[sane-devel] Canon LiDE 90

[Guillaume Gastebois]

Hello,


> What about only setting register 0x7f? that one should do something
> without needing to setup reg 0x1a.

Not better I think. Result : 
http://ggastebois.free.fr/lide90_snoop/10_test0.tar
> 
> I didn't expect reg[0x1a]=0x24 to work without setting the corresponding
> clock bit masks. What happens if you leave line 1159 commented and set
> regs 0x74-0x7d(my guess: works without changes in behaviour)? Does
> setting regs 0x71-0x73 change anything (line 1159 still commented)?
> 
Result of setting only 0x75 0x76 0x79 0x7c 0x7d (not 0x7f) : 
http://ggastebois.free.fr/lide90_snoop/10_test1.tar

Result of setting 0x71 0x72 0x73 0x75 0x76 0x79 0x7c 0x7d (not 0x7f) :
http://ggastebois.free.fr/lide90_snoop/10_test2.tar

> (I have only little understanding of the actual relative timing and use
> of all clock signals going out to the ccd/afe, so i am guessing and
> doing experiments.)
> 
> But this seems to be basically working. Please send your changes leading
> to a usable scan, so i can integrate them.
For now, my code is ugly. I only modified lide60 to lide90. But you can 
find genesys_gl841.c and genesys_devices.c in 
http://ggastebois.free.fr/lide90_snoop/sources

>>>>>> Another thing : when I make several scan with sane backend and sane 
>>>>>> command line, I have alternatively brite and dark images !!! Why ???
>>>>> The calibration is probably giving widely differing results with
>>>>> different starting conditions. It swings between two states. But you
>>>>> shouldn't see this after the gl842 did its shading correction. Then, the
>>>>> problem is probably overexposure of the ccd cells. Try reducing the
>>>>> upper threshold in genesys_gl841.c:4383
>>>>>
>>>>> 	  if (avge > 2000) {
>>>>> 	      expr = (expr * 2000) / avge;
>>>>> 	      expg = (expg * 2000) / avge;
>>>>> 	      expb = (expb * 2000) / avge;
>>>>>
>>>>> Reducing the lower threshold may be needed, too. The current values for
>>>>> your scanner are:
>>>>> expr: 1235
>>>>> expg: 1235
>>>>> expb: 675
>>>>>
>>>>> No guarantee that this helps at all.
I tryed that (upper threshold to 1500 and lower to 250 and it doesn't 
work. You can find the same test as test2 without the same result on : 
http://ggastebois.free.fr/lide90_snoop/10_test2b.tar (I just make two 
consecutive scanimage without recompiling sane).

One other thing : we can see vertical lines with different contrast on 
result images. What is it ?

Regards
Guillaume