再现二维图像的"莫阿锁"

给出了用莫阿（Moire原理再现多灰阶二维图像技术的步骤：用半色调屏对二维图像进行第一次编码，得到半色调屏图像fA（u，v），然后分别对fA（u，v）图像和1一fA（u，v）反转图像用同空间频率为ξ0的基栅进行第二次编码，图像与反转图像之间基栅位相差为π，两次编码的方向夹角为45°。本技术可用于防伪。

Design of "Moir Lock" for Reconstructing 2D Images

This paper presents the steps of reconstructing a 2-dimensional grayscale image using Moir technique. First, the 2D image was encoded with a halftone screen and turned into a halftone-screen image fA(u,v); Secondly the image fA and 1-fA (the reversed image of fA) were encoded by two gratings respectively, while keeping the frequencies of the two gratings the same and the phase difference being π. The angle between the encoding directions of the first and second steps is set to 45° so that the noise of the longitudinal Moiré fringes can be avoided. This technique can be applied for anti-counterfeit purpose.