AK391
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7734d5b
import torch
import torch.nn as nn
import torch.nn.functional as F
import numpy as np
import cv2
import logging
import torchvision.transforms as transforms
class BasicBlock(nn.Module):
def __init__(self, c_in, c_out, is_downsample=False):
super(BasicBlock, self).__init__()
self.is_downsample = is_downsample
if is_downsample:
self.conv1 = nn.Conv2d(
c_in, c_out, 3, stride=2, padding=1, bias=False)
else:
self.conv1 = nn.Conv2d(
c_in, c_out, 3, stride=1, padding=1, bias=False)
self.bn1 = nn.BatchNorm2d(c_out)
self.relu = nn.ReLU(True)
self.conv2 = nn.Conv2d(c_out, c_out, 3, stride=1,
padding=1, bias=False)
self.bn2 = nn.BatchNorm2d(c_out)
if is_downsample:
self.downsample = nn.Sequential(
nn.Conv2d(c_in, c_out, 1, stride=2, bias=False),
nn.BatchNorm2d(c_out)
)
elif c_in != c_out:
self.downsample = nn.Sequential(
nn.Conv2d(c_in, c_out, 1, stride=1, bias=False),
nn.BatchNorm2d(c_out)
)
self.is_downsample = True
def forward(self, x):
y = self.conv1(x)
y = self.bn1(y)
y = self.relu(y)
y = self.conv2(y)
y = self.bn2(y)
if self.is_downsample:
x = self.downsample(x)
return F.relu(x.add(y), True)
def make_layers(c_in, c_out, repeat_times, is_downsample=False):
blocks = []
for i in range(repeat_times):
if i == 0:
blocks += [BasicBlock(c_in, c_out, is_downsample=is_downsample), ]
else:
blocks += [BasicBlock(c_out, c_out), ]
return nn.Sequential(*blocks)
class Net(nn.Module):
def __init__(self, num_classes=751, reid=False):
super(Net, self).__init__()
# 3 128 64
self.conv = nn.Sequential(
nn.Conv2d(3, 64, 3, stride=1, padding=1),
nn.BatchNorm2d(64),
nn.ReLU(inplace=True),
# nn.Conv2d(32,32,3,stride=1,padding=1),
# nn.BatchNorm2d(32),
# nn.ReLU(inplace=True),
nn.MaxPool2d(3, 2, padding=1),
)
# 32 64 32
self.layer1 = make_layers(64, 64, 2, False)
# 32 64 32
self.layer2 = make_layers(64, 128, 2, True)
# 64 32 16
self.layer3 = make_layers(128, 256, 2, True)
# 128 16 8
self.layer4 = make_layers(256, 512, 2, True)
# 256 8 4
self.avgpool = nn.AvgPool2d((8, 4), 1)
# 256 1 1
self.reid = reid
self.classifier = nn.Sequential(
nn.Linear(512, 256),
nn.BatchNorm1d(256),
nn.ReLU(inplace=True),
nn.Dropout(),
nn.Linear(256, num_classes),
)
def forward(self, x):
x = self.conv(x)
x = self.layer1(x)
x = self.layer2(x)
x = self.layer3(x)
x = self.layer4(x)
x = self.avgpool(x)
x = x.view(x.size(0), -1)
# B x 128
if self.reid:
x = x.div(x.norm(p=2, dim=1, keepdim=True))
return x
# classifier
x = self.classifier(x)
return x
class Extractor(object):
def __init__(self, model_path, use_cuda=True):
self.net = Net(reid=True)
self.device = "cuda" if torch.cuda.is_available() and use_cuda else "cpu"
state_dict = torch.load(model_path, map_location=torch.device(self.device))[
'net_dict']
self.net.load_state_dict(state_dict)
logger = logging.getLogger("root.tracker")
logger.info("Loading weights from {}... Done!".format(model_path))
self.net.to(self.device)
self.size = (64, 128)
self.norm = transforms.Compose([
transforms.ToTensor(),
transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225]),
])
def _preprocess(self, im_crops):
"""
TODO:
1. to float with scale from 0 to 1
2. resize to (64, 128) as Market1501 dataset did
3. concatenate to a numpy array
3. to torch Tensor
4. normalize
"""
def _resize(im, size):
return cv2.resize(im.astype(np.float32)/255., size)
im_batch = torch.cat([self.norm(_resize(im, self.size)).unsqueeze(
0) for im in im_crops], dim=0).float()
return im_batch
def __call__(self, im_crops):
im_batch = self._preprocess(im_crops)
with torch.no_grad():
im_batch = im_batch.to(self.device)
features = self.net(im_batch)
return features.cpu().numpy()