[sane-devel] Canon LIDE 90

[Ralf Haueisen]

> -----Ursprüngliche Nachricht-----
> Von: "Pierre Willenbrock" <pierre at pirsoft.dnsalias.org>
> Gesendet: 27.11.07 23:03:13
> An: Ralf Haueisen <ralf.haueisen at web.de>
> CC: sane-devel at lists.alioth.debian.org
> Betreff: Re: [sane-devel] Canon LIDE 90


> 
> Ralf Haueisen schrieb:
> >> -----Ursprüngliche Nachricht-----
> >> Von: "Pierre Willenbrock" <pierre at pirsoft.dnsalias.org>
> >> Gesendet: 27.11.07 22:23:19
> >> An: Ralf Haueisen <ralf.haueisen at web.de>
> >> CC: sane-devel at lists.alioth.debian.org
> >> Betreff: Re: [sane-devel] Canon LIDE 90
> > 
> > 
> >> Ralf Haueisen schrieb:
> >>>> Can you send a small image?
> >>>>
> >>> The image shows the cover of a book...
> >>>
> >> This looks like the shading correction(corrects for the properties of
> >> each ccd cell) is making the image worse. please disable it by changing
> >> gl841_init_optical_regs_scan to only disable it:
> >>
> >> /*    if (flags & OPTICAL_FLAG_DISABLE_SHADING)*/
> >> 	r->value &= ~REG01_DVDSET;
> >> /*    else
> >> 	r->value |= REG01_DVDSET;*/
> >>
> >> The resulting image may give better information. Another possibility is
> >> to look at the generated black_white_shading.pnm when
> >> SANE_DEBUG_GENESYS=255 is set in the environment.
> >>
> > 
> > It is not the shading.
> 
> Well, it does look better. My current guess: either some gpio is
> incorrect, or the sensor needs some other clock settings. The noise may
> stem from too few light or the data bytes from the frontend are swapped.
> 
> The sensor does not seem to switch the read out pixel, but it does
> capture line data, so you end up with the first pixel over and over again.
> 
> First, i'd make sure that i actually get the most significant byte from
> the frontend(by trying the possible byte positions in register 0x52) if
> you get a noise free image from the scanner, you got the msb right. The
> lsb is not that important at the moment(It would be the byte position
> where you get a different noisier image). The "correct" msb may be very
> dark(not 0 though), you are scanning pixels that are under the scanner
> cover).
> 
> Then i'd try to find out which of the clock/gpio registers needs to be
> set. An usb log may reveal this.
> 
> Hope this helps,
>   Pierre
> 

52=4 53=8 gives a picture with much less noise.
setting for the registers 16 to 1d i can not get out of my usb log. I guess there register set the clock for the read out. Maybe someone else has them?
But now it close to midnight.

cu.
Ralf

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