A fast median filter using AltiVec

The paper describes the design and implementation of a median filter for graphics images on the Motorola AltiVec architecture. The filter utilizes 16-way SIMD parallelism to filter images at rates of 1.15 cycles/pixel for 3×3 squares and 6.6 cycles/pixel for 5×5 squares. The median filter is based on a new sorting network which sorts N² numbers (arranged in an N×N square) by sorting all columns, rows, and diagonal lines in the square. The paper also describes a scheme for efficient testing of the sorting network