[sane-devel] Re: strange problems LIDE30

Brian K. White brian@aljex.com
Thu, 7 Oct 2004 11:19:38 -0400

Gerhard Jaeger wrote:
> Hi,
> let's try and shed some light on the plustek-backend and the LiDE30
> scanner:
> - The scanner is a USB1.1 device, as the used chipset, a LM9833 is
>  only capable to do USB1.1.
> - The LM9833 is able to scan @ 8bit per color-channel or @ 16bit
>  where did you get the "full-color" from? You either scan with the
>  "color" option, then it's 8bit per channel or you scan with the
>  "color 42/48" option, then it's 16bit.
> - The LiDE30 is able to scan @1200dpi in X direction, because it's the
>  native resolution of the sensor, and the motor is able to do 2400dpi
>  steps. Therefore X direction information is doubled.
> - The backend does some calibration @ the start of each scan, this
>  might take a while. This time has also been increased from 1.0.13 up
>  to 1.0.14 This is necessary to avoid stripes. To reduce the time,
>  it's now possible to let the backend save the information of the
>  coarse calibration (option cacheCalData in the config file, or
>   --calibration-cache=yes for scanimage). This is working for the
> latest CVs snapshots.
> Please note, all backend before 1.0.14 are not recommendend for use
> with the LiDE devices, as the calibration does not work correctly!
> Also using kernel 2.6.x (x < 8) might cause problems with the USB.
> Also note, that full-size scanning using the 2400dpi might not work.
> At least I've never tested, because I've not that much memory in my
> boxes. 2400dpi also create that much data, that a USB1.1 device
> really needs some time to send the data to the box. Here the
> bandwidth is the limiting factor. We might can tweak the motor
> settings for the 2400dpi to avoid backtracking.
> Before continuing, I suggest to use the latest CVS snapshots, a
> kernel > 2.6.7 and the latests libusb. The next step will be to check
> if you really need to do scans @2400dpi, at least full-size ones.
> Ciao,
>  Gerhard

Very informative
Thanks much

No, I at least have no real use for scanning full sheets in color at 
I only did it for the purpose of testing the system, it's the worst case 
combination of all offered options.
I never had a problem with "normal" jobs.
I've done a few partial pages at 600dpi color, many full pages at 100-600 
gray & b&w
Never had a problem.

Even though I'm just under your recommendation on several fronts.
These are all what's currently available from suse pre-built and 

bwlin1:~ # uname -a
Linux bwlin1 2.6.5-7.108-smp #1 SMP Wed Aug 25 13:34:40 UTC 2004 i686 i686 
i386 GNU/Linux
bwlin1:~ # scanimage --version
scanimage (sane-backends) 1.0.13; backend version 1.0.13
bwlin1:~ # ls /usr/lib/*usb*
/usr/lib/libusb-0.1.so.4      /usr/lib/libusb.a   /usr/lib/libusb.so
/usr/lib/libusb-0.1.so.4.4.0  /usr/lib/libusb.la
bwlin1:~ #

Brian K. White  --  brian@aljex.com  --  http://www.aljex.com/bkw/
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