attention.
+
+        Args:
+            value (Tensor): The value has shape
+                (bs, num_keys, mum_heads, embed_dims//num_heads)
+            value_spatial_shapes (Tensor): Spatial shape of
+                each feature map, has shape (num_levels, 2),
+                last dimension 2 represent (h, w)
+            sampling_locations (Tensor): The location of sampling points,
+                has shape
+                (bs ,num_queries, num_heads, num_levels, num_points, 2),
+                the last dimension 2 represent (x, y).
+            attention_weights (Tensor): The weight of sampling points used
+                when calculate the attention, has shape
+                (bs ,num_queries, num_heads, num_levels, num_points),
+            im2col_step (Tensor): The step used in image to column.
+
+        Returns:
+            Tensor: has shape (bs, num_queries, embed_dims)
+        """
+        ctx.im2col_step = im2col_step
+        output = ext_module.ms_deform_attn_forward(
+            value,
+            value_spatial_shapes,
+            value_level_start_index,
+            sampling_locations,
+            attention_weights,
+            im2col_step=ctx.im2col_step)
+        ctx.save_for_backward(value, value_spatial_shapes,
+                              value_level_start_index, sampling_locations,
+                              attention_weights)
+        return output
+
+    @staticmethod
+    @once_differentiable
+    @custom_bwd
+    def backward(ctx, grad_output):
+        """GPU version of backward function.
+
+        Args:
+            grad_output (Tensor): Gradient
+                of output tensor of forward.
+
+        Returns:
+             Tuple[Tensor]: Gradient
+                of input tensors in forward.
+        """
+        value, value_spatial_shapes, value_level_start_index, \
+            sampling_locations, attention_weights = ctx.saved_tensors
+        grad_value = torch.zeros_like(value)
+        grad_sampling_loc = torch.zeros_like(sampling_locations)
+        grad_attn_weight = torch.zeros_like(attention_weights)
+
+        ext_module.ms_deform_attn_backward(
+            value,
+            value_spatial_shapes,
+            value_level_start_index,
+            sampling_locations,
+            attention_weights,
+            grad_output.contiguous(),
+            grad_value,
+            grad_sampling_loc,
+            grad_attn_weight,
+            im2col_step=ctx.im2col_step)
+
+        return grad_value, None, None, \
+            grad_sampling_loc, grad_attn_weight, None
+
+
+
+shm_size_dict = {
+    "8.0": 163000,
+    "8.6": 99000,
+    "8.7": 163000,
+    "8.9": 99000,
+    "9.0": 227000,
+    "7.5": 64000,
+    "7.0": 96000,
+}
+
+cuda_capability = f"{torch.cuda.get_device_properties(0).major}.{torch.cuda.get_device_properties(0).minor}"
+
+if cuda_capability not in shm_size_dict:
+    raise NotImplementedError
+
+shm_size_cap = shm_size_dict[cuda_capability]
+
+
+class MultiScaleDeformableAttnFunction_fp32_old(Function):
+    
+    @staticmethod
+    @custom_fwd(cast_inputs=torch.float32)
+    def forward(ctx, value, value_spatial_shapes, value_level_start_index,
+                sampling_locations, attention_weights, im2col_step):
+        """GPU version of multi-scale deformable attention.
+
+        Args:
+            value (Tensor): The value has shape
+                (bs, num_keys, mum_heads, embed_dims//num_heads)
+            value_spatial_shapes (Tensor): Spatial shape of
+                each feature map, has shape (num_levels, 2),
+                last dimension 2 represent (h, w)
+            sampling_locations (Tensor): The location of sampling points,
+                has shape
+                (bs ,num_queries, num_heads, num_levels, num_points, 2),
+                the last dimension 2 represent (x, y).
+            attention_weights (Tensor): The weight of sampling points used
+                when calculate the attention, has shape
+                (bs ,num_queries, num_heads, num_levels, num_points),
+            im2col_step (Tensor): The step used in image to column.
+
+        Returns:
+            Tensor: has shape (bs, num_queries, embed_dims)
+        """
+
+        ctx.im2col_step = im2col_step
+        output = ext_module.ms_deform_attn_forward(
+            value,
+            value_spatial_shapes,
+            value_level_start_index,
+            sampling_locations,
+            attention_weights,
+            im2col_step=ctx.im2col_step)
+        ctx.save_for_backward(value, value_spatial_shapes,
+                              value_level_start_index, sampling_locations,
+                              attention_weights)
+        return output
+
+    @staticmethod
+    @once_differentiable
+    @custom_bwd
+    def backward(ctx, grad_output):
+        """GPU version of backward function.
+
+        Args:
+            grad_output (Tensor): Gradient
+                of output tensor of forward.
+
+        Returns:
+             Tuple[Tensor]: Gradient
+                of input tensors in forward.
+        """
+        value, value_spatial_shapes, value_level_start_index, \
+            sampling_locations, attention_weights = ctx.saved_tensors
+        grad_value = torch.zeros_like(value)
+        grad_sampling_loc = torch.zeros_like(sampling_locations)
+        grad_attn_weight = torch.zeros_like(attention_weights)
+
+        ext_module.ms_deform_attn_backward(
+            value,
+            value_spatial_shapes,
+            value_level_start_index,
+            sampling_locations,
+            attention_weights,
+            grad_output.contiguous(),
+            grad_value,
+            grad_sampling_loc,
+            grad_attn_weight,
+            im2col_step=ctx.im2col_step)
+
+        return grad_value, None, None, \
+            grad_sampling_loc, grad_attn_weight, None
+
+
+# Copyright (c) OpenMMLab. All rights reserved.
+import math
+import warnings
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from torch.autograd.function import Function, once_differentiable
+
+from mmcv import deprecated_api_warning
+from mmcv.cnn import constant_init, xavier_init
+from mmcv.cnn.bricks.registry import ATTENTION
+from mmcv.runner import BaseModule
+
+ext_module = ext_loader.load_ext(
+    '_ext', ['ms_deform_attn_backward', 'ms_deform_attn_forward'])
+import functools
+import time
+from collections import defaultdict
+import torch
+from mmcv.ops  import MultiScaleDeformableAttention
+@ATTENTION.register_module()
+class FlashMultiScaleDeformableAttention(MultiScaleDeformableAttention):
+    """An attention module used in Deformable-Detr.
+
+    `Deformable DETR: Deformable Transformers for End-to-End Object Detection.
+    <https://arxiv.org/pdf/2010.04159.pdf>`_.
+
+    Args:
+        embed_dims (int): The embedding dimension of Attention.
+            Default: 256.
+        num_heads (int): Parallel attention heads. Default: 64.
+        num_levels (int): The number of feature map used in
+            Attention. Default: 4.
+        num_points (int): The number of sampling points for
+            each query in each head. Default: 4.
+        im2col_step (int): The step used in image_to_column.
+            Default: 64.
+        dropout (float): A Dropout layer on `inp_identity`.
+            Default: 0.1.
+        batch_first (bool): Key, Query and Value are shape of
+            (batch, n, embed_dim)
+            or (n, batch, embed_dim). Default to False.
+        norm_cfg (dict): Config dict for normalization layer.
+            Default: None.
+        init_cfg (obj:`mmcv.ConfigDict`): The Config for initialization.
+            Default: None.
+    """
+
+    def __init__(self,
+                 use_flash=False,
+                 use_softmax=True,
+                 **kwargs
+):
+        super().__init__(**kwargs)
+
+        self.use_flash = use_flash
+        self.use_softmax = use_softmax
+    
+    @deprecated_api_warning({'residual': 'identity'},
+                            cls_name='FlashMultiScaleDeformableAttention')
+    # @run_time('ms_attention')
+    def forward(self,
+                query,
+                key=None,
+                value=None,
+                identity=None,
+                query_pos=None,
+                key_padding_mask=None,
+                reference_points=None,
+                spatial_shapes=None,
+                level_start_index=None,
+                **kwargs):
+        """Forward Function of MultiScaleDeformAttention.
+
+        Args:
+            query (torch.Tensor): Query of Transformer with shape
+                (num_query, bs, embed_dims).
+            key (torch.Tensor): The key tensor with shape
+                `(num_key, bs, embed_dims)`.
+            value (torch.Tensor): The value tensor with shape
+                `(num_key, bs, embed_dims)`.
+            identity (torch.Tensor): The tensor used for addition, with the
+                same shape as `query`. Default None. If None,
+                `query` will be used.
+            query_pos (torch.Tensor): The positional encoding for `query`.
+                Default: None.
+            key_pos (torch.Tensor): The positional encoding for `key`. Default
+                None.
+            reference_points (torch.Tensor):  The normalized reference
+                points with shape (bs, num_query, num_levels, 2),
+                all elements is range in [0, 1], top-left (0,0),
+                bottom-right (1, 1), including padding area.
+                or (N, Length_{query}, num_levels, 4), add
+                additional two dimensions is (w, h) to
+                form reference boxes.
+            key_padding_mask (torch.Tensor): ByteTensor for `query`, with
+                shape [bs, num_key].
+            spatial_shapes (torch.Tensor): Spatial shape of features in
+                different levels. With shape (num_levels, 2),
+                last dimension represents (h, w).
+            level_start_index (torch.Tensor): The start index of each level.
+                A tensor has shape ``(num_levels, )`` and can be represented
+                as [0, h_0*w_0, h_0*w_0+h_1*w_1, ...].
+
+        Returns:
+            torch.Tensor: forwarded results with shape
+            [num_query, bs, embed_dims].
+        """
+
+        if value is None:
+            value = query
+
+        if identity is None:
+            identity = query
+        if query_pos is not None:
+            query = query + query_pos
+        if not self.batch_first:
+            # change to (bs, num_query ,embed_dims)
+            query = query.permute(1, 0, 2)
+            value = value.permute(1, 0, 2)
+
+        bs, num_query, _ = query.shape
+        bs, num_value, _ = value.shape
+        assert (spatial_shapes[:, 0] * spatial_shapes[:, 1]).sum() == num_value
+
+        value = self.value_proj(value)
+        if key_padding_mask is not None:
+            value = value.masked_fill(key_padding_mask[..., None], 0.0)
+        value = value.view(bs, num_value, self.num_heads, -1)
+        sampling_offsets = self.sampling_offsets(query).view(
+            bs, num_query, self.num_heads, self.num_levels, self.num_points, 2)
+        attention_weights = self.attention_weights(query).view(
+            bs, num_query, self.num_heads, self.num_levels * self.num_points)
+
+        if not self.use_flash:
+            if self.use_softmax:
+                attention_weights = attention_weights.softmax(-1)
+            attention_weights = attention_weights.view(bs, num_query,
+                                                   self.num_heads,
+                                                   self.num_levels,
+                                                   self.num_points)
+
+        else:
+            attention_weights = attention_weights.view(bs, num_query,
+                                                   self.num_heads,
+                                                   self.num_levels,
+                                                   self.num_points, 1)
+
+        if reference_points.shape[-1] == 2:
+            offset_normalizer = torch.stack(
+                [spatial_shapes[..., 1], spatial_shapes[..., 0]], -1)
+            sampling_locations = reference_points[:, :, None, :, None, :] \
+                + sampling_offsets \
+                / offset_normalizer[None, None, None, :, None, :]
+        elif reference_points.shape[-1] == 4:
+            sampling_locations = reference_points[:, :, None, :, None, :2] \
+                + sampling_offsets / self.num_points \
+                * reference_points[:, :, None, :, None, 2:] \
+                * 0.5
+        else:
+            raise ValueError(
+                f'Last dim of reference_points must be'
+                f' 2 or 4, but get {reference_points.shape[-1]} instead.')
+        sampling_locations = sampling_locations.to(sampling_offsets.dtype)
+        if torch.cuda.is_available() and value.is_cuda:
+            if self.use_flash:
+                assert False
+            else:
+                MultiScaleDeformableAttnFunction = MultiScaleDeformableAttnFunction_fp32_old
+
+                output = MultiScaleDeformableAttnFunction.apply(
+                value, spatial_shapes, level_start_index, sampling_locations,
+                attention_weights, self.im2col_step)
+
+        else:
+            output = multi_scale_deformable_attn_pytorch(
+                value, spatial_shapes, sampling_locations, attention_weights)
+        
+        output = self.output_proj(output)
+
+        if not self.batch_first:
+            # (num_query, bs ,embed_dims)
+            output = output.permute(1, 0, 2)
+
+        return self.dropout(output) + identity

detection/mmdet_custom/models/dense_heads/two_stage.py

@@ -0,0 +1,225 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import warnings
+
+import torch
+
+from mmdet.models.builder import DETECTORS, build_backbone, build_head, build_neck
+from mmdet.models.detectors.base import BaseDetector
+from mmcv.runner import BaseModule, force_fp32, auto_fp16
+import functools
+import time
+from collections import defaultdict
+import torch
+
+
+
+# DETECTORS.register_module()
+class TwoStageDetector(BaseDetector):
+    """Base class for two-stage detectors.
+
+    Two-stage detectors typically consisting of a region proposal network and a
+    task-specific regression head.
+    """
+
+    def __init__(self,
+                 backbone,
+                 neck=None,
+                 rpn_head=None,
+                 roi_head=None,
+                 train_cfg=None,
+                 test_cfg=None,
+                 pretrained=None,
+                 init_cfg=None):
+        super(TwoStageDetector, self).__init__(init_cfg)
+        if pretrained:
+            warnings.warn('DeprecationWarning: pretrained is deprecated, '
+                          'please use "init_cfg" instead')
+            backbone.pretrained = pretrained
+        self.backbone = build_backbone(backbone)
+
+        if neck is not None:
+            self.neck = build_neck(neck)
+
+        if rpn_head is not None:
+            rpn_train_cfg = train_cfg.rpn if train_cfg is not None else None
+            rpn_head_ = rpn_head.copy()
+            rpn_head_.update(train_cfg=rpn_train_cfg, test_cfg=test_cfg.rpn)
+            self.rpn_head = build_head(rpn_head_)
+
+        if roi_head is not None:
+            # update train and test cfg here for now
+            # TODO: refactor assigner & sampler
+            rcnn_train_cfg = train_cfg.rcnn if train_cfg is not None else None
+            roi_head.update(train_cfg=rcnn_train_cfg)
+            roi_head.update(test_cfg=test_cfg.rcnn)
+            roi_head.pretrained = pretrained
+            self.roi_head = build_head(roi_head)
+
+        self.train_cfg = train_cfg
+        self.test_cfg = test_cfg
+
+    @property
+    def with_rpn(self):
+        """bool: whether the detector has RPN"""
+        return hasattr(self, 'rpn_head') and self.rpn_head is not None
+
+    @property
+    def with_roi_head(self):
+        """bool: whether the detector has a RoI head"""
+        return hasattr(self, 'roi_head') and self.roi_head is not None
+    
+    def use_backbone(self, img):
+        return self.backbone(img)
+
+    # @auto_fp16(apply_to=('img',))
+    def use_neck(self, img):
+        # x = self.neck([each.float() for each in img])
+        return self.neck(img)
+
+    def extract_feat(self, img):
+        """Directly extract features from the backbone+neck."""
+        x = self.use_backbone(img)
+        if self.with_neck:
+            x = self.use_neck(x)
+        return x
+
+    def forward_dummy(self, img):
+        """Used for computing network flops.
+
+        See `mmdetection/tools/analysis_tools/get_flops.py`
+        """
+        outs = ()
+        # backbone
+        x = self.extract_feat(img)
+        # rpn
+        if self.with_rpn:
+            rpn_outs = self.rpn_head(x)
+            outs = outs + (rpn_outs, )
+        proposals = torch.randn(1000, 4).to(img.device)
+        # roi_head
+        roi_outs = self.roi_head.forward_dummy(x, proposals)
+        outs = outs + (roi_outs, )
+        return outs
+
+    def forward_train(self,
+                      img,
+                      img_metas,
+                      gt_bboxes,
+                      gt_labels,
+                      gt_bboxes_ignore=None,
+                      gt_masks=None,
+                      proposals=None,
+                      **kwargs):
+        """
+        Args:
+            img (Tensor): of shape (N, C, H, W) encoding input images.
+                Typically these should be mean centered and std scaled.
+
+            img_metas (list[dict]): list of image info dict where each dict
+                has: 'img_shape', 'scale_factor', 'flip', and may also contain
+                'filename', 'ori_shape', 'pad_shape', and 'img_norm_cfg'.
+                For details on the values of these keys see
+                `mmdet/datasets/pipelines/formatting.py:Collect`.
+
+            gt_bboxes (list[Tensor]): Ground truth bboxes for each image with
+                shape (num_gts, 4) in [tl_x, tl_y, br_x, br_y] format.
+
+            gt_labels (list[Tensor]): class indices corresponding to each box
+
+            gt_bboxes_ignore (None | list[Tensor]): specify which bounding
+                boxes can be ignored when computing the loss.
+
+            gt_masks (None | Tensor) : true segmentation masks for each box
+                used if the architecture supports a segmentation task.
+
+            proposals : override rpn proposals with custom proposals. Use when
+                `with_rpn` is False.
+
+        Returns:
+            dict[str, Tensor]: a dictionary of loss components
+        """
+        x = self.extract_feat(img)
+
+        losses = dict()
+
+        # RPN forward and loss
+        if self.with_rpn:
+            proposal_cfg = self.train_cfg.get('rpn_proposal',
+                                              self.test_cfg.rpn)
+            rpn_losses, proposal_list = self.rpn_head.forward_train(
+                x,
+                img_metas,
+                gt_bboxes,
+                gt_labels=None,
+                gt_bboxes_ignore=gt_bboxes_ignore,
+                proposal_cfg=proposal_cfg,
+                **kwargs)
+            losses.update(rpn_losses)
+        else:
+            proposal_list = proposals
+
+        roi_losses = self.roi_head.forward_train(x, img_metas, proposal_list,
+                                                 gt_bboxes, gt_labels,
+                                                 gt_bboxes_ignore, gt_masks,
+                                                 **kwargs)
+        losses.update(roi_losses)
+
+        return losses
+
+    async def async_simple_test(self,
+                                img,
+                                img_meta,
+                                proposals=None,
+                                rescale=False):
+        """Async test without augmentation."""
+        assert self.with_bbox, 'Bbox head must be implemented.'
+        x = self.extract_feat(img)
+
+        if proposals is None:
+            proposal_list = await self.rpn_head.async_simple_test_rpn(
+                x, img_meta)
+        else:
+            proposal_list = proposals
+
+        return await self.roi_head.async_simple_test(
+            x, proposal_list, img_meta, rescale=rescale)
+
+    def simple_test(self, img, img_metas, proposals=None, rescale=False):
+        """Test without augmentation."""
+
+        assert self.with_bbox, 'Bbox head must be implemented.'
+        x = self.extract_feat(img)
+        if proposals is None:
+            proposal_list = self.rpn_head.simple_test_rpn(x, img_metas)
+        else:
+            proposal_list = proposals
+
+        return self.roi_head.simple_test(
+            x, proposal_list, img_metas, rescale=rescale)
+
+    def aug_test(self, imgs, img_metas, rescale=False):
+        """Test with augmentations.
+
+        If rescale is False, then returned bboxes and masks will fit the scale
+        of imgs[0].
+        """
+        x = self.extract_feats(imgs)
+        proposal_list = self.rpn_head.aug_test_rpn(x, img_metas)
+        return self.roi_head.aug_test(
+            x, proposal_list, img_metas, rescale=rescale)
+
+    def onnx_export(self, img, img_metas):
+
+        img_shape = torch._shape_as_tensor(img)[2:]
+        img_metas[0]['img_shape_for_onnx'] = img_shape
+        x = self.extract_feat(img)
+        proposals = self.rpn_head.onnx_export(x, img_metas)
+        if hasattr(self.roi_head, 'onnx_export'):
+            return self.roi_head.onnx_export(x, proposals, img_metas)
+        else:
+            raise NotImplementedError(
+                f'{self.__class__.__name__} can not '
+                f'be exported to ONNX. Please refer to the '
+                f'list of supported models,'
+                f'https://mmdetection.readthedocs.io/en/latest/tutorials/pytorch2onnx.html#list-of-supported-models-exportable-to-onnx'  # noqa E501
+            )