On-Machine Calibration Method for <i>In Situ</i> Stereo Deflectometry System

Deflectometry is a promising method for the in situ measurement of specular surfaces. However, accuracy this largely depends on geometrical calibration, which suffers from low convergence rate and local minima during optimization. Off-machine calibration results change geometry parameters due to repeated disassembly system ambient temperature, affects accuracy. This article presents flexible on-machine with fewer intermediate accelerate optimization stereo deflectometry system. An inclined mirror fixed angle was mounted spindle an ultraprecision machine tool used as reference plane reflecting fringe displayed display screen. The reflected captured by cameras encoded moving along $C$ -axis $Z$ tool. preknowledge movement distance rotation nanoscale reduce number variables involved optimization, thus improving speed global reliability. experiment show that has higher accuracy, reliability compared conventional off-machine method.