principle of rt ok, but too slow !
DESCRIPTION
Towards a 3D light model for growth chambers using an experiment-assisted design Michaël Chelle 1 , Mustafa Demirel 1 , Christophe Renaud 2. radiosity photon mapping (Ray Tracing). Test with Radiance (G. Ward) Irradiance distribution in an empty room. A future OO photon mapping - PowerPoint PPT PresentationTRANSCRIPT
Principle of RT
OK, but too slow!
Towards a 3D light model for growth chambers using an experiment-assisted design
Michaël Chelle1, Mustafa Demirel1, Christophe Renaud2
Yes, but what in the real world ?
What next? What next? The next steps are: implementing in Java or C++ this new algorithm testing for contrasted growth chamber types and cultures.
Conclusion Conclusion Simple experiments have enabled us to quickly proposed a new light model, well adapted to the growth chamber case.
1INRA -UMR Environnement et Grandes Cultures78850 Thiverval-Grignon - France
2 Laboratoire d'Informatique du Littoral (LIL) BP 719 - 62228 Calais cedex - France
FSPM modelingPlant organ response law to physical environment
Fine scale analysis of plant growth and development
Genomic studiesAnalysis of various genotypes in the same environment
Isolating a gene for a given function without environment bias.
Comparing plants grown in the same chamberComparing experiments in different growth chambers
Need of spatially homogenous growth conditions Needs of “standardized” conditions between chambers
Growth chamber experiments
Spatial variability of irradiance (Strader chamber, France)
What a diversity for growth chamber models
How to bypass a “growth chamber” effect in ecophysiology due to spatial heterogeneityModeling the incident or absorbed light for each plant (or organ)
But there is two main difficulties:Complexity of light sources High level of multiple scattering
Case of an empty Strader growth chamber
Measurement the spatial distribution of light
by distinguishing using black occultations
the 0, 1 and (2 to ∞) orders of scattering
E=E0(75%) + E1(18%) + Ex(7%)Results for PAR worktable irradiance
≈Ray-tracing
on simple geometry of perfect mirror
Angular radiance distribution measured simulated
Directionality of light sources + glossy materials => choice of the light modelradiosity
photon mapping (Ray Tracing)
Step 2Follow the photon path within the roomuntil having bounced a wall n times or
hitting the foliage bounding box
Step 1Trace a photon
within a light source
Step 3Follow the photon within the plant bounding box
A future OO photon mapping for growth chamber lighting
Test with Radiance (G. Ward) Irradiance distribution in an empty room