| import torch |
| import torch.nn as nn |
| import torchvision |
|
|
| |
| class VGG19(torch.nn.Module): |
| def __init__(self, requires_grad=False): |
| super().__init__() |
| vgg_pretrained_features = torchvision.models.vgg19(pretrained=True).features |
| self.slice1 = torch.nn.Sequential() |
| self.slice2 = torch.nn.Sequential() |
| self.slice3 = torch.nn.Sequential() |
| self.slice4 = torch.nn.Sequential() |
| self.slice5 = torch.nn.Sequential() |
| self.slice6 = torch.nn.Sequential() |
| for x in range(2): |
| self.slice1.add_module(str(x), vgg_pretrained_features[x]) |
| for x in range(2, 7): |
| self.slice2.add_module(str(x), vgg_pretrained_features[x]) |
| for x in range(7, 12): |
| self.slice3.add_module(str(x), vgg_pretrained_features[x]) |
| for x in range(12, 21): |
| self.slice4.add_module(str(x), vgg_pretrained_features[x]) |
| for x in range(21, 32): |
| self.slice5.add_module(str(x), vgg_pretrained_features[x]) |
| for x in range(32, 36): |
| self.slice6.add_module(str(x), vgg_pretrained_features[x]) |
| if not requires_grad: |
| for param in self.parameters(): |
| param.requires_grad = False |
| |
| self.pool = nn.AdaptiveAvgPool2d(output_size=1) |
| |
| self.mean = torch.tensor([0.485, 0.456, 0.406]).view(1,-1, 1, 1).cuda() * 2 - 1 |
| self.std = torch.tensor([0.229, 0.224, 0.225]).view(1,-1, 1, 1).cuda() * 2 |
|
|
| def forward(self, X): |
| X = (X-self.mean)/self.std |
| h_relu1 = self.slice1(X) |
| h_relu2 = self.slice2(h_relu1) |
| h_relu3 = self.slice3(h_relu2) |
| h_relu4 = self.slice4(h_relu3) |
| h_relu5 = self.slice5[:-2](h_relu4) |
| out = [h_relu1, h_relu2, h_relu3, h_relu4, h_relu5] |
| return out |
| |
| |
| class VGGLoss(nn.Module): |
| def __init__(self): |
| super(VGGLoss, self).__init__() |
| self.vgg = VGG19().cuda() |
| self.criterion = nn.L1Loss() |
| self.weights = [1.0 / 32, 1.0 / 16, 1.0 / 8, 1.0 / 4, 1.0] |
|
|
| def forward(self, x, y): |
| x_vgg, y_vgg = self.vgg(x), self.vgg(y) |
| loss = 0 |
| for i in range(len(x_vgg)): |
| loss += self.weights[i] * self.criterion(x_vgg[i], y_vgg[i].detach()) |
| return loss |
