1. A displacement estimation device, for use in estimating a displacement vector from a first pattern in a first original image to a second pattern in a second original image, wherein each original image includes a plurality of pixels, said device comprising: a vector calculator calculating at least a first parameter for a first pixel in said first original image and at least a second parameter for a second pixel in said second original image, said first and second parameters integrating, respectively, the information of: (a) the intensities of pixels in a region of interest surrounding said first and second pixels, and (b) the relative distances from said surrounding pixels to said first and second pixels; and a displacement calculator electrically connected with said vector calculator, and calculating said displacement vector based on said parameters calculated by said vector calculator for said first original image and said second original image.