# APRIL-ZJU/lidar_IMU_calib

[IROS 2020] Targetless Calibration of LiDAR-IMU System Based on Continuous-time Batch Estimation

Repository: https://github.com/APRIL-ZJU/lidar_IMU_calib
Canonical: https://ross.abutalabs.com/products/lidar_imu_calib
Language: C++
License: GPL-3.0
License Family: copyleft
Last push: 2023-05-15T18:51:39+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 2375, "days_push": 1206, "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 1179, forks 247 (observed 2026-08-28T04:03:53.168004+00:00)

## What it is
LI-Calib is a C++/ROS toolkit that calibrates the 6DoF rigid transformation and time offset between a 3D LiDAR and an IMU using continuous-time batch optimization. It jointly minimizes IMU-based costs and LiDAR point-to-surfel distances, enabling targetless calibration in general scenarios.

## Use cases
- calibrate lidar to imu extrinsic transformation
- estimate time offset between lidar and imu sensors
- targetless lidar-imu calibration without calibration targets
- continuous-time batch optimization for sensor calibration
- calibrate velodyne vlp-16 with an imu
- sensor fusion calibration for robotics and autonomous driving

## When to choose
- you need to calibrate a 3D LiDAR-IMU pair without a calibration target
- you want to jointly estimate extrinsics and time offset via continuous-time optimization
- you are working with ROS and a VLP-16 (or similar) LiDAR
- you need research-grade calibration based on the IROS 2020 paper

## When to avoid
- you need camera or multi-sensor (e.g., LiDAR-camera) calibration
- you require support for LiDARs other than VLP-16 out of the box
- you need a real-time or actively maintained production tool
- you are not using ROS or Linux

## Facets
- artifact type: application
- maturity: maintenance
- function: simulation, computer-vision, graphics
- domain: robotics, autonomous-vehicles
- platform: cpp
- tags: lidar, imu, sensor-calibration, continuous-time-optimization, ros, ceres-solver, extrinsic-calibration, time-offset-estimation, targetless-calibration, robotics-research, algorithms, linux

## Member repositories
- APRIL-ZJU/lidar_IMU_calib (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:53.168004+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 2026-08-30T06:25:25.663517+00:00, confidence not recorded.
  - readme: https://github.com/APRIL-ZJU/lidar_IMU_calib (fetched 2026-08-28T04:03:53.168004+00:00, sha 6153ba668a08)
- Data as of 2026-08-30T08:39:29.467469+00:00.