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# coding: utf-8 | |
""" | |
Warping field estimator(W) defined in the paper, which generates a warping field using the implicit | |
keypoint representations x_s and x_d, and employs this flow field to warp the source feature volume f_s. | |
""" | |
from torch import nn | |
import torch.nn.functional as F | |
from .util import SameBlock2d | |
from .dense_motion import DenseMotionNetwork | |
class WarpingNetwork(nn.Module): | |
def __init__( | |
self, | |
num_kp, | |
block_expansion, | |
max_features, | |
num_down_blocks, | |
reshape_channel, | |
estimate_occlusion_map=False, | |
dense_motion_params=None, | |
**kwargs | |
): | |
super(WarpingNetwork, self).__init__() | |
self.upscale = kwargs.get('upscale', 1) | |
self.flag_use_occlusion_map = kwargs.get('flag_use_occlusion_map', True) | |
if dense_motion_params is not None: | |
self.dense_motion_network = DenseMotionNetwork( | |
num_kp=num_kp, | |
feature_channel=reshape_channel, | |
estimate_occlusion_map=estimate_occlusion_map, | |
**dense_motion_params | |
) | |
else: | |
self.dense_motion_network = None | |
self.third = SameBlock2d(max_features, block_expansion * (2 ** num_down_blocks), kernel_size=(3, 3), padding=(1, 1), lrelu=True) | |
self.fourth = nn.Conv2d(in_channels=block_expansion * (2 ** num_down_blocks), out_channels=block_expansion * (2 ** num_down_blocks), kernel_size=1, stride=1) | |
self.estimate_occlusion_map = estimate_occlusion_map | |
def deform_input(self, inp, deformation): | |
return F.grid_sample(inp, deformation, align_corners=False) | |
def forward(self, feature_3d, kp_driving, kp_source): | |
if self.dense_motion_network is not None: | |
# Feature warper, Transforming feature representation according to deformation and occlusion | |
dense_motion = self.dense_motion_network( | |
feature=feature_3d, kp_driving=kp_driving, kp_source=kp_source | |
) | |
if 'occlusion_map' in dense_motion: | |
occlusion_map = dense_motion['occlusion_map'] # Bx1x64x64 | |
else: | |
occlusion_map = None | |
deformation = dense_motion['deformation'] # Bx16x64x64x3 | |
out = self.deform_input(feature_3d, deformation) # Bx32x16x64x64 | |
bs, c, d, h, w = out.shape # Bx32x16x64x64 | |
out = out.view(bs, c * d, h, w) # -> Bx512x64x64 | |
out = self.third(out) # -> Bx256x64x64 | |
out = self.fourth(out) # -> Bx256x64x64 | |
if self.flag_use_occlusion_map and (occlusion_map is not None): | |
out = out * occlusion_map | |
ret_dct = { | |
'occlusion_map': occlusion_map, | |
'deformation': deformation, | |
'out': out, | |
} | |
return ret_dct | |