================================================================================ Huhb3D Compatibility Report Depth Maps & Camera Intrinsics - OpenCV / ROS / Blender / BOP ================================================================================ === 1. OPENCV COMPATIBILITY === cam_K as 3x3 matrix (OpenCV cameraMatrix): [761.267 0.000 400.000] [0.000 761.267 300.000] [0.000 0.000 1.000] distCoeffs = None (pinhole, no distortion) [OK] Standard pinhole model, directly usable with cv2.solvePnP() cv2.Rodrigues(R_m2c) -> rvec = [-1.533229, -0.960920, 1.533148] [OK] Rotation vector for cv2.solvePnP() obtained successfully === 2. DEPTH MAP COMPATIBILITY === .npy format: shape=(600, 800), dtype=uint16 .npy range: [750, 795]mm cv2.imread(UNCHANGED): shape=(600, 800), dtype=uint16 cv2 depth range: [750, 795]mm [OK] OpenCV reads 16-bit depth correctly PIL.Image.open: mode=I;16, shape=(600, 800), dtype=uint16 PIL depth range: [750, 795]mm [OK] PIL reads 16-bit depth correctly npy vs PNG consistency: PASS === 3. ROS COMPATIBILITY === Depth encoding: 16UC1 (16-bit unsigned, 1 channel) Depth unit: mm (conversion to meters: value / 1000.0) ROS2 sensor_msgs/Image fields: encoding: '16UC1' height: 600 width: 800 step: 1600 (width * 2 bytes) [OK] Compatible with ROS depth_image_proc package [OK] depth_scale=1.0 means depth_png_value * 1.0 = depth_mm CameraInfo message: K = [761.267, 0.0, 400, 0.0, 761.267, 300, 0.0, 0.0, 1.0] D = [] (no distortion) R = [1,0,0,0,1,0,0,0,1] (identity) P = [761.267,0,400.0,0, 0,761.267,300.0,0, 0,0,1,0] [OK] Standard ROS CameraInfo format === 4. BLENDER COMPATIBILITY === Blender uses OpenGL convention (Y-up, Z-back) Our data uses OpenCV convention (Y-down, Z-forward) Conversion needed for Blender import: R_opengl = R_opencv @ diag([1, -1, -1]) t_opengl = diag([1, -1, -1]) @ t_opencv Example conversion (Frame 1): R_opencv = [5.25988e-05, 0.0, -1.0, 0.899983, -0.435924, 4.73381e-05, -0.435924, -0.899983, -2.29291e-05] R_opengl = [5.25988e-05, 0.0, 1.0, 0.899983, 0.435924, -4.73381e-05, -0.435924, 0.899983, 2.29291e-05] t_opencv = [16.0, -0.000758278, 799.987] t_opengl = [16.0, 0.000758278, -799.987] [OK] Conversion is a simple sign flip on Y and Z axes [NOTE] Blender Python API can automate this conversion Depth import in Blender: Use .npy (uint16) for highest precision Convert to float: depth_m = depth_mm / 1000.0 Apply as Z-buffer displacement in Compositor [OK] Depth data compatible with Blender Compositor === 5. BOP TOOLKIT COMPATIBILITY === scene_camera.json: BOP standard format scene_gt.json: BOP standard format cam_K: [fx, 0, cx, 0, fy, cy, 0, 0, 1] (row-major, 9 elements) cam_R_m2c: 9-element row-major 3x3 cam_t_m2c: 3-element [tx, ty, tz] in mm depth_scale: 1.0 (depth PNG stores mm directly) BOP depth = pixel_value * depth_scale = pixel_value * 1 BOP depth range: [750, 795]mm [OK] BOP depth_scale=1.0 is correct (depth PNG already in mm) === 6. COCO API COMPATIBILITY === COCO format version: 2.0 Images: 10 Annotations: 103 Categories: 1 Sample annotation keys: ['id', 'image_id', 'category_id', 'segmentation', 'area', 'bbox', 'iscrowd', 'instance_id', 'feature_type_id', 'feature_index', 'segmentation_polygon'] segmentation type: dict RLE size: [600, 800] RLE counts length: 66 [OK] Standard COCO RLE format License field: N/A [OK] Compatible with pycocotools === 7. YOLO COMPATIBILITY === YOLO detection format: 5 values per line Sample: 0 0.499375 0.499167 0.040000 0.160000 [OK] Standard YOLO format (class cx cy w h) YOLO seg format: 25 values per line Sample (first 6): 0 0.505000 0.420000 0.503750 0.465000 0.481250 [OK] Standard YOLO segmentation format ================================================================================ COMPATIBILITY SUMMARY ================================================================================ [OK] OpenCV: Fully compatible (standard cam_K, R_m2c, t_m2c) [OK] ROS/ROS2: Fully compatible (16UC1 depth, depth_scale=1.0) [OK] Blender: Compatible (needs Y/Z sign flip for OpenGL convention) [OK] BOP Toolkit: Fully compatible (standard BOP format) [OK] COCO API: Fully compatible (standard RLE encoding) [OK] YOLO: Fully compatible (standard bbox + segmentation format) [OK] PyTorch/TF: Fully compatible (standard PNG + JSON) BLOCKING ISSUES: None NOTES: 1. Blender import requires coordinate conversion (Y/Z sign flip). This is standard and well-documented for OpenCV->OpenGL conversion. A Python conversion script is provided in the dataset package. 2. Depth PNG uses 16-bit uint16 (mode I;16 in PIL). Some image viewers may display incorrectly (show as 8-bit). Use cv2.imread(UNCHANGED) or PIL with I;16 mode for correct reading. 3. cam_K is stored as flat 9-element array (row-major). Reshape to 3x3: K = np.array(cam_K).reshape(3,3) ================================================================================