PulseFocusPlatform/static/ppdet/modeling/losses/yolo_loss.py

394 lines
16 KiB
Python

# Copyright (c) 2019 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
from paddle import fluid
from ppdet.core.workspace import register
try:
from collections.abc import Sequence
except Exception:
from collections import Sequence
import logging
logger = logging.getLogger(__name__)
__all__ = ['YOLOv3Loss']
@register
class YOLOv3Loss(object):
"""
Combined loss for YOLOv3 network
Args:
train_batch_size (int): training batch size
ignore_thresh (float): threshold to ignore confidence loss
label_smooth (bool): whether to use label smoothing
use_fine_grained_loss (bool): whether use fine grained YOLOv3 loss
instead of fluid.layers.yolov3_loss
"""
__inject__ = ['iou_loss', 'iou_aware_loss']
__shared__ = ['use_fine_grained_loss', 'train_batch_size']
def __init__(
self,
train_batch_size=8,
batch_size=-1, # stub for backward compatable
ignore_thresh=0.7,
label_smooth=True,
use_fine_grained_loss=False,
iou_loss=None,
iou_aware_loss=None,
downsample=[32, 16, 8],
scale_x_y=1.,
match_score=False):
self._train_batch_size = train_batch_size
self._ignore_thresh = ignore_thresh
self._label_smooth = label_smooth
self._use_fine_grained_loss = use_fine_grained_loss
self._iou_loss = iou_loss
self._iou_aware_loss = iou_aware_loss
self.downsample = downsample
self.scale_x_y = scale_x_y
self.match_score = match_score
if batch_size != -1:
logger.warning(
"config YOLOv3Loss.batch_size is deprecated, "
"training batch size should be set by TrainReader.batch_size")
def __call__(self, outputs, gt_box, gt_label, gt_score, targets, anchors,
anchor_masks, mask_anchors, num_classes, prefix_name):
if self._use_fine_grained_loss:
return self._get_fine_grained_loss(
outputs, targets, gt_box, self._train_batch_size, num_classes,
mask_anchors, self._ignore_thresh)
else:
losses = []
for i, output in enumerate(outputs):
scale_x_y = self.scale_x_y if not isinstance(
self.scale_x_y, Sequence) else self.scale_x_y[i]
anchor_mask = anchor_masks[i]
loss = fluid.layers.yolov3_loss(
x=output,
gt_box=gt_box,
gt_label=gt_label,
gt_score=gt_score,
anchors=anchors,
anchor_mask=anchor_mask,
class_num=num_classes,
ignore_thresh=self._ignore_thresh,
downsample_ratio=self.downsample[i],
use_label_smooth=self._label_smooth,
scale_x_y=scale_x_y,
name=prefix_name + "yolo_loss" + str(i))
losses.append(fluid.layers.reduce_mean(loss))
return {'loss': sum(losses)}
def _get_fine_grained_loss(self,
outputs,
targets,
gt_box,
train_batch_size,
num_classes,
mask_anchors,
ignore_thresh,
eps=1.e-10):
"""
Calculate fine grained YOLOv3 loss
Args:
outputs ([Variables]): List of Variables, output of backbone stages
targets ([Variables]): List of Variables, The targets for yolo
loss calculatation.
gt_box (Variable): The ground-truth boudding boxes.
train_batch_size (int): The training batch size
num_classes (int): class num of dataset
mask_anchors ([[float]]): list of anchors in each output layer
ignore_thresh (float): prediction bbox overlap any gt_box greater
than ignore_thresh, objectness loss will
be ignored.
Returns:
Type: dict
xy_loss (Variable): YOLOv3 (x, y) coordinates loss
wh_loss (Variable): YOLOv3 (w, h) coordinates loss
obj_loss (Variable): YOLOv3 objectness score loss
cls_loss (Variable): YOLOv3 classification loss
"""
assert len(outputs) == len(targets), \
"YOLOv3 output layer number not equal target number"
loss_xys, loss_whs, loss_objs, loss_clss = [], [], [], []
if self._iou_loss is not None:
loss_ious = []
if self._iou_aware_loss is not None:
loss_iou_awares = []
for i, (output, target,
anchors) in enumerate(zip(outputs, targets, mask_anchors)):
downsample = self.downsample[i]
an_num = len(anchors) // 2
if self._iou_aware_loss is not None:
ioup, output = self._split_ioup(output, an_num, num_classes)
x, y, w, h, obj, cls = self._split_output(output, an_num,
num_classes)
tx, ty, tw, th, tscale, tobj, tcls = self._split_target(target)
tscale_tobj = tscale * tobj
scale_x_y = self.scale_x_y if not isinstance(
self.scale_x_y, Sequence) else self.scale_x_y[i]
if (abs(scale_x_y - 1.0) < eps):
loss_x = fluid.layers.sigmoid_cross_entropy_with_logits(
x, tx) * tscale_tobj
loss_x = fluid.layers.reduce_sum(loss_x, dim=[1, 2, 3])
loss_y = fluid.layers.sigmoid_cross_entropy_with_logits(
y, ty) * tscale_tobj
loss_y = fluid.layers.reduce_sum(loss_y, dim=[1, 2, 3])
else:
dx = scale_x_y * fluid.layers.sigmoid(x) - 0.5 * (scale_x_y -
1.0)
dy = scale_x_y * fluid.layers.sigmoid(y) - 0.5 * (scale_x_y -
1.0)
loss_x = fluid.layers.abs(dx - tx) * tscale_tobj
loss_x = fluid.layers.reduce_sum(loss_x, dim=[1, 2, 3])
loss_y = fluid.layers.abs(dy - ty) * tscale_tobj
loss_y = fluid.layers.reduce_sum(loss_y, dim=[1, 2, 3])
# NOTE: we refined loss function of (w, h) as L1Loss
loss_w = fluid.layers.abs(w - tw) * tscale_tobj
loss_w = fluid.layers.reduce_sum(loss_w, dim=[1, 2, 3])
loss_h = fluid.layers.abs(h - th) * tscale_tobj
loss_h = fluid.layers.reduce_sum(loss_h, dim=[1, 2, 3])
if self._iou_loss is not None:
loss_iou = self._iou_loss(
x,
y,
w,
h,
tx,
ty,
tw,
th,
anchors,
downsample,
self._train_batch_size,
scale_x_y=scale_x_y)
loss_iou = loss_iou * tscale_tobj
loss_iou = fluid.layers.reduce_sum(loss_iou, dim=[1, 2, 3])
loss_ious.append(fluid.layers.reduce_mean(loss_iou))
if self._iou_aware_loss is not None:
loss_iou_aware = self._iou_aware_loss(
ioup, x, y, w, h, tx, ty, tw, th, anchors, downsample,
self._train_batch_size, scale_x_y)
loss_iou_aware = loss_iou_aware * tobj
loss_iou_aware = fluid.layers.reduce_sum(
loss_iou_aware, dim=[1, 2, 3])
loss_iou_awares.append(fluid.layers.reduce_mean(loss_iou_aware))
loss_obj_pos, loss_obj_neg = self._calc_obj_loss(
output, obj, tobj, gt_box, self._train_batch_size, anchors,
num_classes, downsample, self._ignore_thresh, scale_x_y)
loss_cls = fluid.layers.sigmoid_cross_entropy_with_logits(cls, tcls)
loss_cls = fluid.layers.elementwise_mul(loss_cls, tobj, axis=0)
loss_cls = fluid.layers.reduce_sum(loss_cls, dim=[1, 2, 3, 4])
loss_xys.append(fluid.layers.reduce_mean(loss_x + loss_y))
loss_whs.append(fluid.layers.reduce_mean(loss_w + loss_h))
loss_objs.append(
fluid.layers.reduce_mean(loss_obj_pos + loss_obj_neg))
loss_clss.append(fluid.layers.reduce_mean(loss_cls))
losses_all = {
"loss_xy": fluid.layers.sum(loss_xys),
"loss_wh": fluid.layers.sum(loss_whs),
"loss_obj": fluid.layers.sum(loss_objs),
"loss_cls": fluid.layers.sum(loss_clss),
}
if self._iou_loss is not None:
losses_all["loss_iou"] = fluid.layers.sum(loss_ious)
if self._iou_aware_loss is not None:
losses_all["loss_iou_aware"] = fluid.layers.sum(loss_iou_awares)
return losses_all
def _split_ioup(self, output, an_num, num_classes):
"""
Split output feature map to output, predicted iou
along channel dimension
"""
ioup = fluid.layers.slice(output, axes=[1], starts=[0], ends=[an_num])
oriout = fluid.layers.slice(
output,
axes=[1],
starts=[an_num],
ends=[an_num * (num_classes + 6)])
return (ioup, oriout)
def _split_output(self, output, an_num, num_classes):
"""
Split output feature map to x, y, w, h, objectness, classification
along channel dimension
"""
x = fluid.layers.strided_slice(
output,
axes=[1],
starts=[0],
ends=[output.shape[1]],
strides=[5 + num_classes])
y = fluid.layers.strided_slice(
output,
axes=[1],
starts=[1],
ends=[output.shape[1]],
strides=[5 + num_classes])
w = fluid.layers.strided_slice(
output,
axes=[1],
starts=[2],
ends=[output.shape[1]],
strides=[5 + num_classes])
h = fluid.layers.strided_slice(
output,
axes=[1],
starts=[3],
ends=[output.shape[1]],
strides=[5 + num_classes])
obj = fluid.layers.strided_slice(
output,
axes=[1],
starts=[4],
ends=[output.shape[1]],
strides=[5 + num_classes])
clss = []
stride = output.shape[1] // an_num
for m in range(an_num):
clss.append(
fluid.layers.slice(
output,
axes=[1],
starts=[stride * m + 5],
ends=[stride * m + 5 + num_classes]))
cls = fluid.layers.transpose(
fluid.layers.stack(
clss, axis=1), perm=[0, 1, 3, 4, 2])
return (x, y, w, h, obj, cls)
def _split_target(self, target):
"""
split target to x, y, w, h, objectness, classification
along dimension 2
target is in shape [N, an_num, 6 + class_num, H, W]
"""
tx = target[:, :, 0, :, :]
ty = target[:, :, 1, :, :]
tw = target[:, :, 2, :, :]
th = target[:, :, 3, :, :]
tscale = target[:, :, 4, :, :]
tobj = target[:, :, 5, :, :]
tcls = fluid.layers.transpose(
target[:, :, 6:, :, :], perm=[0, 1, 3, 4, 2])
tcls.stop_gradient = True
return (tx, ty, tw, th, tscale, tobj, tcls)
def _calc_obj_loss(self, output, obj, tobj, gt_box, batch_size, anchors,
num_classes, downsample, ignore_thresh, scale_x_y):
# A prediction bbox overlap any gt_bbox over ignore_thresh,
# objectness loss will be ignored, process as follows:
# 1. get pred bbox, which is same with YOLOv3 infer mode, use yolo_box here
# NOTE: img_size is set as 1.0 to get noramlized pred bbox
bbox, prob = fluid.layers.yolo_box(
x=output,
img_size=fluid.layers.ones(
shape=[batch_size, 2], dtype="int32"),
anchors=anchors,
class_num=num_classes,
conf_thresh=0.,
downsample_ratio=downsample,
clip_bbox=False,
scale_x_y=scale_x_y)
# 2. split pred bbox and gt bbox by sample, calculate IoU between pred bbox
# and gt bbox in each sample
if batch_size > 1:
preds = fluid.layers.split(bbox, batch_size, dim=0)
gts = fluid.layers.split(gt_box, batch_size, dim=0)
else:
preds = [bbox]
gts = [gt_box]
probs = [prob]
ious = []
for pred, gt in zip(preds, gts):
def box_xywh2xyxy(box):
x = box[:, 0]
y = box[:, 1]
w = box[:, 2]
h = box[:, 3]
return fluid.layers.stack(
[
x - w / 2.,
y - h / 2.,
x + w / 2.,
y + h / 2.,
], axis=1)
pred = fluid.layers.squeeze(pred, axes=[0])
gt = box_xywh2xyxy(fluid.layers.squeeze(gt, axes=[0]))
ious.append(fluid.layers.iou_similarity(pred, gt))
iou = fluid.layers.stack(ious, axis=0)
# 3. Get iou_mask by IoU between gt bbox and prediction bbox,
# Get obj_mask by tobj(holds gt_score), calculate objectness loss
max_iou = fluid.layers.reduce_max(iou, dim=-1)
iou_mask = fluid.layers.cast(max_iou <= ignore_thresh, dtype="float32")
if self.match_score:
max_prob = fluid.layers.reduce_max(prob, dim=-1)
iou_mask = iou_mask * fluid.layers.cast(
max_prob <= 0.25, dtype="float32")
output_shape = fluid.layers.shape(output)
an_num = len(anchors) // 2
iou_mask = fluid.layers.reshape(iou_mask, (-1, an_num, output_shape[2],
output_shape[3]))
iou_mask.stop_gradient = True
# NOTE: tobj holds gt_score, obj_mask holds object existence mask
obj_mask = fluid.layers.cast(tobj > 0., dtype="float32")
obj_mask.stop_gradient = True
# For positive objectness grids, objectness loss should be calculated
# For negative objectness grids, objectness loss is calculated only iou_mask == 1.0
loss_obj = fluid.layers.sigmoid_cross_entropy_with_logits(obj, obj_mask)
loss_obj_pos = fluid.layers.reduce_sum(loss_obj * tobj, dim=[1, 2, 3])
loss_obj_neg = fluid.layers.reduce_sum(
loss_obj * (1.0 - obj_mask) * iou_mask, dim=[1, 2, 3])
return loss_obj_pos, loss_obj_neg