vis_preprocessed.py

"""
bash:

python vis_preprocessed.py --npy ./Replica_OCC/preprocessed/office0.npy
"""

import argparse
import numpy as np
import open3d as o3d

def colorize_labels(labels: np.ndarray) -> np.ndarray:
    """Deterministic pseudo-colors for integer labels."""
    labels = labels.astype(np.int64)
    # simple hash -> [0,1]
    r = ((labels * 97) % 255) / 255.0
    g = ((labels * 57) % 255) / 255.0
    b = ((labels * 17) % 255) / 255.0
    return np.stack([r, g, b], axis=1)

def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--npy", type=str, required=True, help="path to preprocessed/<scene>.npy")
    ap.add_argument("--max_points", type=int, default=300000, help="downsample for visualization")
    args = ap.parse_args()

    v = np.load(args.npy)  # (N,7)
    xyz = v[:, :3].astype(np.float32)
    lab = v[:, 6].astype(np.int32)

    # remove empty
    mask = lab > 0
    xyz = xyz[mask]
    lab = lab[mask]

    # random downsample for speed
    if xyz.shape[0] > args.max_points:
        idx = np.random.choice(xyz.shape[0], args.max_points, replace=False)
        xyz = xyz[idx]
        lab = lab[idx]

    colors = colorize_labels(lab)

    pcd = o3d.geometry.PointCloud()
    pcd.points = o3d.utility.Vector3dVector(xyz)
    pcd.colors = o3d.utility.Vector3dVector(colors)
    print("points:", np.asarray(pcd.points).shape[0], "unique labels:", len(np.unique(lab)))

    o3d.visualization.draw_geometries([pcd])

if __name__ == "__main__":
    main()