pixel axis origin

radiance-general
1

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

2

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 <[email protected]>
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