Gentlemen, being author of the backend let me thank you for spotting the pixel behavior. As I mentioned somewhat earlier I discovered the duplex mode in original Windows driver occasionally. That means there some aspects to be discovered such as the pixel indicator one.
Meanwhile, let's account for most of use cases - can you please redo your experiments but with grayscale/BW modes? I'm wondering if there would be similar indicator and would interesting to see its value for both cases. Also, we will still need to account for nearest paper size even with pixel indicator, otherwise scanner might drop the indicator if scan area is smaller than actual sheet. Another set of experiments would shed some light on this as well. Finally, some frontends might require user to account for doubled count of output pages vs. fed ones (eg. Xsane if I remember correctly), some doing continuos operation should handle this well (eg. scanadf probably). Hence, can you please conduct the following: - redo scanning with ADF duplex, same parameters as you did previously but with grayscale, and look for potential pixel indicator value? - same as previous attempt, but with BW? - same as first one but with paper size intentionally set smaller than sheet being fed? Then please report back your findings. Unfortunately, I don't have access to the scanner model so will totally rely on your input. --- Ilia Sotnikov > On Nov 8, 2014, at 15:03, Protected <[email protected]> wrote: > > Hello Rainer, > > I have actually discovered yet another trick with the blue pixels: the > pixel's blue RGB value is not random; in fact it even signals the end of > the document (170 when there are pages left to be scanned, and 255 at > the end of the document). > > In the meantime, I have also wrote a Perl script using ImageMagick to > crop the images properly. Still, it would be nice having the driver do > that automatically. > > ADF with 150 dpi does not look bad at all on my end. > > Best, > > Augusto > > Rainer Keller wrote: >> Hello Augusto, >> >> I tried to handle the blue pixel as a page change. >> Additional lines will be skipped until the blue pixel is found. >> But now the scanimage tool will not terminate properly, maybe because just >> skipping lines like I do is not the correct way to do this. >> >> See attached patch. >> >> Given the complexity of the sane code and limited spare time I tend more to >> write a new frontend to handle the page change marker. It could then also >> handle the mirrored backsides. >> >> I tested it with duplex and 300 dpi. >> >> BTW, have you tried using the ADF with 150 dpi? For me the scanned images are >> all bad. >> >> - Rainer > > -- > sane-devel mailing list: [email protected] > http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel > Unsubscribe: Send mail with subject "unsubscribe your_password" > to [email protected] -- sane-devel mailing list: [email protected] http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/sane-devel Unsubscribe: Send mail with subject "unsubscribe your_password" to [email protected]
