METHOD AND APPARATUS FOR FAST TWO-DIMENSIONAL COSINE TRANSFORM FILTERING

摘要

An image filtering module (20) provides a method for applying a filter matrix (14) to a source image-data set (30), generated by an image digitizer (10), to yield a digital filtered image (18). The filtering method is performed by: i) converting the source image-data set (30) into frequency-coefficient matrices (33) by an overlapping operation and a scaled forward orthogonal transformation, ii) converting the filter matrix (14) into a descaled frequency filter matrix (34) by a descaled orthogonal transformation, and iii) multiplying the frequency-coefficient matrices (33) by the descaled frequency filter matrix (34) to form filtered coefficient matrices (35) for conversion into the digital filtered image (18) by an inverse orthogonal transformation process.