# 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. from __future__ import absolute_import from __future__ import division from __future__ import print_function import numpy as np import paddle import paddle.nn.functional as F from ppdet.core.workspace import register, serializable from ..bbox_utils import xywh2xyxy, bbox_iou __all__ = ['IouLoss', 'GIoULoss', 'DIouLoss'] @register @serializable class IouLoss(object): """ iou loss, see https://arxiv.org/abs/1908.03851 loss = 1.0 - iou * iou Args: loss_weight (float): iou loss weight, default is 2.5 max_height (int): max height of input to support random shape input max_width (int): max width of input to support random shape input ciou_term (bool): whether to add ciou_term loss_square (bool): whether to square the iou term """ def __init__(self, loss_weight=2.5, giou=False, diou=False, ciou=False, loss_square=True): self.loss_weight = loss_weight self.giou = giou self.diou = diou self.ciou = ciou self.loss_square = loss_square def __call__(self, pbox, gbox): iou = bbox_iou( pbox, gbox, giou=self.giou, diou=self.diou, ciou=self.ciou) if self.loss_square: loss_iou = 1 - iou * iou else: loss_iou = 1 - iou loss_iou = loss_iou * self.loss_weight return loss_iou @register @serializable class GIoULoss(object): """ Generalized Intersection over Union, see https://arxiv.org/abs/1902.09630 Args: loss_weight (float): giou loss weight, default as 1 eps (float): epsilon to avoid divide by zero, default as 1e-10 reduction (string): Options are "none", "mean" and "sum". default as none """ def __init__(self, loss_weight=1., eps=1e-10, reduction='none'): self.loss_weight = loss_weight self.eps = eps assert reduction in ('none', 'mean', 'sum') self.reduction = reduction def bbox_overlap(self, box1, box2, eps=1e-10): """calculate the iou of box1 and box2 Args: box1 (Tensor): box1 with the shape (..., 4) box2 (Tensor): box1 with the shape (..., 4) eps (float): epsilon to avoid divide by zero Return: iou (Tensor): iou of box1 and box2 overlap (Tensor): overlap of box1 and box2 union (Tensor): union of box1 and box2 """ x1, y1, x2, y2 = box1 x1g, y1g, x2g, y2g = box2 xkis1 = paddle.maximum(x1, x1g) ykis1 = paddle.maximum(y1, y1g) xkis2 = paddle.minimum(x2, x2g) ykis2 = paddle.minimum(y2, y2g) w_inter = (xkis2 - xkis1).clip(0) h_inter = (ykis2 - ykis1).clip(0) overlap = w_inter * h_inter area1 = (x2 - x1) * (y2 - y1) area2 = (x2g - x1g) * (y2g - y1g) union = area1 + area2 - overlap + eps iou = overlap / union return iou, overlap, union def __call__(self, pbox, gbox, iou_weight=1., loc_reweight=None): x1, y1, x2, y2 = paddle.split(pbox, num_or_sections=4, axis=-1) x1g, y1g, x2g, y2g = paddle.split(gbox, num_or_sections=4, axis=-1) box1 = [x1, y1, x2, y2] box2 = [x1g, y1g, x2g, y2g] iou, overlap, union = self.bbox_overlap(box1, box2, self.eps) xc1 = paddle.minimum(x1, x1g) yc1 = paddle.minimum(y1, y1g) xc2 = paddle.maximum(x2, x2g) yc2 = paddle.maximum(y2, y2g) area_c = (xc2 - xc1) * (yc2 - yc1) + self.eps miou = iou - ((area_c - union) / area_c) if loc_reweight is not None: loc_reweight = paddle.reshape(loc_reweight, shape=(-1, 1)) loc_thresh = 0.9 giou = 1 - (1 - loc_thresh ) * miou - loc_thresh * miou * loc_reweight else: giou = 1 - miou if self.reduction == 'none': loss = giou elif self.reduction == 'sum': loss = paddle.sum(giou * iou_weight) else: loss = paddle.mean(giou * iou_weight) return loss * self.loss_weight @register @serializable class DIouLoss(GIoULoss): """ Distance-IoU Loss, see https://arxiv.org/abs/1911.08287 Args: loss_weight (float): giou loss weight, default as 1 eps (float): epsilon to avoid divide by zero, default as 1e-10 use_complete_iou_loss (bool): whether to use complete iou loss """ def __init__(self, loss_weight=1., eps=1e-10, use_complete_iou_loss=True): super(DIouLoss, self).__init__(loss_weight=loss_weight, eps=eps) self.use_complete_iou_loss = use_complete_iou_loss def __call__(self, pbox, gbox, iou_weight=1.): x1, y1, x2, y2 = paddle.split(pbox, num_or_sections=4, axis=-1) x1g, y1g, x2g, y2g = paddle.split(gbox, num_or_sections=4, axis=-1) cx = (x1 + x2) / 2 cy = (y1 + y2) / 2 w = x2 - x1 h = y2 - y1 cxg = (x1g + x2g) / 2 cyg = (y1g + y2g) / 2 wg = x2g - x1g hg = y2g - y1g x2 = paddle.maximum(x1, x2) y2 = paddle.maximum(y1, y2) # A and B xkis1 = paddle.maximum(x1, x1g) ykis1 = paddle.maximum(y1, y1g) xkis2 = paddle.minimum(x2, x2g) ykis2 = paddle.minimum(y2, y2g) # A or B xc1 = paddle.minimum(x1, x1g) yc1 = paddle.minimum(y1, y1g) xc2 = paddle.maximum(x2, x2g) yc2 = paddle.maximum(y2, y2g) intsctk = (xkis2 - xkis1) * (ykis2 - ykis1) intsctk = intsctk * paddle.greater_than( xkis2, xkis1) * paddle.greater_than(ykis2, ykis1) unionk = (x2 - x1) * (y2 - y1) + (x2g - x1g) * (y2g - y1g ) - intsctk + self.eps iouk = intsctk / unionk # DIOU term dist_intersection = (cx - cxg) * (cx - cxg) + (cy - cyg) * (cy - cyg) dist_union = (xc2 - xc1) * (xc2 - xc1) + (yc2 - yc1) * (yc2 - yc1) diou_term = (dist_intersection + self.eps) / (dist_union + self.eps) # CIOU term ciou_term = 0 if self.use_complete_iou_loss: ar_gt = wg / hg ar_pred = w / h arctan = paddle.atan(ar_gt) - paddle.atan(ar_pred) ar_loss = 4. / np.pi / np.pi * arctan * arctan alpha = ar_loss / (1 - iouk + ar_loss + self.eps) alpha.stop_gradient = True ciou_term = alpha * ar_loss diou = paddle.mean((1 - iouk + ciou_term + diou_term) * iou_weight) return diou * self.loss_weight