[sane-devel] Problems with Canon MP990 transparency unit

[Rolf Bensch]

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.
>
>