DSP For Surface Deformation Measurement

The development of the technique of the optical measurement shows its great vigor. Combining with the optical technique and the computer technique,it forms many features, such as non-contact,high precise,high capacity of information and high efficiency.The applications of the optical measurement technique cover every aspect of work and life.In the paper,many aspects of the speckle photography are studied,such as the basic theory,working principle and measurement method and characteristic of the measure technique.The digitalization of the speckle photography is realized based on the application of he CCD(charge-coupled device),which is used to record the speckle,and EALCD(electrically addressed liquid crystal display),which is used to read out and write in the speckle.Both of the systems of the subjective speckle and the objective speckle are designed.The two different states of the speckle patterns are recorded.The methods of the full field analysis and the point for point analysis,have been successfully used the speckle interferogram with good contrast,including the information of deformation and displacement.Then,the image processing has been used to reduce the influence of the high noise and the inhomogeneous grey of the speckle interferogram.The image enhancement and the mathematical morphology have been use to reduce the noise for realization of high SNR of the speckle interferogram.At last,the method of the digital simulation has been used in the research of the speckle photography based on MATLAB and C++.The speckle interferogram is also obtained. Compared with the optical speckle photography,the contrast of the speckle interferogram, which is obtained by the method of the digital simulation,is lower than the contrast of the optical speckle interferogram.Moreover,the method needs complicated algorithm design. The research results show that the research and practical value of the digital speckle photography studied in the paper are very high.