[sane-devel] Canon LiDE 90

[Pierre Willenbrock]

Pierre Willenbrock schrieb:
> Hi,
> 
> Guillaume Gastebois schrieb:
>> Hello,
>>
>> So, what's the next step ? Re-enabling shading ?
> 
> Yes, but only after the shading-calibration is able to get black level
> information.(This really needs a better api..)

I commited a prerequisite for shading calibration to work for your
scanner. When enabling shading, update from cvs and then use
GENESYS_FLAG_DARK_CALIBRATION instead of
GENESYS_FLAG_DARK_WHITE_CALIBRATION.

Regards,
  Pierre

>> Do you think that last modification "for (i = 150; i..." is necessary ?
> 
> Yes. Some time back, that part of the code just used the middle half of
> the scan, exactly to drop the dummy black pixels at the begin. That
> didn't work too well, missing some low black levels.
> 
>> Is it time to fine tune registers 52... ?
> 
> Try increasing register 53, 55, 57 by one. Attached is a small program,
> that shows the probability of any two-byte pair appearing in a file. It
> takes the file as input and dumps an portable anymap(pnm) as output.
> I created that program for something completely unrelated, but it proved
> useful.
> 
> I used it on offset1_1.pnm(as offset1_0.pnm is only black).
> The image should show a fuzzy vertical and horizontal bar, near
> top/left. Currently, the horizontal bar is more a line, the vertical bar
> is correct(it shows the relationship between the low byte of one pixel
> and the high byte of the _next_ pixel).
> 
>> Regards
>> Guillaume
> 
> Regards,
>   Pierre
> 
>> Pierre Willenbrock a écrit :
>>> Guillaume Gastebois schrieb:
>>>> Hello,
>>>>
>>>> Yep, I write "for (j = 150; j...." instead of "for (i = 150; i....."
>>>> Now second set seems good. Result is on : 
>>>> http://ggastebois.free.fr/lide90_snoop/20_test1.tar
>>>>
>>> Hi,
>>>
>>> i am sorry, i actually wanted 450, but didn't realize until just now. I
>>> missed that the calibration dump images are really grayscale images,
>>> although stored in color pnms. 1 pixel in image is 3 pixels for the
>>> calibration...
>>>
>>> I hope this fixes that part of the calibration.
>>>
>>> Regards,
>>>   Pierre
>>>
>>>> Regards
>>>> Guillaume
>>>>
>