Research on Graphics

I've come to graphics in the year 2000 or so, and up to now I've been working on the following projects:

  • Voxel global illumination (global illumination using voxels)
  • Geometric modeling using linear programming
  • 3D Reconstruction and Augmented Reality
  • I wrote a textbook on graphic algorithms (in French)
  • Plus some, including some confidential public private parnerships.

I think the most significant, and the least succesful of these works was the Voxel Based Global Illumination Method.
Basically, either poeple laughed at the idea, or they got mad at me for proposing such a radical approach.
In any way, I had most difficulty publishing the thing.
You can find a selection of papers of papers here, here and here.
I have to admit we were slow to develop an interactive GPU version of the method. But never mind.
Anyway, I am happy that some people are effectively applying some of the ideas.

Voxel Global Illumination

I've proposed a Voxel method
for radiosity which was published as a poster at DGCI'2002. This is a
completely
new approach to global illumination. Basically,
when we want to render a 3D scene, we approximate the surfaces of
all the objects by a voxel surface (see the topological part
of my research for a theoretical study of such discrete surfaces).

Once we have a discrete scene composed of voxels, encoded
in an octree data structure, we discretize both surfaces
and directions in the space in the continuous diffuse illumination
equation
(a classical equation used in radiosity), thus obtaining
a discrete equation. As in classical radiosity, this
discrete equation fullfils the requirements for applying
(say) the Gauss-Seidel method, so we can numerically compute
a solution of the equation.



This method has been much improved and made practical by my PhD student
Pierre Chatelier, who
made substantial optimization (providing optimal complexity for the
visibility problem) and generalized the method for general
BRDF. Lukasz Piwowar
is
currently improving the method a lot, by providing unaliased display
which enables to
reduce the number of voxels dramatically, and including all source code
in a comprehensive software.



The method is being developped with a parallel algorithm for cluster by
my student Rita Zrour,
under the joint supervision of Fabien Feschet.

Here is a recent test image (sponza atrium) :




Here are a few more images, some of which are voxel global illumination
combined with local specular models:








Here are the two first images, (with only
lambertian reflexion and
aliased display) ever obtained by our method

(at that time, the method was
very slow and nobody took it seriously. It was published as a poster):



Result of radiosity, display by
z-buffer




same scene as above, other
viewpoint, display by z-buffer.