resnet 50 第五層 5_1步長改爲1

5_layers = nn.Sequential(
            Bottleneck(1024, 512, downsample=nn.Sequential(nn.Conv2d(1024, 2048, 1, bias=False), nn.BatchNorm2d(2048))),
            Bottleneck(2048, 512),
            Bottleneck(2048, 512))

如果設計自己的網絡，只需要把resnet從torchvision.models.resnet50 裏邊導出來resnet50 ,然後，根據自己的需要 ，重新搭建即可，

self.backbone = nn.Sequential(
            resnet.conv1,
            resnet.bn1,
            resnet.relu,
            resnet.maxpool,
            resnet.layer1,
            resnet.layer2,
            resnet.layer3[0],
        )