I have just pushed v59 of the canon_dr backend up to our git repo. This is an updated version of the patch I shared previously. The calibration values are currently hard-coded for the C225, so the quality is poor. But, we can at least get duplex color scans now. I expect grayscale scans will segfault until I do some more work.
allan On Thu, Jul 30, 2020 at 4:57 PM m. allan noah <kitno...@gmail.com> wrote: > > Marek et al- > > I've spent a couple evenings looking at all the various logs that I > have for the C225, and have discovered that it does a different type > of fine calibration from other models. So, I've worked up the attached > patch, against the current sane-backends sources. The idea is to > re-use some of the existing calibration code instead of writing a new > version just for this scanner. I expect this may not work, and if it > does, it will only give us poor quality images. But, it should be > enough to validate that the issue is caused by calibration. You will > need to apply this patch to sane-backends source, and > rebuild/reinstall. I don't have access to any Canon scanners at this > time, so I have only verified that this compiles, unfortunately. > > Let me know what you find out, or if you need help. > > allan > > On Thu, Jul 23, 2020 at 8:53 PM m. allan noah <kitno...@gmail.com> wrote: > > > > Marek, I'm sorry it has taken me a month to reply, life is a little > > 'different' these days :) > > > > So I have gone back through every email thread I have had about the > > DR-C225, and do have a set of logs from the windows driver. I will > > attempt to determine which bit of magic we are missing. It will take > > me some time, as I am travelling now. If you do not hear from me soon, > > please feel free to reach out. Also, if you want to study up on > > rebuilding sane-backends from source in the meantime, we will need it. > > > > allan > > > > On Fri, Jun 26, 2020 at 4:33 PM Marek <mrupn...@tlen.pl> wrote: > > > > > > Dear developers, > > > I wonder if you could help me with resolving a problem with Canon > > > DR-C225 II scanner (canon_dr backend). The output scan is all black. In > > > 2015 there was a thread on the predecessor of this scanner: DR-C225 > > > (without 'II'), which suffered from similar problem. Unfortunately that > > > thread seems to be prematurely abandoned without solving the issue. > > > I'm attaching a scanimage log for a page scanned in a grayscale mode (for > > > the color mode the output scan is black as well). > > > Best regards, > > > Marek > > > > > > > > -- > > "well, I stand up next to a mountain- and I chop it down with the edge > > of my hand" > > > > -- > "well, I stand up next to a mountain- and I chop it down with the edge > of my hand" -- "well, I stand up next to a mountain- and I chop it down with the edge of my hand"