Volume illustration: nonphotorealistic rendering of volume models

Abstract

AbstractÐAccurately and automatically conveying the structure of a volume model is a problem not fully solved by existing volume rendering approaches. Physics-based volume rendering approaches create images which may match the appearance of translucent materials in nature, but may not embody important structural details. Transfer function approaches allow flexible design of the volume appearance, but generally require substantial hand tuning for each new data set in order to be effective. We introduce the volume illustration approach, combining the familiarity of a physics-based illumination model with the ability to enhance important features using nonphotorealistic rendering techniques. Since features to be enhanced are defined on the basis of local volume characteristics rather than volume sample value, the application of volume illustration techniques requires less manual tuning than the design of a good transfer function. Volume illustration provides a flexible unified framework for enhancing structural perception of volume models through the amplification of features and the addition of illumination effects.

Hybrid Focal Region-Based Volume Rendering of Medical Data

“…Recently, nonphotorealistic rendering, which originally has been used for computer graphics in general, has been proposed for volume rendering [1,2,3], definitely extending the abilities for the investigation of 3D data. Rheingans [2] introduced the volume illustration approach to enhance important features (boundary enhancement, sketch lines, etc.)…”

“…Rheingans [2] introduced the volume illustration approach to enhance important features (boundary enhancement, sketch lines, etc.) using nonphotorealistic rendering techniques.…”

Distance Based Enhancement for Focal Region Based Volume Rendering

“…This technique dims the color of objects far from the viewer, creating an effect similar to viewing the scene through haze. Rheingans et al [4] adapted this technique for volume rendering, dimming volume sample colors as they recede from the viewer. Lu et al [3] introduced a method to use distance as one of the factor to create the nonphotorealistic volume stippling.…”

Viewpoint information channel for illustrative volume rendering

“…Illustrative techniques are suitable for emphasizing certain features or properties while omitting or greatly simplifying less important details [17]. The most popular styles, such as stippling, hatching, and silhouettes are from the pen-and-ink family [5,16].…”