Corners positioning for binocular ultra-wide angle long-wave infrared camera calibration

Abstract In this paper a approach of corners positioning for calibrating binocular ultra-wide angle long-wave infrared camera is presented. Firstly, the generalized camera model which suits for its imaging relationship is introduced. Secondly, a method for subpixel corners positioning is proposed, containing edge extraction, gray centroid and curve fitting. Thirdly, aiming at calibrating extrinsic parameters of the camera, we raise a method with least squares optimization. The calibration experiments are conducted on the basis of an active infrared radiation calibration checkerboard. The performance of the approach is discussed by using other data sets. The results reveal that: MRE (mean reprojection error) and RMS (root mean square) respectively reduce to 0.23pixels and 0.33pixels, and the error of the baseline length declines from 1.00% to 0.23% in comparison with common methods.