A comparison of gradient estimation methods for volume rendering on unstructured meshes

Carlos D. Correa, Robert Hero, Kwan-Liu Ma

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

This paper presents a study of gradient estimation methods for rendering unstructured-mesh volume data. Gradient estimation is necessary for rendering shaded isosurfaces and specular highlights, which provide important cues for shape and depth. Gradient estimation has been widely studied and deployed for regular-grid volume data to achieve local illumination effects, but has been, otherwise, for unstructured-mesh data. As a result, most of the unstructured-mesh volume visualizations made so far were unlit. In this paper, we present a comprehensive study of gradient estimation methods for unstructured meshes with respect to their cost and performance. Through a number of benchmarks, we discuss the effects of mesh quality and scalar function complexity in the accuracy of the reconstruction, and their impact in lighting-enabled volume rendering. Based on our study, we also propose two heuristic improvements to the gradient reconstruction process. The first heuristic improves the rendering quality with a hybrid algorithm that combines the results of the multiple reconstruction methods, based on the properties of a given mesh. The second heuristic improves the efficiency of its GPU implementation, by restricting the computation of the gradient on a fixed-size local neighborhood.

Original languageEnglish (US)
Article number5262940
Pages (from-to)305-319
Number of pages15
JournalIEEE Transactions on Visualization and Computer Graphics
Volume17
Issue number3
DOIs
StatePublished - Jan 1 2011

Keywords

  • flow visualization
  • flow visualization.
  • gradient estimation
  • local illumination
  • unstructured meshes
  • Volume rendering

ASJC Scopus subject areas

  • Software
  • Signal Processing
  • Computer Vision and Pattern Recognition
  • Computer Graphics and Computer-Aided Design

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