dataset_metadata.json

{
  "dataset_name": "Huhb3D",
  "version": "1.0.0",
  "license": "CC-BY-4.0",
  "description": "Industrial-Grade Synthetic Dataset for 6DoF Pose Estimation, Instance-Level Segmentation, and STEP Topology Ground Truth",
  "created_date": "2026-05-31",
  "publisher": "Huhb3D",
  "citation": "Huhb3D v1.0, Industrial-Grade Synthetic Dataset, CC-BY-4.0",
  "keywords": ["6DoF", "pose estimation", "instance segmentation", "BOP", "COCO", "YOLO", "industrial", "synthetic", "depth", "CAD"],

  "model_unit": "mm",
  "coordinate_convention": "OpenCV (Y-down, Z-forward)",
  "image_width": 800,
  "image_height": 600,
  "fov_degrees": 45.0,
  "fov_jitter_degrees": 3.0,
  "camera_radius_mm": 800.0,
  "near_plane_mm": 40.0,
  "far_plane_mm": 16000.0,
  "near_far_ratio": "400:1",

  "depth_format": "uint16 PNG",
  "depth_unit": "mm",
  "depth_scale": 1.0,
  "depth_zero_means": "no depth (background)",
  "depth_formula": "depth_mm = (near * far) / (far - z_buf * (far - near))",
  "depth_rounding": "round(depth_mm + 0.5) -> uint16",

  "num_objects": 20,
  "num_frames_per_object": 10,
  "total_images": 200,

  "reprojection_error_mean_px": 0.0144,
  "reprojection_error_max_px": 0.0144,
  "rotation_matrix_det_deviation": 0.000001,

  "objects": [
    {"obj_id": 1, "name": "bearing_block", "category": "bearing", "variant": "default", "depth_range_mm": [770, 801], "mean_depth_mm": 782.4, "cam_dist_mm": 800.0},
    {"obj_id": 2, "name": "bearing_medium", "category": "bearing", "variant": "medium", "depth_range_mm": [770, 803], "mean_depth_mm": 782.6, "cam_dist_mm": 800.0},
    {"obj_id": 3, "name": "bearing_small", "category": "bearing", "variant": "small", "depth_range_mm": [779, 801], "mean_depth_mm": 787.1, "cam_dist_mm": 800.0},
    {"obj_id": 4, "name": "connector_housing", "category": "connector", "variant": "default", "depth_range_mm": [778, 805], "mean_depth_mm": 789.2, "cam_dist_mm": 800.6},
    {"obj_id": 5, "name": "coupling", "category": "coupling", "variant": "default", "depth_range_mm": [775, 796], "mean_depth_mm": 780.4, "cam_dist_mm": 800.4},
    {"obj_id": 6, "name": "flange", "category": "flange", "variant": "default", "depth_range_mm": [750, 795], "mean_depth_mm": 769.3, "cam_dist_mm": 800.1},
    {"obj_id": 7, "name": "flange_large", "category": "flange", "variant": "large", "depth_range_mm": [730, 795], "mean_depth_mm": 753.9, "cam_dist_mm": 800.2},
    {"obj_id": 8, "name": "flange_medium", "category": "flange", "variant": "medium", "depth_range_mm": [750, 797], "mean_depth_mm": 769.2, "cam_dist_mm": 800.2},
    {"obj_id": 9, "name": "flange_small", "category": "flange", "variant": "small", "depth_range_mm": [765, 812], "mean_depth_mm": 778.8, "cam_dist_mm": 799.7},
    {"obj_id": 10, "name": "gear", "category": "gear", "variant": "default", "depth_range_mm": [773, 797], "mean_depth_mm": 783.1, "cam_dist_mm": 800.1},
    {"obj_id": 11, "name": "gear_large", "category": "gear", "variant": "large", "depth_range_mm": [752, 794], "mean_depth_mm": 768.5, "cam_dist_mm": 800.2},
    {"obj_id": 12, "name": "gear_medium", "category": "gear", "variant": "medium", "depth_range_mm": [773, 796], "mean_depth_mm": 783.2, "cam_dist_mm": 800.1},
    {"obj_id": 13, "name": "gear_small", "category": "gear", "variant": "small", "depth_range_mm": [782, 810], "mean_depth_mm": 789.8, "cam_dist_mm": 800.1},
    {"obj_id": 14, "name": "heat_sink", "category": "heat_sink", "variant": "default", "depth_range_mm": [754, 844], "mean_depth_mm": 812.2, "cam_dist_mm": 794.7},
    {"obj_id": 15, "name": "hex_bolt", "category": "bolt", "variant": "default", "depth_range_mm": [791, 799], "mean_depth_mm": 795.7, "cam_dist_mm": 800.3},
    {"obj_id": 16, "name": "l_bracket", "category": "bracket", "variant": "default", "depth_range_mm": [784, 812], "mean_depth_mm": 795.5, "cam_dist_mm": 801.8},
    {"obj_id": 17, "name": "mounting_plate", "category": "plate", "variant": "default", "depth_range_mm": [745, 806], "mean_depth_mm": 764.6, "cam_dist_mm": 800.0},
    {"obj_id": 18, "name": "pipe_tee", "category": "pipe", "variant": "default", "depth_range_mm": [776, 811], "mean_depth_mm": 783.4, "cam_dist_mm": 796.4},
    {"obj_id": 19, "name": "step_shaft", "category": "shaft", "variant": "default", "depth_range_mm": [780, 797], "mean_depth_mm": 787.6, "cam_dist_mm": 800.8},
    {"obj_id": 20, "name": "valve_body", "category": "valve", "variant": "default", "depth_range_mm": [759, 838], "mean_depth_mm": 783.5, "cam_dist_mm": 800.2}
  ],

  "feature_types": [
    {"id": 0, "name": "FreeSurface", "description": "Free-form curved surface"},
    {"id": 1, "name": "HorizontalPlane", "description": "Plane with normal along Y-axis"},
    {"id": 2, "name": "LateralPlane_X", "description": "Plane with normal along X-axis"},
    {"id": 3, "name": "LateralPlane_Z", "description": "Plane with normal along Z-axis"},
    {"id": 4, "name": "NearHorizontal", "description": "Surface within 30 deg of horizontal"},
    {"id": 5, "name": "NearLateral_X", "description": "Surface within 30 deg of X-lateral"},
    {"id": 6, "name": "NearLateral_Z", "description": "Surface within 30 deg of Z-lateral"},
    {"id": 7, "name": "Degenerate", "description": "Degenerate surface (fillet, chamfer)"},
    {"id": 8, "name": "ConvexFeature_Bolt", "description": "Convex bolt boss feature"},
    {"id": 9, "name": "ConcaveFeature_Hole", "description": "Concave hole feature"},
    {"id": 10, "name": "Flange", "description": "Flange feature"},
    {"id": 11, "name": "Boss", "description": "Boss feature"}
  ],

  "instance_mask_encoding": {
    "R_channel": "Instance ID (1-255, 0=background)",
    "G_channel": "Feature Type ID (0-11)",
    "B_channel": "Feature Index within type (0-255)"
  },

  "formats": {
    "bop": {
      "scene_camera": "Per-frame camera intrinsics (cam_K, depth_scale, cam_R_w2c, cam_t_w2c)",
      "scene_gt": "Per-frame 6DoF ground truth (cam_R_m2c, cam_t_m2c, obj_id)"
    },
    "coco": {
      "semantic": "coco_annotations.json - Standard COCO with RLE segmentation",
      "instance": "coco_instance_annotations.json - Instance-level COCO"
    },
    "yolo": {
      "detection": "yolo_labels/labels/ - class cx cy w h (normalized)",
      "segmentation": "yolo_labels/seg_labels/ - class x1 y1 x2 y2 ... (polygon)",
      "instance": "yolo_instance_labels/ - class cx cy w h (per instance)"
    }
  },

  "generation_pipeline": {
    "cad_kernel": "OpenCASCADE (LGPL-2.1)",
    "cad_library": "cadquery 2.x (Apache-2.0)",
    "rendering_engine": "OpenGL 3.3 Core Profile",
    "compiler": "MSVC 19.x (Visual Studio Build Tools 2022)",
    "depth_formula": "depth_mm = (near * far) / (far - z_buf * (far - near))",
    "coordinate_transform": "OpenGL->OpenCV: negate Y-row, Z-row of rotation and Y,Z of translation",
    "anti_aliasing_mask": "Disabled (glDisable(GL_MULTISAMPLE)) for clean instance IDs"
  },

  "quality_metrics": {
    "reprojection_error_mean_px": 0.0144,
    "reprojection_error_max_px": 0.0144,
    "fx_fy_diff": 0.0,
    "rotation_det_deviation": 0.000001,
    "depth_scale_accuracy": 1.0,
    "depth_range_mm": [730, 844],
    "camera_distance_accuracy_mm": 0.8,
    "verification_checks_total": 62,
    "verification_checks_passed": 62
  }
}