KIT | KIT-Bibliothek | Impressum | Datenschutz

Low-Pass Filtered Volumetric Shadows

Ament, Marco; Sadlo, Filip; Dachsbacher, Carsten; Weiskopf, Daniel

We present a novel and efficient method to compute volumetric soft shadows for interactive direct volume visualization to improve the perception of spatial depth. By direct control of the softness of volumetric shadows, disturbing visual patterns due to hard shadows can be avoided and users can adapt the illumination to their personal and application-specific requirements. We compute the shadowing of a point in the data set by employing spatial filtering of the optical depth over a finite area patch pointing toward each light source. Conceptually, the area patch spans a volumetric region that is sampled with shadow rays; afterward, the resulting optical depth values are convolved with a low-pass filter on the patch. In the numerical computation, however, to avoid expensive shadow ray marching, we show how to align and set up summed area tables for both directional and point light sources. Once computed, the summed area tables enable efficient evaluation of soft shadows for each point in constant time without shadow ray marching and the softness of the shadows can be controlled interactively. We integrated our method in a GPU-based volume renderer with ray casting from the camera, which offers interactive control of the transfer function, light source positions, and viewpoint, for both static and time-dependent data sets. ... mehr

Open Access Logo

DOI: 10.1109/TVCG.2014.2346333
Zitationen: 18
Web of Science
Zitationen: 13
Zugehörige Institution(en) am KIT Institut für Visualisierung und Datenanalyse (IVD)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2014
Sprache Englisch
Identifikator ISSN: 1077-2626
KITopen-ID: 1000049923
Erschienen in IEEE Transactions on Visualization and Computer Graphics
Verlag Institute of Electrical and Electronics Engineers (IEEE)
Band 20
Heft 12
Seiten 2437-2446
Nachgewiesen in Web of Science
KIT – Die Forschungsuniversität in der Helmholtz-Gemeinschaft
KITopen Landing Page