A Fast Implementation of Image Rotation with Bresenham's Line-Scanning Algorithm.

Image rotation is a fundamental task in image processing. It has two primary stages: rasterization of the rotated domain and evaluation of these pixel values. This paper mainly proposes a novel strategy for the first stage with Bresenham’s line description, and further a natural way for the second stage. Two neighbouring sides of the boundary of the rotated image are expressed by a variation of Bresenham scanning lines, one taken as the supporting side and the other as the moving side. Then the rotated region can be expressed as stacking the copies of the moving side along the supporting side. We re-implement Bresenham’s line algorithm in such a scheme that a line is expressed as successive runs of line segments, so as to rapidly realize the rasterization of the defined domain of the rotated image. At the same time, an incremental method is used to assign values to the pixels. Our method avoids lots of computation that must be conducted in previous works for determining whether a point is in the rotated domain and therefore, according to experiments, significantly decreases running time of image rotation.