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| from torch import nn | |
| import torch.nn.functional as F | |
| import torch | |
| from modules.util import Hourglass, AntiAliasInterpolation2d, make_coordinate_grid, kp2gaussian | |
| class DenseMotionNetwork(nn.Module): | |
| """ | |
| Module that predicting a dense motion from sparse motion representation given by kp_source and kp_driving | |
| """ | |
| def __init__(self, block_expansion, num_blocks, max_features, num_kp, num_channels, estimate_occlusion_map=False, | |
| scale_factor=1, kp_variance=0.01): | |
| super(DenseMotionNetwork, self).__init__() | |
| self.hourglass = Hourglass(block_expansion=block_expansion, in_features=(num_kp + 1) * (num_channels + 1), | |
| max_features=max_features, num_blocks=num_blocks) | |
| self.mask = nn.Conv2d(self.hourglass.out_filters, num_kp + 1, kernel_size=(7, 7), padding=(3, 3)) | |
| if estimate_occlusion_map: | |
| self.occlusion = nn.Conv2d(self.hourglass.out_filters, 1, kernel_size=(7, 7), padding=(3, 3)) | |
| else: | |
| self.occlusion = None | |
| self.num_kp = num_kp | |
| self.scale_factor = scale_factor | |
| self.kp_variance = kp_variance | |
| if self.scale_factor != 1: | |
| self.down = AntiAliasInterpolation2d(num_channels, self.scale_factor) | |
| def create_heatmap_representations(self, source_image, kp_driving, kp_source): | |
| """ | |
| Eq 6. in the paper H_k(z) | |
| """ | |
| spatial_size = source_image.shape[2:] | |
| gaussian_driving = kp2gaussian(kp_driving, spatial_size=spatial_size, kp_variance=self.kp_variance) | |
| gaussian_source = kp2gaussian(kp_source, spatial_size=spatial_size, kp_variance=self.kp_variance) | |
| heatmap = gaussian_driving - gaussian_source | |
| #adding background feature | |
| zeros = torch.zeros(heatmap.shape[0], 1, spatial_size[0], spatial_size[1]).type(heatmap.type()) | |
| heatmap = torch.cat([zeros, heatmap], dim=1) | |
| heatmap = heatmap.unsqueeze(2) | |
| return heatmap | |
| def create_sparse_motions(self, source_image, kp_driving, kp_source): | |
| """ | |
| Eq 4. in the paper T_{s<-d}(z) | |
| """ | |
| bs, _, h, w = source_image.shape | |
| identity_grid = make_coordinate_grid((h, w), type=kp_source['value'].type()) | |
| identity_grid = identity_grid.view(1, 1, h, w, 2) | |
| coordinate_grid = identity_grid - kp_driving['value'].view(bs, self.num_kp, 1, 1, 2) | |
| if 'jacobian' in kp_driving: | |
| jacobian = torch.matmul(kp_source['jacobian'], torch.inverse(kp_driving['jacobian'])) | |
| jacobian = jacobian.unsqueeze(-3).unsqueeze(-3) | |
| jacobian = jacobian.repeat(1, 1, h, w, 1, 1) | |
| coordinate_grid = torch.matmul(jacobian, coordinate_grid.unsqueeze(-1)) | |
| coordinate_grid = coordinate_grid.squeeze(-1) | |
| driving_to_source = coordinate_grid + kp_source['value'].view(bs, self.num_kp, 1, 1, 2) | |
| #adding background feature | |
| identity_grid = identity_grid.repeat(bs, 1, 1, 1, 1) | |
| sparse_motions = torch.cat([identity_grid, driving_to_source], dim=1) | |
| return sparse_motions | |
| def create_deformed_source_image(self, source_image, sparse_motions): | |
| """ | |
| Eq 7. in the paper \hat{T}_{s<-d}(z) | |
| """ | |
| bs, _, h, w = source_image.shape | |
| source_repeat = source_image.unsqueeze(1).unsqueeze(1).repeat(1, self.num_kp + 1, 1, 1, 1, 1) | |
| source_repeat = source_repeat.view(bs * (self.num_kp + 1), -1, h, w) | |
| sparse_motions = sparse_motions.view((bs * (self.num_kp + 1), h, w, -1)) | |
| sparse_deformed = F.grid_sample(source_repeat, sparse_motions) | |
| sparse_deformed = sparse_deformed.view((bs, self.num_kp + 1, -1, h, w)) | |
| return sparse_deformed | |
| def forward(self, source_image, kp_driving, kp_source): | |
| if self.scale_factor != 1: | |
| source_image = self.down(source_image) | |
| bs, _, h, w = source_image.shape | |
| out_dict = dict() | |
| heatmap_representation = self.create_heatmap_representations(source_image, kp_driving, kp_source) | |
| sparse_motion = self.create_sparse_motions(source_image, kp_driving, kp_source) | |
| deformed_source = self.create_deformed_source_image(source_image, sparse_motion) | |
| out_dict['sparse_deformed'] = deformed_source | |
| input = torch.cat([heatmap_representation, deformed_source], dim=2) | |
| input = input.view(bs, -1, h, w) | |
| prediction = self.hourglass(input) | |
| mask = self.mask(prediction) | |
| mask = F.softmax(mask, dim=1) | |
| out_dict['mask'] = mask | |
| mask = mask.unsqueeze(2) | |
| sparse_motion = sparse_motion.permute(0, 1, 4, 2, 3) | |
| deformation = (sparse_motion * mask).sum(dim=1) | |
| deformation = deformation.permute(0, 2, 3, 1) | |
| out_dict['deformation'] = deformation | |
| # Sec. 3.2 in the paper | |
| if self.occlusion: | |
| occlusion_map = torch.sigmoid(self.occlusion(prediction)) | |
| out_dict['occlusion_map'] = occlusion_map | |
| return out_dict | |