— Image alignment is a widely used technique in computer vision, and it can be applied to many areas such as image registration and region tracking. Hager and Belhumeur proposed an efficient image alignment algorithm which can find out translation and affine deformations quickly. However, it is known that their algorithm cannot be applied to homographies. Image alignment with a homography is important because general motions of object in 3D space are observed as perspective motions which are another name of homographies. In this paper, we propose an expanded inverse additive algorithm for homographies, and apply the algorithm to region tracking. We conduct real-time tracking experiments to show the performance of the proposed algorithm. Keywords—Hager-Belhumeur algorithm, inverse additive algorithm, region tracking, image alignment, homography