# Ultralytics YOLO 🚀, AGPL-3.0 license import torch import torch.nn as nn import torch.nn.functional as F from ultralytics.vit.utils.ops import HungarianMatcher from ultralytics.yolo.utils.loss import FocalLoss, VarifocalLoss from ultralytics.yolo.utils.metrics import bbox_iou class DETRLoss(nn.Module): def __init__(self, nc=80, loss_gain=None, aux_loss=True, use_fl=True, use_vfl=False, use_uni_match=False, uni_match_ind=0): """ DETR loss function. Args: nc (int): The number of classes. loss_gain (dict): The coefficient of loss. aux_loss (bool): If 'aux_loss = True', loss at each decoder layer are to be used. use_vfl (bool): Use VarifocalLoss or not. use_uni_match (bool): Whether to use a fixed layer to assign labels for auxiliary branch. uni_match_ind (int): The fixed indices of a layer. """ super().__init__() if loss_gain is None: loss_gain = {'class': 1, 'bbox': 5, 'giou': 2, 'no_object': 0.1, 'mask': 1, 'dice': 1} self.nc = nc self.matcher = HungarianMatcher(cost_gain={'class': 2, 'bbox': 5, 'giou': 2}) self.loss_gain = loss_gain self.aux_loss = aux_loss self.fl = FocalLoss() if use_fl else None self.vfl = VarifocalLoss() if use_vfl else None self.use_uni_match = use_uni_match self.uni_match_ind = uni_match_ind self.device = None def _get_loss_class(self, pred_scores, targets, gt_scores, num_gts, postfix=''): # logits: [b, query, num_classes], gt_class: list[[n, 1]] name_class = f'loss_class{postfix}' bs, nq = pred_scores.shape[:2] # one_hot = F.one_hot(targets, self.nc + 1)[..., :-1] # (bs, num_queries, num_classes) one_hot = torch.zeros((bs, nq, self.nc + 1), dtype=torch.int64, device=targets.device) one_hot.scatter_(2, targets.unsqueeze(-1), 1) one_hot = one_hot[..., :-1] gt_scores = gt_scores.view(bs, nq, 1) * one_hot if self.fl: if num_gts and self.vfl: loss_cls = self.vfl(pred_scores, gt_scores, one_hot) else: loss_cls = self.fl(pred_scores, one_hot.float()) loss_cls /= max(num_gts, 1) / nq else: loss_cls = nn.BCEWithLogitsLoss(reduction='none')(pred_scores, gt_scores).mean(1).sum() # YOLO CLS loss return {name_class: loss_cls.squeeze() * self.loss_gain['class']} def _get_loss_bbox(self, pred_bboxes, gt_bboxes, postfix=''): # boxes: [b, query, 4], gt_bbox: list[[n, 4]] name_bbox = f'loss_bbox{postfix}' name_giou = f'loss_giou{postfix}' loss = {} if len(gt_bboxes) == 0: loss[name_bbox] = torch.tensor(0., device=self.device) loss[name_giou] = torch.tensor(0., device=self.device) return loss loss[name_bbox] = self.loss_gain['bbox'] * F.l1_loss(pred_bboxes, gt_bboxes, reduction='sum') / len(gt_bboxes) loss[name_giou] = 1.0 - bbox_iou(pred_bboxes, gt_bboxes, xywh=True, GIoU=True) loss[name_giou] = loss[name_giou].sum() / len(gt_bboxes) loss[name_giou] = self.loss_gain['giou'] * loss[name_giou] loss = {k: v.squeeze() for k, v in loss.items()} return loss def _get_loss_mask(self, masks, gt_mask, match_indices, postfix=''): # masks: [b, query, h, w], gt_mask: list[[n, H, W]] name_mask = f'loss_mask{postfix}' name_dice = f'loss_dice{postfix}' loss = {} if sum(len(a) for a in gt_mask) == 0: loss[name_mask] = torch.tensor(0., device=self.device) loss[name_dice] = torch.tensor(0., device=self.device) return loss num_gts = len(gt_mask) src_masks, target_masks = self._get_assigned_bboxes(masks, gt_mask, match_indices) src_masks = F.interpolate(src_masks.unsqueeze(0), size=target_masks.shape[-2:], mode='bilinear')[0] # TODO: torch does not have `sigmoid_focal_loss`, but it's not urgent since we don't use mask branch for now. loss[name_mask] = self.loss_gain['mask'] * F.sigmoid_focal_loss(src_masks, target_masks, torch.tensor([num_gts], dtype=torch.float32)) loss[name_dice] = self.loss_gain['dice'] * self._dice_loss(src_masks, target_masks, num_gts) return loss def _dice_loss(self, inputs, targets, num_gts): inputs = F.sigmoid(inputs) inputs = inputs.flatten(1) targets = targets.flatten(1) numerator = 2 * (inputs * targets).sum(1) denominator = inputs.sum(-1) + targets.sum(-1) loss = 1 - (numerator + 1) / (denominator + 1) return loss.sum() / num_gts def _get_loss_aux(self, pred_bboxes, pred_scores, gt_bboxes, gt_cls, gt_groups, match_indices=None, postfix='', masks=None, gt_mask=None): """Get auxiliary losses""" # NOTE: loss class, bbox, giou, mask, dice loss = torch.zeros(5 if masks is not None else 3, device=pred_bboxes.device) if match_indices is None and self.use_uni_match: match_indices = self.matcher(pred_bboxes[self.uni_match_ind], pred_scores[self.uni_match_ind], gt_bboxes, gt_cls, gt_groups, masks=masks[self.uni_match_ind] if masks is not None else None, gt_mask=gt_mask) for i, (aux_bboxes, aux_scores) in enumerate(zip(pred_bboxes, pred_scores)): aux_masks = masks[i] if masks is not None else None loss_ = self._get_loss(aux_bboxes, aux_scores, gt_bboxes, gt_cls, gt_groups, masks=aux_masks, gt_mask=gt_mask, postfix=postfix, match_indices=match_indices) loss[0] += loss_[f'loss_class{postfix}'] loss[1] += loss_[f'loss_bbox{postfix}'] loss[2] += loss_[f'loss_giou{postfix}'] # if masks is not None and gt_mask is not None: # loss_ = self._get_loss_mask(aux_masks, gt_mask, match_indices, postfix) # loss[3] += loss_[f'loss_mask{postfix}'] # loss[4] += loss_[f'loss_dice{postfix}'] loss = { f'loss_class_aux{postfix}': loss[0], f'loss_bbox_aux{postfix}': loss[1], f'loss_giou_aux{postfix}': loss[2]} # if masks is not None and gt_mask is not None: # loss[f'loss_mask_aux{postfix}'] = loss[3] # loss[f'loss_dice_aux{postfix}'] = loss[4] return loss def _get_index(self, match_indices): batch_idx = torch.cat([torch.full_like(src, i) for i, (src, _) in enumerate(match_indices)]) src_idx = torch.cat([src for (src, _) in match_indices]) dst_idx = torch.cat([dst for (_, dst) in match_indices]) return (batch_idx, src_idx), dst_idx def _get_assigned_bboxes(self, pred_bboxes, gt_bboxes, match_indices): pred_assigned = torch.cat([ t[I] if len(I) > 0 else torch.zeros(0, t.shape[-1], device=self.device) for t, (I, _) in zip(pred_bboxes, match_indices)]) gt_assigned = torch.cat([ t[J] if len(J) > 0 else torch.zeros(0, t.shape[-1], device=self.device) for t, (_, J) in zip(gt_bboxes, match_indices)]) return pred_assigned, gt_assigned def _get_loss(self, pred_bboxes, pred_scores, gt_bboxes, gt_cls, gt_groups, masks=None, gt_mask=None, postfix='', match_indices=None): """Get losses""" if match_indices is None: match_indices = self.matcher(pred_bboxes, pred_scores, gt_bboxes, gt_cls, gt_groups, masks=masks, gt_mask=gt_mask) idx, gt_idx = self._get_index(match_indices) pred_bboxes, gt_bboxes = pred_bboxes[idx], gt_bboxes[gt_idx] bs, nq = pred_scores.shape[:2] targets = torch.full((bs, nq), self.nc, device=pred_scores.device, dtype=gt_cls.dtype) targets[idx] = gt_cls[gt_idx] gt_scores = torch.zeros([bs, nq], device=pred_scores.device) if len(gt_bboxes): gt_scores[idx] = bbox_iou(pred_bboxes.detach(), gt_bboxes, xywh=True).squeeze(-1) loss = {} loss.update(self._get_loss_class(pred_scores, targets, gt_scores, len(gt_bboxes), postfix)) loss.update(self._get_loss_bbox(pred_bboxes, gt_bboxes, postfix)) # if masks is not None and gt_mask is not None: # loss.update(self._get_loss_mask(masks, gt_mask, match_indices, postfix)) return loss def forward(self, pred_bboxes, pred_scores, batch, postfix='', **kwargs): """ Args: pred_bboxes (torch.Tensor): [l, b, query, 4] pred_scores (torch.Tensor): [l, b, query, num_classes] batch (dict): A dict includes: gt_cls (torch.Tensor) with shape [num_gts, ], gt_bboxes (torch.Tensor): [num_gts, 4], gt_groups (List(int)): a list of batch size length includes the number of gts of each image. postfix (str): postfix of loss name. """ self.device = pred_bboxes.device match_indices = kwargs.get('match_indices', None) gt_cls, gt_bboxes, gt_groups = batch['cls'], batch['bboxes'], batch['gt_groups'] total_loss = self._get_loss(pred_bboxes[-1], pred_scores[-1], gt_bboxes, gt_cls, gt_groups, postfix=postfix, match_indices=match_indices) if self.aux_loss: total_loss.update( self._get_loss_aux(pred_bboxes[:-1], pred_scores[:-1], gt_bboxes, gt_cls, gt_groups, match_indices, postfix)) return total_loss class RTDETRDetectionLoss(DETRLoss): def forward(self, preds, batch, dn_bboxes=None, dn_scores=None, dn_meta=None): pred_bboxes, pred_scores = preds total_loss = super().forward(pred_bboxes, pred_scores, batch) if dn_meta is not None: dn_pos_idx, dn_num_group = dn_meta['dn_pos_idx'], dn_meta['dn_num_group'] assert len(batch['gt_groups']) == len(dn_pos_idx) # denoising match indices match_indices = self.get_dn_match_indices(dn_pos_idx, dn_num_group, batch['gt_groups']) # compute denoising training loss dn_loss = super().forward(dn_bboxes, dn_scores, batch, postfix='_dn', match_indices=match_indices) total_loss.update(dn_loss) else: total_loss.update({f'{k}_dn': torch.tensor(0., device=self.device) for k in total_loss.keys()}) return total_loss @staticmethod def get_dn_match_indices(dn_pos_idx, dn_num_group, gt_groups): """Get the match indices for denoising. Args: dn_pos_idx (List[torch.Tensor]): A list includes positive indices of denoising. dn_num_group (int): The number of groups of denoising. gt_groups (List(int)): a list of batch size length includes the number of gts of each image. Returns: dn_match_indices (List(tuple)): Matched indices. """ dn_match_indices = [] idx_groups = torch.as_tensor([0, *gt_groups[:-1]]).cumsum_(0) for i, num_gt in enumerate(gt_groups): if num_gt > 0: gt_idx = torch.arange(end=num_gt, dtype=torch.long) + idx_groups[i] gt_idx = gt_idx.repeat(dn_num_group) assert len(dn_pos_idx[i]) == len(gt_idx), 'Expected the same length, ' f'but got {len(dn_pos_idx[i])} and {len(gt_idx)} respectively.' dn_match_indices.append((dn_pos_idx[i], gt_idx)) else: dn_match_indices.append((torch.zeros([0], dtype=torch.long), torch.zeros([0], dtype=torch.long))) return dn_match_indices