[Radiance-general] pinterp on a rectangle image

[Greg Ward]

Hi Ery,

The output of pinterp in this case shouldn't be square, but may be "almost square" because 132 and 112 degrees are closer to each other in a hemispherical fisheye than they are in an angular fisheye.  In fact, what you have given me here with -vtv is not a fisheye view at all, but a perspective projection.  In this case, the aspect ratio is even greater.

Unless you go all the way to 180 degrees in each direction, you cannot compute an exact value for the illuminance.  You can come reasonably close if there aren't any really bright areas just out of view.  The cosine correction on most illuminance meters is not much better.

-Greg

> From: Ery Djunaedy <ery.mailinglist at gmail.com>
> Date: February 12, 2012 5:16:15 AM PST
> 
> Thanks Greg,
> 
> The view is:
> VIEW= -vtv -vh 132.125290 -vv 112.682388
> 
> Ery
> 
>> Hi Ery,
>> 
>> Pcompos isn't smart enough to adjust the view after cropping, so it doesn't write it into the header in a way that pinterp can use it.
>> 
>> The image may be coming out square because a hemispherical fisheye can encompass at most 180 degrees vertically and horizontally, whereas an angular fisheye can be up to 360 degrees.  You can of course specify a different horizontal and vertical size with the -vh and -vv options, but both must be less than 180.
>> 
>> What is the view in your original fish.hdr file?
>> 
>> -Greg
>> 
>>> From: Ery Djunaedy<ery.mailinglist at gmail.com>
>>> Date: February 11, 2012 4:54:07 PM PST
>>> 
>>> Folks,
>>> 
>>> I want to convert an angular fisheye to a hemispherical fisheye, like the example in pinterp man page.
>>> 
>>> pinterp -vf fish.hdr -vth -ff fish.hdr 1>  hemi.hdr
>>> 
>>> My concern is that pinterp force the result image to be a square. The image that I have is a rectangular image, with the fisheye circle in the middle. When I use the above command, the result is always a square.
>>> 
>>> My question: is the interpolation also applied to the black region on the left and right side of the fisheye circle?
>>> 
>>> I tried to crop the input hdr to square with the following command (from 5616x3744 to 3744x3744 pixels):
>>> 
>>> ra_xyze -r -u -o fisheye.hdr | pcompos -x 3744 - -936 0>  fisheye_crop.hdr
>>> 
>>> But when I use fisheye_crop.hdr as an input to the pinterp command, it gives a "bad view file"error. Does this simply confirm that man page that the output of pcompos cannot be used with pinterp?
>>> 
>>> Thanks,
>>> 
>>> Ery