Polynomial-fitting based calibration for an active 3D sensing system using dynamic light section method

Abstract

This paper proposes a polynomial-fitting based calibration method for an active 3D sensing using a dynamic light section method. In the dynamic light section method, the relative position of the line laser is dynamically changed at high speed to extend the measurement area with a low computational cost. To conduct 3D sensing, it is necessary to find the equation of the laser plane. In the proposed calibration method, a part of the line laser is irradiated on a reference plane fixed in the 3D sensing system, and correspondences between the normal vectors of the line laser and the image coordinates of the bright point on the reference plane are obtained. Then, the correspondences are regressed to a polynomial function. As a result, the plane equation of the line laser can be obtained at any given moment without considering the complicated system model. Through the measurement accuracy evaluation of the dynamic light section method calibrated by the polynomial fitting, we showed that a measurement target at a distance of 800 mm can be measured with an accuracy of an average of -5.94 mm and a standard deviation of 13.19 mm by rotating the line laser at 210 rpm.