by Ivan Viola, Armin Kanitsar, Meister Eduard Gröller

Abstract

Non-linear filtering is an important task for volume analysis. This paper presents hardware-based implementations of various non-linear filters for volume smoothing with edge preservation. The Cg high-level shading language is used in combination with latest PC consumer graphics hardware. Filtering is divided into per-vertex and per-fragment stages. In both stages we propose techniques to increase the filtering performance. The vertex program pre-computes texture coordinates in order to address all contributing input samples of the operator mask. Thus additional computations are avoided in the fragment program. The presented fragment programs preserve cache coherence, exploit 4D vector arithmetic, and internal fixed point arithmetic to increase performance. We show the applicability of non-linear filters as part of a GPU-based segmentation pipeline. The resulting binary mask is compressed and decompressed in the graphics memory on-the-fly.

Keywords: Non-Linear Filtering, Segmentation, Hardware Acceleration

Download full paper

Ivan Viola, Armin Kanitsar, Meister Eduard Gröller, "Hardware-Based Nonlinear Filtering and Segmentation using High-Level Shading Languages", in proceedings of IEEE Visualization 2003 (pages 309-316), hwnlfilt.pdf (8,781 KB).

Figures in the paper

Figure 1:

Liver data set and its segmented vessel structure using Median, Bilateral and Rotated mask filters.
Figure 2:

The filtering and segmentation pipeline.
Figure 3:

Setup for 2D texture slices and corresponding pbuffers.
Figure 4:

Setup for rendering context and rendered quad geometry.
Figure 5:

Pre-computed addressing of neighboring samples within one slice.
Figure 9:

Sub-regions of the decomposed operator mask.
Figure 11:

Liver dataset segmented via thresholding without and with pre-filtering using the median filter, rotated mask (upper row) and bilateral filters (bottom row).

Additional Material

Video showing the filtering results can be found here.

BibTeX Entry

@InProceedings{vis-viola03,
  author =      {I. Viola and A. Kanitsar and M. E. Gr{\"o}ller},
  title =       {Hardware-Based Nonlinear Filtering and Segmentation using High-Level Shading Languages},
  booktitle =	{Proceedings of {IEEE} Visualization '03},
  year =        {2003},
  pages =        {309--316},