[Radiance-general] Radiance 2007 Scientific Workshop - SCHEDULE
Katja Doerschner
doers003 at umn.edu
Thu Sep 20 17:41:10 PDT 2007
Radiance 2007 Scientific Workshop - SCHEDULE
01-02 (Mon-Tues) October 2007, Digital Technology Center, University
of Minnesota, Minneapolis, USA.
Dear All,
Here is the tentative schedule for this year's Radiance workshop.
Tomorrow you will also be able to view it online at http://
www.dtc.umn.edu/cgi-bin/seminars/symposia/radiance.php.
In general, we will have presentations (talks) in the mornings and
tutorial sections in the afternoons.
If you haven't registered yet, please try to do so sooner rather than
later, as it will help us to get a proper head count for the tour,
reception and banquet.
See below what you can look forward to/ what you are missing out on
(if you don't attend!).
Looking forward to see you at the workshop!
Greg,
& Katja
MEETING SCHEDULE
----
October 1:
8:30-9:30 Meet & Greet / Coffee
9:30-9:45 Greg Ward & Katja Doerschner, Introduction
9:45-10:25
Roland Fleming, Max Planck Institute for Biological Cybernetics,
Tuebingen, Germany
“Visual Perception of Surface Material”
Different materials such as silk, bronze and marmalade have
distinctive visual appearances. Human observers are remarkably adept
at recognizing materials across a wide range of viewing conditions
and we are only just beginning to work out how. What gives a
material its characteristic ‘look’? What cues does the visual system
use to identify materials? How can we leverage the assumptions made
by the visual system to improve computer graphics? I will review
some of our research on the perception of material properties such as
gloss, translucency and refractive index that attempts to shed some
light on these questions. I’ll talk about how illumination and 3D
geometry interact with material perception, and discuss the role of
various image statistics (e.g. intensity histogram, amplitude
spectrum) in the visual estimation of material attributes. I’ll then
show one application in which we exploit the heuristics made by the
visual system to enable illusory modifications of material appearance
in photographs.
10.30-10.50 Coffee Break
10:50-11:20
Yu Sheng, Rensselaer Polytechnic Institute, Troy, NY
"Comparing an interactive hybrid global illumination method with
Radiance"
Complex fenestration systems (CFS) can be used to redirect intense
illumination from the sun to more evenly illuminate an architectural
space and thus reduce the lighting needs of buildings. However,
standard distribution of Radiance does not support rendering of CFS
or arbitrary BRDF/BTDF material data. In this talk, we present an
interactive rendering system for architectural design which simulates
a CFS based on 4D Bidirectional Transmission Distribution Function
(BTDF) data. We use a hybrid method of shadow volumes for direct
illumination and radiosity for indirect illumination to achieve
interactive rendering rates.
Our system is appropriate for use in schematic design: an early stage
of the architectural design process where scale, appearance, and
adjacencies of an evolving design are explored. We demonstrate our
system on several models inspired by field observations and the
designs of architecture students we have consulted during the
development of this project.
11:20-11:50
Bei Xiao, University of Pennsylvania, Philadelphia, PA
“Effect of test patch location on color appearance, in the context of
3D objects”
Bei Xiao (1) and David Brainard (2)
(1) Department of Neuroscience, School of Medicine, University of
Pennsylvania, Philadelphia, PA, 19104, USA. (2) Department of
Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
The light reflected from different locations on a single object can
vary enormously. This variation is enhanced when the material
properties of the object are changed from matte to glossy. Yet
humans have no trouble perceiving an object as having a unified
color. We conducted a psychophysical experiment to study how people
perceive the color of different parts of an object. Observers viewed
graphics simulations of a three-dimensional scene containing two
objects, test and match (generated with Radiance in conjunction with
custom software that provided full spectral rendering). The test
object was a soccer ball that had one colored hexagonal face (test
patch). Observers were asked to adjust the color appearance of a
match sphere to the test patch. The match sphere was always matte,
while we varied the surface gloss of the entire soccer ball
(including the test patch). The test patch could be located at
either an upper or lower location on the soccer ball. The data show
that there is an effect of test patch location on observers’ color
matching, but this effect is small compared to the physical change in
the average light reflected from the test patch across the two
locations. In addition, we found that observers exhibit stability of
color perception of the test patch in the face of variation of
surface gloss.
12:00-1:30 Lunch
1:30 -2:30
Gary Meyer, Victoria Interrante, University of Minnesota, Department
of Computer Science
Digital Design Consortium and VR lab tour/demos
2:30-3:15
Greg Ward, Anyhere Software, Albany, CA
Tutorial: “Image-based Lighting”
Image-based lighting (IBL) is a set of techniques originated by Paul
Debevec for incorporating synthetic objects into real-world scenery
<www.debevec.org>. IBL is widely used by the movie industry for
special effects production, and offers some interesting possibilities
for daylight simulation as well. In this tutorial, Greg will
demonstrate how easy it is to capture a high dynamic-range
environment map (a.k.a. a "light probe") using a standard digital
camera and use it to render synthetic objects into a background plate
with the help of Photosphere and the "mksource" program. We will
discuss how other researchers, such as Santiago Torres, have employed
IBL and Radiance for daylighting simulation.
3.15-3:30 Coffee Break
3:30-4:00
Zack Rogers, Architectural Energy Corporation, Boulder, CO
Tutorial: “Sensor Placement + Optimization Tool (SPOT) Update”
Zack Rogers, Jennifer Scheib, Architectural Energy Corporation
This talk will present recent updates to the Sensor Placement +
Optimization Tool software that acts as a front-end interface to
Radiance. SPOT has grown to provide more detailed electric lighting
and annual daylighting analysis as well as providing photosensor
control analysis. The focus of the presentation will be on the new
features of the software and a case study will be presented of a
project in which we used SPOT to help design a daylight responsive
control system. The talk will be 25 minutes followed by a question
and answer period.
6:30-7.30 Reception
7.30-10:30 Banquet
----
October 2:
9:00-10:00
Zack Rogers, Architectural Energy Corporation, Boulder, CO
“Experiences with Radiance in Daylighting Design, Part III”
Zack Rogers, Galen Burrell and Jennifer Scheib, Architectural Energy
Corporation
This talk will present some of the Radiance modeling Architectural
Energy Corporation has done in support of our Daylighting Design
Consulting work, focusing on the various ways we have used Radiance
to guide the design process.
Radiance has proved to be extremely effective in analyzing and
visualizing daylighting designs, allowing numerous daylighting design
alternatives to be explored beforehand, informing and guiding the
daylighting design decisions of a project. The types of daylighting
design projects that will be highlighted vary widely and include
schools, laboratories, offices, museums, atriums, and others. The
focus of the presentation will be on new work that has occurred since
the Montreal radiance conference in 2005.
The talk will be broken into three-20 minute sections, one section
given by each of the presenters followed by a brief question and
answer period.
10:00-10:25 Coffee break
10:25-10:50
Greg Ward, Anyhere Software, Albany, CA
“Utilizing BTDF Window Data”
This talk presents some new ideas and software for exploiting
measured and simulated bidirectional transmittance distribution
function (BTDF) data in Radiance. Programs and standards for
providing BTDF data are emerging (e.g., LBNL Window 6), and we wish
to take advantage of it in our simulations. Two approaches will be
presented, one geared towards traditional daylight simulation and
rendering and the other towards annual calculations. The first
approach resembles mkillum but without the usual restrictions, since
BTDFs can represent virtually any complex fenestration type. The
second approach requires two passes of rtcontrib, one to account for
the building exterior, and the other for the interior. This fully
separates illumination from geometry and permits time-based
fenestration controls to be simulated efficiently. As this
constitutes work in progress, suggestions will be most appreciated.
10:50-11:20
Daniel Lichtman, University of Pennsylvania, Philadelphia, PA
“RenderToolbox: A MATLAB Toolkit for Hyperspectral Rendering with
Radiance and PBRT”
Daniel P. Lichtman, Bei Xiao, David H. Brainard
We describe a set of Matlab software tools, the RenderToolbox, that
aid in the modeling and rendering of images for use in psychophysical
experiments. The toolbox, which we are making freely available, has
several important features. First, it allows the user to model scenes
in the popular Maya software package and export these into the
remainder of the rendering pipeline. Second, although the toolbox
inherits the scene geometry from the Maya modeler, it allows the user
to associate full spectral reflectance functions and parametric BRDFs
with each object, and full spectral power distributions with each
illuminant. The toolbox then parses the scenes and associated
reflectance/illuminant parameters and passes these to either of two
renderers. These are Radiance and Physically Based Rendering Tools
(PBRT). It invokes the renderers on a wavelength-by-wavelength basis
to produce a hyperspectral image of the scene. The fact that the
toolbox transparently supports two renderers allows easy comparison
of their performance. In addition, the toolbox is configured to make
it easy to re-render the same scene geometry with different choices
of reflectance/illuminant parameters. Fourth, the package provides
support for converting the hyperspectral image to standard color
representations. Finally, the package supports parallel rendering of
the separate wavelength images if a computer cluster is available.
Several example scenes are included with the toolbox to demonstrate
its use and to compare the two renderers’ performance. The simplest
example, a uniformly reflective surface and a single point-light
source, yields two nearly identical images. Each of these matches an
analytical prediction based on the light's spectral power
distribution and surface's reflectance function. A second example
scene includes a single sphere with uniform reflectance under a
distant point-light source. Again, images rendered by Radiance and
PBRT are well-matched to each other and to the directly calculated
image based on the Ward model of surface reflectance. The close
agreement of the two renderers with each other and with direct
calculations for simple scenes provides added confidence that each
renderer is doing a good job simulating physical light flow.
11:20-12:00
Susan Ubbelohde, Loisos + Ubbelohde Associates, Oakland, CA
“Daylighting in Practice: Radiance and the Design Process”
Loisos + Ubbelohde is a consulting and design firm specializing in
sustainable architecture. Our consulting work focuses on advanced
daylighting design and performance, energy modeling and alternative
energy sources. In practice, the use of tools such as Radiance and
physical models is never as direct and linear as theory might
assume. Rather, our use of design and evaluation tools is
continually adapted to the design direction of the project, the
questions posed by the architects, the tradeoffs and negotiations
necessary with mechanical, structural, electrical engineers, lighting
designers and interior designers on the design team, and the goals
and concerns of the building owners and the requirements of outside
agencies such as the US Green Building Council. We will present a
range of recent projects, both consulting projects and design
projects, discussing our use of modeling tools in the projects.
12:00-1:30 Lunch
1:30-2:30
Greg Ward, Anyhere Software, Albany, CA
Tutorial: “Improved Color Rendering with RGB”
Accurate color rendering requires the consideration of many samples
over the visible spectrum, and advanced rendering tools developed by
the research community offer multispectral sampling towards this
goal. However, for practical reasons including efficiency, white
balance, and data demands, Radiance still employs a simple RGB model
in its lighting calculations. Applied naively, this can result in
colors that are qualitatively different from the correct ones. In
this tutorial, we demonstrate two independent and complementary
techniques for improving RGB rendering accuracy in Radiance without
impacting calculation time: spectral prefiltering and color space
selection. Spectral prefiltering is an obvious but overlooked method
of preparing input colors for a conventional RGB rendering
calculation, which achieves exact results for the direct component,
and very accurate results for the interreflected component when
compared with full-spectral rendering. In particular, we demonstrate
the merits of a particular color space transform that has emerged
from the research community as the best performer in computing white
point adaptation under changing illuminants: the Sharp RGB space.
2:30-2:45 Coffee
2:45-3:45 Tutorial, to be announced
End of workshop
Katja Doerschner
University of Minnesota
Psychology Department
218 Elliott Hall
75 East River Road
Minneapolis, MN 55455-0344
Phone:+1 612 626-8551
http://vision.psych.umn.edu/~doerschner
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://radiance-online.org/pipermail/radiance-general/attachments/20070920/c3343016/attachment-0001.html
More information about the Radiance-general
mailing list