在基于条纹投影的物体表面形貌测量中,条纹相位畸变是影响物体测量精度的主要因素。为了准确判断条纹相位是否发生相位畸变,在相位矫正算法中借助傅里叶变换,从频域中分析条纹图样,形成了一种基于频域分析辨别干涉条纹相位畸变的技术。利用迈克耳孙干涉的基本原理搭建平行光束干涉投影装置,将干涉条纹投射到光屏上,通过CCD相机进行图像采集,并将得到的干涉条纹图像传输到计算机上,再利用小波滤波对图像进行滤波,噪声和干扰通过傅里叶变换将空域图像转换为频域图像,分析频域图像中的基频临近位置的能量分布信息,判断是否发生相位畸变。实验结果表明,该方法能够准确判别采集条纹图像是否发生相位畸变,识别灵敏度为60 mrad。

In the measurement of surface topography of objects based on fringe projection, the fringe phase distortion is the main factor affecting the accuracy of object measurement. In order to accurately determine whether the fringe phase has phase distortion, the fringe pattern is analyzed from the frequency domain by means of Fourier transform in the phase correction algorithm, and a technique for discriminating the phase distortion of the interference fringe based on frequency domain analysis is formed. Using the basic principle of Michelson interference, the parallel beam interference projection device is built, the interference fringes are projected onto the light screen, the image is collected by the CCD camera, and the obtained interference fringe image is transmitted to the computer, and then the image is filtered by wavelet filtering. The noise and interference are transformed into a frequency domain image by Fourier transform, and the energy distribution information of the adjacent position of the fundamental frequency in the frequency domain image is analyzed to determine whether phase distortion occurs. The experimental results show that the method can accurately determine whether the fringe image has phase distortion, and the recognition sensitivity is 60 mrad.