[sane-devel] Scan slow to start on Canon N670U (plustek)

Gerhard Jaeger gerhard@gjaeger.de
Wed, 13 Apr 2005 11:27:29 +0200

On Tuesday 12 April 2005 03:59, Jon Niehof wrote:
> First off, I apologize for my impatience. Caching the
> calibration certainly makes a difference.

Good to hear ;)

> 300 dpi 230x150mm grey scans, with the lamp left on and thus
> warmup time set to zero:
> no caching, full calibration:
> 1m12.999s
> cache coarse:
> 57.469s
> no calibration:
> 50.729s (and, indeed, ugly lines)
> With no calibration at all, there are still about five seconds
> of head activity before the scan starts--move out from the rest
> position, back, blink lamp, pause, then start. So I see 12
> seconds of *potential* savings here, which on a 200-page book is
> 40 minutes. If I can do something to get those 12 seconds back
> it'd help a lot :) (if not, well, I live with it).

A lot of time ;)

> I didn't see an option in plustek.conf for debugging output, and
> the -v option for scanimage wasn't particularly verbose.

This could not be enabled via plustek.conf. It is done with the
environment variable:
Then start the scan-application.

How are you doing these batch scans? Simply call scanimage 
each time? Ore are you using xsane?

I ask, because it will be easier to save the calibration results
while the backend is not shutdown between consecutive scans. If the 
backend will be shutdown, I have to save the fine calibration results
within the .cal file too...