[Radiance-general] image formatting for input to evalglare

[kkonis at berkeley.edu]

Dear list,

I am trying to format HDR images produced from a Canon A570 digital camera
with a 180 deg fisheye converter attached.

The images are 1600,1200 pixels (x,y) and have the circular "fisheye" view
centered in the image.

I need to do three operations:

1) crop image down to a square shape, so that it bounds the hemispherical
view of the lens and

2) filter the cropped image down to less than 800 x 800 pixels to input to
evalglare (i can do this with pfilt -1, and this works fine so long as
pcompos is not involved)

3) then i need to edit the image file's header info and trick it into
thinking it has a 180 view (since the camera does not know it has a
converter attached!) e.g.


VIEW= -vta -vh 180 -vv 180 -vp 0 0 0 -vd 1 0 0 -vu 0 0 1


Right now i am perplexed when i use pcompos to crop the image via:

pcompos -x 1200 input/$image -200 0 > output/{$image}

The result is a new "cropped" hdr image that looks great from a cropping
standpoint, but the luminance values are much lower when viewed in
photosphere (compared to the orig image)

My guess is there is something happening to the header:

here is the original header:


#?RADIANCE
CAMERA= Canon Canon PowerShot A570 IS version v.0
EXPOSURE=8.278360e-02
VIEW= -vtv -vh 52.456387 -vv 40.558973
CAPDATE= 2010:10:07 10:41:59
hdrgen created HDR image from 'IMG_0450.JPG' 'IMG_0449.JPG' 'IMG_0448.JPG'
'IMG_0447.JPG' 'IMG_0446.JPG' 'IMG_0445.JPG' 'IMG_0444.JPG' 'IMG_0443.JPG'
'IMG_0442.JPG' 'IMG_0441.JPG'
PRIMARIES= 0.6400 0.3300 0.3000 0.6000 0.1500 0.0600 0.3127 0.3290
FORMAT=32-bit_rle_rgbe

-Y 1200 +X 1600

................ and the result after the pcompos ...................

#?RADIANCE
CAPDATE= 2011:03:01 06:30:57
GMT= 2011:03:01 14:30:57
input/201010071045.hdr:
	CAMERA= Canon Canon PowerShot A570 IS version v.0
	EXPOSURE=8.778544e-02
	VIEW= -vtv -vh 52.456387 -vv 40.558973
	CAPDATE= 2010:10:07 10:46:59
	hdrgen created HDR image from 'IMG_0460.JPG' 'IMG_0459.JPG'
'IMG_0458.JPG' 'IMG_0457.JPG' 'IMG_0456.JPG' 'IMG_0455.JPG'
'IMG_0454.JPG' 'IMG_0453.JPG' 'IMG_0452.JPG' 'IMG_0451.JPG'
	PRIMARIES= 0.6400 0.3300 0.3000 0.6000 0.1500 0.0600 0.3127 0.3290
pcompos -x 1200 input/201010071045.hdr -200 0
FORMAT=32-bit_rle_rgbe

-Y 1200 +X 1200

..................................................................

While on the subject of header manipulation, I am eager for suggestions
for how to edit lines of the header. In my case i want to replace the
original view line

VIEW= -vtv -vh 52.456387 -vv 40.558973


with


VIEW= -vta -vh 180 -vv 180 -vp 0 0 0 -vd 1 0 0 -vu 0 0 1



I have tried doing this "manually" in BBedit and Xcode, but get an
"unexpected end of file" error



Any suggestions are appreciated!

-Kyle

Kyle Konis
Ph.D. Candidate
Dept. of Architecture (Building Science)
University of California, Berkeley
Research Assistant, Lawrence Berkeley National Lab
Tel. (206) 303 9786
Email: kkonis at berkeley.edu