A stepwise camera calibration method incorporating compensation for eccentricity error

In visual measurement, high-precision camera calibration often employs circular targets. To address issues in mainstream methods, such as the eccentricity error of the circle from using the circle’s center for calibration, overfitting or local minimum from full-parameter optimization, and calibration errors due to neglecting the center of distortion, a stepwise camera calibration method incorporating compensation for eccentricity error was proposed to enhance monocular camera calibration precision. Initially, the multi-image distortion correction method calculated the common center of distortion and coefficients, improving precision, stability, and efficiency compared to single-image distortion correction methods. Subsequently, the projection point of the circle’s center was compared with the center of the contour’s projection to iteratively correct the eccentricity error, leading to more precise and stable calibration. Finally, nonlinear optimization refined the calibration parameters to minimize reprojection error and boosts precision. These processes achieved stepwise camera calibration, which enhanced robustness. In addition, the module comparison experiment showed that both the eccentricity error compensation and the camera parameter optimization could improve the calibration precision, but the latter had a greater impact. The combined use of the two methods further improved the precision and stability. Simulations and experiments confirmed that the proposed method achieved high precision, stability, and robustness, suitable for high-precision visual measurements.