[sane-devel] Canon CanoScan LiDE 35

[Pierre Willenbrock]

Cameron Harris schrieb:
> On 10/30/05, Pierre Willenbrock <pierre at pirsoft.dnsalias.org> wrote:
> 
>>
>>Thanks for the log.
>>
>>Please try the attached patch.
>>I don't know if it helps. The backend is trying to read 1560000 bytes
>>from the scanner, but libusb does not provide that much. We need to find
>>out where the data is lost. The patch addresses one possible cause.
>>
>>Regards,
>>  Pierre
>>
> 
> Ummmm.. well... good and bad news.
> 
> The patch made it get past where it was stopping before, and now loads
> of rubbish appears on the terminal when I do scanimage. I ran xsane to
> see if it was scanning anything, hit acquire preview.

The "loads of rubbish" actually are the requested image. scanimage
outputs on stdout per default.

> 
> The scanner made a few noises, then went "beeeeeeeeeeeeeeeeeeeeeeeep"
> until the scan was done. While it was beeping, the scanner head was
> lit green.

Did the head move? xsanes default is to scan in grey mode, which is
translated into a monochrome green scan.

> 
> The image produced was just grey lines on a black-ish background. One
> good thing is that if I open the scanner lid mid-scan, it seems to
> have an effect on the image appearing on screen.
> 
> Sane Screenshot: http://htsc01.b3ta.org/scan.png
> 
> Where it gets lighter is where I opened the lid, and darker again when
> I closed it.
> 

I guess the calibration step failed.

Each scan should look like this:
- (optionally)move head home
- blink lamp
- move head away from home
- blink lamp
- move head home
- (maybe) blink lamp
- move head away from home
- blink lamp
- move head home
- do a short scan
- move head home
- do the real scan

If the head moved in the "short scan" part, please compress and send me
black_white_shading.pnm. That image should be generated while using
scanimage with SANE_DEBUG_GENESYS=255.

> I'll try getting it onto a Windows system and actually making sure the
> scanner works properly :|, maybe I could get a USB snoop while I'm at
> it, just in case.
> 

Regards,
  Pierre