[sane-devel] Backend for plustek Opticbook 3600

[stef]

Le mardi 9 février 2010 18:05:15 Chris Berry, vous avez écrit :
> Ok so ive managed to fix the problem with the FLAG being set, the
> REG01_DVDSET part was screwing me up, so im not sure what that was
> about... More details are here
> http://sites.google.com/site/bez625/updates-1/update090210 with a new
> attachment of the scanning image.
> 
> The scans now have a red tint which is a bit weird. Im still not sure
> how i am supposed to turn the brightness up, do you think there might be
> something specialist because of the AD AFE and its not wolfson?
> 
> Chris
> 
	Hello,

	I am facing the same issues than you while adding support for the HP3670. I 
eventually found that one of my decoding script was buggy and hide most of AFE 
accesses. I have appended the fixed version. By decoding usbsnoop again, you 
may find more AFE writes to be coded in backend. That may fix the red tint 
issue you have. I wouldn't be surprised if only write to red gain was showing 
in decoded log, leaving other channels untouched.
	You'll also have to look at the base gamma coefficient in the Genesys_Sensor 
entry for your model.
	When doing a calibrated scan, the REG01_DVDSET bit is set to activate shading 
calibration. Clearing it may side step issues with shading calibration, but 
defeat the purpose of calibration. When tuning shading calibration, you must 
look at the black/white_shading.pnm and black/white_average pnm files that are 
written when full debug is enabled. With proper offset and gain values, you 
must have a full black picture (with some values slightly above 0) and a full 
white one. If not, the computed shading calibration coefficient will be bogus 
and you'll get black scans.

Regards,
	Ste  
-------------- next part --------------
A non-text attachment was scrubbed...
Name: genesys_fe_write_data.awk
Type: application/x-awk
Size: 231 bytes
Desc: not available
URL: <http://lists.alioth.debian.org/pipermail/sane-devel/attachments/20100210/ab200307/attachment-0001.bin>