Two-Pass Image and Volume Rotation

We present a novel two-pass approach for both 2D image and 3D volume rotation. Each pass is a pseudo shear. However, it has a similar regularity as a pure shear in that a beam remains rigid while being sheared. Furthermore, the 3D pseudo shear guarantees that beams within one major axis slice remain in the same directional plane after the shearing. These properties make it feasible to implement the pseudo shears on a multi-pipelined hardware or a massively parallel machine. Compared with the existing decompositions, ours offer a minimum number of shears to realize an arbitrary 3D rotation. Our decomposition also preserves the image/volume quality by guaranteeing no minification for the first pass shear.