[sane-devel] Canon DR-C125: Wrong colors when scanning Duplex

[m. allan noah]

Ok, that's better.

The yellow cast along the edge looks like a calibration problem. It
exists in all resolutions under 300 because this scanner only has 300
and 600 dpi modes in the X direction. The sane backend creates all the
lower resolutions. The sane backend also does the coarse and fine
calibration for this model, so it is possible that the calibration
could be improved. However, this is the hardest part of the code to
work with, as it is entirely reverse engineered without docs about the
calibration algorithm.

allan

On Sun, Mar 20, 2016 at 5:55 AM, el-ti <tl at ewetel.net> wrote:
> Wow! Amazing! That did the job – you should be paid by Canon! :-)
>
> There’s only a little color strip (a yellow tint) at one side (for dpi 100-300; 400 and 600 don’t have it), but I guess, we have to live with that.
>
> Really amazing! Thank you so much for your work!
>
> See here: https://de.owncube.com/index.php/s/tJSe7f1Mlq7g1fG
>
> el-ti
>
> Am 20.03.2016 um 02:39 schrieb m. allan noah:
>> Ok, after further digging, I think the margin and color problems are
>> related. I have attached a new patch, please give it a try instead.
>>
>> allan
>>
>> On Sat, Mar 19, 2016 at 5:51 AM, el-ti <tl at ewetel.net> wrote:
>> > Hello Allan,
>> >
>> > I’m afraid, the cdr-55b didn’t change anything – although I don’t understand this. I also double checked: first I followed your instructions, but thenI unpacked the backends.tar.gz again to apply cdr-55b on the fresh files, because I wanted to make sure, I did not make a mistake. But even then, the scans returned the same results. Is that even possible?
>> >
>> > See here: https://de.owncube.com/index.php/s/Dkqvp3O0hJEVPu7
>> >
>> > best regards,
>> > el-ti
>> >
>> > Am 18.03.2016 um 12:53 schrieb m. allan noah:
>> >> I have attached another patch. We will have to remove the first one,
>> >> and add this new one to the source code directory you made before:
>> >>
>> >> 1. Change into the source directory (update name as required)
>> >> cd sane-backends-gitXXXXXX/
>> >>
>> >> 2. Remove the old patch (update location as required, perhaps also ~/Downloads)
>> >> cat ~/Downloads/cdr-55a.diff | patch -p1 -R
>> >>
>> >> 3. Apply the new patch (update location as required, perhaps also ~/Downloads)
>> >> cat ~/Downloads/cdr-55b.diff | patch -p1
>> >>
>> >> 4. Rebuild, reinstall
>> >> make
>> >> sudo make install
>> >>
>> >> 5. Test again.
>> >>
>> >> allan
>> >>
>> >>
>> >> On Fri, Mar 18, 2016 at 6:04 AM, el-ti <tl at ewetel.net> wrote:
>> >>> Oh, I see!
>> >>>
>> >>> Now I did the scans again, each time power cycling the scanner:
>> >>>
>> >>> 1. Power on scanner.
>> >>> 2. Plug scanner in.
>> >>> 3. Start gscan2pdf.
>> >>> 4. Adjust settings and scan and save.
>> >>> 5. Quit gscan2pdf.
>> >>> 6. Plug out scanner.
>> >>> 7. Power off scanner.
>> >>>
>> >>> You can find the results here:
>> >>> https://de.owncube.com/index.php/s/wQuYx6dkz5D8Gau
>> >>>
>> >>> As far as I can see, nothing changed to the previous test. Hope this helps.
>> >>>
>> >>> el-ti
>> >>>
>> >>>
>> >>> Am 17.03.2016 um 12:20 schrieb m. allan noah:
>> >>>> Yes, the patch changed something, you can look at it and see what it
>> >>>> did, it is fairly small. The problem is that I don't think it should
>> >>>> have changed 240, so if you are seeing a behavior change there, we
>> >>>> need to do further investigation. So, I will be more explicit:
>> >>>>
>> >>>> Please make another set of scans, the same as you last did, but turn
>> >>>> the scanner off and back on between each scan. Presumably you will
>> >>>> have to stop and restart your scanning program too. I want to see if
>> >>>> the earlier scans somehow pollute the later ones.
>> >>>>
>> >>>> After that, I will walk you thru adjusting the code, and we will try again.
>> >>>>
>> >>>> allan
>> >>>>
>> >>>> On Thu, Mar 17, 2016 at 4:28 AM, el-ti <tl at ewetel.net> wrote:
>> >>>>> Hmmm, but the patch changed something, didn’t it? Without the patch 300dpi was wrong colors, now 300dpi is good. Unfortunately now 240dpi is wrong.
>> >>>>>
>> >>>>> If it’s too much work to get it running, It’s maybe okay, I normally do color scans with 300dpi. But I would probably consider getting rid of this model.
>> >>>>>
>> >>>>> If by power cycling you mean turning the scanner off and on, before using it (after installing the patched version) – yes, I always do that.
>> >>>>>
>> >>>>> best regards,
>> >>>>> el-ti
>> >>>>>
>> >>>>>
>> >>>>> Am 16.03.2016 um 22:11 schrieb m. allan noah:
>> >>>>>> My patch did not change anything about 240dpi, since you said that was
>> >>>>>> already working. I think perhaps there is something else going on
>> >>>>>> here. Can you power cycle the scanner after each test?
>> >>>>>>
>> >>>>>> allan
>> >>>>>>
>> >>>>>> On Wed, Mar 16, 2016 at 1:45 PM, el-ti <tl at ewetel.net> wrote:
>> >>>>>>> Oh! Mea culpa – I missed that point. But now the scanner works again,
>> >>>>>>> and the behavior changed!  – That’s the good news. Not so good news is,
>> >>>>>>> that now I have the following:
>> >>>>>>>
>> >>>>>>> Resolutions 300 and 600 have the right colors.
>> >>>>>>>
>> >>>>>>> Scanning with 100,150, 200 and 400 is now:
>> >>>>>>> Blue -> Green
>> >>>>>>> Green -> Red
>> >>>>>>> Red -> Blue
>> >>>>>>>
>> >>>>>>> Scanning with 240 is now:
>> >>>>>>> Blue -> Red
>> >>>>>>> Red -> Green
>> >>>>>>> Green -> Blue
>> >>>>>>>
>> >>>>>>> I don’t know if it helps, but I created a pdf document with scans in
>> >>>>>>> color mode of the same page with the different resolutions in ascending
>> >>>>>>> order: 100,150,200,240,300,400,600
>> >>>>>>>
>> >>>>>>> You can get it here:
>> >>>>>>> https://de.owncube.com/index.php/s/KaSuVc4vRFWdOk4
>> >>>>>>>
>> >>>>>>> What you can also see there, is that there is a color strip on the left
>> >>>>>>> side and that the page is a bit shifted horizontally – but this is not
>> >>>>>>> our discussed problem at the moment.
>> >>>>>>>
>> >>>>>>> I hope this helps you.
>> >>>>>>>
>> >>>>>>> Thanks!
>> >>>>>>> el-ti
>> >>>>>>>
>> >>>>>>> Am 16.03.2016 um 15:01 schrieb m. allan noah:
>> >>>>>>>> Did you install libusb-devel before you compiled sane-backends?
>> >>>>>>>>
>> >>>>>>>> allan
>> >>>>>>>>
>> >>>>>>>> On Wed, Mar 16, 2016 at 9:29 AM, el-ti <tl at ewetel.net> wrote:
>> >>>>>>>>> All right, I’m pretty sure I got everything right, but surprisingly the scanner is not detected anymore... ("scanimage -L" only gives back the internal notebook camera) – is it even possible, that this is caused by the steps above? Or did I do something wrong?
>> >>>>>>>>>
>> >>>>>>>>> Sorry for all the work…
>> >>>>>>>>>
>> >>>>>>>>>
>> >>>>>>>>> Am 16.03.2016 um 13:24 schrieb m. allan noah:
>> >>>>>>>>>> 1. Download sane-backends-git snapshot from:
>> >>>>>>>>>> http://www.sane-project.org/snapshots/
>> >>>>>>>>>>
>> >>>>>>>>>> 2. In a terminal, cd to the directory where you downloaded the file
>> >>>>>>>>>> (perhaps ~/Downloads)
>> >>>>>>>>>> cd ~/Downloads
>> >>>>>>>>>>
>> >>>>>>>>>> 3. Extract the file (update name as required)
>> >>>>>>>>>> tar xzf sane-backends-gitXXXXXXXX.tar.gz
>> >>>>>>>>>>
>> >>>>>>>>>> 4. Change into the source directory (update name as required)
>> >>>>>>>>>> cd sane-backends-gitXXXXXX/
>> >>>>>>>>>>
>> >>>>>>>>>> 5. Apply the patch (update location as required, perhaps also ~/Downloads)
>> >>>>>>>>>> cat ~/Downloads/cdr-55a.diff | patch -p1
>> >>>>>>>>>>
>> >>>>>>>>>> 6. Then you need to follow the instructions at
>> >>>>>>>>>> http://www.sane-project.org/README.linux That will have you installing
>> >>>>>>>>>> an updated version of sane-backends in /usr/local, where it has a
>> >>>>>>>>>> reduced change of causing problems for your system.
>> >>>>>>>>>>
>> >>>>>>>>>> Let me know if you have questions.
>> >>>>>>>>>>
>> >>>>>>>>>> allan
>> >>>>>>>>>>
>> >>>>>>>>>> On Wed, Mar 16, 2016 at 6:38 AM, el-ti <tl at ewetel.net> wrote:
>> >>>>>>>>>>> Thank you very much for your work.
>> >>>>>>>>>>>
>> >>>>>>>>>>> Unfortunately, I have no experience with patching something like this so far. I did some research, though – seems to be quite doable. I’m familiar with the terminal etc. As I understand this, I have to apply the diff-file on the original file with the patch command. So far, so good – but I have no idea, which file it is. I couldn’t figure out by looking at the diff file.
>> >>>>>>>>>>>
>> >>>>>>>>>>> If you could tell, on which file I have to apply this, that would be great! Thanks!
>> >>>>>>>>>>>
>> >>>>>>>>>>> Tobias
>> >>>>>>>>>>>
>> >>>>>>>>>>>
>> >>>>>>>>>>> Am 16.03.2016 um 01:33 schrieb m. allan noah:
>> >>>>>>>>>>>> I have attached a patch for the sane-backends source code. This
>> >>>>>>>>>>>> attempts to provide alternate color de-interlacing for your scanner.
>> >>>>>>>>>>>> It does not attempt to fix any edge cropping issues. Let me know if
>> >>>>>>>>>>>> you need more instructions.
>> >>>>>>>>>>>>
>> >>>>>>>>>>>> allan
>> >>>>>>>>>>>>
>> >>>>>>>>>>>> On Tue, Mar 15, 2016 at 7:59 PM, m. allan noah <kitno455 at gmail.com> wrote:
>> >>>>>>>>>>>>> Canon scanners often have this variable interlacing at different
>> >>>>>>>>>>>>> resolutions, so I am not surprised to see this. However, this
>> >>>>>>>>>>>>> particular scanner has the weirdest interlacing that canon does. If
>> >>>>>>>>>>>>> you can compile from source, I can send you some patches to try. See
>> >>>>>>>>>>>>> http://www.sane-project.org/README.linux
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> allan
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> On Tue, Mar 15, 2016 at 9:17 AM, el-ti <tl at ewetel.net> wrote:
>> >>>>>>>>>>>>>> Unfortunately, yes.
>> >>>>>>>>>>>>>>
>> >>>>>>>>>>>>>> I uninstalled "cndrvsane-drc125" and restartet the system. The color shift is still there.
>> >>>>>>>>>>>>>>
>> >>>>>>>>>>>>>> And there is also the problem, that there is a 1/2 cm cut on the long edge of the scanned page (the "duplex-offset" option only handles the short edge) – but I guess this is another problem.
>> >>>>>>>>>>>>>>
>> >>>>>>>>>>>>>> If you need more information, do not hesitate to tell me.
>> >>>>>>>>>>>>>>
>> >>>>>>>>>>>>>> el-ti
>> >>>>>>>>>>>>>>
>> >>>>>>>>>>>>>> Am 15.03.2016 um 12:41 schrieb m. allan noah:
>> >>>>>>>>>>>>>>> If you uninstall the Canon "DR-C125 Driver for Linux V1.0 (v1.0)"
>> >>>>>>>>>>>>>>> software, does this color shift still happen?
>> >>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>> allan
>> >>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>> On Tue, Mar 15, 2016 at 7:37 AM, el-ti <tl at ewetel.net> wrote:
>> >>>>>>>>>>>>>>>> The system is using the libsane version from the PPA: 1.0.26-git20160305-wily0
>> >>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>> It was installed above the one from Ubuntu’s repositories, when I added the PPA.
>> >>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>> el-ti
>> >>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>> Am 15.03.2016 um 12:22 schrieb m. allan noah:
>> >>>>>>>>>>>>>>>>> You have installed both sane-backends, and canon's driver? Which one
>> >>>>>>>>>>>>>>>>> are you using? Assuming you are actually using sane-backends, we will
>> >>>>>>>>>>>>>>>>> have to modify the code to control the color descrambling.
>> >>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>> allan
>> >>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>> On Tue, Mar 15, 2016 at 6:08 AM, el-ti <tl at ewetel.net> wrote:
>> >>>>>>>>>>>>>>>>>> Hello,
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> I have an appendix to make – maybe someone has a hint for me, why the
>> >>>>>>>>>>>>>>>>>> scanner behaves really strange:
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> Depending on the scanning resolution, the shifting on the color range is
>> >>>>>>>>>>>>>>>>>> different! I used the following command to test this:
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> scanimage --batch --source "ADF Duplex" --page-width 210
>> >>>>>>>>>>>>>>>>>> --page-height=297 -l 0 -t 0 -x 210 -y 297 --mode Color --resolution 300
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> Then I tried all available resolutions: 100, 150, 200, 240, 300, 400,
>> >>>>>>>>>>>>>>>>>> 600. The results are strange:
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> Scanning with 100,150,200 gives me:
>> >>>>>>>>>>>>>>>>>> Blue -> Red
>> >>>>>>>>>>>>>>>>>> Red -> Green
>> >>>>>>>>>>>>>>>>>> Green -> Blue
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> Scanning with 300 and 400 gives me:
>> >>>>>>>>>>>>>>>>>> Blue -> Green
>> >>>>>>>>>>>>>>>>>> Green -> Red
>> >>>>>>>>>>>>>>>>>> Red -> Blue
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> And scanning with 240 and 600 shows the RIGHT colors.
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> How is that possible? And how can this problem be solved?
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> I installed Rolf Bensch’s PPA
>> >>>>>>>>>>>>>>>>>> (https://launchpad.net/~rolfbensch/+archive/ubuntu/sane-git), because it
>> >>>>>>>>>>>>>>>>>> solved the back page cutting problem when scanning Duplex. (see
>> >>>>>>>>>>>>>>>>>> http://permalink.gmane.org/gmane.comp.graphics.scanning.sane.devel/24903)
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> Other than that, I only installed the Canon "DR-C125 Driver for Linux
>> >>>>>>>>>>>>>>>>>> V1.0 (v1.0)".
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> Any hint is appreciated!
>> >>>>>>>>>>>>>>>>>> el-ti
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> Am 04.03.2016 um 10:59 schrieb el-ti:
>> >>>>>>>>>>>>>>>>>>> Dear Sane-developers and users,
>> >>>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>>> through this very helpful discussion
>> >>>>>>>>>>>>>>>>>>> (http://permalink.gmane.org/gmane.comp.graphics.scanning.sane.devel/24903),
>> >>>>>>>>>>>>>>>>>>> I managed to get my Canon Scanner working in Duplex without cutting 1 cm
>> >>>>>>>>>>>>>>>>>>> of the back page.
>> >>>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>>> Everything seems to work fine. However, I discovered a very strange
>> >>>>>>>>>>>>>>>>>>> behaviour regarding the colour management: When scanning in simplex
>> >>>>>>>>>>>>>>>>>>> mode, everything works fine. There is no page cutting and colours are as
>> >>>>>>>>>>>>>>>>>>> they should be. But in duplex mode, the colours are somehow shifted on
>> >>>>>>>>>>>>>>>>>>> the colour range: Blue is scanned as green, green is scanned as red, red
>> >>>>>>>>>>>>>>>>>>> is scanned as blue (for both back and front page).
>> >>>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>>> Is there an easy solution for this? Or did I forget to install something?
>> >>>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>>> Thank you very much!
>> >>>>>>>>>>>>>>>>>>> el-ti
>> >>>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>> --
>> >>>>>>>>>>>>>>>>>> sane-devel mailing list: sane-devel at lists.alioth.debian.org
>> >>>>>>>>>>>>>>>>>> http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel
>> >>>>>>>>>>>>>>>>>> Unsubscribe: Send mail with subject "unsubscribe your_password"
>> >>>>>>>>>>>>>>>>>>              to sane-devel-request at lists.alioth.debian.org
>> >>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>>
>> >>>>>>>>>>>>> --
>> >>>>>>>>>>>>> "well, I stand up next to a mountain- and I chop it down with the edge
>> >>>>>>>>>>>>> of my hand"
>> >>>>>>>>>>>>
>> >>>>>>>>>>>>
>> >>>>>>>>>>>>
>> >>>>>>>>>>>
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>



-- 
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"