基于图像处理的莫尔条纹测量的CCD亚像素标定

 Talbot-Moiré技术是目前长焦距测量研究的热点。利用Talbot-Moiré技术测量长焦距时，很多都需要测量莫尔条纹的宽度或斜率，而CCD的标定精度直接影响测量精度，因此需要对CCD精确标定。文中提出采用光栅作为系统的自基准进行标定，再用图像处理的方法标定CCD。为了检验该方法的精度，在MATLAB中生成一个标准条纹图案，用图像处理和灰度拟合对其进行亚像素定位。经过对标准条纹的标定，验证了采用该文的定位方法条纹中心定位误差小于0.1个像素。最后用光栅为自基准标定了CCD，并与量块的标定结果进行了对比，证明该文的标定方法不但简单可行，而且精度较高。

Sub-pixel calibration of CCD in Moiré fringes measurement based on image processing

The measurement based on Talbot effect and Moiré fringes is suitable for lens of long focal length. To get the focal length accurately, the width or slope coefficient of Moiré fringes are essential parameters. The CCD calibration precision should be improved due to its significant impact on measurement accuracy. A CCD calibration is put forward. The grating is set as the self-reference to calibrate the equivalent length of CCD pixel. The calibration is presented based on image processing and Gauss curve fitting. The calibration accuracy is proved less than 0.1 pixel by calibrating the standard fringes generated by MATLAB. Finally, the CCD pixel is calibrated by grating and gauge block separately, the results show that the calibration method using grating is simple and precise.