image formatting for input to evalglare

radiance-general
1

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: [email protected]

2

Hi Kyle,

This discussion probably belongs on the HDRI list, so I'm cross-posting there.

The thing about pcompos is that it doesn't transfer exposure information, which you need for most images to get the absolute numbers back. Here are the commands you want:

echo "VIEW= -vta -vh 180 -vv 180 -vp 0 0 0 -vd 1 0 0 -vu 0 0 1" > corrected.hdr
ra_xyze -r -o -u orig.hdr | pcompos -x 1200 - -200 0 >> corrected.hdr

The first one puts the view information you want in the header. The ra_xyze command undoes the exposure on the image before passing it to pcompos, which does the cropping and appends it to the view header.

Hope this works.
-Greg

···

From: [email protected]
Date: March 1, 2011 6:48:48 AM PST

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: [email protected]