# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import paddle import paddle.nn as nn import paddle.nn.functional as F from paddle.nn.initializer import Normal, XavierUniform from paddle.regularizer import L2Decay from ppdet.core.workspace import register, create from ppdet.modeling import ops from .bbox_head import BBoxHead, TwoFCHead from .roi_extractor import RoIAlign from ..shape_spec import ShapeSpec from ..bbox_utils import bbox2delta, delta2bbox, clip_bbox, nonempty_bbox @register class CascadeTwoFCHead(nn.Layer): __shared__ = ['num_cascade_stage'] def __init__(self, in_dim=256, mlp_dim=1024, resolution=7, num_cascade_stage=3): super(CascadeTwoFCHead, self).__init__() self.in_dim = in_dim self.mlp_dim = mlp_dim self.head_list = [] for stage in range(num_cascade_stage): head_per_stage = self.add_sublayer( str(stage), TwoFCHead(in_dim, mlp_dim, resolution)) self.head_list.append(head_per_stage) @classmethod def from_config(cls, cfg, input_shape): s = input_shape s = s[0] if isinstance(s, (list, tuple)) else s return {'in_dim': s.channels} @property def out_shape(self): return [ShapeSpec(channels=self.mlp_dim, )] def forward(self, rois_feat, stage=0): out = self.head_list[stage](rois_feat) return out @register class CascadeHead(BBoxHead): __shared__ = ['num_classes', 'num_cascade_stages'] __inject__ = ['bbox_assigner'] """ head (nn.Layer): Extract feature in bbox head in_channel (int): Input channel after RoI extractor roi_extractor (object): The module of RoI Extractor bbox_assigner (object): The module of Box Assigner, label and sample the box. num_classes (int): The number of classes bbox_weight (List[List[float]]): The weight to get the decode box and the length of weight is the number of cascade stage num_cascade_stages (int): THe number of stage to refine the box """ def __init__(self, head, in_channel, roi_extractor=RoIAlign().__dict__, bbox_assigner='BboxAssigner', num_classes=80, bbox_weight=[[10., 10., 5., 5.], [20.0, 20.0, 10.0, 10.0], [30.0, 30.0, 15.0, 15.0]], num_cascade_stages=3): nn.Layer.__init__(self, ) self.head = head self.roi_extractor = roi_extractor if isinstance(roi_extractor, dict): self.roi_extractor = RoIAlign(**roi_extractor) self.bbox_assigner = bbox_assigner self.num_classes = num_classes self.bbox_weight = bbox_weight self.num_cascade_stages = num_cascade_stages self.bbox_score_list = [] self.bbox_delta_list = [] for i in range(num_cascade_stages): score_name = 'bbox_score_stage{}'.format(i) delta_name = 'bbox_delta_stage{}'.format(i) bbox_score = self.add_sublayer( score_name, nn.Linear( in_channel, self.num_classes + 1, weight_attr=paddle.ParamAttr(initializer=Normal( mean=0.0, std=0.01)))) bbox_delta = self.add_sublayer( delta_name, nn.Linear( in_channel, 4, weight_attr=paddle.ParamAttr(initializer=Normal( mean=0.0, std=0.001)))) self.bbox_score_list.append(bbox_score) self.bbox_delta_list.append(bbox_delta) self.assigned_label = None self.assigned_rois = None def forward(self, body_feats=None, rois=None, rois_num=None, inputs=None): """ body_feats (list[Tensor]): Feature maps from backbone rois (Tensor): RoIs generated from RPN module rois_num (Tensor): The number of RoIs in each image inputs (dict{Tensor}): The ground-truth of image """ targets = [] if self.training: rois, rois_num, targets = self.bbox_assigner(rois, rois_num, inputs) targets_list = [targets] self.assigned_rois = (rois, rois_num) self.assigned_targets = targets pred_bbox = None head_out_list = [] for i in range(self.num_cascade_stages): if i > 0: rois, rois_num = self._get_rois_from_boxes(pred_bbox, inputs['im_shape']) if self.training: rois, rois_num, targets = self.bbox_assigner( rois, rois_num, inputs, i, is_cascade=True) targets_list.append(targets) rois_feat = self.roi_extractor(body_feats, rois, rois_num) bbox_feat = self.head(rois_feat, i) scores = self.bbox_score_list[i](bbox_feat) deltas = self.bbox_delta_list[i](bbox_feat) head_out_list.append([scores, deltas, rois]) pred_bbox = self._get_pred_bbox(deltas, rois, self.bbox_weight[i]) if self.training: loss = {} for stage, value in enumerate(zip(head_out_list, targets_list)): (scores, deltas, rois), targets = value loss_stage = self.get_loss(scores, deltas, targets, rois, self.bbox_weight[stage]) for k, v in loss_stage.items(): loss[k + "_stage{}".format( stage)] = v / self.num_cascade_stages return loss, bbox_feat else: scores, deltas, self.refined_rois = self.get_prediction( head_out_list) return (deltas, scores), self.head def _get_rois_from_boxes(self, boxes, im_shape): rois = [] for i, boxes_per_image in enumerate(boxes): clip_box = clip_bbox(boxes_per_image, im_shape[i]) if self.training: keep = nonempty_bbox(clip_box) clip_box = paddle.gather(clip_box, keep) rois.append(clip_box) rois_num = paddle.concat([paddle.shape(r)[0] for r in rois]) return rois, rois_num def _get_pred_bbox(self, deltas, proposals, weights): pred_proposals = paddle.concat(proposals) if len( proposals) > 1 else proposals[0] pred_bbox = delta2bbox(deltas, pred_proposals, weights) num_prop = [p.shape[0] for p in proposals] return pred_bbox.split(num_prop) def get_prediction(self, head_out_list): """ head_out_list(List[Tensor]): scores, deltas, rois """ pred_list = [] scores_list = [F.softmax(head[0]) for head in head_out_list] scores = paddle.add_n(scores_list) / self.num_cascade_stages # Get deltas and rois from the last stage _, deltas, rois = head_out_list[-1] return scores, deltas, rois def get_refined_rois(self, ): return self.refined_rois