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from pathlib import Path | |
import einops | |
import numpy as np | |
import torch | |
import torch.nn as nn | |
import torch.nn.init as init | |
class PoseNet(nn.Module): | |
"""a tiny conv network for introducing pose sequence as the condition | |
""" | |
def __init__(self, noise_latent_channels=320, *args, **kwargs): | |
super().__init__(*args, **kwargs) | |
# multiple convolution layers | |
self.conv_layers = nn.Sequential( | |
nn.Conv2d(in_channels=3, out_channels=3, kernel_size=3, padding=1), | |
nn.SiLU(), | |
nn.Conv2d(in_channels=3, out_channels=16, kernel_size=4, stride=2, padding=1), | |
nn.SiLU(), | |
nn.Conv2d(in_channels=16, out_channels=16, kernel_size=3, padding=1), | |
nn.SiLU(), | |
nn.Conv2d(in_channels=16, out_channels=32, kernel_size=4, stride=2, padding=1), | |
nn.SiLU(), | |
nn.Conv2d(in_channels=32, out_channels=32, kernel_size=3, padding=1), | |
nn.SiLU(), | |
nn.Conv2d(in_channels=32, out_channels=64, kernel_size=4, stride=2, padding=1), | |
nn.SiLU(), | |
nn.Conv2d(in_channels=64, out_channels=64, kernel_size=3, padding=1), | |
nn.SiLU(), | |
nn.Conv2d(in_channels=64, out_channels=128, kernel_size=3, stride=1, padding=1), | |
nn.SiLU() | |
) | |
# Final projection layer | |
self.final_proj = nn.Conv2d(in_channels=128, out_channels=noise_latent_channels, kernel_size=1) | |
# Initialize layers | |
self._initialize_weights() | |
self.scale = nn.Parameter(torch.ones(1) * 2) | |
def _initialize_weights(self): | |
"""Initialize weights with He. initialization and zero out the biases | |
""" | |
for m in self.conv_layers: | |
if isinstance(m, nn.Conv2d): | |
n = m.kernel_size[0] * m.kernel_size[1] * m.in_channels | |
init.normal_(m.weight, mean=0.0, std=np.sqrt(2. / n)) | |
if m.bias is not None: | |
init.zeros_(m.bias) | |
init.zeros_(self.final_proj.weight) | |
if self.final_proj.bias is not None: | |
init.zeros_(self.final_proj.bias) | |
def forward(self, x): | |
if x.ndim == 5: | |
x = einops.rearrange(x, "b f c h w -> (b f) c h w") | |
x = self.conv_layers(x) | |
x = self.final_proj(x) | |
return x * self.scale | |
def from_pretrained(cls, pretrained_model_path): | |
"""load pretrained pose-net weights | |
""" | |
if not Path(pretrained_model_path).exists(): | |
print(f"There is no model file in {pretrained_model_path}") | |
print(f"loaded PoseNet's pretrained weights from {pretrained_model_path}.") | |
state_dict = torch.load(pretrained_model_path, map_location="cpu") | |
model = PoseNet(noise_latent_channels=320) | |
model.load_state_dict(state_dict, strict=True) | |
return model | |