vgopal@cbnewsc.ATT.COM (venu.p.gopal) (10/28/89)
Has anyone written a program that takes a high resolution monochrome image (only two levels of intensity - black and white) and converted it to low resolution image but with greyscale information ? Thus trading off spatial resolution for intensity resolution.. I am interested in looking at the results of such conversions and also in such a program itself. TIFF or GIF pics if possible, else any file format. Venu P. Gopal UUCP: ..!att!ihuxy!vgopal Internet: vgopal@ihuxy.att.com
meuchen@grad1.cis.upenn.edu (Paul Eric Menchen) (10/28/89)
In article <4155@cbnewsc.ATT.COM> vgopal@cbnewsc.ATT.COM writes: >Has anyone written a program that takes a high resolution monochrome >image (only two levels of intensity - black and white) and converted >it to low resolution image but with greyscale information ? Thus >trading off spatial resolution for intensity resolution.. > > On the Mac a program called Vision Lab does this kind of thing. It is available at sumex-aim.stanford.edu in /info-mac/demo. It converts from all sorts of file formats to all other sorts of file formats. Specifically, in regard to your question, it can take MacPaint files which are only black and white and "undigitize" them its words. This produces a grey-scale image reduced 33 or 50% (you determine) in size. You can then save this in whatever form you like. The image could be scaled to produce a low-res of the original. I've been very impressed with the program and only wish the author included his address so I could get a full featured version. /-------------- / /| /| Paul Eric Menchen /------ / | / | meuchen@grad1.cis.upenn.edu / / |/ | meuchen@eniac.seas.upenn.edu /__________________
keith@csli.Stanford.EDU (Neil Hunt) (10/31/89)
In article <4155@cbnewsc.ATT.COM> vgopal@cbnewsc.ATT.COM writes: >Has anyone written a program that takes a high resolution monochrome >image (only two levels of intensity - black and white) and converted >it to low resolution image but with greyscale information ? Thus >trading off spatial resolution for intensity resolution.. Check out Dvipage, which renders a page of a document typeset by TeX or LaTeX using 300 dot per inch bilevel fonts (the same bits used for a LaserWriter) and then performs averaging and sampling to produce 75 dot per inch grey scale pages for display on a colour sun. Lookup tables are used extensively to enable the conversion process to be performed in about 2 to 5 seconds on sun 4/260 and 3/160 respectively, for 8.5x11 inch pages (~8.5e6 pixels). (Other operating modes are also supported.) Dvipage (3.0) is available (in source) from june.cs.washington.edu, or from the sun spots archive. I believe that these sources also have the patches for PK font reading. (As far as I can tell, no one has made dvipage work on a 386i yet, due to byte order problems.) Neil/. Neil%teleos.com@ai.sri.com ...decwrl!argosy!teleos!Neil