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model/loss.py

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+import torch
+import numpy as np
+import torch.nn as nn
+import torch.nn.functional as F
+import torchvision.models as models
+
+device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+
+
+class EPE(nn.Module):
+    def __init__(self):
+        super(EPE, self).__init__()
+
+    def forward(self, flow, gt, loss_mask):
+        loss_map = (flow - gt.detach()) ** 2
+        loss_map = (loss_map.sum(1, True) + 1e-6) ** 0.5
+        return (loss_map * loss_mask)
+
+
+class Ternary(nn.Module):
+    def __init__(self):
+        super(Ternary, self).__init__()
+        patch_size = 7
+        out_channels = patch_size * patch_size
+        self.w = np.eye(out_channels).reshape(
+            (patch_size, patch_size, 1, out_channels))
+        self.w = np.transpose(self.w, (3, 2, 0, 1))
+        self.w = torch.tensor(self.w).float().to(device)
+
+    def transform(self, img):
+        patches = F.conv2d(img, self.w, padding=3, bias=None)
+        transf = patches - img
+        transf_norm = transf / torch.sqrt(0.81 + transf**2)
+        return transf_norm
+
+    def rgb2gray(self, rgb):
+        r, g, b = rgb[:, 0:1, :, :], rgb[:, 1:2, :, :], rgb[:, 2:3, :, :]
+        gray = 0.2989 * r + 0.5870 * g + 0.1140 * b
+        return gray
+
+    def hamming(self, t1, t2):
+        dist = (t1 - t2) ** 2
+        dist_norm = torch.mean(dist / (0.1 + dist), 1, True)
+        return dist_norm
+
+    def valid_mask(self, t, padding):
+        n, _, h, w = t.size()
+        inner = torch.ones(n, 1, h - 2 * padding, w - 2 * padding).type_as(t)
+        mask = F.pad(inner, [padding] * 4)
+        return mask
+
+    def forward(self, img0, img1):
+        img0 = self.transform(self.rgb2gray(img0))
+        img1 = self.transform(self.rgb2gray(img1))
+        return self.hamming(img0, img1) * self.valid_mask(img0, 1)
+
+
+class SOBEL(nn.Module):
+    def __init__(self):
+        super(SOBEL, self).__init__()
+        self.kernelX = torch.tensor([
+            [1, 0, -1],
+            [2, 0, -2],
+            [1, 0, -1],
+        ]).float()
+        self.kernelY = self.kernelX.clone().T
+        self.kernelX = self.kernelX.unsqueeze(0).unsqueeze(0).to(device)
+        self.kernelY = self.kernelY.unsqueeze(0).unsqueeze(0).to(device)
+
+    def forward(self, pred, gt):
+        N, C, H, W = pred.shape[0], pred.shape[1], pred.shape[2], pred.shape[3]
+        img_stack = torch.cat(
+            [pred.reshape(N*C, 1, H, W), gt.reshape(N*C, 1, H, W)], 0)
+        sobel_stack_x = F.conv2d(img_stack, self.kernelX, padding=1)
+        sobel_stack_y = F.conv2d(img_stack, self.kernelY, padding=1)
+        pred_X, gt_X = sobel_stack_x[:N*C], sobel_stack_x[N*C:]
+        pred_Y, gt_Y = sobel_stack_y[:N*C], sobel_stack_y[N*C:]
+
+        L1X, L1Y = torch.abs(pred_X-gt_X), torch.abs(pred_Y-gt_Y)
+        loss = (L1X+L1Y)
+        return loss
+
+class MeanShift(nn.Conv2d):
+    def __init__(self, data_mean, data_std, data_range=1, norm=True):
+        c = len(data_mean)
+        super(MeanShift, self).__init__(c, c, kernel_size=1)
+        std = torch.Tensor(data_std)
+        self.weight.data = torch.eye(c).view(c, c, 1, 1)
+        if norm:
+            self.weight.data.div_(std.view(c, 1, 1, 1))
+            self.bias.data = -1 * data_range * torch.Tensor(data_mean)
+            self.bias.data.div_(std)
+        else:
+            self.weight.data.mul_(std.view(c, 1, 1, 1))
+            self.bias.data = data_range * torch.Tensor(data_mean)
+        self.requires_grad = False
+            
+class VGGPerceptualLoss(torch.nn.Module):
+    def __init__(self, rank=0):
+        super(VGGPerceptualLoss, self).__init__()
+        blocks = []
+        pretrained = True
+        self.vgg_pretrained_features = models.vgg19(pretrained=pretrained).features
+        self.normalize = MeanShift([0.485, 0.456, 0.406], [0.229, 0.224, 0.225], norm=True).cuda()
+        for param in self.parameters():
+            param.requires_grad = False
+
+    def forward(self, X, Y, indices=None):
+        X = self.normalize(X)
+        Y = self.normalize(Y)
+        indices = [2, 7, 12, 21, 30]
+        weights = [1.0/2.6, 1.0/4.8, 1.0/3.7, 1.0/5.6, 10/1.5]
+        k = 0
+        loss = 0
+        for i in range(indices[-1]):
+            X = self.vgg_pretrained_features[i](X)
+            Y = self.vgg_pretrained_features[i](Y)
+            if (i+1) in indices:
+                loss += weights[k] * (X - Y.detach()).abs().mean() * 0.1
+                k += 1
+        return loss
+
+if __name__ == '__main__':
+    img0 = torch.zeros(3, 3, 256, 256).float().to(device)
+    img1 = torch.tensor(np.random.normal(
+        0, 1, (3, 3, 256, 256))).float().to(device)
+    ternary_loss = Ternary()
+    print(ternary_loss(img0, img1).shape)

model/warplayer.py

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+import torch
+import torch.nn as nn
+
+device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+backwarp_tenGrid = {}
+
+
+def warp(tenInput, tenFlow):
+    k = (str(tenFlow.device), str(tenFlow.size()))
+    if k not in backwarp_tenGrid:
+        tenHorizontal = torch.linspace(-1.0, 1.0, tenFlow.shape[3], device=device).view(
+            1, 1, 1, tenFlow.shape[3]).expand(tenFlow.shape[0], -1, tenFlow.shape[2], -1)
+        tenVertical = torch.linspace(-1.0, 1.0, tenFlow.shape[2], device=device).view(
+            1, 1, tenFlow.shape[2], 1).expand(tenFlow.shape[0], -1, -1, tenFlow.shape[3])
+        backwarp_tenGrid[k] = torch.cat(
+            [tenHorizontal, tenVertical], 1).to(device)
+
+    tenFlow = torch.cat([tenFlow[:, 0:1, :, :] / ((tenInput.shape[3] - 1.0) / 2.0),
+                         tenFlow[:, 1:2, :, :] / ((tenInput.shape[2] - 1.0) / 2.0)], 1)
+
+    g = (backwarp_tenGrid[k] + tenFlow).permute(0, 2, 3, 1)
+    return torch.nn.functional.grid_sample(input=tenInput, grid=g, mode='bilinear', padding_mode='border', align_corners=True)