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GST.py
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GST.py
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import torch
import torch.nn as nn
import math
import torch.utils.model_zoo as model_zoo
import torchvision.models as models
__all__ = ['ResNet', 'resnet50', 'resnet101','resnet152']
model_urls = {
'resnet18': 'https://download.pytorch.org/models/resnet18-5c106cde.pth',
'resnet34': 'https://download.pytorch.org/models/resnet34-333f7ec4.pth',
'resnet50': 'https://download.pytorch.org/models/resnet50-19c8e357.pth',
'resnet101': 'https://download.pytorch.org/models/resnet101-5d3b4d8f.pth',
'resnet152': 'https://download.pytorch.org/models/resnet152-b121ed2d.pth',
}
class Bottleneck(nn.Module):
expansion = 4
def __init__(self, inplanes, planes, alpha, beta, stride = 1, downsample = None):
super(Bottleneck, self).__init__()
self.conv1 = nn.Conv3d(inplanes, planes, kernel_size=1, bias=False) #定义一个逐点卷积进行通道融合
self.bn1 = nn.BatchNorm3d(planes) #定义一个3DBN操作
#定义2D的空间卷积Kernal_size = 1X3X3
self.conv2 = nn.Conv3d(planes// beta, planes//alpha*(alpha-1), kernel_size=(1,3,3), stride=(1,stride,stride),
padding=(0,1,1), bias=False)
#定义时间卷积Kernal_size = 3X3X3
self.Tconv = nn.Conv3d(planes//beta, planes//alpha, kernel_size = 3, bias = False,stride=(1,stride,stride), #时域使用的3D卷积并未使用
padding = (1,1,1))
self.bn2 = nn.BatchNorm3d(planes)#通道数没变!经过GST后通道数还是planes
self.conv3 = nn.Conv3d(planes, planes * self.expansion, kernel_size=1, bias=False) #再一次进行3D的逐点卷积扩充通道
self.bn3 = nn.BatchNorm3d(planes * self.expansion)#在一次进行3DBN
self.relu = nn.ReLU(inplace=True)
self.downsample = downsample
self.stride = stride
self.alpha = alpha
self.beta = beta
def forward(self, x):
residual = x
out = self.conv1(x)
out = self.bn1(out)
out = self.relu(out) #out ==> [batch_size,C,T,W,H]
if self.beta == 2:
nchannels = out.size()[1] // self.beta #out.size()[1]即为输出的通道数
left = out[:,:nchannels] #将通道进行拆分
right = out[:,nchannels:]
out1 = self.conv2(left)
out2 = self.Tconv(right)
else:
out1 = self.conv2(out)
out2 = self.Tconv(out)
out = torch.cat((out1,out2),dim=1) #在通道维度上进行拼接索引1即为通道
out = self.bn2(out)
out = self.relu(out)
out = self.conv3(out)
out = self.bn3(out)
if self.downsample is not None:
residual = self.downsample(residual)
out += residual #加上残差
out = self.relu(out) #再进行激活一次
return out
class ResNet(nn.Module):
def __init__(self, block, layers, alpha, beta, num_classes=1000):
self.inplanes = 64
super(ResNet, self).__init__()
self.conv1 = nn.Conv3d(3, 64, kernel_size=(1,7,7), stride=(1,2,2), padding=(0,3,3),
bias=False)
self.bn1 = nn.BatchNorm3d(64)
self.relu = nn.ReLU(inplace=True) #定义Relu激活
self.maxpool = nn.MaxPool3d(kernel_size=(1,3,3), stride=(1,2,2), padding=(0,1,1))
self.layer1 = self._make_layer(block, 64, layers[0], alpha, beta)
self.layer2 = self._make_layer(block, 128, layers[1], alpha, beta, stride=2)
self.layer3 = self._make_layer(block, 256, layers[2], alpha, beta, stride=2)
self.layer4 = self._make_layer(block, 512, layers[3], alpha, beta, stride=2)
self.avgpool = nn.AvgPool2d(7, stride=1)
self.fc = nn.Linear(512 * block.expansion, num_classes)
for m in self.modules():
if isinstance(m, nn.Conv3d):
nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
elif isinstance(m, nn.BatchNorm3d):
nn.init.constant_(m.weight, 1)
nn.init.constant_(m.bias, 0)
def _make_layer(self, block, planes, blocks, alpha, beta, stride=1):
downsample = None
if stride != 1 or self.inplanes != planes * block.expansion:
downsample = nn.Sequential(
nn.Conv3d(self.inplanes, planes * block.expansion,
kernel_size=1, stride=(1,stride,stride), bias=False),
nn.BatchNorm3d(planes * block.expansion),
)
layers = []
layers.append(block(self.inplanes, planes, alpha, beta, stride, downsample))
self.inplanes = planes * block.expansion
for i in range(1, blocks):
layers.append(block(self.inplanes, planes, alpha, beta))
return nn.Sequential(*layers)
def forward(self, x):
x = self.conv1(x)
x = self.bn1(x)
x = self.relu(x)
x = self.maxpool(x)
x = self.layer1(x)
x = self.layer2(x)
x = self.layer3(x)
x = self.layer4(x)
print("layer4_out.size()",x.size())
x = x.transpose(1,2).contiguous()
x = x.view((-1,)+x.size()[2:]) #resize成(N*T,C,W,H)
print("x.view()",x.size())
x = self.avgpool(x)
print("avg:",x.size())
x = x.view(x.size(0), -1)
x = self.fc(x)
print("out.size():",x.size())
return x
def resnet50(alpha, beta,**kwargs):
"""Constructs a ResNet-50 based model.
"""
model = ResNet(Bottleneck, [3, 4, 6, 3], alpha, beta, **kwargs)
checkpoint = model_zoo.load_url(model_urls['resnet50'],model_dir='./pretrained/') #加载Imagenet预训练的模型参数
layer_name = list(checkpoint.keys()) #checkpoint是一个字典{'layer_name','权重tensor'}
for ln in layer_name:
if 'conv' in ln or 'downsample.0.weight' in ln:
checkpoint[ln] = checkpoint[ln].unsqueeze(2) #扩充维度,很重要!
if 'conv2' in ln:
n_out, n_in, _, _, _ = checkpoint[ln].size()
checkpoint[ln] = checkpoint[ln][:n_out // alpha * (alpha - 1), :n_in//beta,:,:,:]
model.load_state_dict(checkpoint,strict = False)
return model
def resnet101(alpha, beta):
"""Constructs a ResNet-101 model.
Args:
groups
"""
model = ResNet(Bottleneck, [3, 4, 23, 3], alpha,beta)
checkpoint = model_zoo.load_url(model_urls['resnet101'],model_dir='./pretrained/')
layer_name = list(checkpoint.keys())
for ln in layer_name:
if 'conv' in ln or 'downsample.0.weight' in ln:
checkpoint[ln] = checkpoint[ln].unsqueeze(2)
if 'conv2' in ln:
n_out, n_in, _, _, _ = checkpoint[ln].size()
checkpoint[ln] = checkpoint[ln][:n_out // alpha * (alpha - 1),:n_in//beta,:,:,:] #保留空间通道的预训练权重。
model.load_state_dict(checkpoint,strict = False)
return model
if __name__ == '__main__':
model = resnet50(8,2)
Input = torch.randn([1, 3, 8, 224, 224]) # N,C,T,W,H
out = model(Input)