Camera calibration with active standard Gaussian stripes for 3D measurement

Abstract

The extraction accuracy of the mark points is directly related to the calibration accuracy of the camera. However, traditional ceramic calibration boards with checkerboard or circle dot markers are not suitable for defocused conditions and lack adaptability to changes in the measuring field. Therefore, liquid crystal displays (LCDs) that display phase-shifting patterns are widely used as phase active targets for cameral calibration. While phase-shifting patterns accurately extract feature points in defocused conditions, they are susceptible to LCD screen nonlinear errors. To address these shortcomings, we propose a practical method that involves displaying standard Gaussian stripes on LCD. Specifically, this method displays Gaussian stripes in two directions and extracts their centerline subpixel coordinates. The intersection points of the two orthogonal centerlines are then considered as the feature points. Simulation and experimental results demonstrate that the standard Gaussian stripes still accurately extract feature points when affected by LCD nonlinearity or image defocus.