converting floating point to RADIANCE HDR format

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" <[email protected]>
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 <[email protected]>
> 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
> 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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