In this paper the second cross-grating of a cross-grating interferometer is replaced with two one-dimensional gratings and the two fringe boxes of x and y directions are separated. When an object is composed of N discrete points, the image, N2 points, can be obtained from the two fringe boxes, consisting of the N correct ones and N(N - 1) false reconstructions. The second image is obtained by rotating the cross-grating interferometer an angle about its axis of symmetry. Comparing the first image to the second, we discover that the N(N-1) false reoonstruotiong are different and the N oorrect image points are the same. By multiplying the two images, the false reoons—tmotions are eliminated and the correot ones are obtained. The experimental results are given.