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New project: camera color profile calculation

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Offline hiker_jon

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Re: New project: camera color profile calculation
« Reply #170 on: 28 / May / 2008, 19:10:18 »
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Quote from: brainwash on 28 / May / 2008, 13:05:40
Are you using DCRaw as-is without any frontend? You should try UFRaw as frontend.

Unfortunately the current version (.13) of UFRaw cannot read my A720 raw files. 

I find color matching to be a mystery.  I need to start with a good approximation to Canon's jpegs.  dng4ps conversion produces good results.  Rawtherapee and  dcraw give poor results when used directly on the A720 raw file
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Offline brainwash

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Re: New project: camera color profile calculation
« Reply #171 on: 29 / May / 2008, 03:36:05 »
dng4ps is currently outdated, so it seemed for my S2IS. Please use dng4ps2 which might give an accurate color balance (the camera's, that is).
But, as I stated, RAW files as written by the camera do not have any white balance performed on them (someone please correct me if I'm wrong).
Also, DNG4PS2 has profile information for A720IS: DNG4PS-2 but I think you must be using the latest beta version, which is what I'm using.
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DawMatt

Re: New project: camera color profile calculation
« Reply #172 on: 29 / May / 2008, 08:26:12 »
Hi sunmoon,

Quote from: sunmoon on 05 / May / 2008, 13:09:25
s5is shot of the calibration palette has been uploaded to zSHARE - dng4ps2_s5is.zip .

I've tried to use the photo for calibration purposes but it needs to be retaken.  Some suggestions:
  • Set your zoom to the middle (approx 38mm on your camera)
  • Clean some of the marks off your monitor
  • Consider increasing your monitor's refresh rate
  • Try to take the photo from directly in front of the monitor to reduce diagonal lines in the picture

It might help you to look at the calibration instructions I'm adding to the wiki.  If you take a new photo of the calibration target you can follow the steps to see for yourself if it generates a usable color matrix.

Thanks,
Matt
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DawMatt

Re: New project: camera color profile calculation
« Reply #173 on: 29 / May / 2008, 10:35:21 »
lukg,

I've tried to download your S5 calibration photos and 7zip won't open the rar archives you've uploaded, and some of the links you've included result in "file not found" errors.

Can you please try to recompress and upload the calibration photos?

Thanks,
Matt
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DawMatt

Calibration instructions now available on the wiki
« Reply #174 on: 29 / May / 2008, 10:37:47 »
For all that are interested, I've completed the main section of the DNG4PS-2 calibration instructions on the wiki.  If you want support for your camera added to DNG4PS-2, why not test the instructions out and let us know the results?

Thanks,
Matt
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Offline oversky

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Re: New project: camera color profile calculation
« Reply #175 on: 30 / May / 2008, 01:50:26 »
Hi, ArtDen

Have you consider to use the test image from imaging-resource? Such as
Digital Cameras, Canon  PowerShot A650 IS Digital Camera Test Image

Here are some good reasons:
1. The test image was taken from real color check board. This eliminates the color issue from the current LCD method.
2. The lab has very high qulity lighting setup. According to Digital Camera Test Lighting - HMIs! , it gives  true ~5500K daylight, balanced to within 0.1EV across our entire target area. This is definitely much better than the most users on this forum.
3. There are three different color check boards in the test image. These should result in a more accurate matrix.
4. imaging-resource has tested almost all canon cameras.

The only issue I see from here is that we do not know exactly how they setup the camera. For example, according to the exif of the test image, the canon a650is uses custom WB on the test image,  while G9 uses auto WB. Following is how they prepare for the test image, Imaging Resource Digital Camera Test Methods. It would be interested to compare it to our current method.

OK, I see the problem. We don't have the raw file.
« Last Edit: 30 / May / 2008, 02:21:15 by oversky »
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DawMatt

Re: New project: camera color profile calculation
« Reply #176 on: 30 / May / 2008, 04:52:05 »
Hi Oversky,

Quote from: oversky on 30 / May / 2008, 01:50:26
Have you consider to use the test image from imaging-resource? Such as
Digital Cameras, Canon  PowerShot A650 IS Digital Camera Test Image
...
OK, I see the problem. We don't have the raw file.
You've got it in one.  Without the matching raw file the test image doesn't help us at all.

But thanks for pointing out the pages about their testing techniques.  They might give more tips about how we can fine tune the calibration photo taking steps.  I'm looking to buy an equivalent of the Kodak chart (the multi-colored chart below the Gretag Macbeth Color Checker in the test image) so I can generate more accurate matricies for Canon cameras I can get access to (IXUS 860IS, G7, and one of the A series cameras).  I'm sure their advice will help in this endeavor.

Thanks,
Matt
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Offline lukg

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Re: New project: camera color profile calculation
« Reply #177 on: 30 / May / 2008, 06:53:09 »
Quote from: DawMatt on 29 / May / 2008, 10:35:21
lukg,

I've tried to download your S5 calibration photos and 7zip won't open the rar archives you've uploaded, and some of the links you've included result in "file not found" errors.

Can you please try to recompress and upload the calibration photos?

Thanks,
Matt

Ok!!! I really appreciated the work you're doing!

EDIT: I've just downloaded my palette pics from zshare...and winrar opens it with no problem! Should I use some particular settings to make it compatible with 7zip?

EDIT2: :D...i did a try to calibrate by myself using my palette, but with no success! I took many palette pics with still no success! (best gamut error about 42%). Can I ask you what are the reasons for setting zoom to middle and focus to infinity? Is it just to smooth and have homogeneous colors?
Thanks!
« Last Edit: 30 / May / 2008, 09:06:06 by lukg »
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Offline lukg

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Re: New project: camera color profile calculation
« Reply #178 on: 30 / May / 2008, 13:45:37 »
This the only palette I get some success with! I had to deselect the black and dark grey patches (used 22 patches)  to get an acceptable gamut error, and also I had to set im. bright. to 0.5.
But I have not understood how to use this matrix now without compile dng4ps :D
Hope someone could take a better palette than mines (i took many)

Camera -> XYZ matrix:
3,679790 1,286464 1,690627
1,145118 3,685682 0,174926
0,245843 -1,636507 11,881179
XYZ -> Camera matrix:
0,314732 -0,128898 -0,042887
-0,096843 0,309220 0,009228
-0,019851 0,045259 0,086325

zSHARE - s5palette.rar

EDIT: ok, i found "dngsetmatrix" instructions...with this matrix I get some good results:
If someone wants to try (you need dngsetmatrix.exe in the same directory) I wrote a simple batch file, just to avoid to rewrite the matrix everytime:

Quote
@echo off
dngsetmatrix.exe %~nx1 M1 0.340055 -0.138680 -0.051226 -0.129504 0.346033 0.005147 -0.026039 0.033814 0.103860
pause

Just save it as "blabla.bat". To execute just drag n drop DNG file over the bat file.

For what I saw it seems better than DNG4PS matrix (S5 and also a720).



« Last Edit: 31 / May / 2008, 13:15:00 by lukg »
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Offline lks

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Re: New project: camera color profile calculation
« Reply #179 on: 30 / May / 2008, 18:19:11 »
It's a much better color matrix than the default provided by dcraw / dng4ps2.  Still looks a tad green to me.
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