full-凯发网

with the advent of intelligent manufacturing, phase measuring deflectometry (pmd) has been widely studied for the measurement of the three-dimensional (3d) shape of specular objects. however, existing pmds cannot measure objects having discontinuous specular surfaces. this paper presents a new direct pmd (dpmd) method that measures the full-field 3d shape of complicated specular objects. a mathematical model is derived to directly relate an absolute phase map to depth data, instead of the gradient. two relevant parameters are calibrated using a machine vision-based method. on the basis of the derived model, a full-field 3d measuring system was developed. the accuracy of the system was evaluated using a mirror with known positions along an accurate translating stage. the 3d shape of a monolithic multi-mirror array having multiple specular surfaces was measured. experimental results show that the proposed dpmd method can obtain the full-field 3d shape of specular objects having isolated and/or discontinuous surfaces accurately and effectively.