Re: [sane-devel] HP Scanjet 3670 bad colors
On 27/05/2014 18:13, Octavio Alvarez wrote:
On 05/24/2014 08:25 AM, Octavio Alvarez wrote:
On 05/23/2014 10:58 PM, Stef wrote:
target_code is giving the desired target value for white. Once this
value is correct : not too low, and not too high to avoid
solarization, you should turn to tuning gamma values. They are defined
in genesys_devices.c for the CCD_HP3670. Currently it is 1.0 for each
color channels, and this need to be adjusted. This will improve the
histogram.
For some reason I haven't been able to find out yet, changing gamma
values on genesys_devices.c:350 doesn't seem to change anything, no
matter if I set them to 1.5, 2, 3, 10 or 0.5, 0.2, etc.
Changing target_code makes a difference (just to make sure my
compilation environment is correct).
Hello again.
Considering I wasn't able to play with gamma values in code, I took
sample scan images with a calibration sheet for all combinations of:
target_code = { 0x, 0x1000, 0x2000, ..., 0xe000, 0xf000 } in
descending order
resolution = { 75, 100, 150, 300 }
I uploaded the images to the following URL:
http://blog.alvarezp.org/files/scan-hp3670/calibration/
The 300 dpi scans are bigger, of course, but I found different scan
results for different dpi. I wonder if this is just a cheap scanner.
Anyway, I find 0x4000 to have the best value to have no solarization but
the higher the dpi, the darker the images.
While trying to fix the images in Gimp with the Levels and Curves tool I
find that green is more sensible to low light so its 0 point should be
moved to about 15/255 to prevent the shadows to come out greenish. Also
it needs a gamma of about 1.20 to balance the midtones out.
Blue needs a gamma of about 0.80. Red is ok.
Hope this helps.
Hello,
many thanks for your work. Once I fixed an intermittent issue in
LiDE 210 head parking, I'll use all these information to improve HP3670
color scan quality.
Regards,
Stef
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Re: [sane-devel] HP Scanjet 3670 bad colors
On 05/24/2014 08:25 AM, Octavio Alvarez wrote:
On 05/23/2014 10:58 PM, Stef wrote:
target_code is giving the desired target value for white. Once this
value is correct : not too low, and not too high to avoid
solarization, you should turn to tuning gamma values. They are defined
in genesys_devices.c for the CCD_HP3670. Currently it is 1.0 for each
color channels, and this need to be adjusted. This will improve the
histogram.
For some reason I haven't been able to find out yet, changing gamma
values on genesys_devices.c:350 doesn't seem to change anything, no
matter if I set them to 1.5, 2, 3, 10 or 0.5, 0.2, etc.
Changing target_code makes a difference (just to make sure my
compilation environment is correct).
Hello again.
Considering I wasn't able to play with gamma values in code, I took
sample scan images with a calibration sheet for all combinations of:
target_code = { 0x, 0x1000, 0x2000, ..., 0xe000, 0xf000 } in
descending order
resolution = { 75, 100, 150, 300 }
I uploaded the images to the following URL:
http://blog.alvarezp.org/files/scan-hp3670/calibration/
The 300 dpi scans are bigger, of course, but I found different scan
results for different dpi. I wonder if this is just a cheap scanner.
Anyway, I find 0x4000 to have the best value to have no solarization but
the higher the dpi, the darker the images.
While trying to fix the images in Gimp with the Levels and Curves tool I
find that green is more sensible to low light so its 0 point should be
moved to about 15/255 to prevent the shadows to come out greenish. Also
it needs a gamma of about 1.20 to balance the midtones out.
Blue needs a gamma of about 0.80. Red is ok.
Hope this helps.
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Re: [sane-devel] HP Scanjet 3670 bad colors
On 05/23/2014 10:58 PM, Stef wrote: target_code is giving the desired target value for white. Once this value is correct : not too low, and not too high to avoid solarization, you should turn to tuning gamma values. They are defined in genesys_devices.c for the CCD_HP3670. Currently it is 1.0 for each color channels, and this need to be adjusted. This will improve the histogram. For some reason I haven't been able to find out yet, changing gamma values on genesys_devices.c:350 doesn't seem to change anything, no matter if I set them to 1.5, 2, 3, 10 or 0.5, 0.2, etc. Changing target_code makes a difference (just to make sure my compilation environment is correct). Best regards. -- sane-devel mailing list: sane-devel@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-requ...@lists.alioth.debian.org
Re: [sane-devel] HP Scanjet 3670 bad colors
On 20/05/2014 18:42, Octavio Alvarez wrote: On 05/20/2014 12:27 AM, Octavio Alvarez wrote: So far, I have repeated some of the tests with scanimage only and target_code seems to be too high for my taste. 0x8000 seems like a lot better value. I'm still testing though. Hi, Stef. I have made some tests using scanimage only. I, effectively, don't get the artifacts anymore. Thanks a lot! However, you were right, the image quality has problems. Using target_code = 0xe000, the currently coded value, I get a bluish and saturated image. I tried lowering target_code across multiple values down to 0x4000. The lower the value, the better the quality but the darker the image. At 0xb000, the horizontal extremes of the image are white balanced but it is still noticeably bluish towards the center. This is, two small vertical correctly white-balanced sections are noticed at the left and right extremes. For example, at 0x8000, the image is not saturated anymore, and the image is way better white-balanced overall. However, the image is noticeably darker image (75% of the histogram with typical white at 55% luminosity). There is still a noticeably vertical stripe towards the blue, a bit off the center towards the right. At 0x4000, I don't get bluish stripes and perfect white-balance, but it results in only half of the histogram. I tried tweaking the o value (offset?) but I didn't seem to find any kind of pattern, except that if I set it too high I get badly colored stripes, so I just left them at their original values. Thanks again. Hello, the offset shouldn't be touched. For some undocumented reason the ASIC needs it to have the shading coefficients match the right pixels. target_code is giving the desired target value for white. Once this value is correct : not too low, and not too high to avoid solarization, you should turn to tuning gamma values. They are defined in genesys_devices.c for the CCD_HP3670. Currently it is 1.0 for each color channels, and this need to be adjusted. This will improve the histogram. Regards, Stef -- sane-devel mailing list: sane-devel@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-requ...@lists.alioth.debian.org
Re: [sane-devel] HP Scanjet 3670 bad colors
Hello, Could you run a preview with debug traces enabled like you already done? Since the fix works great here, I'd like to check what is going wrong. Regards, Stef Octavio Alvarez alvar...@alvarezp.ods.org a écrit : On 05/12/2014 09:40 PM, Stef wrote: On 05/04/2014 03:10, Octavio Alvarez wrote: On 03/04/14 12:20, Stef wrote: On 01/04/2014 05:42, Octavio Alvarez wrote: On 03/31/2014 08:37 PM, Stef wrote: thanks for all the data. It'll take me a couple of days to analyze them and compare with the results of my hp3670. If you also have one and works then we may have different versions of the 3670. Mine has regulatory model GRLYB-0306. Hello, I have reproduced the bug with my scanner. The calibration needs to be tuned or reworked. I'll have a fixed version in a few days. Great to know! Thanks in advance. Octavio. Hello, I have just pushed the fix in git. However I have some doubt about scan quality. And I'm afraid that my HP3670 is failing. Please let me know if scan quality is OK. Hi, Stef. I appreciate you working on this. I just tested the latest commit. I'm sorry to say that changes in genesys files sources did not improve scan results. Color is still incorrect in the same way as before. I made sure I used the most recent commit isolated from the install from my system. I used xscanimage under ~/sane-install/bin. [Mon May 19 21:38:31 -0700 -- alvarezp@laptop:~/sane-install] $ ls -l $(find -iname '*genesys*') -rw-r--r-- 1 alvarezp alvarezp1937 Mar 30 15:03 ./etc/sane.d/genesys.conf -rwxr-xr-x 1 alvarezp alvarezp 991 May 19 21:31 ./lib/sane/libsane-genesys.la lrwxrwxrwx 1 alvarezp alvarezp 25 May 19 21:31 ./lib/sane/libsane-genesys.so - libsane-genesys.so.1.0.25 lrwxrwxrwx 1 alvarezp alvarezp 25 May 19 21:31 ./lib/sane/libsane-genesys.so.1 - libsane-genesys.so.1.0.25 -rwxr-xr-x 1 alvarezp alvarezp 1123367 Mar 30 21:13 ./lib/sane/libsane-genesys.so.1.0.23 -rwxr-xr-x 1 alvarezp alvarezp 1325444 May 19 21:31 ./lib/sane/libsane-genesys.so.1.0.25 -rw-r--r-- 1 alvarezp alvarezp 10854 May 19 21:31 ./share/man/man5/sane-genesys.5 [Mon May 19 21:38:35 -0700 -- alvarezp@laptop:~/sane-install] $ cd ../src/sane/sane-backends/ [Mon May 19 21:39:33 -0700 -- alvarezp@laptop:~/src/sane/sane-backends (master)] $ git status On branch master Your branch is up-to-date with 'origin/master'. nothing to commit, working directory clean [Mon May 19 21:40:18 -0700 -- alvarezp@laptop:~/src/sane/sane-backends (master)] $ git log HEAD^..HEAD commit 18de732bbf80e35ad9247f5668da84e14e76fa8e Author: Rolf Bensch roben-gu...@alioth.debian.org Date: Fri May 16 15:41:18 2014 +0200 changelog for recent work -- sane-devel mailing list: sane-devel@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-requ...@lists.alioth.debian.org
Re: [sane-devel] HP Scanjet 3670 bad colors
On 05/19/2014 09:51 PM, Octavio Alvarez wrote: I made sure I used the most recent commit isolated from the install from my system. I used xscanimage under ~/sane-install/bin. I'd like to correct myself. Please take my previous message with a grain of salt (or disregard it altogether). I'm noticing that xscanimage is behaving differently than scanimage, regardless of whether I recompile both sane-backends and sane-frontends or just sane-backends. I noticed this because xscanimage is not affected when target_code is changed (and after a make make install), but scanimage is. I need to find some ground on this. Apparently scanimage *is* regenerated when sane-backends are recompiled. So far, I have repeated some of the tests with scanimage only and target_code seems to be too high for my taste. 0x8000 seems like a lot better value. I'm still testing though. Thanks. -- sane-devel mailing list: sane-devel@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-requ...@lists.alioth.debian.org
Re: [sane-devel] HP Scanjet 3670 bad colors
On 05/20/2014 12:27 AM, Octavio Alvarez wrote: So far, I have repeated some of the tests with scanimage only and target_code seems to be too high for my taste. 0x8000 seems like a lot better value. I'm still testing though. Hi, Stef. I have made some tests using scanimage only. I, effectively, don't get the artifacts anymore. Thanks a lot! However, you were right, the image quality has problems. Using target_code = 0xe000, the currently coded value, I get a bluish and saturated image. I tried lowering target_code across multiple values down to 0x4000. The lower the value, the better the quality but the darker the image. At 0xb000, the horizontal extremes of the image are white balanced but it is still noticeably bluish towards the center. This is, two small vertical correctly white-balanced sections are noticed at the left and right extremes. For example, at 0x8000, the image is not saturated anymore, and the image is way better white-balanced overall. However, the image is noticeably darker image (75% of the histogram with typical white at 55% luminosity). There is still a noticeably vertical stripe towards the blue, a bit off the center towards the right. At 0x4000, I don't get bluish stripes and perfect white-balance, but it results in only half of the histogram. I tried tweaking the o value (offset?) but I didn't seem to find any kind of pattern, except that if I set it too high I get badly colored stripes, so I just left them at their original values. Thanks again. -- sane-devel mailing list: sane-devel@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-requ...@lists.alioth.debian.org
Re: [sane-devel] HP Scanjet 3670 bad colors
On 05/04/2014 03:10, Octavio Alvarez wrote: On 03/04/14 12:20, Stef wrote: On 01/04/2014 05:42, Octavio Alvarez wrote: On 03/31/2014 08:37 PM, Stef wrote: thanks for all the data. It'll take me a couple of days to analyze them and compare with the results of my hp3670. If you also have one and works then we may have different versions of the 3670. Mine has regulatory model GRLYB-0306. Hello, I have reproduced the bug with my scanner. The calibration needs to be tuned or reworked. I'll have a fixed version in a few days. Great to know! Thanks in advance. Octavio. Hello, I have just pushed the fix in git. However I have some doubt about scan quality. And I'm afraid that my HP3670 is failing. Please let me know if scan quality is OK. Regards, Stef -- sane-devel mailing list: sane-devel@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-requ...@lists.alioth.debian.org
