m. allan noah wrote: > > are you using lineart mode? the threshold option should help...
No, i'm using Greyscale, because there's some shaded regions, and I really need the scanned document to look good. Jim. > > allan > > On Mon, 10 Jul 2006, Jim McQuillan wrote: > >> Allan, >> >> I don't have an answer, but I'd like to comment that I sure could use >> such a feature. >> >> I'm using the Fujitsu fi-5120C scanner, as you know, because you >> helped me get it working. >> >> And so far, it's working really well. I did find one issue though. >> I'm scanning both sides of the page at the same time, and i've found >> that documents printed on 20lb paper are getting some "bleed >> through". That is, the scan of the front is actually showing some of >> the stuff that is on the back of the page. >> >> Also, the scans come out looking somewhat "dirty". Again, because I >> think light from the other side is bleeding through. >> >> I tried printing the same documents on 28lb paper, and the scans look >> beautiful, no bleeding is seen. >> >> This turns out to be a big issue, because when I scan the document >> printed on 20lb paper, the two images tarred together and compressed >> with bzip are taking about 2.7mb. While the same document printed on >> 28lb paper compresses down to about 900kb. HUGE difference in >> compressability. >> >> I'm thinking that if I could reduce the brightness of the light, it >> may not bleed through so badly. >> >> Thanks, >> Jim McQuillan >> j...@ltsp.org >> >> >> >> >> m. allan noah wrote: >>> recent model fujitsu scanners dont have native >>> brightness/contrast/gamma support, instead they use an 256x256 or >>> 1024x256 bit look up table to convert the raw scan data before 8 bit >>> output. >>> >>> while it is true that the 8bit square LUT could be done after >>> scanning with no data loss, most command line front-ends dont do >>> this, and the 10 bit lut has 'access' to more data that never gets >>> out of the scanner, so i would like to extend the backend to provide >>> at least brightness/contrast for these scanners. >>> >>> i need suggestions or pointers to code that i could use. what things >>> i can find are far over my head, but i have a simple brightness >>> adjustment that shifts the linear slope of the in-out function up or >>> down, and a crude contrast setting that changes the slope of the >>> function around the center of the table. i think both of these >>> methods are likely too simplistic. >>> >>> anyone? >>> >>> allan >>> >> >
