Three-Dimensional Deformation Testing Based On Speckle Photography

Speckle photography compared with holography, is the first choice which is used in nondestructive measured the object of in-plane displacement、strain、rotation、title and vibration etc. In practical measurement, the measurement of in-plane tiny displacement is a used widely method. So speckle photography is an important development direction of speckle measurement technology.In the paper, many aspects of the speckle photography are studied, such as the basic theory, working principle and measurement method. Based on the principle of speckle photography, this paper uses CCD (Charge-Coupled Device) as a recorder, EALCD(Electrically Addressed Liquid Crystal Display) as a read-out element, and the3D phase measurement of a deformed object is performed. Using digital technology interference fringes is displayed in real-time, and using digital image processing technology realizes four steps phase shitting. With phase-unwrapping method realizes3D deformation phase testing. So omit PZT (Piezoelectric Translator)、phase controller and so on, simplify testing system. Then, the image processing has been used to reduce the influence of the high noise and the inhomogeneous grey of the speckle interferogram in the paper. At last, the method of the digital simulation has been used in the research of the speckle photography based on MATLAB. The speckle interferogram is also obtained.