[Radiance-general] converting floating point to RADIANCE HDR format

[Katja Doerschner]

Thank you very much for the fast reply & comprehensive information!
I believe I have everything I need now ;-).

katja


----- Original Message -----
From: "Gregory J. Ward" <gregoryjward at gmail.com>
Date: Tuesday, January 25, 2005 5:32 pm
Subject: Re: [Radiance-general] converting floating point to RADIANCE 
HDR	format

> Hi Katja,
> 
> Why don't you just borrow the OpenSource C code in the Radiance 
> distribution?  No need to roll your own, really.  The Radiance 
> picture 
> format is well-described in:
> 
> 	http://radsite.lbl.gov/radiance/refer/filefmts.pdf
> 
> The code you want is in the ray/src/common directory in the 
> distribution, which may be downloaded from:
> 
> 	http://www.radiance-online.org/software
> or:
> 	http://radsite.lbl.gov/radiance/download.html
> 
> There is also a program that will convert from floating-point raw 
> files 
> to and from Radiance pictures, called pvalue.  It's use is a 
> little 
> obscure, though.  It's described in the man pages section on radsite:
> 
> 	http://radsite.lbl.gov/radiance/man_html/whatis.html
> 
> I assume you read the article in Graphics Gems II, already?
> 
> -Greg
> 
> > From: Katja Doerschner <kd462 at nyu.edu>
> > Date: January 25, 2005 2:07:28 PM PST
> >
> > Hi,
> >  I have an array of M x N x 3 (as in RGB) single precision floating
> > point numbers,
> >  and would like to save it as a RADIANCE hdr format which uses 
> 32 bits
> > per pixel,
> >  i.e. R G B have each 8 bits and they all share one exponent 
> which is
> > also 8 bits.( If I understand this correctly)
> >  I would like to know how exactly the format works. How does one 
> pick> the common exponent? How does one deal with extrem intensity 
> values in
> > the different color channels?
> > I am writing the program in C.
> >  Can anyone help?
> >
> > THANKS
> 
> 
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