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Probabilistic visibility evaluation using geometry proxies
Author(s) -
Billen Niels,
Lagae Ares,
Dutré Philip
Publication year - 2014
Publication title -
computer graphics forum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 120
eISSN - 1467-8659
pISSN - 0167-7055
DOI - 10.1111/cgf.12421
Subject(s) - visibility , shadow (psychology) , ray tracing (physics) , probabilistic logic , intersection (aeronautics) , computer science , geometry , computation , distributed ray tracing , path (computing) , set (abstract data type) , computer vision , artificial intelligence , algorithm , mathematics , rendering (computer graphics) , optics , psychology , physics , psychotherapist , programming language , engineering , aerospace engineering
Evaluating the visibility between two points is a fundamental problem for ray‐tracing and path‐tracing algorithms. Ideally, visibility computations are organized such that a minimum number of geometric primitives need to be checked for each ray. Replacing complex geometric shapes by a simpler set of primitives is one strategy to control the amount of intersection calculations. However, approximating the original geometry introduces inaccuracies in e.g. shadow regions when shadow rays are intersected with the approximate geometry. This paper presents a theoretical framework for probabilistic visibility evaluation. When intersecting a shadow ray with the scene, we randomly select the original geometry, the approximated geometry, or one of several correction terms, to be tested. Not all shadow rays will therefore intersect the original geometry, but our method is able to produce unbiased images that converge to the correct solution. Although probabilistic visibility evaluation is an experimental idea, we show several example scenes that highlight the potential for future improvements.