Hierarchical block matching method for fast rotation of binary images

In this paper, we develop a block matching method for fast rotation of bina ry images. We define coarse and fine blocks to extract bit patterns of an o riginal image and calculate their predrawn mapping patterns (PMPs) using th e given rotation angle. The traditional calculation for rotation of images can be thus replaced with simple matching of bit patterns of blocks and dra wing of their two-dimensional (2-D) PMPs at the output plane. A scheme of o verlapping blocks is also used to solve problems of hole generation and top ology variation usually occurring in rotation. Experimental results demonst rate that our proposed method performs best in terms of rotation speed comp ared to other algorithms.