MR·CAL GUIDE
Multiple Robot Calibration — and we also think it's friendlier if you read it as "Mr. Cal."
An interactive guide to robot sensor calibration. Plain English, real research, permissively-licensed software, and 3D animations you can poke at. Free for everyone.
Read the deep stuff: GitHub repo ↗ · long-form docs ↗ · technique deep-dives ↗ · glossary
© 2026 Valpatel Software · Created by Matthew Valancy
Fundamentals — start here if you're new
Calibration jargon trips up everyone the first time. These pages define the core terms before you dive into a specific sensor.
Topics by sensor
Once the fundamentals click, dive into the specific relationship you're trying to calibrate. The groupings below mirror how teams actually organise the work — single sensor → pairwise extrinsic → cross-modal → the deep cross-cutting topics that touch every sensor.
Single-sensor — calibrate one device at a time
Pairwise extrinsic — relate two devices of the same kind
Cross-modal — relate two different sensor types
Cross-cutting — topics that touch every sensor
Deep dives — single-topic walkthroughs
Why this exists
Robotics calibration is critical, copyleft-heavy, and woefully under-explained for newcomers. Standing up a camera, a LiDAR, or an IMU on a new robot today means stitching together vendor PDFs, GPL-tainted GitHub repos, and 1990s-era IEEE papers behind paywalls.
This guide is a deliberate counter-program — every technique explained in plain English, every paper linked to an open version, every implementation flagged with its real license, and the 3D math made visible with Three.js so you can rotate the rig and see what the algorithm actually sees.
How to read a topic
- In plain English — the one-paragraph version.
- How it works — the interactive 3D animation.
- Techniques — alternative algorithms with citations.
- Tradeoffs — when to use which, in a table.
- Hardware — real sensor models with datasheets.
- References — the paper / software / part library.