使用离散小波变换的相位轮廓术  

Phase Profilometry Using Discrete Wavelet Transform

作　　者：周翔[1] 赵宏[1] 

机构地区：[1]西安交通大学机械制造系统工程国家重点实验室,陕西西安710049

出　　处：《光学学报》2009年第6期1563-1569,共7页Acta Optica Sinica

基　　金：国家自然科学基金(50575169)资助项目;国家973计划(2005CB724106)资助项目

摘　　要：提出了两种在相位轮廓术中使用离散小波变换提取条纹相位的方法:单次分解法和多次分解法。前者用多分辨率分析的多孔算法计算变形条纹解析信号的离散小波变换,寻找每一位置的小波系数在尺度方向上的模极大值点,通过提取该点的相位就可以得到原条纹的相位值;后者是在前者的基础上,通过插值改变条纹信号的抽样率,再次进行多分辨率分析,得到冗余的小波系数,提取条纹相位。单次分解法适合处理正弦载频条纹图,多次分解法抗噪性好,可以处理带有高次谐波的准正弦载频条纹图。相对于使用连续小波变换的方法,这两种方法较适合处理离散信号,对于512 pixel×512 pixel的条纹图计算速度分别提高90%和50%。计算机模拟和实验验证了方法的有效性。Two approaches, single decomposition approach and multi-decomposition approach,using discrete wavelet transform for extracting phase in phase profilometry are proposed. In the former approach, wavelet multi-resolution analysis is chosen to perform discrete wavelet transform of the pattern after converting original signal into the analytic form. The phase distribution is recovered from every coefficient whose modulus reaches maximum in the scale direction at the position. In the latter one, an interpolation to original signal is used to vary the sampling rate and multi-resolution analysis is reused to acquire redundant detail coefficients. The first approach is suitable for sinusoidal fringe pattern. In contrast, the second one is more robust to noise and capable of handling quasi-sinusoidal fringe pattern. Compared with the method employing continuous wavelet transform, these two approaches have 90 % and 50% increases in computing speed respectively for a 512 pixel × 512 pixel image, and are more appropriate to discrete signal processing. The numerical simulation and experiment have proved the validity of the approaches.

关 键 词：傅里叶光学 相位轮廓术 小波变换 多分辨率分析 

分 类 号：O439[机械工程—光学工程]