The analysis of misalignment errors of optical masks for wavefront coded passive-ranging systems

A typical wavefront coding passive-ranging system and its alignment error coordinate is introduced. Based on this, we have analyzed off-axis error, tilt error of x–y plane and tilt error of y–z plane for the plane of mask. The results show the off-axis error of mask does not affect the magnitude transfer function (MTF) of optical–digital system and the light spots will has a plane shift. The tilt error of x–y plane makes us realize that the coordinate must be selected on the basis of the optical mask plane in wavefront coded passive-ranging system. The tilt angle in y–z plane brings errors to the final ranging result. Therefore, the passive ranging system requires higher assembly accuracy between modulating plane and optical system plane. We noted that it bring errors to the final ranging result with wide field of view condition on the passive ranging system.