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206 lines
7.5 KiB
206 lines
7.5 KiB
# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved. |
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# |
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# Licensed under the Apache License, Version 2.0 (the "License"); |
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# you may not use this file except in compliance with the License. |
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# You may obtain a copy of the License at |
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# |
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# http://www.apache.org/licenses/LICENSE-2.0 |
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# |
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# Unless required by applicable law or agreed to in writing, software |
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# distributed under the License is distributed on an "AS IS" BASIS, |
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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# See the License for the specific language governing permissions and |
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# limitations under the License. |
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from __future__ import absolute_import |
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from __future__ import division |
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from __future__ import print_function |
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import paddle |
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import paddle.nn as nn |
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import paddle.nn.functional as F |
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from paddlers.models.ppdet.core.workspace import register |
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from ..bbox_utils import decode_yolo, xywh2xyxy, iou_similarity |
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__all__ = ['YOLOv3Loss'] |
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def bbox_transform(pbox, anchor, downsample): |
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pbox = decode_yolo(pbox, anchor, downsample) |
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pbox = xywh2xyxy(pbox) |
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return pbox |
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@register |
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class YOLOv3Loss(nn.Layer): |
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__inject__ = ['iou_loss', 'iou_aware_loss'] |
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__shared__ = ['num_classes'] |
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def __init__(self, |
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num_classes=80, |
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ignore_thresh=0.7, |
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label_smooth=False, |
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downsample=[32, 16, 8], |
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scale_x_y=1., |
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iou_loss=None, |
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iou_aware_loss=None): |
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""" |
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YOLOv3Loss layer |
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Args: |
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num_calsses (int): number of foreground classes |
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ignore_thresh (float): threshold to ignore confidence loss |
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label_smooth (bool): whether to use label smoothing |
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downsample (list): downsample ratio for each detection block |
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scale_x_y (float): scale_x_y factor |
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iou_loss (object): IoULoss instance |
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iou_aware_loss (object): IouAwareLoss instance |
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""" |
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super(YOLOv3Loss, self).__init__() |
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self.num_classes = num_classes |
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self.ignore_thresh = ignore_thresh |
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self.label_smooth = label_smooth |
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self.downsample = downsample |
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self.scale_x_y = scale_x_y |
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self.iou_loss = iou_loss |
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self.iou_aware_loss = iou_aware_loss |
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self.distill_pairs = [] |
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def obj_loss(self, pbox, gbox, pobj, tobj, anchor, downsample): |
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# pbox |
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pbox = decode_yolo(pbox, anchor, downsample) |
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pbox = xywh2xyxy(pbox) |
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pbox = paddle.concat(pbox, axis=-1) |
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b = pbox.shape[0] |
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pbox = pbox.reshape((b, -1, 4)) |
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# gbox |
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gxy = gbox[:, :, 0:2] - gbox[:, :, 2:4] * 0.5 |
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gwh = gbox[:, :, 0:2] + gbox[:, :, 2:4] * 0.5 |
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gbox = paddle.concat([gxy, gwh], axis=-1) |
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iou = iou_similarity(pbox, gbox) |
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iou.stop_gradient = True |
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iou_max = iou.max(2) # [N, M1] |
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iou_mask = paddle.cast(iou_max <= self.ignore_thresh, dtype=pbox.dtype) |
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iou_mask.stop_gradient = True |
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pobj = pobj.reshape((b, -1)) |
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tobj = tobj.reshape((b, -1)) |
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obj_mask = paddle.cast(tobj > 0, dtype=pbox.dtype) |
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obj_mask.stop_gradient = True |
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loss_obj = F.binary_cross_entropy_with_logits( |
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pobj, obj_mask, reduction='none') |
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loss_obj_pos = (loss_obj * tobj) |
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loss_obj_neg = (loss_obj * (1 - obj_mask) * iou_mask) |
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return loss_obj_pos + loss_obj_neg |
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def cls_loss(self, pcls, tcls): |
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if self.label_smooth: |
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delta = min(1. / self.num_classes, 1. / 40) |
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pos, neg = 1 - delta, delta |
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# 1 for positive, 0 for negative |
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tcls = pos * paddle.cast( |
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tcls > 0., dtype=tcls.dtype) + neg * paddle.cast( |
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tcls <= 0., dtype=tcls.dtype) |
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loss_cls = F.binary_cross_entropy_with_logits( |
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pcls, tcls, reduction='none') |
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return loss_cls |
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def yolov3_loss(self, p, t, gt_box, anchor, downsample, scale=1., |
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eps=1e-10): |
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na = len(anchor) |
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b, c, h, w = p.shape |
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if self.iou_aware_loss: |
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ioup, p = p[:, 0:na, :, :], p[:, na:, :, :] |
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ioup = ioup.unsqueeze(-1) |
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p = p.reshape((b, na, -1, h, w)).transpose((0, 1, 3, 4, 2)) |
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x, y = p[:, :, :, :, 0:1], p[:, :, :, :, 1:2] |
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w, h = p[:, :, :, :, 2:3], p[:, :, :, :, 3:4] |
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obj, pcls = p[:, :, :, :, 4:5], p[:, :, :, :, 5:] |
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self.distill_pairs.append([x, y, w, h, obj, pcls]) |
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t = t.transpose((0, 1, 3, 4, 2)) |
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tx, ty = t[:, :, :, :, 0:1], t[:, :, :, :, 1:2] |
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tw, th = t[:, :, :, :, 2:3], t[:, :, :, :, 3:4] |
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tscale = t[:, :, :, :, 4:5] |
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tobj, tcls = t[:, :, :, :, 5:6], t[:, :, :, :, 6:] |
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tscale_obj = tscale * tobj |
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loss = dict() |
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x = scale * F.sigmoid(x) - 0.5 * (scale - 1.) |
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y = scale * F.sigmoid(y) - 0.5 * (scale - 1.) |
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if abs(scale - 1.) < eps: |
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loss_x = F.binary_cross_entropy(x, tx, reduction='none') |
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loss_y = F.binary_cross_entropy(y, ty, reduction='none') |
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loss_xy = tscale_obj * (loss_x + loss_y) |
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else: |
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loss_x = paddle.abs(x - tx) |
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loss_y = paddle.abs(y - ty) |
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loss_xy = tscale_obj * (loss_x + loss_y) |
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loss_xy = loss_xy.sum([1, 2, 3, 4]).mean() |
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loss_w = paddle.abs(w - tw) |
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loss_h = paddle.abs(h - th) |
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loss_wh = tscale_obj * (loss_w + loss_h) |
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loss_wh = loss_wh.sum([1, 2, 3, 4]).mean() |
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loss['loss_xy'] = loss_xy |
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loss['loss_wh'] = loss_wh |
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if self.iou_loss is not None: |
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# warn: do not modify x, y, w, h in place |
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box, tbox = [x, y, w, h], [tx, ty, tw, th] |
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pbox = bbox_transform(box, anchor, downsample) |
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gbox = bbox_transform(tbox, anchor, downsample) |
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loss_iou = self.iou_loss(pbox, gbox) |
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loss_iou = loss_iou * tscale_obj |
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loss_iou = loss_iou.sum([1, 2, 3, 4]).mean() |
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loss['loss_iou'] = loss_iou |
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if self.iou_aware_loss is not None: |
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box, tbox = [x, y, w, h], [tx, ty, tw, th] |
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pbox = bbox_transform(box, anchor, downsample) |
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gbox = bbox_transform(tbox, anchor, downsample) |
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loss_iou_aware = self.iou_aware_loss(ioup, pbox, gbox) |
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loss_iou_aware = loss_iou_aware * tobj |
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loss_iou_aware = loss_iou_aware.sum([1, 2, 3, 4]).mean() |
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loss['loss_iou_aware'] = loss_iou_aware |
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box = [x, y, w, h] |
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loss_obj = self.obj_loss(box, gt_box, obj, tobj, anchor, downsample) |
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loss_obj = loss_obj.sum(-1).mean() |
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loss['loss_obj'] = loss_obj |
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loss_cls = self.cls_loss(pcls, tcls) * tobj |
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loss_cls = loss_cls.sum([1, 2, 3, 4]).mean() |
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loss['loss_cls'] = loss_cls |
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return loss |
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def forward(self, inputs, targets, anchors): |
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np = len(inputs) |
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gt_targets = [targets['target{}'.format(i)] for i in range(np)] |
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gt_box = targets['gt_bbox'] |
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yolo_losses = dict() |
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self.distill_pairs.clear() |
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for x, t, anchor, downsample in zip(inputs, gt_targets, anchors, |
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self.downsample): |
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yolo_loss = self.yolov3_loss(x, t, gt_box, anchor, downsample, |
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self.scale_x_y) |
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for k, v in yolo_loss.items(): |
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if k in yolo_losses: |
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yolo_losses[k] += v |
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else: |
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yolo_losses[k] = v |
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loss = 0 |
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for k, v in yolo_losses.items(): |
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loss += v |
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yolo_losses['loss'] = loss |
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return yolo_losses
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