File size: 3,572 Bytes
c1a4584 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 | #!/usr/bin/env python3
"""
Convert a per-frame layout JSON from pose frame to camera frame.
Applies the same transformation as visualize_mesh_3d_video.py:
1. Reorder translation [tx,ty,tz] -> [tz,tx,ty] and scale by --translation-scale
2. Convert rotation and translation from pose frame (x-fwd, y-left, z-up)
to camera frame (x-right, y-down, z-fwd)
Usage:
python convert_layout_to_camera_frame.py \
--input /path/to/video_dir/obj_tracking_out/<object>/combined_visualization/layout.json \
--output /path/to/video_dir/obj_tracking_out/<object>/combined_visualization/layout_camera_frame.json
"""
import argparse
import json
import numpy as np
from scipy.spatial.transform import Rotation as R
# Pose frame -> Camera frame rotation matrix (for row vectors: v_cam = v_pose @ P)
# x_cam = -y_pose, y_cam = -z_pose, z_cam = x_pose
P = np.array([
[0, 0, 1],
[-1, 0, 0],
[0, -1, 0],
], dtype=np.float64)
def convert_translation(tx, ty, tz, translation_scale):
"""Reorder and scale translation, then convert to camera frame."""
# Reorder as done in visualize_mesh_3d_video.py
t_pose = np.array([tz * translation_scale, tx * translation_scale, ty * translation_scale])
# Convert to camera frame: v_cam = v_pose @ P
t_cam = t_pose @ P
return t_cam.tolist()
def convert_rotation(quat_wxyz):
"""Convert rotation from pose frame to camera frame."""
# new_quat is wxyz
quat_xyzw = [quat_wxyz[1], quat_wxyz[2], quat_wxyz[3], quat_wxyz[0]]
R_pose = R.from_quat(quat_xyzw).as_matrix()
# R_cam = P.T @ R_pose (change of basis)
R_cam = P.T @ R_pose
quat_cam_xyzw = R.from_matrix(R_cam).as_quat() # returns xyzw
quat_cam_wxyz = [float(quat_cam_xyzw[3]), float(quat_cam_xyzw[0]),
float(quat_cam_xyzw[1]), float(quat_cam_xyzw[2])]
return quat_cam_wxyz
def main():
parser = argparse.ArgumentParser(
description='Convert layout JSON poses from pose frame to camera frame.',
formatter_class=argparse.ArgumentDefaultsHelpFormatter,
)
parser.add_argument('--input', type=str, required=True, help='Input layout JSON')
parser.add_argument('--output', type=str, required=True, help='Output layout JSON')
parser.add_argument('--scale', type=float, default=None,
help='Mesh scale (written to output for reference, does not affect transform)')
parser.add_argument('--translation-scale', type=float, default=1.0,
help='Scale factor for translation values')
args = parser.parse_args()
with open(args.input) as f:
data = json.load(f)
for obj in data["objects"]:
pose = obj["local_to_scene"]
tx, ty, tz = pose["translation"]
quat_wxyz = pose["new_quat"]
t_cam = convert_translation(tx, ty, tz, args.translation_scale)
q_cam = convert_rotation(quat_wxyz)
pose["translation_camera_frame"] = t_cam
pose["quat_wxyz_camera_frame"] = q_cam
data["frame"] = "camera_frame"
data["note"] = (
"Poses converted to camera frame (x-right, y-down, z-fwd). "
f"translation_scale={args.translation_scale}. "
"Original pose-frame values preserved."
)
if args.scale is not None:
data["mesh_scale"] = args.scale
with open(args.output, 'w') as f:
json.dump(data, f, indent=2)
num = len([o for o in data["objects"] if "frame_idx" in o or "frame_index" in o])
print(f"Converted {num} frames to camera frame -> {args.output}")
if __name__ == "__main__":
main()
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