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GRADE_Dataset / processing_code /utils /extract_camera_data.py
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Document anonymized videos and publish SDK-free processor
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"""Load aligned ZED RGB and metric depth without the ZED SDK."""
from typing import Iterable, Tuple
import cv2
import h5py
import numpy as np
from tqdm import tqdm
def extract_camera_data(
rgb_video_path: str,
depth_h5_path: str,
frame_indices: Iterable[int],
) -> Tuple[np.ndarray, np.ndarray, np.ndarray]:
"""Return selected rectified-left RGB frames and aligned uint16-mm depth.
Frame index zero is the first frame in both files. Depth zero means invalid.
"""
indices = np.unique(np.asarray(list(frame_indices), dtype=np.int64))
if indices.size == 0:
return (np.empty((0, 0, 0, 3), dtype=np.uint8),
np.empty((0, 0, 0), dtype=np.uint16),
np.empty(4, dtype=np.float32))
if indices[0] < 0:
raise ValueError("ZED frame indices must be nonnegative")
with h5py.File(depth_h5_path, "r") as f:
if "depth_mm" not in f:
raise ValueError(f"Missing depth_mm dataset: {depth_h5_path}")
depth = f["depth_mm"]
if depth.ndim != 3 or depth.dtype != np.uint16:
raise ValueError("depth_mm must have shape (frames, height, width) and dtype uint16")
frame_count, height, width = depth.shape
if indices[-1] >= frame_count:
raise ValueError(f"ZED index {indices[-1]} exceeds {frame_count} depth frames")
intrinsics = np.asarray(f.attrs["intrinsics_fx_fy_cx_cy"], dtype=np.float32)
if intrinsics.shape != (4,):
raise ValueError("Invalid ZED intrinsics")
cap = cv2.VideoCapture(rgb_video_path)
if not cap.isOpened():
raise RuntimeError(f"Could not open ZED RGB video: {rgb_video_path}")
try:
video_count = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
if video_count > 0 and video_count != frame_count:
raise ValueError(f"ZED RGB/depth frame count differs: {video_count} vs {frame_count}")
if (int(cap.get(cv2.CAP_PROP_FRAME_WIDTH)),
int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))) != (width, height):
raise ValueError("ZED RGB/depth resolution differs")
rgb_frames = []
depth_frames = []
wanted = set(indices.tolist())
for frame_idx in tqdm(range(int(indices[-1]) + 1), desc="ZED extraction", unit="frame"):
ok, bgr = cap.read()
if not ok:
raise ValueError(f"ZED RGB video ends before frame {frame_idx}")
if frame_idx in wanted:
rgb_frames.append(cv2.cvtColor(bgr, cv2.COLOR_BGR2RGB))
depth_frames.append(depth[frame_idx])
finally:
cap.release()
return np.stack(rgb_frames), np.stack(depth_frames), intrinsics