 |
validation
abstract:
We present a technique for calibrating a CCD camera for direct colorimetric comparison between the captured images of the real environment and synthetic images of the simulated environments. We use this comparison to validate lighting simulation algorithms used for computing synthetic images.
publication:
- S. N. Pattanaik, James Ferwerda, Kenneth E. Torrance and Donald P. Greenberg,Proceedings of IS&T/SID's 5th Color Conference, Arizona, 17-21 November, 1997.
related publication:
algorithms
abstract:
We introduce the potential equation which along with the rendering equation forms an adjoint system of equations and provides the mathematical framework for all known approaches to illumination computation. The potential equation is more natural for illumination computations which simulate light propagation starting from the light sources, such as, progressive radiosity and particle tracing. Using the mathematical handles provided by the adjoint system of equations and the random walk model, we present a number of biasing schemes for improving the computation of flux estimation. Of particular significance is the scheme to use an approximate potential value as the biasing function for directing a majority of the random walks through regions of importance in the environment thus reducing the variance in the estimates of flux in these regions. Finally results from a simple implementation of this scheme is presented.
publication:
- S. N. Pattanaik and S. P. Mudur, ACM Transactions on Computer Graphics, January 1995.
related publication:
- S. N.
Pattanaik and
Kadi Bouatouch, "Interactive
Walk-Through
Using Particle Tracing", CG International 1995, Leeds, UK,
25-30
June, 1995.
- S. N.
Pattanaik and
Kadi Bouatouch, "Adjoint
Equations and Particle Tracing for Global Illumination", Technical
Report IRISA-903, 1994.
- S. N.
Pattanaik and
S.P. Mudur, "The
Potential Equation and Importance in Illumination Computations", Computer
Graphics
Forum, Vol. 12(2), pp. 131-136,1993.
- S. N.
Pattanaik and
S.P. Mudur, "Efficient
Potential Equation Solutions for Global Illumination Computation", Computers
& Graphics, Vol. 17(4), pp. 387-396, 1993.
- S. N.
Pattanaik and
S.P. Mudur, "Computation
of Global Illumination in a Participating Medium by Monte Carlo
Simulation", The Journal of Visualisation and Computer Animation.
Vol. 4(3), pp. 133-152, 1993.
- S. N.
Pattanaik and
S.P. Mudur, "The
Mathematical Framework of Adjoint Equations for Illumination Computation",
Proceedings of the International Conference on Computer Graphics
(IFIP-ICCG93), Bombay, India, 1993.
- S. N.
Pattanaik, Computational
Methods for Global Illumination and Visualization of Complex 3D
Environments, Ph.D.
Thesis, BITS-Pilani, India, 1993.
abstract:
We present a simple and inexpensive method for computing the estimates of error in a hierarchical linear radiosity method. We compute lower and upper linear bounds of the actual radiosity function over the surface elements. We carry out this by computing linear upper and lower bounds of the kernel of the radiosity equation. Also we compute these bounds in a form which makes trivial the effort of projecting the integral equation involving such kernels. We provide the hierarchical algorithm for computing the radiosity bounds. We derive the expression for computing error-estimates from these bounds. Finally we propose a refinement indicator for carrying out the link refinement.
publication:
- S. N. Pattanaik and Kadi Bouatouch, Eurographics Rendering Workshop'95, Dublin, 12-14 June, 1995.
abstract:
In this paper we propose the use of higher order radiosity (multi-wavelet radiosity) along with discontinuity meshing. Unlike regular multi-wavelet subdivision, we carry out the subdivision along the discontinuity boundary. That means, instead of deriving the finer basis functions by uniform parametric dilations of a mother basis function, we derive the finer basis by mapping the mother basis to arbitrary subdomains created during the subdivision along the discontinuity boundary. To carry out push and pull operations, which are crucial to the hierarchical algorithm, we compute the necessary
lter functions. Our method combines the advantages of wavelet radiosity and discontinuity meshing. The preliminary result shows significant computational improvement.
publication:
- Kadi Bouatouch and S. N. Pattanaik, Graphics Interface, May 15-19, 1995, Quebec City.
related publication:
|
|
university of central florida : graphics group |
|
 |
