[Radiance-general] macbethcal error

[Gregory J. Ward]

Hi Rob,

I suspect that the corners of your image are not specified in the  
proper coordinates, or are not the right corners -- assuming you used  
the -p option to macbethcal.  Remember that the y-coordinate from  
Photosphere is reversed from that produced by ximage, which is what  
macbethcal expects...

-Greg

P.S.  If you're still stuck, send me your image and I'll see what I  
can do with it.

> From: Rob Guglielmetti <rpg at rumblestrip.org>
> Date: February 5, 2006 10:36:16 AM PST
>
> Howdy.
>
> So, I'm trying to use the macbethcal utility for the first time,  
> and am getting an odd error.  The first time I tried to create a  
> calibration file I got an "out of gamut" error, which I understand  
> points to a poorly exposed gretag photo.  Before re-photographing  
> everything, I thought maybe cropping my gretag image to the  
> registration marks may help (lazy Sunday thinking).  But now, after  
> cropping the photo and re-creating the pic file, I now get the  
> following error when running macbethcal (macbethcal -d debug.pic  
> mbscan.pic colorcal.cal):
>
> macbethcal: non-increasing neutral patch
>
> The resulting debug.pic is 59 bytes and is useless.  Two questions:  
> how can I get a better image to avoid the out of gamut error, and  
> what caused the error above?  I was using northern skylight on a  
> fairly cloudless day for my lighting, and f2.0 1/125 for all  
> exposures.
>