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nerfstudio/nerfactory/cameras/utils.py
Ethan Weber 9bc39d895c
Export camera path (#398)
* export button working

* view changes

* adding copy to clipboard feature

* camera choice dropdown

* going to add script saving next

* copy paste working. need to add aspect ratio

* aspect overlay kind of working

* lint

* aspect ratio fixed. version specified

* merge

* openrelay back
2022-09-13 11:33:58 -07:00

478 lines
15 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.
# pylint: skip-file
"""
Camera transformation helper code.
"""
import math
from turtle import width
from typing import List, Literal, Optional, Tuple
import numpy as np
import torch
from torchtyping import TensorType
_EPS = np.finfo(float).eps * 4.0
def unit_vector(data, axis: Optional[int] = None) -> np.ndarray:
"""Return ndarray normalized by length, i.e. Euclidean norm, along axis.
Args:
axis: the axis along which to normalize into unit vector
out: where to write out the data to. If None, returns a new np ndarray
"""
data = np.array(data, dtype=np.float64, copy=True)
if data.ndim == 1:
data /= math.sqrt(np.dot(data, data))
return data
length = np.atleast_1d(np.sum(data * data, axis))
np.sqrt(length, length)
if axis is not None:
length = np.expand_dims(length, axis)
data /= length
return data
def quaternion_from_matrix(matrix, isprecise: bool = False) -> np.ndarray:
"""Return quaternion from rotation matrix.
Args:
matrix: rotation matrix to obtain quaternion
isprecise: if True, input matrix is assumed to be precise rotation matrix and a faster algorithm is used.
"""
M = np.array(matrix, dtype=np.float64, copy=False)[:4, :4]
if isprecise:
q = np.empty((4,))
t = np.trace(M)
if t > M[3, 3]:
q[0] = t
q[3] = M[1, 0] - M[0, 1]
q[2] = M[0, 2] - M[2, 0]
q[1] = M[2, 1] - M[1, 2]
else:
i, j, k = 1, 2, 3
if M[1, 1] > M[0, 0]:
i, j, k = 2, 3, 1
if M[2, 2] > M[i, i]:
i, j, k = 3, 1, 2
t = M[i, i] - (M[j, j] + M[k, k]) + M[3, 3]
q[i] = t
q[j] = M[i, j] + M[j, i]
q[k] = M[k, i] + M[i, k]
q[3] = M[k, j] - M[j, k]
q *= 0.5 / math.sqrt(t * M[3, 3])
else:
m00 = M[0, 0]
m01 = M[0, 1]
m02 = M[0, 2]
m10 = M[1, 0]
m11 = M[1, 1]
m12 = M[1, 2]
m20 = M[2, 0]
m21 = M[2, 1]
m22 = M[2, 2]
# symmetric matrix K
K = np.array(
[
[m00 - m11 - m22, 0.0, 0.0, 0.0],
[m01 + m10, m11 - m00 - m22, 0.0, 0.0],
[m02 + m20, m12 + m21, m22 - m00 - m11, 0.0],
[m21 - m12, m02 - m20, m10 - m01, m00 + m11 + m22],
]
)
K /= 3.0
# quaternion is eigenvector of K that corresponds to largest eigenvalue
w, V = np.linalg.eigh(K)
q = V[np.array([3, 0, 1, 2]), np.argmax(w)]
if q[0] < 0.0:
np.negative(q, q)
return q
def quaternion_slerp(quat0, quat1, fraction: float, spin: int = 0, shortestpath: bool = True) -> np.ndarray:
"""Return spherical linear interpolation between two quaternions.
Args:
quat0: first quaternion
quat1: second quaternion
fraction: how much to interpolate between quat0 vs quat1 (if 0, closer to quat0; if 1, closer to quat1)
spin: how much of an additional spin to place on the interpolation
shortestpath: whether to return the short or long path to rotation
"""
q0 = unit_vector(quat0[:4])
q1 = unit_vector(quat1[:4])
if q0 is None or q1 is None:
raise ValueError("Input quaternions invalid.")
if fraction == 0.0:
return q0
elif fraction == 1.0:
return q1
d = np.dot(q0, q1)
if abs(abs(d) - 1.0) < _EPS:
return q0
if shortestpath and d < 0.0:
# invert rotation
d = -d
np.negative(q1, q1)
angle = math.acos(d) + spin * math.pi
if abs(angle) < _EPS:
return q0
isin = 1.0 / math.sin(angle)
q0 *= math.sin((1.0 - fraction) * angle) * isin
q1 *= math.sin(fraction * angle) * isin
q0 += q1
return q0
def quaternion_matrix(quaternion) -> np.ndarray:
"""Return homogeneous rotation matrix from quaternion.
Args:
quaternion: value to convert to matrix
"""
q = np.array(quaternion, dtype=np.float64, copy=True)
n = np.dot(q, q)
if n < _EPS:
return np.identity(4)
q *= math.sqrt(2.0 / n)
q = np.outer(q, q)
return np.array(
[
[1.0 - q[2, 2] - q[3, 3], q[1, 2] - q[3, 0], q[1, 3] + q[2, 0], 0.0],
[q[1, 2] + q[3, 0], 1.0 - q[1, 1] - q[3, 3], q[2, 3] - q[1, 0], 0.0],
[q[1, 3] - q[2, 0], q[2, 3] + q[1, 0], 1.0 - q[1, 1] - q[2, 2], 0.0],
[0.0, 0.0, 0.0, 1.0],
]
)
def get_interpolated_poses(poseA, poseB, steps: int = 10) -> List[float]:
"""Return interpolation of poses with specified number of steps.
Args:
poseA: first pose
poseB: second pose
steps: number of steps the interpolated pose path should contain
"""
quatA = quaternion_from_matrix(poseA[:3, :3])
quatB = quaternion_from_matrix(poseB[:3, :3])
ts = np.linspace(0, 1, steps)
quats = [quaternion_slerp(quatA, quatB, t) for t in ts]
trans = [(1 - t) * poseA[:3, 3] + t * poseB[:3, 3] for t in ts]
posesAB = []
for quat, tran in zip(quats, trans):
pose = np.identity(4)
pose[:3, :3] = quaternion_matrix(quat)[:3, :3]
pose[:3, 3] = tran
posesAB.append(pose)
return posesAB
def get_interpolated_K(KA, KB, steps: int = 10) -> TensorType[3, 4]:
"""
Returns interpolated path between two camera poses with specified number of steps.
Args:
KA: camera matrix 1
KB: camera matrix 2
steps: number of steps the interpolated pose path should contain
"""
Ks = []
ts = np.linspace(0, 1, steps)
for t in ts:
newK = KA * (1.0 - t) + KB * t
Ks.append(newK)
return Ks
def get_interpolated_poses_many(
poses: TensorType["num_poses", 3, 4],
Ks: TensorType["num_poses", 3, 3],
steps_per_transition=10,
) -> Tuple[TensorType["num_poses", 3, 4], TensorType["num_poses", 3, 3]]:
"""Return interpolated poses for many camera poses.
Args:
poses: list of camera poses
Ks: list of camera intrinsics
steps_per_transition: number of steps per transition
Returns:
tuple of new poses and intrinsics
"""
traj = []
Ks = []
for idx in range(poses.shape[0] - 1):
poseA = poses[idx]
poseB = poses[idx + 1]
posesAB = get_interpolated_poses(poseA, poseB, steps=steps_per_transition)
traj += posesAB
Ks += get_interpolated_K(Ks[idx], Ks[idx + 1], steps_per_transition)
return torch.stack(traj, dim=0), torch.stack(Ks, dim=0)
def get_swirl_poses(pose):
"""
Returns a swirl around the camera poses.
# TODO(ethan): add parameters and make this work + add docstrings + return type
"""
N_frames = 30 * 4
dx = np.linspace(0, 0.03, N_frames)
dy = np.linspace(0, -0.1, N_frames)
dz = np.linspace(0, 0.5, N_frames)
poses = np.tile(pose, (N_frames, 1, 1))
for i in range(N_frames):
poses[i, 0, 3] += dx[i]
poses[i, 1, 3] += dy[i]
poses[i, 2, 3] += dz[i]
return poses
def normalize(x) -> TensorType[...]:
"""Returns a normalized vector."""
return x / torch.linalg.norm(x)
def viewmatrix(lookat, up, pos) -> TensorType[...]:
"""Returns a camera transformation matrix.
Args:
lookat: The direction the camera is looking.
up: The upward direction of the camera.
pos: The position of the camera.
Returns:
A camera transformation matrix.
"""
vec2 = normalize(lookat)
vec1_avg = normalize(up)
vec0 = normalize(torch.cross(vec1_avg, vec2))
vec1 = normalize(torch.cross(vec2, vec0))
m = torch.stack([vec0, vec1, vec2, pos], 1)
return m
def get_distortion_params(
k1: float = 0.0,
k2: float = 0.0,
k3: float = 0.0,
k4: float = 0.0,
p1: float = 0.0,
p2: float = 0.0,
) -> TensorType[...]:
"""Returns a distortion parameters matrix.
Args:
k1: The first radial distortion parameter.
k2: The second radial distortion parameter.
k3: The third radial distortion parameter.
k4: The fourth radial distortion parameter.
p1: The first tangential distortion parameter.
p2: The second tangential distortion parameter.
Returns:
torch.Tensor: A distortion parameters matrix.
"""
return torch.Tensor([k1, k2, k3, k4, p1, p2])
def radial_and_tangential_undistort(
coords: TensorType["num_coords":..., 2],
distortion_params: TensorType["num_coords":..., 6],
eps: float = 1e-9,
max_iterations=10,
) -> TensorType["num_coords":..., 2]:
"""Computes undistorted coords given opencv distortion parameters.
Addapted from MultiNeRF
https://github.com/google-research/multinerf/blob/b02228160d3179300c7d499dca28cb9ca3677f32/internal/camera_utils.py#L477-L509
Args:
coords: The distorted coordinates.
distortion_params: The distortion parameters [k1, k2, k3, k4, p1, p2].
eps: The epsilon for the convergence.
max_iterations: The maximum number of iterations to perform.
Returns:
The undistorted coordinates.
"""
# Initialize from the distorted point.
x = torch.clone(coords[..., 0])
y = torch.clone(coords[..., 1])
for _ in range(max_iterations):
fx, fy, fx_x, fx_y, fy_x, fy_y = _compute_residual_and_jacobian(
x=x, y=y, xd=coords[..., 0], yd=coords[..., 1], distortion_params=distortion_params
)
denominator = fy_x * fx_y - fx_x * fy_y
x_numerator = fx * fy_y - fy * fx_y
y_numerator = fy * fx_x - fx * fy_x
step_x = torch.where(torch.abs(denominator) > eps, x_numerator / denominator, torch.zeros_like(denominator))
step_y = torch.where(torch.abs(denominator) > eps, y_numerator / denominator, torch.zeros_like(denominator))
x = x + step_x
y = y + step_y
return torch.stack([x, y], dim=-1)
def _compute_residual_and_jacobian(
x: TensorType["num_coords":...],
y: TensorType["num_coords":...],
xd: TensorType["num_coords":...],
yd: TensorType["num_coords":...],
distortion_params: TensorType["num_coords":..., 6],
) -> Tuple[
TensorType["num_coords":...],
TensorType["num_coords":...],
TensorType["num_coords":...],
TensorType["num_coords":...],
TensorType["num_coords":...],
TensorType["num_coords":...],
]:
"""Auxiliary function of radial_and_tangential_undistort() that computes residuals and jacobians.
Adapted from MultiNeRF:
https://github.com/google-research/multinerf/blob/b02228160d3179300c7d499dca28cb9ca3677f32/internal/camera_utils.py#L427-L474
Args:
x: The updated x coordinates.
y: The updated y coordinates.
xd: The distorted x coordinates.
yd: The distorted y coordinates.
distortion_params: The distortion parameters [k1, k2, k3, k4, p1, p2].
Returns:
The residuals (fx, fy) and jacobians (fx_x, fx_y, fy_x, fy_y).
"""
k1 = distortion_params[..., 0]
k2 = distortion_params[..., 1]
k3 = distortion_params[..., 2]
k4 = distortion_params[..., 3]
p1 = distortion_params[..., 4]
p2 = distortion_params[..., 5]
# let r(x, y) = x^2 + y^2;
# d(x, y) = 1 + k1 * r(x, y) + k2 * r(x, y) ^2 + k3 * r(x, y)^3 +
# k4 * r(x, y)^4;
r = x * x + y * y
d = 1.0 + r * (k1 + r * (k2 + r * (k3 + r * k4)))
# The perfect projection is:
# xd = x * d(x, y) + 2 * p1 * x * y + p2 * (r(x, y) + 2 * x^2);
# yd = y * d(x, y) + 2 * p2 * x * y + p1 * (r(x, y) + 2 * y^2);
#
# Let's define
#
# fx(x, y) = x * d(x, y) + 2 * p1 * x * y + p2 * (r(x, y) + 2 * x^2) - xd;
# fy(x, y) = y * d(x, y) + 2 * p2 * x * y + p1 * (r(x, y) + 2 * y^2) - yd;
#
# We are looking for a solution that satisfies
# fx(x, y) = fy(x, y) = 0;
fx = d * x + 2 * p1 * x * y + p2 * (r + 2 * x * x) - xd
fy = d * y + 2 * p2 * x * y + p1 * (r + 2 * y * y) - yd
# Compute derivative of d over [x, y]
d_r = k1 + r * (2.0 * k2 + r * (3.0 * k3 + r * 4.0 * k4))
d_x = 2.0 * x * d_r
d_y = 2.0 * y * d_r
# Compute derivative of fx over x and y.
fx_x = d + d_x * x + 2.0 * p1 * y + 6.0 * p2 * x
fx_y = d_y * x + 2.0 * p1 * x + 2.0 * p2 * y
# Compute derivative of fy over x and y.
fy_x = d_x * y + 2.0 * p2 * y + 2.0 * p1 * x
fy_y = d + d_y * y + 2.0 * p2 * x + 6.0 * p1 * y
return fx, fy, fx_x, fx_y, fy_x, fy_y
def rotation_matrix(a: TensorType[3], b: TensorType[3]) -> TensorType[3, 3]:
"""Compute the rotation matrix that rotates vector a to vector b.
Args:
a: The vector to rotate.
b: The vector to rotate to.
Returns:
The rotation matrix.
"""
a = a / torch.linalg.norm(a)
b = b / torch.linalg.norm(b)
v = torch.cross(a, b)
c = torch.dot(a, b)
# If vectors are exactly opposite, we add a little noise to one of them
if c < -1 + 1e-8:
eps = (torch.rand(3) - 0.5) * 0.01
return rotmat(a + eps, b)
s = torch.linalg.norm(v)
skew_sym_mat = torch.Tensor(
[
[0, -v[2], v[1]],
[v[2], 0, -v[0]],
[-v[1], v[0], 0],
]
)
return torch.eye(3) + skew_sym_mat + skew_sym_mat @ skew_sym_mat * ((1 - c) / (s**2 + 1e-8))
def auto_orient_poses(
poses: TensorType["num_poses":..., 4, 4], method: Literal["pca", "up"] = "up"
) -> TensorType["num_poses":..., 3, 4]:
"""Orients and centers the poses. We provide two methods for orientation: pca and up.
pca: Orient the poses so that the principal component of the points is aligned with the axes.
This method works well when all of the cameras are in the same plane.
up: Orient the poses so that the average up vector is aligned with the z axis.
This method works well when images are not at arbitrary angles.
Args:
poses: The poses to orient.
method: The method to use for orientation. Either "pca" or "up".
Returns:
The oriented poses.
"""
translation = poses[..., :3, 3]
mean_translation = torch.mean(translation, dim=0)
translation = translation - mean_translation
if method == "pca":
_, eigvec = torch.linalg.eigh(translation.T @ translation)
eigvec = torch.flip(eigvec, dims=(-1,))
if torch.linalg.det(eigvec) < 0:
eigvec[:, 2] = -eigvec[:, 2]
transform = torch.cat([eigvec, eigvec @ -mean_translation[..., None]], dim=-1)
oriented_poses = transform @ poses
if oriented_poses.mean(axis=0)[2, 1] < 0:
oriented_poses[:, 1:3] = -1 * oriented_poses[:, 1:3]
elif method == "up":
up = torch.mean(poses[:, :3, 1], dim=0)
up = up / torch.linalg.norm(up)
rotation = rotation_matrix(up, torch.Tensor([0, 0, 1]))
transform = torch.cat([rotation, rotation @ -mean_translation[..., None]], dim=-1)
oriented_poses = transform @ poses
return oriented_poses