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lingbot-map/lingbot_map/utils/pose_enc.py
LinZhuoChen f9b3ae457a first commit
2026-04-16 09:51:30 +08:00

331 lines
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Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
import torch
from .rotation import quat_to_mat, mat_to_quat
import os
import torch
import numpy as np
import gzip
import json
import random
import logging
import warnings
from lingbot_map.utils.geometry import closed_form_inverse_se3, closed_form_inverse_se3_general
def extri_intri_to_pose_encoding(
extrinsics, intrinsics, image_size_hw=None, pose_encoding_type="absT_quaR_FoV" # e.g., (256, 512)
):
"""Convert camera extrinsics and intrinsics to a compact pose encoding.
This function transforms camera parameters into a unified pose encoding format,
which can be used for various downstream tasks like pose prediction or representation.
Args:
extrinsics (torch.Tensor): Camera extrinsic parameters with shape BxSx3x4,
where B is batch size and S is sequence length.
In OpenCV coordinate system (x-right, y-down, z-forward), representing camera from world transformation.
The format is [R|t] where R is a 3x3 rotation matrix and t is a 3x1 translation vector.
intrinsics (torch.Tensor): Camera intrinsic parameters with shape BxSx3x3.
Defined in pixels, with format:
[[fx, 0, cx],
[0, fy, cy],
[0, 0, 1]]
where fx, fy are focal lengths and (cx, cy) is the principal point
image_size_hw (tuple): Tuple of (height, width) of the image in pixels.
Required for computing field of view values. For example: (256, 512).
pose_encoding_type (str): Type of pose encoding to use. Currently only
supports "absT_quaR_FoV" (absolute translation, quaternion rotation, field of view).
Returns:
torch.Tensor: Encoded camera pose parameters with shape BxSx9.
For "absT_quaR_FoV" type, the 9 dimensions are:
- [:3] = absolute translation vector T (3D)
- [3:7] = rotation as quaternion quat (4D)
- [7:] = field of view (2D)
"""
# extrinsics: BxSx3x4
# intrinsics: BxSx3x3
if pose_encoding_type == "absT_quaR_FoV":
R = extrinsics[:, :, :3, :3] # BxSx3x3
T = extrinsics[:, :, :3, 3] # BxSx3
quat = mat_to_quat(R)
# Note the order of h and w here
H, W = image_size_hw
fov_h = 2 * torch.atan((H / 2) / intrinsics[..., 1, 1])
fov_w = 2 * torch.atan((W / 2) / intrinsics[..., 0, 0])
pose_encoding = torch.cat([T, quat, fov_h[..., None], fov_w[..., None]], dim=-1).float()
else:
raise NotImplementedError
return pose_encoding
def pose_encoding_to_extri_intri(
pose_encoding, image_size_hw=None, pose_encoding_type="absT_quaR_FoV", build_intrinsics=True # e.g., (256, 512)
):
"""Convert a pose encoding back to camera extrinsics and intrinsics.
This function performs the inverse operation of extri_intri_to_pose_encoding,
reconstructing the full camera parameters from the compact encoding.
Args:
pose_encoding (torch.Tensor): Encoded camera pose parameters with shape BxSx9,
where B is batch size and S is sequence length.
For "absT_quaR_FoV" type, the 9 dimensions are:
- [:3] = absolute translation vector T (3D)
- [3:7] = rotation as quaternion quat (4D)
- [7:] = field of view (2D)
image_size_hw (tuple): Tuple of (height, width) of the image in pixels.
Required for reconstructing intrinsics from field of view values.
For example: (256, 512).
pose_encoding_type (str): Type of pose encoding used. Currently only
supports "absT_quaR_FoV" (absolute translation, quaternion rotation, field of view).
build_intrinsics (bool): Whether to reconstruct the intrinsics matrix.
If False, only extrinsics are returned and intrinsics will be None.
Returns:
tuple: (extrinsics, intrinsics)
- extrinsics (torch.Tensor): Camera extrinsic parameters with shape BxSx3x4.
In OpenCV coordinate system (x-right, y-down, z-forward), representing camera from world
transformation. The format is [R|t] where R is a 3x3 rotation matrix and t is
a 3x1 translation vector.
- intrinsics (torch.Tensor or None): Camera intrinsic parameters with shape BxSx3x3,
or None if build_intrinsics is False. Defined in pixels, with format:
[[fx, 0, cx],
[0, fy, cy],
[0, 0, 1]]
where fx, fy are focal lengths and (cx, cy) is the principal point,
assumed to be at the center of the image (W/2, H/2).
"""
intrinsics = None
if pose_encoding_type == "absT_quaR_FoV":
T = pose_encoding[..., :3]
quat = pose_encoding[..., 3:7]
fov_h = pose_encoding[..., 7]
fov_w = pose_encoding[..., 8]
R = quat_to_mat(quat)
extrinsics = torch.cat([R, T[..., None]], dim=-1)
if build_intrinsics:
H, W = image_size_hw
fy = (H / 2.0) / torch.tan(fov_h / 2.0)
fx = (W / 2.0) / torch.tan(fov_w / 2.0)
intrinsics = torch.zeros(pose_encoding.shape[:2] + (3, 3), device=pose_encoding.device)
intrinsics[..., 0, 0] = fx
intrinsics[..., 1, 1] = fy
intrinsics[..., 0, 2] = W / 2
intrinsics[..., 1, 2] = H / 2
intrinsics[..., 2, 2] = 1.0 # Set the homogeneous coordinate to 1
elif pose_encoding_type == "absT_quaR":
T = pose_encoding[..., :3]
quat = pose_encoding[..., 3:7]
R = quat_to_mat(quat)
extrinsics = torch.cat([R, T[..., None]], dim=-1)
intrinsics = None
return extrinsics, intrinsics
def convert_pt3d_RT_to_opencv(Rot, Trans):
"""
Convert Point3D extrinsic matrices to OpenCV convention.
Args:
Rot: 3D rotation matrix in Point3D format
Trans: 3D translation vector in Point3D format
Returns:
extri_opencv: 3x4 extrinsic matrix in OpenCV format
"""
rot_pt3d = np.array(Rot)
trans_pt3d = np.array(Trans)
trans_pt3d[:2] *= -1
rot_pt3d[:, :2] *= -1
rot_pt3d = rot_pt3d.transpose(1, 0)
extri_opencv = np.hstack((rot_pt3d, trans_pt3d[:, None]))
return extri_opencv
def build_pair_index(N, B=1):
"""
Build indices for all possible pairs of frames.
Args:
N: Number of frames
B: Batch size
Returns:
i1, i2: Indices for all possible pairs
"""
i1_, i2_ = torch.combinations(torch.arange(N), 2, with_replacement=False).unbind(-1)
i1, i2 = [(i[None] + torch.arange(B)[:, None] * N).reshape(-1) for i in [i1_, i2_]]
return i1, i2
def rotation_angle(rot_gt, rot_pred, batch_size=None, eps=1e-15):
"""
Calculate rotation angle error between ground truth and predicted rotations.
Args:
rot_gt: Ground truth rotation matrices
rot_pred: Predicted rotation matrices
batch_size: Batch size for reshaping the result
eps: Small value to avoid numerical issues
Returns:
Rotation angle error in degrees
"""
q_pred = mat_to_quat(rot_pred)
q_gt = mat_to_quat(rot_gt)
loss_q = (1 - (q_pred * q_gt).sum(dim=1) ** 2).clamp(min=eps)
err_q = torch.arccos(1 - 2 * loss_q)
rel_rangle_deg = err_q * 180 / np.pi
if batch_size is not None:
rel_rangle_deg = rel_rangle_deg.reshape(batch_size, -1)
return rel_rangle_deg
def translation_angle(tvec_gt, tvec_pred, batch_size=None, ambiguity=True):
"""
Calculate translation angle error between ground truth and predicted translations.
Args:
tvec_gt: Ground truth translation vectors
tvec_pred: Predicted translation vectors
batch_size: Batch size for reshaping the result
ambiguity: Whether to handle direction ambiguity
Returns:
Translation angle error in degrees
"""
rel_tangle_deg = compare_translation_by_angle(tvec_gt, tvec_pred)
rel_tangle_deg = rel_tangle_deg * 180.0 / np.pi
if ambiguity:
rel_tangle_deg = torch.min(rel_tangle_deg, (180 - rel_tangle_deg).abs())
if batch_size is not None:
rel_tangle_deg = rel_tangle_deg.reshape(batch_size, -1)
return rel_tangle_deg
def compare_translation_by_angle(t_gt, t, eps=1e-15, default_err=1e6):
"""
Normalize the translation vectors and compute the angle between them.
Args:
t_gt: Ground truth translation vectors
t: Predicted translation vectors
eps: Small value to avoid division by zero
default_err: Default error value for invalid cases
Returns:
Angular error between translation vectors in radians
"""
t_norm = torch.norm(t, dim=1, keepdim=True)
t = t / (t_norm + eps)
t_gt_norm = torch.norm(t_gt, dim=1, keepdim=True)
t_gt = t_gt / (t_gt_norm + eps)
loss_t = torch.clamp_min(1.0 - torch.sum(t * t_gt, dim=1) ** 2, eps)
err_t = torch.acos(torch.sqrt(1 - loss_t))
err_t[torch.isnan(err_t) | torch.isinf(err_t)] = default_err
return err_t
def calculate_auc_np(r_error, t_error, max_threshold=30):
"""
Calculate the Area Under the Curve (AUC) for the given error arrays using NumPy.
Args:
r_error: numpy array representing R error values (Degree)
t_error: numpy array representing T error values (Degree)
max_threshold: Maximum threshold value for binning the histogram
Returns:
AUC value and the normalized histogram
"""
error_matrix = np.concatenate((r_error[:, None], t_error[:, None]), axis=1)
max_errors = np.max(error_matrix, axis=1)
bins = np.arange(max_threshold + 1)
histogram, _ = np.histogram(max_errors, bins=bins)
num_pairs = float(len(max_errors))
normalized_histogram = histogram.astype(float) / num_pairs
return np.mean(np.cumsum(normalized_histogram)), normalized_histogram
def se3_to_relative_pose_error(pred_se3, gt_se3, num_frames):
"""
Compute rotation and translation errors between predicted and ground truth poses.
This function assumes the input poses are world-to-camera (w2c) transformations.
Args:
pred_se3: Predicted SE(3) transformations (w2c), shape (N, 4, 4)
gt_se3: Ground truth SE(3) transformations (w2c), shape (N, 4, 4)
num_frames: Number of frames (N)
Returns:
Rotation and translation angle errors in degrees
"""
pair_idx_i1, pair_idx_i2 = build_pair_index(num_frames)
relative_pose_gt = gt_se3[pair_idx_i1].bmm(
closed_form_inverse_se3(gt_se3[pair_idx_i2])
)
relative_pose_pred = pred_se3[pair_idx_i1].bmm(
closed_form_inverse_se3(pred_se3[pair_idx_i2])
)
rel_rangle_deg = rotation_angle(
relative_pose_gt[:, :3, :3], relative_pose_pred[:, :3, :3]
)
rel_tangle_deg = translation_angle(
relative_pose_gt[:, :3, 3], relative_pose_pred[:, :3, 3]
)
return rel_rangle_deg, rel_tangle_deg
def colmap_to_opencv_intrinsics(K):
"""
Modify camera intrinsics to follow a different convention.
Coordinates of the center of the top-left pixels are by default:
- (0.5, 0.5) in Colmap
- (0,0) in OpenCV
"""
K = K.copy()
K[..., 0, 2] -= 0.5
K[..., 1, 2] -= 0.5
return K
def read_camera_parameters(filename):
with open(filename) as f:
lines = f.readlines()
lines = [line.rstrip() for line in lines]
# extrinsics: line [1,5), 4x4 matrix
extrinsics = np.fromstring(' '.join(lines[1:5]), dtype=np.float32, sep=' ').reshape((4, 4))
# intrinsics: line [7-10), 3x3 matrix
intrinsics = np.fromstring(' '.join(lines[7:10]), dtype=np.float32, sep=' ').reshape((3, 3))
return intrinsics, extrinsics