https://mp.weixin.qq.com/s?__biz=MzA3MzI4MjgzMw==&mid=2650736740&idx=3&sn=cdce446703e69b47cf48f12b3d451afc&chksm=871acc1ab06d450ccde3148df96436c98adb2de3b6a34559b95af322c5186513460329dc20bd&pass_ticket=fRFENbG47o6E12opTV0zxlHKhCFDxvRrZMSQpTw%2BcZ9h0Z38WqvICgwk5ynPYCBm#rd后RCNN时代的物体检测及实例分割进展
def conv3x3(in_channels, out_channels, stride=1):
return nn.Conv2d(in_channels, out_channels, kernel_size=3,
stride=stride, padding=1, bias=False) class ResidualBlock(nn.Module):
def __init__(self, in_channels, out_channels, stride=1, downsample=None):
super(ResidualBlock, self).__init__()
self.conv1 = conv3x3(in_channels, out_channels, stride)
self.bn1 = nn.BatchNorm2d(out_channels)
self.relu = nn.ReLU(inplace=True)
self.conv2 = conv3x3(out_channels, out_channels, stride)
self.bn2 = nn.BatchNorm2d(out_channels)
self.downsample = downsample def forward(self, x):
residual = x
out = self.conv1(x)
out = self.bn1(out)
out = self.relu(out)
out = self.conv2(out)
out = self.bn2(out)
if self.downsample:
residual = self.downsample(residual) out += residual
out = self.relu(out)
return out class ResNet(nn.Module):
def __init__(self, block, layers, num_classes=10):
super(ResNet, self).__init__()
self.in_channels = 16
self.conv = conv3x3(1, 16)
self.bn = nn.BatchNorm2d(16)
#self.relu = nn.Relu(inplace=True)
self.relu = nn.ReLU(inplace=True)
self.layers1 = self.make_layers(block, 16, layers[0])
self.layers2 = self.make_layers(block, 32, layers[1])
self.layers3 = self.make_layers(block, 64, layers[2])
self.avg_pool = nn.AvgPool2d(8)
self.fc = nn.Linear(64, num_classes) def make_layers(self, block, out_channels, blocks, stride=1):
downsample = None
if(stride!=1) or (self.in_channels != out_channels):
downsample = nn.Sequential(conv3x3(self.in_channels, out_channels, stride = stride),
nn.BatchNorm2d(out_channels)) layers = []
layers.append(block(self.in_channels, out_channels, stride, downsample))
self.in_channels = out_channels
for i in range(blocks):
layers.append(block(self.in_channels, out_channels, stride, downsample)) return nn.Sequential(*layers) def forward(self, x):
out = self.conv(x)
out = self.bn(out)
out = self.relu(out)
out = self.layers1(out)
out = self.layers2(out)
out = self.layers3(out)
out = self.avg_pool(out)
out = self.fc(out) return out resnet = ResNet(ResidualBlock, layers=[2, 2, 2, 2])