环栅图像的数字莫尔条纹扫描定中方法

Digital Moiré fringe scanning method for centering ring grating images

提出了数字环栅莫尔条纹扫描方法。该方法不是用实物环光栅与无衍射光的光斑重叠产生环形莫尔条纹。而是先用CCD摄像机将光斑摄入计算机 ,再与一基本同心的数字环光栅重叠产生环形莫尔条纹。改变该数字光栅的相位 ,可实现莫尔条纹扫描 ,用多幅扫描图像可算出光斑图像整体中心。由于利用了整幅图像的数据 ,该法实现了含噪环栅状光斑图像的亚像素级灵敏度定中心。统计模拟实验证明 ,它具有良好的抗干扰能力。并介绍了该方法在空间直线度测量方面的应用实验。

Moire fringe scanning method of digital ring gratings is proposed. Instead of generating ring Moire fringe by superposition of real circular grating and nondiffractive beam, the author photographed the beam images into computer,and then superposed them with a digital circular grating, whose center position is close to the measured images. Changing the phase of digital grating can realize Moire fringe scanning. The global center of beam pattern can be calculated by multi_frame scanning images. Because the total data of pattern are used in calculation, the determination of center of the ring pattern with noise is realized with subelement sensitivity. Statistical analysis shows that this method features good anti_interference ability. The application of this method in the measurement of space straightness error is also introduced.