Re: MicroTek scanner

Rogier Wolff (R.E.Wolff@BitWizard.nl)
Thu, 19 Mar 1998 13:11:44 +0100 (MET)

Wolfgang Kvhler wrote:
>
>
> Hello Theo,
>
> a little add-on to this topic.
>
> Yesterday I measured the exact scanning times (in grey-scale mode, 8bit,
> with 300 dpi). The threshold value for icreased time consumption is
> between a scan width of 1150 and 1175 pixels.
>
> A value above 1175 takes approx. 13 (thirteen!) times more time !!!
> eg. window size 1150 x 200 = 5 sec
> 1175 x 200 = 65 sec !!
>
> Scanning the whole A4 sheet this way would take more then 20 min.
>
> Or am I doing something completely wrong ?

Things to do:

- find an answer to the question: "Is that limit (1150) resolution
dependent?"
- expected answer: Yes. In fact the limit is when an area of xxx
inch height exceeds yyy bytes.

- It would be highly beneficial for SANE to adopt a partial scan
approach. The problem is, that scanned files can become enormously
humongous. Buffering in the driver would then be neccesary, requiring
extraordinary amounts of data.
(A4 @ 600DPI @ 24bpp == 100Mb. Taking two passes requires 50Mb
of "temp" space.....)

Roger. 

-- 
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