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 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