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# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
#
# NVIDIA CORPORATION and its licensors retain all intellectual property
# and proprietary rights in and to this software, related documentation
# and any modifications thereto. Any use, reproduction, disclosure or
# distribution of this software and related documentation without an express
# license agreement from NVIDIA CORPORATION is strictly prohibited.
"""Project given image to the latent space of pretrained network pickle."""
import copy
import numpy as np
import torch
import torch.nn.functional as F
from tqdm import tqdm
from configs import global_config, hyperparameters
import dnnlib
from utils.log_utils import log_image_from_w
def project(
G,
target: torch.Tensor, # [C,H,W] and dynamic range [0,255], W & H must match G output resolution
*,
num_steps=1000,
w_avg_samples=10000,
initial_learning_rate=0.01,
initial_noise_factor=0.05,
lr_rampdown_length=0.25,
lr_rampup_length=0.05,
noise_ramp_length=0.75,
regularize_noise_weight=1e5,
verbose=False,
device: torch.device,
use_wandb=False,
initial_w=None,
image_log_step=global_config.image_rec_result_log_snapshot,
w_name: str
):
assert target.shape == (G.img_channels, G.img_resolution, G.img_resolution)
def logprint(*args):
if verbose:
print(*args)
G = copy.deepcopy(G).eval().requires_grad_(False).to(device).float() # type: ignore
# Compute w stats.
logprint(f'Computing W midpoint and stddev using {w_avg_samples} samples...')
z_samples = np.random.RandomState(123).randn(w_avg_samples, G.z_dim)
w_samples = G.mapping(torch.from_numpy(z_samples).to(device), None) # [N, L, C]
w_samples = w_samples[:, :1, :].cpu().numpy().astype(np.float32) # [N, 1, C]
w_avg = np.mean(w_samples, axis=0, keepdims=True) # [1, 1, C]
w_avg_tensor = torch.from_numpy(w_avg).to(global_config.device)
w_std = (np.sum((w_samples - w_avg) ** 2) / w_avg_samples) ** 0.5
start_w = initial_w if initial_w is not None else w_avg
# Setup noise inputs.
noise_bufs = {name: buf for (name, buf) in G.synthesis.named_buffers() if 'noise_const' in name}
# Load VGG16 feature detector.
url = 'https://nvlabs-fi-cdn.nvidia.com/stylegan2-ada-pytorch/pretrained/metrics/vgg16.pt'
with dnnlib.util.open_url(url) as f:
vgg16 = torch.jit.load(f).eval().to(device)
# Features for target image.
target_images = target.unsqueeze(0).to(device).to(torch.float32)
if target_images.shape[2] > 256:
target_images = F.interpolate(target_images, size=(256, 256), mode='area')
target_features = vgg16(target_images, resize_images=False, return_lpips=True)
start_w = np.repeat(start_w, G.mapping.num_ws, axis=1)
w_opt = torch.tensor(start_w, dtype=torch.float32, device=device,
requires_grad=True) # pylint: disable=not-callable
optimizer = torch.optim.Adam([w_opt] + list(noise_bufs.values()), betas=(0.9, 0.999),
lr=hyperparameters.first_inv_lr)
# Init noise.
for buf in noise_bufs.values():
buf[:] = torch.randn_like(buf)
buf.requires_grad = True
for step in tqdm(range(num_steps)):
# Learning rate schedule.
t = step / num_steps
w_noise_scale = w_std * initial_noise_factor * max(0.0, 1.0 - t / noise_ramp_length) ** 2
lr_ramp = min(1.0, (1.0 - t) / lr_rampdown_length)
lr_ramp = 0.5 - 0.5 * np.cos(lr_ramp * np.pi)
lr_ramp = lr_ramp * min(1.0, t / lr_rampup_length)
lr = initial_learning_rate * lr_ramp
for param_group in optimizer.param_groups:
param_group['lr'] = lr
# Synth images from opt_w.
w_noise = torch.randn_like(w_opt) * w_noise_scale
ws = (w_opt + w_noise)
synth_images = G.synthesis(ws, noise_mode='const', force_fp32=True)
# Downsample image to 256x256 if it's larger than that. VGG was built for 224x224 images.
synth_images = (synth_images + 1) * (255 / 2)
if synth_images.shape[2] > 256:
synth_images = F.interpolate(synth_images, size=(256, 256), mode='area')
# Features for synth images.
synth_features = vgg16(synth_images, resize_images=False, return_lpips=True)
dist = (target_features - synth_features).square().sum()
# Noise regularization.
reg_loss = 0.0
for v in noise_bufs.values():
noise = v[None, None, :, :] # must be [1,1,H,W] for F.avg_pool2d()
while True:
reg_loss += (noise * torch.roll(noise, shifts=1, dims=3)).mean() ** 2
reg_loss += (noise * torch.roll(noise, shifts=1, dims=2)).mean() ** 2
if noise.shape[2] <= 8:
break
noise = F.avg_pool2d(noise, kernel_size=2)
loss = dist + reg_loss * regularize_noise_weight
if step % image_log_step == 0:
with torch.no_grad():
if use_wandb:
global_config.training_step += 1
wandb.log({f'first projection _{w_name}': loss.detach().cpu()}, step=global_config.training_step)
log_image_from_w(w_opt, G, w_name)
# Step
optimizer.zero_grad(set_to_none=True)
loss.backward()
optimizer.step()
logprint(f'step {step + 1:>4d}/{num_steps}: dist {dist:<4.2f} loss {float(loss):<5.2f}')
# Normalize noise.
with torch.no_grad():
for buf in noise_bufs.values():
buf -= buf.mean()
buf *= buf.square().mean().rsqrt()
del G
return w_opt
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