[sane-devel] Problems with Canon MP990 transparency unit

Sun Nov 9 20:12:18 UTC 2014

Hi,

Worked a few hours again on the problem. It seems like I don't get the 
correct datas from the scanner (or it's being badly post-processed) when 
I'm using bigger resolutions than 300 dpi with TPU unit. Flatbed seems 
all ok.

300 dpi scans do not give me underruns, but all the others do, and with 
bigger and bigger values. The resulting pictures are bigger and bigger 
in size, but the image inside them is worse : it seems like the bigger 
the resolution I choose, the less I get actual lines of datas.

Again, if you have any ideas, that would be cool. I can provide datas, 
logs, whatever you want.

Thanks guys.

Bye.

Le 02/11/2014 16:47, Guillaume Courtois a écrit :
> Hi Rolf,
> 
> I've just seen I sent my first response to you but not the list, sorry
> about that (but it contained nothing interesting in fact).
> 
> I made some progress today, color shifting seem ok and I don't have
> the white columns anymore.
> I'll have to give a clean patch to the list for that, but first I have
> to solve my last problem, which is underrun.
> 
> I tried to find the source of that problem but with no luck until now.
> It seem to happen only with TPU unit, strange ?
> 
> Here is the result at 1200 dpi :
> 
> pixma] **mp810_fill_buffer***** end of image *****
> [pixma] WARNING:image size mismatches
> [pixma]     859431936 expected (14032 lines) but 222452736 received 
> (3632 lines)
> [pixma] pixma_read_image(): completed (underrun detected)
> 
> (in debug :
> [pixma] *mp810_fill_buffer***** moving 504704 bytes into buffer *****
> [pixma] *mp810_fill_buffer***** 507904 bytes received by 
> read_image_block *****
> )
> 
> and at 600 dpi :
> 
> [pixma] **mp810_fill_buffer***** end of image *****
> [pixma] WARNING:image size mismatches
> [pixma]     214857984 expected (7016 lines) but 111226368 received 
> (3632 lines)
> [pixma] pixma_read_image(): completed (underrun detected)
> 
> (in debug :
> [pixma] *mp810_fill_buffer***** moving 260096 bytes into buffer *****
> [pixma] *mp810_fill_buffer***** 245760 bytes received by 
> read_image_block *****
> )
> 
> Buffer size seem to be twice the size when raising the resolution.
> Shouldn't it be 4 times bigger ?
> 
> I hope you have an idea here because my head is exploding...
> 
> Thanks !
> 
> Bye.
> 
> Le 27/10/2014 16:57, Rolf Bensch a écrit :
>> Hi Guillaume,
>> 
>> If you want to dig into the source code, you can look here:
>> 
>> file: pixma_mp810.c
>> function: post_process_image_data()
>> 
>> It's possible that post processing image data is broken. Please check
>> these git commits:
>> b4bb0062c5cbb77c895b439b5f47e70b506305b1 (2013-01-11 16:37:00) and
>> 1da5bcc2aa16a6382e5bd78a47cb3ec222a9aafc (2012-01-15 03:48:19)
>> 
>> Many thanks for your help.
>> 
>> Cheers,
>> Rolf
>> 
>> 
>> Am 19.10.2014 um 15:20 schrieb Guillaume Courtois:
>>> 
>>> Hi guys,
>>> 
>>> I'm currently trying to make the TPU correctly work on my MP990
>>> scanner. It seems like there are shifting problems both in datas and
>>> in the 3 colors (which seem to be 2 separate issues, but not sure).
>>> 
>>> I'm currently testing on my debian SID with sane GIT version, but I
>>> have tested packages from SID and made tests on a Mint 17 netbook
>>> also. All seem to give the same results.
>>> 
>>> It seems like datas are not shifted in 300 dpi but are more and more
>>> shifted when you choose higher resolutions (600, 1200, 2400 dpi).
>>> 
>>> I'm happy to provide pictures if you want to see what it gives, but
>>> that gives vertical black stripes on the captured picture.
>>> 
>>> Here is the output of xscanimage with some debug activated :
>>> 
>>> Here is the 300 dpi correct scan :
>>> 
>>> [pixma] pixma_scan(): start
>>> [pixma]   line_size=3378 image_size=9674592 channels=3 depth=16
>>> [pixma] Reader task id=140539733346048 (threaded)
>>> [pixma]   dpi=300x300 offset=(780,88) dimension=563x2864
>>> [pixma]   gamma_table=0xd939e0 source=2
>>> [pixma]   threshold=127 threshold_curve=0
>>> [pixma]   ADF page count: 0
>>> [pixma] Setting non-blocking mode
>>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>>> [pixma] Lamp status: 3 , timeout in: 19
>>> [pixma] pixma_read_image():completed
>>> [pixma] Reader task terminated
>>> [pixma] Reader task started
>>> [pixma] Reader task id=140539733346048 (threaded)
>>> 
>>> Here is the not-so-correct 1200 dpi scan :
>>> 
>>> [pixma] pixma_scan(): start
>>> [pixma]   line_size=13938 image_size=67376292 channels=3 depth=16
>>> [pixma]   dpi=1200x1200 offset=(282,446) dimension=2323x4834
>>> [pixma]   gamma_table=0xd939e0 source=2
>>> [pixma]   threshold=127 threshold_curve=0
>>> [pixma]   ADF page count: 0
>>> [pixma] Setting non-blocking mode
>>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>>> [pixma] Current status: paper=0 cal=0 lamp=2 busy=0
>>> [pixma] Lamp status: 3 , timeout in: 19
>>> [pixma] WARNING:image size mismatches
>>> [pixma]     67376292 expected (4834 lines) but 44044080 received 
>>> (3160
>>> lines)
>>> [pixma] pixma_read_image(): completed (underrun detected)
>>> 
>>> As you can see, mismatch and underrun tells me I have to dig around 
>>> that.
>>> 
>>> Also, it seems like data coming from the preview window is
>>> mis-interpreted : I have to pick a smaller and decaled window in 
>>> order
>>> to get the actual correct part of the scan I want to have (I don't
>>> know if I'm pretty clear on that one ?).
>>> 
>>> I'm still digging into the code to see if I can correct that but if
>>> you guys could point me to the right direction, that would save me
>>> lots of time.
>>> 
>>> Thanks for your attention, keep up the nice work on sane !
>>> 
>>> Bye.
>>> 
>>> 