are you using lineart mode? the threshold option should help... 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 > [email protected] > > > > > 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 >> > -- "so don't tell us it can't be done, putting down what you don't know. money isn't our god, integrity will free our souls" - Max Cavalera
