Detection of image scaling-factors and scaling-center positions in scale-changed images with the phase-difference spectrum analysis

Abstract

Precise detections of scaling factors and scale-change center positions for input images is needed for correcting scale-changed input-images. In this paper, scale factors for images with different scale-change center positions are detected by SPSA technique. Furthermore, a new simple and precise detection approach for analytically detecting scale-change center positions is proposed. From conscientious experiments using three kinds of image types, it becomes clear that scaling factors of input images can be detected accurately independently of scale-change center positions and that the center positions can be located with as a high accuracy as averagely 1 pixel except for a few cases. These results show the effectiveness of the proposed approach.