在研究二维快速傅里叶变换法进行干涉测试基本原理的基础上,提出一种基于二维快速傅里叶变换的长度测量法.以量块长度的测量为对象,被测量块置于泰曼格林干涉仪测试光路中,参考光波分别与待测长度的量块表面和辅助平面反射的测试光波形成干涉条纹,条纹由图像采集系统采集.利用编制的算法处理软件,通过处理干涉条纹图中量块边缘识别、区域延拓、滤波、波面统一,获得了量块全场表面的空间长度分布,实现了对量块长度的自动化测量.结果表明：该测量法不仅具有较高的测量准确度,而且具有全场测试和非接触测量等优点.

Based on the study of basic principle of interferometry using 2D FFT arithmetic,a method to measure the length is proposed.The gauge block,as a measured sample,is placed into the light path in a TwymanGreen interferometer,and the interference fringes are generated between the reference beam and the reflected beam of the tested block upper surface and the assistant plane respectively.The interferogram is collected by a image acquisition system.The algorithm processing software is used to achieve block edge identification,region extension,filtering,phase unwrapping etc.The length distribution with block information can be obtained in the whole field and the length of the gauge block can be obtained automatically.The results indicate that the proposed method has advantages of high precision,whole field and noncontact in the measuring.