# ethz-asl/lidar_align

A simple method for finding the extrinsic calibration between a 3D lidar and a 6-dof pose sensor

Repository: https://github.com/ethz-asl/lidar_align
Canonical: https://ross.abutalabs.com/products/lidar_align
Language: C++
License: BSD-3-Clause
License Family: permissive
Last push: 2025-03-11T12:39:32+00:00

## Health v2 (maintenance only)
Score: 37/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 10, release rhythm 35, longevity 100
- inputs: {"age_days": 3600, "days_push": 540, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1054, forks 282 (observed 2026-08-28T04:03:24.009999+00:00)

## What it is
A ROS-based C++ tool that estimates the extrinsic transformation between a 3D lidar and a 6-DOF pose sensor. It works by fusing lidar pointclouds using candidate transforms and optimizing so the combined pointcloud is maximally 'crisp' (minimal nearest-neighbor distances).

## Use cases
- calibrate extrinsic transform between 3D lidar and pose sensor
- find lidar to IMU/odometry extrinsics from a rosbag
- estimate sensor-to-lidar rotation and translation offline
- calibrate lidar mounted on a drone or handheld rig with non-planar motion
- produce transformation matrix for SLAM or mapping pipelines

## When to choose
- you have a 3D lidar and a 6-DOF pose source (VIO, motion capture, odometry) with recorded data
- your sensor setup can perform highly non-planar motions
- you want a simple, mostly parameter-free ROS-based calibration tool

## When to avoid
- calibrating sensors on cars or other platforms with mostly planar motion
- you need online/real-time calibration rather than offline batch estimation
- you are not using ROS or cannot provide PointCloud2 and pose data

## Facets
- artifact type: library
- maturity: maintenance
- function: robotics, simulation, math, developer-tools
- domain: robotics, autonomous-vehicles, computer-vision
- platform: cpp
- tags: lidar-calibration, extrinsic-calibration, ros, pointcloud, sensor-fusion, pose-sensor, optimization, nlopt, algorithms, linux

## Member repositories
- ethz-asl/lidar_align (main) score 37

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:24.009999+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:58:46.956798+00:00, confidence not recorded.
  - readme: https://github.com/ethz-asl/lidar_align (fetched 2026-08-28T04:03:24.009999+00:00, sha 142ffdc87dee)
- Data as of 2026-08-30T08:39:29.467469+00:00.