radiance pic output

radiance-general
1

What is the bit depth of the pic(s) that Radiance generates?
I use ra_pict to view them on my Mac - and switch the photoshop setting from
8 bits per channel to 16 bits per channel.
Then when I look at the histogram, values are spaced over the entire range.
Is it producing high dynamic range images?
Am I losing anything when I convert to pict?

thanks
Rob

2

Hi Rob,

It is difficult to compare Radiance picture resolution to traditional integer images as understood by Photoshop. Radiance uses a 32-bit RGBE floating-point format, which is described in an article I wrote for Graphics Gems II, but some information may also be found in the following text file distributed with the system:

  ray/doc/notes/picture.format

I recently added an option to the pvalue program to output raw 16-bit/primary files which may be imported into Photoshop using the "raw" type. Use the following command:

  pvalue -dw image.pic > image.raw

Then, import it in Photoshop as a "raw" 16-bit interleaved image with header. You'll have to tell it the resolution, and ask Photoshop to guess the header length, which you can have it preserve in case you ever want to get back into Radiance format with a reverse conversion.

-Greg

···

From: "Fitzsimmons, Rob" <[email protected]>
Date: Tue May 13, 2003 10:13:41 AM US/Pacific
To: "'[email protected]'" <[email protected]>
Subject: [Radiance-general] radiance pic output
Reply-To: [email protected]

What is the bit depth of the pic(s) that Radiance generates?
I use ra_pict to view them on my Mac - and switch the photoshop setting from
8 bits per channel to 16 bits per channel.
Then when I look at the histogram, values are spaced over the entire range.
Is it producing high dynamic range images?
Am I losing anything when I convert to pict?

thanks
Rob