[Radiance-general] Infrared outdoor scene simulation

[Peter Apian-Bennewitz]

my two toughts:

Andrew Bettison wrote:

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> ....
> I will need to make some modifications to RADIANCE for this project:
>
> * The first modification is a way to specify very irregular 
> subdivision of
> the image plane so that the level of detail of and around objects of
> interest can be wound up, while "uninteresting" parts of the scene can be
> rendered in much lower detail to speed computation.  Essentially, this 
> would
> provide a kind of selective oversampling.

Either use rtrace as render engine and plug a point/direction generator 
before and an value-to-image assembler behind that, or start from rpict.

> * The second modification is a different atmospheric propagation model 
> that
> can accurately compute infrared as well as visible spectral path 
> emissions
> and attenuations between any two points under specified environmental
> conditions.  The model itself is very extensive, highly validated, and of
> military pedigree.  The modification to RADIANCE would take the form 
> of an
> atmospheric model "plug-in" scheme for rpict(1) and a gensky(1)-like 
> program
> that would use the plug-in to compute a sky radiance map and solar/lunar
> position+radiance. 

Gendaylit (Perez sky model) is the only other sky model (gensky 
substitute) I'm aware of.
Simulating IR viewing through the atmosphere would require 
fixes/changes/add-ons to the mist material.

> ....
> - Does anyone have any comments that might assist me to plan this 
> work, or
>  make the outcome more useful for the RADIANCE community?  I would 
> like to
>  know about any issues such as outstanding performance/accuracy concerns
>  with the existing ray propagation model, or limitations to be aware 
> of in
>  the rendering of large-scale, outdoor scenes, or any wish-list features
>  that may dovetail into this work. 

Since Radiance uses a bounding box for the scene, a very large scene 
probably requires adjusting some default rpict parameters (e.g. -ar).
Otherwise, most internal variables are 'double'.

-Peter

-- 
 pab-opto, Freiburg, Germany, www.pab-opto.de