README.md

calibration

This module provides tools for camera calibration, including checkerboard detection and lens distortion estimation.

Checker Detection

The CheckerDetector class detects checkerboard patterns in images. It supports:

• Heavily distorted images
• Blurred images
• Partially occluded checkerboards (even occluded at the center)
• Checkerboards without size information
• Simple and nested grids (when centered on the image center)

A checkerboard corner is described by:

• Its center position
• Its two principal dimensions
• A scale of detection (higher scale means better detection quality)

The detection is based on the following references: [ROCHADE], [Geiger], [Chen], [Liu], [Abdulrahman], [Bok].

aliceVision::calibration::CheckerDetector detector;
// detect checkerboard corners in an image
detector.process(image);
// retrieve detected corners and boards
const auto& corners = detector.getCorners();
const auto& boards = detector.getBoards();

Distortion Estimation

Several methods are provided to estimate lens distortion from calibration data:

• distortionEstimationGeometry: estimates distortion from geometric constraints
• distortionEstimationLine: estimates distortion from lines in the scene
• distortionEstimationPoint: estimates distortion from point correspondences

Each method produces a Statistics struct describing the quality of the estimation:

struct Statistics {
    double mean;
    double stddev;
    double median;
    double lastDecile;
    double max;
};