Efficient Opacity Specification Based on Feature Visibilities in Direct Volume Rendering

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dc.contributor.authorWang, Yunhaien_US
dc.contributor.authorZhang, Jianen_US
dc.contributor.authorChen, Weien_US
dc.contributor.authorZhang, Huaien_US
dc.contributor.authorChi, Xuebinen_US
dc.contributor.editorBing-Yu Chen, Jan Kautz, Tong-Yee Lee, and Ming C. Linen_US
dc.date.accessioned2015-02-27T16:14:14Z
dc.date.available2015-02-27T16:14:14Z
dc.date.issued2011en_US
dc.description.abstractDue to 3D occlusion, the specification of proper opacities in direct volume rendering is a time-consuming and unintuitive process. The visibility histograms introduced by Correa and Ma reflect the effect of occlusion by measuring the influence of each sample in the histogram to the rendered image. However, the visibility is defined on individual samples, while volume exploration focuses on conveying the spatial relationships between features. Moreover, the high computational cost and large memory requirement limits its application in multi-dimensional transfer function design. In this paper, we extend visibility histograms to feature visibility, which measures the contribution of each feature in the rendered image. Compared to visibility histograms, it has two distinctive advantages for opacity specification. First, the user can directly specify the visibilities for features and the opacities are automatically generated using an optimization algorithm. Second, its calculation requires only one rendering pass with no additional memory requirement. This feature visibility based opacity specification is fast and compatible with all types of transfer function design. Furthermore, we introduce a two-step volume exploration scheme, in which an automatic optimization is first performed to provide a clear illustration of the spatial relationship and then the user adjusts the visibilities directly to achieve the desired feature enhancement. The effectiveness of this scheme is demonstrated by experimental results on several volumetric datasets.en_US
dc.description.seriesinformationComputer Graphics Forumen_US
dc.identifier.doi10.1111/j.1467-8659.2011.02045.xen_US
dc.identifier.issn1467-8659en_US
dc.identifier.urihttps://doi.org/10.1111/j.1467-8659.2011.02045.xen_US
dc.publisherThe Eurographics Association and Blackwell Publishing Ltd.en_US
dc.titleEfficient Opacity Specification Based on Feature Visibilities in Direct Volume Renderingen_US
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