小波变换在数字全息中的应用

Application of wavelet transform in digital holography

数字全息是通过数字重构来同时获取被测物强度与相位,但记录时的激光散斑效应和重构时的零级衍射斑成为了这种方法的瓶颈。将小波变换引入数字全息,可直接消除零级衍射像,无需相移,也不需要采集多幅图像;小波非线性滤波器还可消除散斑噪声。模拟和实验结果表明,小波分析的引入,可以消除零级衍射影响,改善图像质量,提高测试分辨率。

Digital holography acquires intensity and phase of the measured object simultaneously through digital reconstruction, but laser speckles effect during recording and zero-order diffraction speckle in reconstruction became the bottleneck of the method. Dispensing with phase shift and sampling a number of images, the introduction of wavelet transform into digital holography can directly eliminate zero-order diffraction image. Speckle noise can be eliminated by nonlinear filter designed by wavelet transform. Simulation and experimental results show that the introduction of wavelet analysis can eliminate the effect of zero-order diffraction, improve image quality and testing resolution.