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Vide Restoration using Deep Learning
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# adapted from: https://github.com/fastai/course-v3/blob/master/nbs/dl1/lesson7-superres.ipynb | |
t = data.valid_ds[0][1].data | |
t = torch.stack([t,t]) | |
def gram_matrix(x): | |
n,c,h,w = x.size() | |
x = x.view(n, c, -1) | |
return (x @ x.transpose(1,2))/(c*h*w) | |
base_loss = F.l1_loss | |
vgg_m = vgg16_bn(True).features.cuda().eval() | |
requires_grad(vgg_m, False) | |
blocks = [i-1 for i,o in enumerate(children(vgg_m)) if isinstance(o,nn.MaxPool2d)] | |
blocks, [vgg_m[i] for i in blocks] | |
class FeatureLoss(nn.Module): | |
def __init__(self, m_feat, layer_ids, layer_wgts): | |
super().__init__() | |
self.m_feat = m_feat | |
self.loss_features = [self.m_feat[i] for i in layer_ids] | |
self.hooks = hook_outputs(self.loss_features, detach=False) | |
self.wgts = layer_wgts | |
self.metric_names = ['pixel',] + [f'feat_{i}' for i in range(len(layer_ids)) | |
] + [f'gram_{i}' for i in range(len(layer_ids))] | |
def make_features(self, x, clone=False): | |
self.m_feat(x) | |
return [(o.clone() if clone else o) for o in self.hooks.stored] | |
def forward(self, input, target): | |
out_feat = self.make_features(target, clone=True) | |
in_feat = self.make_features(input) | |
self.feat_losses = [base_loss(input,target)] | |
self.feat_losses += [base_loss(f_in, f_out)*w | |
for f_in, f_out, w in zip(in_feat, out_feat, self.wgts)] | |
self.feat_losses += [base_loss(gram_matrix(f_in), gram_matrix(f_out))*w**2 * 5e3 | |
for f_in, f_out, w in zip(in_feat, out_feat, self.wgts)] | |
self.metrics = dict(zip(self.metric_names, self.feat_losses)) | |
return sum(self.feat_losses) | |
def __del__(self): self.hooks.remove() | |
feat_loss = FeatureLoss(vgg_m, blocks[2:5], [5,15,2]) |
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