Files
nerfstudio/nerfactory/models/modules/ray_losses.py
T
evonneng d50c71ac43 update docstrings and random cleanups (#387)
* fixing docstrings and small nits; up to fileds

* finished adding and fixing docstrings
2022-09-10 23:09:44 -07:00

53 lines
2.0 KiB
Python

# Copyright 2022 The Plenoptix Team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Collection of Ray Losses"""
import torch
from torchtyping import TensorType
from nerfactory.cameras.rays import RaySamples
def distortion_loss(
ray_samples: RaySamples, densities: TensorType["bs":..., "num_samples", 1]
) -> TensorType["bs":..., 1]:
"""Ray baserd distortion loss proposed in MipNeRF-360. Returns distortion Loss.
.. math::
\\mathcal{L}(\\mathbf{s}, \\mathbf{w}) =\\iint\\limits_{-\\infty}^{\\,\\,\\,\\infty}
\\mathbf{w}_\\mathbf{s}(u)\\mathbf{w}_\\mathbf{s}(v)|u - v|\\,d_{u}\\,d_{v}
where :math:`\\mathbf{w}_\\mathbf{s}(u)=\\sum_i w_i \\mathbb{1}_{[\\mathbf{s}_i, \\mathbf{s}_{i+1})}(u)`
is the weight at location :math:`u` between bin locations :math:`s_i` and :math:`s_{i+1}`.
Args:
ray_samples: Ray samples to compute loss over
densities: Predicted sample densities
"""
# Compute the weight at each sample location
weights = ray_samples.get_weights(densities)
midpoints = (ray_samples.frustums.starts + ray_samples.frustums.ends) / 2.0 # (..., num_samples, 1)
loss = (
weights * weights[..., None, :, 0] * torch.abs(midpoints - midpoints[..., None, :, 0])
) # (..., num_samples, num_samples)
loss = torch.sum(loss, dim=(-1, -2))[..., None] # (..., num_samples)
loss = loss + 1 / 3.0 * torch.sum(weights**2 * (ray_samples.frustums.ends - ray_samples.frustums.starts), dim=-2)
return loss