[Radiance-general] pixel axis origin

[Greg Ward]

Hi Ery,

See page 31 of:

	http://radsite.lbl.gov/radiance/refer/filefmts.pdf

The standard ordering follows from the upper-left to the upper-right, then down by scanlines.  The final row starts with (0,0), which is the left-most X coordinate and bottom-most Y coordinate.

If you want a different ordering, you can pass the image through pflip, first.

Cheers,
-Greg

> From: Ery Djunaedy <ery.mailinglist at gmail.com>
> Date: January 23, 2012 8:04:41 AM PST
> 
> Folks,
> 
> I reported the RGB values from an HDR image using the following command:
> pvalue -h -H -o filename.hdr
> 
> I get something like:
>      0    3743       2.713e-03       2.541e-03       2.541e-03
>      1    3743       2.713e-03       2.541e-03       2.541e-03
>      2    3743       2.730e-03       2.558e-03       2.627e-03
>      3    3743       2.747e-03       2.592e-03       2.661e-03
>      4    3743       2.696e-03       2.610e-03       2.661e-03
>      5    3743       2.730e-03       2.644e-03       2.696e-03
>      6    3743       2.627e-03       2.644e-03       2.661e-03
>      7    3743       2.696e-03       2.696e-03       2.713e-03
>      8    3743       2.782e-03       2.696e-03       2.747e-03
> 
> My question is: where is the (0,0) located? Bottom left of the image? And then the result of that command prints the pixel from top left?
> 
> Thanks,
> 
> Ery