pytorch3d/tests/common_camera_utils.py
Emilien Garreau 29b8ebd802 Add utils to approximate the conical frustums as multivariate gaussians.
Summary:
Introduce methods to approximate the radii of conical frustums along rays as described in [MipNerf](https://arxiv.org/abs/2103.13415):

- Two new attributes are added to ImplicitronRayBundle: bins and radii. Bins is of size n_pts_per_ray + 1. It allows us to manipulate easily and n_pts_per_ray intervals. For example we need the intervals coordinates in the radii computation for \(t_{\mu}, t_{\delta}\). Radii are used to store the radii of the conical frustums.

- Add 3 new methods to compute the radii:
   - approximate_conical_frustum_as_gaussians: It computes the mean along the ray direction, the variance of the
      conical frustum  with respect to t and variance of the conical frustum with respect to its radius. This
      implementation follows the stable computation defined in the paper.
   - compute_3d_diagonal_covariance_gaussian: Will leverage the two previously computed variances to find the
     diagonal covariance of the Gaussian.
   - conical_frustum_to_gaussian: Mix everything together to compute the means and the diagonal covariances along
     the ray of the Gaussians.

- In AbstractMaskRaySampler, introduces the attribute `cast_ray_bundle_as_cone`. If False it won't change the previous behaviour of the RaySampler. However if True, the samplers will sample `n_pts_per_ray +1` instead of `n_pts_per_ray`. This points are then used to set the bins attribute of ImplicitronRayBundle. The support of HeterogeneousRayBundle has not been added since the current code does not allow it. A safeguard has been added to avoid a silent bug in the future.

Reviewed By: shapovalov

Differential Revision: D45269190

fbshipit-source-id: bf22fad12d71d55392f054e3f680013aa0d59b78
2023-07-06 01:55:41 -07:00

78 lines
3.1 KiB
Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.
import typing
import torch
from pytorch3d.common.datatypes import Device
from pytorch3d.renderer.cameras import (
CamerasBase,
FoVOrthographicCameras,
FoVPerspectiveCameras,
OpenGLOrthographicCameras,
OpenGLPerspectiveCameras,
OrthographicCameras,
PerspectiveCameras,
SfMOrthographicCameras,
SfMPerspectiveCameras,
)
from pytorch3d.renderer.fisheyecameras import FishEyeCameras
from pytorch3d.transforms.so3 import so3_exp_map
def init_random_cameras(
cam_type: typing.Type[CamerasBase],
batch_size: int,
random_z: bool = False,
device: Device = "cpu",
):
cam_params = {}
T = torch.randn(batch_size, 3) * 0.03
if not random_z:
T[:, 2] = 4
R = so3_exp_map(torch.randn(batch_size, 3) * 3.0)
cam_params = {"R": R, "T": T, "device": device}
if cam_type in (OpenGLPerspectiveCameras, OpenGLOrthographicCameras):
cam_params["znear"] = torch.rand(batch_size) * 10 + 0.1
cam_params["zfar"] = torch.rand(batch_size) * 4 + 1 + cam_params["znear"]
if cam_type == OpenGLPerspectiveCameras:
cam_params["fov"] = torch.rand(batch_size) * 60 + 30
cam_params["aspect_ratio"] = torch.rand(batch_size) * 0.5 + 0.5
else:
cam_params["top"] = torch.rand(batch_size) * 0.2 + 0.9
cam_params["bottom"] = -(torch.rand(batch_size)) * 0.2 - 0.9
cam_params["left"] = -(torch.rand(batch_size)) * 0.2 - 0.9
cam_params["right"] = torch.rand(batch_size) * 0.2 + 0.9
elif cam_type in (FoVPerspectiveCameras, FoVOrthographicCameras):
cam_params["znear"] = torch.rand(batch_size) * 10 + 0.1
cam_params["zfar"] = torch.rand(batch_size) * 4 + 1 + cam_params["znear"]
if cam_type == FoVPerspectiveCameras:
cam_params["fov"] = torch.rand(batch_size) * 60 + 30
cam_params["aspect_ratio"] = torch.rand(batch_size) * 0.5 + 0.5
else:
cam_params["max_y"] = torch.rand(batch_size) * 0.2 + 0.9
cam_params["min_y"] = -(torch.rand(batch_size)) * 0.2 - 0.9
cam_params["min_x"] = -(torch.rand(batch_size)) * 0.2 - 0.9
cam_params["max_x"] = torch.rand(batch_size) * 0.2 + 0.9
elif cam_type in (
SfMOrthographicCameras,
SfMPerspectiveCameras,
OrthographicCameras,
PerspectiveCameras,
):
cam_params["focal_length"] = torch.rand(batch_size) * 10 + 0.1
cam_params["principal_point"] = torch.randn((batch_size, 2))
elif cam_type == FishEyeCameras:
cam_params["focal_length"] = torch.rand(batch_size, 1) * 10 + 0.1
cam_params["principal_point"] = torch.randn((batch_size, 2))
cam_params["radial_params"] = torch.randn((batch_size, 6))
cam_params["tangential_params"] = torch.randn((batch_size, 2))
cam_params["thin_prism_params"] = torch.randn((batch_size, 4))
else:
raise ValueError(str(cam_type))
return cam_type(**cam_params)