Anti-aliasing two-pass image rotation

In image rotation, a two-pass algorithm has many advantages over a one-pass algorithm in high speed computation. The reported two-pass algorithm gives a serious performance degradation in high frequency area at large rotation angles (30 degrees to 45 degrees). This paper presents a new two-pass algorithm that overcomes the limitations of previously reported approaches at large rotation angles. The hardware structure for the two-pass algorithm needs only four additional counters. We have also developed a novel three-dimensional Fourier- theoretical basis including the effect of interpolation. A brief comparison of existing techniques and the two-pass algorithm newly suggested is presented. At large rotation angles, the suggested algorithm has almost the same performance as that of the one-pass algorithm and much better performance than that of an existing two-pass algorithm