# Copyright (c) 2018 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 division import unittest import numpy as np from scipy.special import logit from scipy.special import expit from op_test import OpTest from paddle.fluid import core def l2loss(x, y): return 0.5 * (y - x) * (y - x) def sce(x, label): sigmoid_x = expit(x) term1 = label * np.log(sigmoid_x) term2 = (1.0 - label) * np.log(1.0 - sigmoid_x) return -term1 - term2 def sigmoid(x): return 1.0 / (1.0 + np.exp(-1.0 * x)) def batch_xywh_box_iou(box1, box2): b1_left = box1[:, :, 0] - box1[:, :, 2] / 2 b1_right = box1[:, :, 0] + box1[:, :, 2] / 2 b1_top = box1[:, :, 1] - box1[:, :, 3] / 2 b1_bottom = box1[:, :, 1] + box1[:, :, 3] / 2 b2_left = box2[:, :, 0] - box2[:, :, 2] / 2 b2_right = box2[:, :, 0] + box2[:, :, 2] / 2 b2_top = box2[:, :, 1] - box2[:, :, 3] / 2 b2_bottom = box2[:, :, 1] + box2[:, :, 3] / 2 left = np.maximum(b1_left[:, :, np.newaxis], b2_left[:, np.newaxis, :]) right = np.minimum(b1_right[:, :, np.newaxis], b2_right[:, np.newaxis, :]) top = np.maximum(b1_top[:, :, np.newaxis], b2_top[:, np.newaxis, :]) bottom = np.minimum(b1_bottom[:, :, np.newaxis], b2_bottom[:, np.newaxis, :]) inter_w = np.clip(right - left, 0., 1.) inter_h = np.clip(bottom - top, 0., 1.) inter_area = inter_w * inter_h b1_area = (b1_right - b1_left) * (b1_bottom - b1_top) b2_area = (b2_right - b2_left) * (b2_bottom - b2_top) union = b1_area[:, :, np.newaxis] + b2_area[:, np.newaxis, :] - inter_area return inter_area / union def YOLOv3Loss(x, gtbox, gtlabel, attrs): n, c, h, w = x.shape b = gtbox.shape[1] anchors = attrs['anchors'] an_num = len(anchors) // 2 anchor_mask = attrs['anchor_mask'] mask_num = len(anchor_mask) class_num = attrs["class_num"] ignore_thresh = attrs['ignore_thresh'] downsample = attrs['downsample'] input_size = downsample * h x = x.reshape((n, mask_num, 5 + class_num, h, w)).transpose((0, 1, 3, 4, 2)) loss = np.zeros((n)).astype('float32') pred_box = x[:, :, :, :, :4].copy() grid_x = np.tile(np.arange(w).reshape((1, w)), (h, 1)) grid_y = np.tile(np.arange(h).reshape((h, 1)), (1, w)) pred_box[:, :, :, :, 0] = (grid_x + sigmoid(pred_box[:, :, :, :, 0])) / w pred_box[:, :, :, :, 1] = (grid_y + sigmoid(pred_box[:, :, :, :, 1])) / h x[:, :, :, :, 5:] = np.where(x[:, :, :, :, 5:] < -0.5, x[:, :, :, :, 5:], np.ones_like(x[:, :, :, :, 5:]) * 1.0 / class_num) mask_anchors = [] for m in anchor_mask: mask_anchors.append((anchors[2 * m], anchors[2 * m + 1])) anchors_s = np.array( [(an_w / input_size, an_h / input_size) for an_w, an_h in mask_anchors]) anchor_w = anchors_s[:, 0:1].reshape((1, mask_num, 1, 1)) anchor_h = anchors_s[:, 1:2].reshape((1, mask_num, 1, 1)) pred_box[:, :, :, :, 2] = np.exp(pred_box[:, :, :, :, 2]) * anchor_w pred_box[:, :, :, :, 3] = np.exp(pred_box[:, :, :, :, 3]) * anchor_h pred_box = pred_box.reshape((n, -1, 4)) pred_obj = x[:, :, :, :, 4].reshape((n, -1)) objness = np.zeros(pred_box.shape[:2]).astype('float32') ious = batch_xywh_box_iou(pred_box, gtbox) ious_max = np.max(ious, axis=-1) objness = np.where(ious_max > ignore_thresh, -np.ones_like(objness), objness) gtbox_shift = gtbox.copy() gtbox_shift[:, :, 0] = 0 gtbox_shift[:, :, 1] = 0 anchors = [(anchors[2 * i], anchors[2 * i + 1]) for i in range(0, an_num)] anchors_s = np.array( [(an_w / input_size, an_h / input_size) for an_w, an_h in anchors]) anchor_boxes = np.concatenate( [np.zeros_like(anchors_s), anchors_s], axis=-1) anchor_boxes = np.tile(anchor_boxes[np.newaxis, :, :], (n, 1, 1)) ious = batch_xywh_box_iou(gtbox_shift, anchor_boxes) iou_matches = np.argmax(ious, axis=-1) gt_matches = iou_matches.copy() for i in range(n): for j in range(b): if gtbox[i, j, 2:].sum() == 0: gt_matches[i, j] = -1 continue if iou_matches[i, j] not in anchor_mask: gt_matches[i, j] = -1 continue an_idx = anchor_mask.index(iou_matches[i, j]) gt_matches[i, j] = an_idx gi = int(gtbox[i, j, 0] * w) gj = int(gtbox[i, j, 1] * h) tx = gtbox[i, j, 0] * w - gi ty = gtbox[i, j, 1] * w - gj tw = np.log(gtbox[i, j, 2] * input_size / mask_anchors[an_idx][0]) th = np.log(gtbox[i, j, 3] * input_size / mask_anchors[an_idx][1]) scale = (2.0 - gtbox[i, j, 2] * gtbox[i, j, 3]) loss[i] += sce(x[i, an_idx, gj, gi, 0], tx) * scale loss[i] += sce(x[i, an_idx, gj, gi, 1], ty) * scale loss[i] += l2loss(x[i, an_idx, gj, gi, 2], tw) * scale loss[i] += l2loss(x[i, an_idx, gj, gi, 3], th) * scale objness[i, an_idx * h * w + gj * w + gi] = 1.0 for label_idx in range(class_num): loss[i] += sce(x[i, an_idx, gj, gi, 5 + label_idx], float(label_idx == gtlabel[i, j])) for j in range(mask_num * h * w): if objness[i, j] > 0: loss[i] += sce(pred_obj[i, j], 1.0) elif objness[i, j] == 0: loss[i] += sce(pred_obj[i, j], 0.0) return (loss, objness.reshape((n, mask_num, h, w)).astype('float32'), \ gt_matches.astype('int32')) class TestYolov3LossOp(OpTest): def setUp(self): self.initTestCase() self.op_type = 'yolov3_loss' x = logit(np.random.uniform(0, 1, self.x_shape).astype('float32')) gtbox = np.random.random(size=self.gtbox_shape).astype('float32') gtlabel = np.random.randint(0, self.class_num, self.gtbox_shape[:2]) gtmask = np.random.randint(0, 2, self.gtbox_shape[:2]) gtbox = gtbox * gtmask[:, :, np.newaxis] gtlabel = gtlabel * gtmask self.attrs = { "anchors": self.anchors, "anchor_mask": self.anchor_mask, "class_num": self.class_num, "ignore_thresh": self.ignore_thresh, "downsample": self.downsample, } self.inputs = { 'X': x, 'GTBox': gtbox.astype('float32'), 'GTLabel': gtlabel.astype('int32'), } loss, objness, gt_matches = YOLOv3Loss(x, gtbox, gtlabel, self.attrs) self.outputs = { 'Loss': loss, 'ObjectnessMask': objness, "GTMatchMask": gt_matches } def test_check_output(self): place = core.CPUPlace() self.check_output_with_place(place, atol=1e-3) def test_check_grad_ignore_gtbox(self): place = core.CPUPlace() self.check_grad_with_place( place, ['X'], 'Loss', no_grad_set=set(["GTBox", "GTLabel"]), max_relative_error=0.3) def initTestCase(self): self.anchors = [10, 13, 16, 30, 33, 23] self.anchor_mask = [1, 2] self.class_num = 5 self.ignore_thresh = 0.5 self.downsample = 32 self.x_shape = (3, len(self.anchor_mask) * (5 + self.class_num), 5, 5) self.gtbox_shape = (3, 5, 4) if __name__ == "__main__": unittest.main()