A Fast, Small-Radius GPU Median Filter

This chapter describes a very fast median filter for today's GPUs, and explains how to port it to future GPUs and other data-parallel processors like DSPs and CPUs with vector instructions (e.g., MMX, SIMD). The technique used in this chapter is inherently fast because it is designed with ideal characteristics for streaming parallel architectures:

* No branches
* Single-pass
* Data-parallel across pixels
* Data-parallel at each pixel
* High compute-to-memory ratio

On a GeForce 8800 or comparable GPU, this optimized filter can process multiple 4096x4096 video sequences at over 100 fps, which is important for real-time video processing. We give shaders for the 3x3 and 5x5 kernels for which our filter is appopriate and for a sample higher-order real-time non-photorealistic filter built on several applications median.

Morgan McGuire (Williams College)
Publication Date: 
Friday, February 1, 2008
Research Area: