[sane-devel] Canon P215II

Tony kangear at 163.com
Sat Mar 28 09:54:50 GMT 2020


I tried to fix it out, I can know this brightness => protcol map from Usbpcap on Windows OS. 

0: 0x80

1: 0x81

-1: 0x7f

-100: 0x01

100: 0xff

sb[0x16] and sb[0x17] is sync.

to sane-backends, I can see this

#define set_WD_threshold(sb, val)  sb[0x16] = val

there miss sb[0x17], so I try to force to 0x80(0). I added this in canon_dr.c

  desc1[0x16] = 0x80;

  desc1[0x17] = 0x80;

with SANE_DEBUG_CANON_DR, I can see brightness number is cool from log. but the image from scanner is also bad. I have no idear for it. I thought it will work fine when I set the brightness value like Windows OS driver. but It wasn't.


At 2020-03-21 17:45:49, "Tony" <kangear at 163.com> wrote:

Hi allan:

there is picture, win7 vs 1.0.24 vs 1.0.29
1.0.24 only little red;
1.0.29 only little brightness problem.

And I want to try fix it, if you can help me. I also do some reverse engineered. :P


At 2020-03-20 08:19:05, "m. allan noah" <kitno455 at gmail.com> wrote:
>Thanks for the report. I've been unable to correct the calibration
>issues on these scanners in the past, as all the calibration code is
>reverse engineered. It would be helpful if someone else could pick it
>up and try to improve it.
>On Thu, Mar 19, 2020 at 10:58 AM Tony <kangear at 163.com> wrote:
>> Hi all, I tried to test Canon P215II, backend version: 1.0.29.
>> ./scanimage --format=png  > test.png
>> > test.png is gray;
>> ./scanimage --format=png --mode=Color  > test.png
>> > test.png is color, but seems brightness high. The image looks like adjust brightness to max effect on Windows OS;
>> ./scanimage --format=png --mode=Color --brightness=-100 > test.png
>> > test.png always like that, Maybe brightness option has no effect for now.
>> And scan speed is slow.
>> that's all. if you need more, just email me. I'll try to be the best tester. :P
>> kangear
>"well, I stand up next to a mountain- and I chop it down with the edge
>of my hand"
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