[sane-devel] Backend for plustek Opticbook 3600
stef.dev at free.fr
Wed Mar 17 04:35:51 UTC 2010
Le mardi 16 mars 2010 20:02:33 Chris Berry, vous avez écrit :
> On 03/09/2010 05:15 AM, stef wrote:
> > Le lundi 8 mars 2010 17:20:23 Chris Berry, vous avez écrit :
> >> Ok Stef I have a bit more time to concentrate on this at the minute. I
> >> have updated the white_shading.pnm and included it at
> >> http://sites.google.com/site/bez625/updates-1/update080310 there is also
> >> a copy of the latest scan there too. I only have 20 shading lines in the
> >> shading area because there is a lot of blue in that area. Should I widen
> >> it (more shading lines) or should those blue areas be included?
> >> Also how do I disable the averaging? Is it a software thing or is it on
> >> one of the registers? I'm also not too sure what you mean about the
> >> offset, is it the DAC offset?
> >> Thanks
> >> Chris
> > Hello,
> > the white shading picture must be all white. The picture you posted is
> > mostly OK, but there is still some blue on the right. This is not a
> > blocker, but it will certainly have to be fixed to reach best image
> > quality.
> > By averaging, I was thinking of the AVEENB bit of register 3 which tells
> > the ASIC to delete extra data points or average them to produce data from
> > higher dpi.
> > Regards,
> > Stef
> Hey guys,
> I have experimented with disabling average and altering the offset as
> Stef suggested. Disabling averaging seems to make things worse (dark and
> light lines where solid colour appears with AVEENB) and changing the
> offset seems to make no real difference so i'm not sure what is
> happening. Also I am unsure about what target code I should use for the
> shading compute_coefficients (assumed 0xdc00 as it seems popular).
> At the project site (update ) there are a few images in a bzip file to
> show what I mean about toggling the AVEENB. It certainly seems better to
> have it on but this might just be misleading images.
> The main issue now seems to be the different coloured vertical lines
> down the document. In addition I performed higer dpi scans (300, 600)
> and the whole image seems darker and the vertical lines are more
> prominent, i cant say im entirely sure whats causing them but im
> guessing its the shading function.
> I have also attached my source on the project update if this will make
> it easier to advise on what im doing wrong. I will get around to tidying
> up my code soon so i can commit to git without it looking messy. Has
> there been anymore information about a next release date? I have been
> skimming the mailing list and not seen anything mentioned.
in order to properly review the result of your hard work, we need the changes
you done as patches. Either against the version you started to modify, or as a
git patchset against latest version, which is the best solution. On your site,
I only found the full sources, may you have a look into it ?
More information about the sane-devel