Appendix - Developer Data Guide

Developer Data V1.1.0

1 Data Overview

2 Data Details

2.1 Raw Images, Masks, and Camera Parameters

• Content: High-definition raw fisheye images captured by the Lixel device
• Frame Rate: Adjusted according to the reconstruction quality option (low/medium/high)
• Mask Details: Marks the pixel semantics in the image. Among them, 255 indicates regions unsuitable for reconstruction, such as humans, the capture device, etc.
• Format: Provides the visual mapping results in COLMAP format aligned with the LAS point cloud, including the intrinsics and extrinsics of each image

• Use Cases:

  • Development of customized visual mapping algorithms
  • Further optimization of existing visual mapping results
  • Customized image undistortion operations based on specific business requirements

2.2 Undistorted Images, Masks, and Camera Parameters

• Content: Ideal perspective images derived from raw fisheye images
• Masks and Parameters: Includes the masks of the perspective images and the intrinsics and extrinsics in COLMAP format
• Image Segmentation: Each fisheye image is segmented into 3 perspective images (60° wide, 90° high field of view). Two fisheye images can capture a panoramic image of horizontal 360° and vertical 90°

• Use Cases:

  • Suitable for 3DGS, MVS, or other algorithms that require ideal perspective images

2.3 Optimized Laser Point Cloud, Device Poses, and High-Frequency Device Poses

• Content:

  • Globally optimized LAS point cloud with dynamic point filtering capability
  • Device poses in the Lixel IMU coordinate system (10Hz)
  • High-frequency device poses at the raw IMU frequency (200Hz)

• Coordinate Alignment:

  • Without RTK: The LAS point cloud coordinates are in the same coordinate system as the extrinsics of the raw images and undistorted images
  • With RTK: After the LAS point cloud coordinates are corrected by the offset in the LAS header, they are in the same coordinate system as the extrinsics of the raw images and undistorted images

• Use Cases:

  • Combined with raw or undistorted images for visual and laser post-processing reconstruction

• Pose Data Format:

  • The pose data is provided in poses.csv and high_frequency_poses.csv files, in the following format:

    timestamp, tx, ty, tz, qw, qx, qy, qz
    
    Where:
    1. timestamp: time (seconds)
    2. tx, ty, tz: translation from the IMU to the world coordinate system (meters)
    3. qw, qx, qy, qz: rotation from the IMU to the world coordinate system (quaternion, unitless)