干涉图的预处理技术研究

 提出了一种干涉图预处理的新方法。该方法利用数学形态学的方法对干涉图进行有效区域的边缘提取，利用二维快速傅里叶变换迭代法对干涉图进行区域延拓，并采用非加权离散余弦变换最小二乘算法对干涉图进行波面统一，最终恢复出被测物体的表面面形，为后续结果分析奠定了基础。对一个实际SiO2薄膜样片进行了干涉图的预处理。结果表明，通过该算法得到的干涉图预处理结果，与Zygo干涉仪的分析测试结果基本一致。

Investigation of interferogram pre-processing

The modern interferometry measurment features high precision and non-contact, which makes it widely used. As an essential part of the measruement, apre-processing of interferogram was proposed, and it included edge identification based on mathematical morphology, regional extension based on 2-D fast fourier transformation (FFT), as well as unwrapped and wrapped phase based on non-weighted least square method for discrete cosine transform (DCT). At last, surface distribution was obtained. The image aquisition of the SiO2 film and the pre-processing of interferogram was performed.The result indicates that it is consistent with the result measured by Zygo interferometer.