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import torch |
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from mmdet.core import multi_apply |
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from ..builder import HEADS |
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from ..losses import CrossEntropyLoss, SmoothL1Loss, carl_loss, isr_p |
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from .ssd_head import SSDHead |
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@HEADS.register_module() |
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class PISASSDHead(SSDHead): |
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def loss(self, |
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cls_scores, |
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bbox_preds, |
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gt_bboxes, |
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gt_labels, |
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img_metas, |
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gt_bboxes_ignore=None): |
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"""Compute losses of the head. |
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Args: |
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cls_scores (list[Tensor]): Box scores for each scale level |
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Has shape (N, num_anchors * num_classes, H, W) |
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bbox_preds (list[Tensor]): Box energies / deltas for each scale |
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level with shape (N, num_anchors * 4, H, W) |
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gt_bboxes (list[Tensor]): Ground truth bboxes of each image |
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with shape (num_obj, 4). |
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gt_labels (list[Tensor]): Ground truth labels of each image |
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with shape (num_obj, 4). |
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img_metas (list[dict]): Meta information of each image, e.g., |
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image size, scaling factor, etc. |
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gt_bboxes_ignore (list[Tensor]): Ignored gt bboxes of each image. |
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Default: None. |
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Returns: |
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dict: Loss dict, comprise classification loss regression loss and |
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carl loss. |
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""" |
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featmap_sizes = [featmap.size()[-2:] for featmap in cls_scores] |
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assert len(featmap_sizes) == self.anchor_generator.num_levels |
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device = cls_scores[0].device |
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anchor_list, valid_flag_list = self.get_anchors( |
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featmap_sizes, img_metas, device=device) |
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cls_reg_targets = self.get_targets( |
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anchor_list, |
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valid_flag_list, |
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gt_bboxes, |
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img_metas, |
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gt_bboxes_ignore_list=gt_bboxes_ignore, |
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gt_labels_list=gt_labels, |
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label_channels=1, |
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unmap_outputs=False, |
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return_sampling_results=True) |
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if cls_reg_targets is None: |
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return None |
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(labels_list, label_weights_list, bbox_targets_list, bbox_weights_list, |
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num_total_pos, num_total_neg, sampling_results_list) = cls_reg_targets |
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num_images = len(img_metas) |
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all_cls_scores = torch.cat([ |
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s.permute(0, 2, 3, 1).reshape( |
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num_images, -1, self.cls_out_channels) for s in cls_scores |
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], 1) |
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all_labels = torch.cat(labels_list, -1).view(num_images, -1) |
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all_label_weights = torch.cat(label_weights_list, |
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-1).view(num_images, -1) |
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all_bbox_preds = torch.cat([ |
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b.permute(0, 2, 3, 1).reshape(num_images, -1, 4) |
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for b in bbox_preds |
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], -2) |
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all_bbox_targets = torch.cat(bbox_targets_list, |
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-2).view(num_images, -1, 4) |
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all_bbox_weights = torch.cat(bbox_weights_list, |
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-2).view(num_images, -1, 4) |
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all_anchors = [] |
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for i in range(num_images): |
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all_anchors.append(torch.cat(anchor_list[i])) |
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isr_cfg = self.train_cfg.get('isr', None) |
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all_targets = (all_labels.view(-1), all_label_weights.view(-1), |
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all_bbox_targets.view(-1, |
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4), all_bbox_weights.view(-1, 4)) |
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if isr_cfg is not None: |
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all_targets = isr_p( |
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all_cls_scores.view(-1, all_cls_scores.size(-1)), |
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all_bbox_preds.view(-1, 4), |
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all_targets, |
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torch.cat(all_anchors), |
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sampling_results_list, |
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loss_cls=CrossEntropyLoss(), |
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bbox_coder=self.bbox_coder, |
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**self.train_cfg.isr, |
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num_class=self.num_classes) |
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(new_labels, new_label_weights, new_bbox_targets, |
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new_bbox_weights) = all_targets |
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all_labels = new_labels.view(all_labels.shape) |
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all_label_weights = new_label_weights.view(all_label_weights.shape) |
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all_bbox_targets = new_bbox_targets.view(all_bbox_targets.shape) |
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all_bbox_weights = new_bbox_weights.view(all_bbox_weights.shape) |
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carl_loss_cfg = self.train_cfg.get('carl', None) |
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if carl_loss_cfg is not None: |
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loss_carl = carl_loss( |
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all_cls_scores.view(-1, all_cls_scores.size(-1)), |
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all_targets[0], |
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all_bbox_preds.view(-1, 4), |
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all_targets[2], |
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SmoothL1Loss(beta=1.), |
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**self.train_cfg.carl, |
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avg_factor=num_total_pos, |
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num_class=self.num_classes) |
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assert torch.isfinite(all_cls_scores).all().item(), \ |
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'classification scores become infinite or NaN!' |
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assert torch.isfinite(all_bbox_preds).all().item(), \ |
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'bbox predications become infinite or NaN!' |
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losses_cls, losses_bbox = multi_apply( |
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self.loss_single, |
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all_cls_scores, |
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all_bbox_preds, |
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all_anchors, |
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all_labels, |
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all_label_weights, |
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all_bbox_targets, |
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all_bbox_weights, |
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num_total_samples=num_total_pos) |
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loss_dict = dict(loss_cls=losses_cls, loss_bbox=losses_bbox) |
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if carl_loss_cfg is not None: |
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loss_dict.update(loss_carl) |
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return loss_dict |
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