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import ipdb # noqa: F401
import numpy as np
import torch
import torch.nn as nn
from diffusionsfm.model.dit import DiT
from diffusionsfm.model.feature_extractors import PretrainedVAE, SpatialDino
from diffusionsfm.model.scheduler import NoiseScheduler
class RayDiffuser(nn.Module):
def __init__(
self,
model_type="dit",
depth=8,
width=16,
hidden_size=1152,
P=1,
max_num_images=1,
noise_scheduler=None,
freeze_encoder=True,
feature_extractor="dino",
append_ndc=True,
use_unconditional=False,
diffuse_depths=False,
depth_resolution=1,
use_homogeneous=False,
cond_depth_mask=False,
):
super().__init__()
if noise_scheduler is None:
self.noise_scheduler = NoiseScheduler()
else:
self.noise_scheduler = noise_scheduler
self.diffuse_depths = diffuse_depths
self.depth_resolution = depth_resolution
self.use_homogeneous = use_homogeneous
self.ray_dim = 3
if self.use_homogeneous:
self.ray_dim += 1
self.ray_dim += self.ray_dim * self.depth_resolution**2
if self.diffuse_depths:
self.ray_dim += 1
self.append_ndc = append_ndc
self.width = width
self.max_num_images = max_num_images
self.model_type = model_type
self.use_unconditional = use_unconditional
self.cond_depth_mask = cond_depth_mask
if feature_extractor == "dino":
self.feature_extractor = SpatialDino(
freeze_weights=freeze_encoder, num_patches_x=width, num_patches_y=width
)
self.feature_dim = self.feature_extractor.feature_dim
elif feature_extractor == "vae":
self.feature_extractor = PretrainedVAE(
freeze_weights=freeze_encoder, num_patches_x=width, num_patches_y=width
)
self.feature_dim = self.feature_extractor.feature_dim
else:
raise Exception(f"Unknown feature extractor {feature_extractor}")
if self.use_unconditional:
self.register_parameter(
"null_token", nn.Parameter(torch.randn(self.feature_dim, 1, 1))
)
self.input_dim = self.feature_dim * 2
if self.append_ndc:
self.input_dim += 2
if model_type == "dit":
self.ray_predictor = DiT(
in_channels=self.input_dim,
out_channels=self.ray_dim,
width=width,
depth=depth,
hidden_size=hidden_size,
max_num_images=max_num_images,
P=P,
)
self.scratch = nn.Module()
self.scratch.input_conv = nn.Linear(self.ray_dim + int(self.cond_depth_mask), self.feature_dim)
def forward_noise(
self, x, t, epsilon=None, zero_out_mask=None
):
"""
Applies forward diffusion (adds noise) to the input.
If a mask is provided, the noise is only applied to the masked inputs.
"""
t = t.reshape(-1, 1, 1, 1, 1)
if epsilon is None:
epsilon = torch.randn_like(x)
else:
epsilon = epsilon.reshape(x.shape)
alpha_bar = self.noise_scheduler.alphas_cumprod[t]
x_noise = torch.sqrt(alpha_bar) * x + torch.sqrt(1 - alpha_bar) * epsilon
if zero_out_mask is not None and self.cond_depth_mask:
x_noise = x_noise * zero_out_mask
return x_noise, epsilon
def forward(
self,
features=None,
images=None,
rays=None,
rays_noisy=None,
t=None,
ndc_coordinates=None,
unconditional_mask=None,
return_dpt_activations=False,
depth_mask=None,
):
"""
Args:
images: (B, N, 3, H, W).
t: (B,).
rays: (B, N, 6, H, W).
rays_noisy: (B, N, 6, H, W).
ndc_coordinates: (B, N, 2, H, W).
unconditional_mask: (B, N) or (B,). Should be 1 for unconditional samples
and 0 else.
"""
if features is None:
# VAE expects 256x256 images while DINO expects 224x224 images.
# Both feature extractors support autoresize=True, but ideally we should
# set this to be false and handle in the dataloader.
features = self.feature_extractor(images, autoresize=True)
B = features.shape[0]
if (
unconditional_mask is not None
and self.use_unconditional
):
null_token = self.null_token.reshape(1, 1, self.feature_dim, 1, 1)
unconditional_mask = unconditional_mask.reshape(B, -1, 1, 1, 1)
features = (
features * (1 - unconditional_mask) + null_token * unconditional_mask
)
if isinstance(t, int) or isinstance(t, np.int64):
t = torch.ones(1, dtype=int).to(features.device) * t
else:
t = t.reshape(B)
if rays_noisy is None:
if self.cond_depth_mask:
rays_noisy, epsilon = self.forward_noise(rays, t, zero_out_mask=depth_mask.unsqueeze(2))
else:
rays_noisy, epsilon = self.forward_noise(rays, t)
else:
epsilon = None
if self.cond_depth_mask:
if depth_mask is None:
depth_mask = torch.ones_like(rays_noisy[:, :, 0])
ray_repr = torch.cat([rays_noisy, depth_mask.unsqueeze(2)], dim=2)
else:
ray_repr = rays_noisy
ray_repr = ray_repr.permute(0, 1, 3, 4, 2)
ray_repr = self.scratch.input_conv(ray_repr).permute(0, 1, 4, 2, 3).contiguous()
scene_features = torch.cat([features, ray_repr], dim=2)
if self.append_ndc:
scene_features = torch.cat([scene_features, ndc_coordinates], dim=2)
epsilon_pred = self.ray_predictor(
scene_features,
t,
return_dpt_activations=return_dpt_activations,
)
if return_dpt_activations:
return epsilon_pred, rays_noisy, epsilon
return epsilon_pred, epsilon