$ account hku-mars
FAST-Calib is a ROS-based application for LiDAR-camera extrinsic calibration that uses a target-based approach with ArUco markers and circular holes. The system processes synchronized camera images and LiDAR point clouds to detect calibration target features in both modalities, then computes the extrinsic transformation between sensor frames. It supports both solid-state (Livox) and mechanical (Ouster, Hesai) LiDAR sensors through adaptive preprocessing pipelines. The application includes single-scene calibration for immediate results and multi-scene joint calibration for improved accuracy. Key components include modular LiDAR and camera processing pipelines, geometric validation for target detection, and coordinate transformation utilities.
GS-SDF is a research prototype from HKU-MARS that fuses LiDAR-augmented 3D Gaussian Splatting with a neural Signed Distance Field (SDF) for photorealistic rendering and high-fidelity surface reconstruction. The system ingests data from multiple sensor modalities (LiDAR, RGB-D, stereo) via a modular data parser hierarchy supporting Replica, FAST-LIVO2, KITTI, COLMAP, Oxford Spires, and other formats. It trains a neural SDF field with eikonal and curvature regularization, then initializes and refines 3D Gaussians guided by the SDF to produce view-dependent color and geometry. The pipeline includes real-time ROS visualization (RVIZ), offline mesh extraction via a custom CUDA marching cubes implementation, and evaluation scripts for image metrics (PSNR, SSIM, LPIPS) and structural metrics (Chamfer distance, F-score). The codebase is pre-release, with many TODOs and commented-out code, but exhibits strong modularity in its data loaders, loss functions, optimizer utilities, and coordinate transformations. While primarily a research codebase, it includes application-like features such as a ROS node with interactive keyboard commands and headless rendering modes.