An accurate calibration method for non-overlapping cameras with double-sided telecentric lenses

Abstract

In the application of displacement-relay videometrics for surface subsidence surveillance, double-sided telecentric lenses are especially suited as their constant perspective and large magnification among depth of field. As a serial camera network, it is necessary to calibrate the geometrical relationships between rigidly linked cameras in displacement-relay videometrics. Hence a calibration method for non-overlapping cameras with double-sided telecentric lenses is first proposed. The proposed method utilizes several laser planes, which can be generated by a line laser projector, as the calibration objects. The method connects the double-sided telecentric cameras using the coplanarity of laser plane which goes through the FOVs of cameras. It does not require high-precision 3D measurement equipment, but only requires an ordinary line laser projector and two plane patterns. Real data experiments are performed to validate the proposed method. The experimental results show that the given method is quite reliable and accurate, which can be used to calibrate geometrical relationships of double-sided telecentric cameras in displacement-relay videometrics.