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import paddle
import paddle.nn as nn
import paddle.nn.functional as F
from paddle import ParamAttr
from paddle.regularizer import L2Decay
from paddlers.models.ppdet.core.workspace import register
def _de_sigmoid(x, eps=1e-7):
x = paddle.clip(x, eps, 1. / eps)
x = paddle.clip(1. / x - 1., eps, 1. / eps)
x = -paddle.log(x)
return x
@register
class YOLOv3Head(nn.Layer):
__shared__ = ['num_classes', 'data_format']
__inject__ = ['loss']
def __init__(self,
in_channels=[1024, 512, 256],
anchors=[[10, 13], [16, 30], [33, 23], [30, 61], [62, 45],
[59, 119], [116, 90], [156, 198], [373, 326]],
anchor_masks=[[6, 7, 8], [3, 4, 5], [0, 1, 2]],
num_classes=80,
loss='YOLOv3Loss',
iou_aware=False,
iou_aware_factor=0.4,
data_format='NCHW'):
"""
Head for YOLOv3 network
Args:
num_classes (int): number of foreground classes
anchors (list): anchors
anchor_masks (list): anchor masks
loss (object): YOLOv3Loss instance
iou_aware (bool): whether to use iou_aware
iou_aware_factor (float): iou aware factor
data_format (str): data format, NCHW or NHWC
"""
super(YOLOv3Head, self).__init__()
assert len(in_channels) > 0, "in_channels length should > 0"
self.in_channels = in_channels
self.num_classes = num_classes
self.loss = loss
self.iou_aware = iou_aware
self.iou_aware_factor = iou_aware_factor
self.parse_anchor(anchors, anchor_masks)
self.num_outputs = len(self.anchors)
self.data_format = data_format
self.yolo_outputs = []
for i in range(len(self.anchors)):
if self.iou_aware:
num_filters = len(self.anchors[i]) * (self.num_classes + 6)
else:
num_filters = len(self.anchors[i]) * (self.num_classes + 5)
name = 'yolo_output.{}'.format(i)
conv = nn.Conv2D(
in_channels=self.in_channels[i],
out_channels=num_filters,
kernel_size=1,
stride=1,
padding=0,
data_format=data_format,
bias_attr=ParamAttr(regularizer=L2Decay(0.)))
conv.skip_quant = True
yolo_output = self.add_sublayer(name, conv)
self.yolo_outputs.append(yolo_output)
def parse_anchor(self, anchors, anchor_masks):
self.anchors = [[anchors[i] for i in mask] for mask in anchor_masks]
self.mask_anchors = []
anchor_num = len(anchors)
for masks in anchor_masks:
self.mask_anchors.append([])
for mask in masks:
assert mask < anchor_num, "anchor mask index overflow"
self.mask_anchors[-1].extend(anchors[mask])
def forward(self, feats, targets=None):
assert len(feats) == len(self.anchors)
yolo_outputs = []
for i, feat in enumerate(feats):
yolo_output = self.yolo_outputs[i](feat)
if self.data_format == 'NHWC':
yolo_output = paddle.transpose(yolo_output, [0, 3, 1, 2])
yolo_outputs.append(yolo_output)
if self.training:
return self.loss(yolo_outputs, targets, self.anchors)
else:
if self.iou_aware:
y = []
for i, out in enumerate(yolo_outputs):
na = len(self.anchors[i])
ioup, x = out[:, 0:na, :, :], out[:, na:, :, :]
b, c, h, w = x.shape
no = c // na
x = x.reshape((b, na, no, h * w))
ioup = ioup.reshape((b, na, 1, h * w))
obj = x[:, :, 4:5, :]
ioup = F.sigmoid(ioup)
obj = F.sigmoid(obj)
obj_t = (obj**(1 - self.iou_aware_factor)) * (
ioup**self.iou_aware_factor)
obj_t = _de_sigmoid(obj_t)
loc_t = x[:, :, :4, :]
cls_t = x[:, :, 5:, :]
y_t = paddle.concat([loc_t, obj_t, cls_t], axis=2)
y_t = y_t.reshape((b, c, h, w))
y.append(y_t)
return y
else:
return yolo_outputs
@classmethod
def from_config(cls, cfg, input_shape):
return {'in_channels': [i.channels for i in input_shape], }