Image alignment with scaling and global translation

摘要

A technique for image alignment with global translation and linear stretch determines translation parameters for three corresponding linearly displaced blocks in a reference image and a corresponding distorted test image. From the differences between the translation parameters for the three blocks the presence of stretch is detected and, if detected, a stretch factor is estimated. The estimated stretch factor is used as a starting point to stretch the reference image to overlap the distorted test image as a refinement process. The resulting refined stretch factor is then used in a reverse stretch process to shrink the distorted test image, and the distorted test image is then aligned with the reference image to obtain picture quality metrics.