I used the Any2DjVu Server at http://any2djvu.djvuzone.org/any2djvu.php
to convert this 18Mb full color TIFF to a 38 kilobyte DJVU file. (By the way, why did you save it with no compression? ZIP compression reduced the original from 18mb to 15.5 mb ... not much, but a little savings.) http://rpresser.googlepages.com/example.djvu (38k) There are a number of different freely available DJVU readers; Google is your friend here. When it is initially viewed as a DJVU file, it appears exactly the same as the color TIFF. But the View menu allows you to see only the black and white layer, suppressing the color background. (It also suppresses the color photographs.) Now the black text is easily readable on a white background. Viewing only the color layer, we can see the color photos are still there, as well as some soft residue from the text. I wasn't able to easily find a way to export only the b/w layer using the viewer I have. But I was able to select it and copy it to the clipboard, then paste it into a new grayscale graphic (in another graphic editor) and save that. (It claimed to be 3 unique colors, therefore grayscale rather than true black and white.) The result is here: http://rpresser.googlepages.com/example-bw.tif (79k) Note the incredible efficiency of DJVU here. The entire layered DJVU file, with all the color information and appearing identical to the original when viewed, is half the size of JUST THE TEXT, even when compressed using G4 compression -- one of the best available for bw images. The final step in this work, if desired, would be to extract the color photos from the color layer, clean them up, and paste them back into the b/w layer. On 8/30/07, Paul Smith <[EMAIL PROTECTED]> wrote: > > On 8/30/07, Ross Presser < [EMAIL PROTECTED]> wrote: > > The best solution to this problem may be in the domain of JPEG2000 / > djvu > > image segmentation algorithms. Look up some scanned books on > archive.org, > > particularly in djvu format. The djvu plugin lets you suppress the > > background completely ... so identifying what is "background" is part of > the > > djvu construction. > > Thanks, Ross and Anthony. My figure is available at: > > http://rapidshare.com/files/52236170/example.tif.html > > (Note please that the file has the size of 18MB.) > > Paul > > > > > > On 8/29/07, Paul Smith <[EMAIL PROTECTED]> wrote: > > > > > > Dear All, > > > > > > I have got a colored scanned TIFF image from a newspaper article. Can > > > ImageMagick be used to convert the color of the image background to > > > white, with no loss? > > > > > > Thanks in advance, > > > > > > Paul > > > _______________________________________________ > > > Magick-users mailing list > > > [email protected] > > > > > http://studio.imagemagick.org/mailman/listinfo/magick-users > > > > > > > > _______________________________________________ > Magick-users mailing list > [email protected] > http://studio.imagemagick.org/mailman/listinfo/magick-users > _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
