Calibration Board

A flat board printed with a pattern of precisely known size, used to give a camera calibration accurate reference points.

A calibration board is a flat target with a printed pattern of precisely known dimensions, used for camera calibration and hand-eye calibration. The most common type is the black-and-white checkerboard: it detects the internal corners where squares meet, achieving sub-pixel precision, but usually requires the whole board to be visible in frame. A dot-array board uses circle centers as its features instead. A ChArUco board embeds ArUco markers into the checkerboard's white squares, using the markers to identify each corner individually, so it still works when partially occluded or only partly in view, while keeping the checkerboard's corner-detection precision; OpenCV has built-in support for it. In practice, using one well requires an accurately printed size, a flat board (often mounted on aluminum or glass), and shots taken from multiple angles and distances so the detected corners cover the whole frame.

ExampleGenerate a ChArUco board with OpenCV, print it, and mount it on a flat aluminum plate, measuring the square edge length precisely. Hand-hold the camera and shoot from a dozen or more different angles, then feed the images to the calibration function to solve for intrinsics and distortion.

Also called

Checkerboard, ChArUco Board, Calibration Target, Dot-Array Calibration Board

Related

Camera Calibration · Hand-Eye Calibration · ArUco Marker · AprilTag · Camera Intrinsics · Lens Distortion

Sources

OpenCV Tutorial: Detection of ChArUco Boards
MATLAB: What Is Camera Calibration?