Measurement of Absolute Three-dimensional Displace-ment Gradients Using Tri-color Quad-beam Digital Shearography Author Name Affiliation Postcode LI Xuan0  Beijing Information Science & Technology University  100101 WU Sijin*  Beijing Information Science & Technology University  100101 TANG Xiaojun0  Beijing Spacecrafts, China Academy of Space Technology  LI Weixian0  Beijing Information Science & Technology University  Abstract:       A tri-color quad-beam digital shearography is proposed to achieve the measurement of absolute three-dimensional dis-placement gradients. Four laser beams with three different center wavelengths are symmetrically irradiated to the object surface from the upper and lower left and right directions. Four phase maps are then extracted from the two inter-ferograms obtained from two shots. Based on these four phase maps, the absolute three-dimensional displacement gra-dients are determined. This means of absolute three-dimensional displacement gradient measurement effectively improves the measurement capability of digital shearography and expands its application range. Hits: 0 Download times: 0 The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan)     Download reader