By Topic

Structured penumbral irradiance computation

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Drettakis, G. ; Inst. Nat. de Recherche en Inf. et Autom., Grenoble, France ; Flume, E.L.

A definitive understanding of irradiance behavior in penumbral regions has been hard to come by, mainly due to the computational expense of determining the visible parts of an area light source. Consequently, sampling strategies have been mostly ad hoc, and evaluation of the resulting approximations has been difficult. In this paper, the structure of penumbral irradiance is investigated empirically and numerically. This study has been made feasible by the use of the discontinuity mesh and the backprojection, an efficient data structure representing visibility in regions of partial occlusion. Regions of penumbrae in which irradiance varies nonmonotonically are characterized empirically, and numerical tests are performed to determine the frequency of their occurrence. This study inspired the development of two algorithms for the construction of interpolating approximations to irradiance: one algorithm reduces the number of edges in the mesh defining the interpolant domain; and the other algorithm chooses among linear, quadratic, and mixed interpolants based on irradiance monotonicity. Results from numerical tests and images are presented that demonstrate good performance of the new algorithms for various realistic test configurations

Published in:

Visualization and Computer Graphics, IEEE Transactions on  (Volume:2 ,  Issue: 4 )