slim@ee.ualberta.ca (Sau Tsien Lim) (06/17/91)
Hello Everyone, I am looking for a line thinning algorithm. I would like to convert thick raster lines into single-pixel-width lines. Does anyone know of one? Are there any programs out there that performs line thinning? (Skeletonizing) Any comments or suggestions are welcome. Few weeks ago, I posted a request for any free DEMs and landsat images. As indicated by most of the people who are kind enough to give my suggestions, these two items are very hard to find and they cost a lot to purchase. So far, I only receive one landsat image contributed by Larry Ammann and nothing in DEMs. Larry is kind enough to provide me with a 7 band landsat dataset of Denton County, Texas. The resolution of the image is 512x512. I have now put this dataset and a few other landsat images I gathered from the net for anonymous ftp. They are located in site: bode.ee.ualberta.ca (129.128.16.96) directory: /pub/landsat Enjoy! slim... -- --------------------------------------------------------------------------- Sau-Tsien, LIM (HP 9000/835 HP-UX 7.0 ) (Department of Electrical Engineering ) (University Of Alberta, Edmonton, Alberta, Canada ) (uucp: ...!alberta!edson!bode!slim ) (internet: slim@bode.ee.ualberta.ca 129.128.16.96 ) (Addr: BOX 60257 UofA Postal Outlet ) ( Edmonton, Alberta ) ( Canada T6G 2S5 ) (Tel.: (403) 439-9770 ) ---------------------------------------------------------------------------
davis@3d.enet.dec.com (Peter Davis) (06/18/91)
In article <1991Jun16.223452.2252@ee.ualberta.ca>, slim@ee.ualberta.ca (Sau Tsien Lim) writes... > > I am looking for a line thinning algorithm. I would like to > convert thick raster lines into single-pixel-width lines. > Does anyone know of one? Are there any programs out there that > performs line thinning? (Skeletonizing) > You might check out Theo Pavlidis' 1982 book. I think the title is is _Algorithms for Computer Graphics and Image Processing_. This is the only place I recall seeing line thinning discussed explicitly. There are probably more recent references. I think Academic Press publishes a journal called "Computer Graphics and Image Processing," which deals a lot with subjects like this. I think the name of the journal may have changed to include computer vision, but I'm not sure. -pd
parker@cpsc.ucalgary.ca (Jim Parker) (06/18/91)
In article <1991Jun17.141329.1466@engage.pko.dec.com> davis@3d.enet.dec.com (Peter Davis) writes: > >In article <1991Jun16.223452.2252@ee.ualberta.ca>, slim@ee.ualberta.ca (Sau Tsien Lim) writes... >> >> I am looking for a line thinning algorithm. I would like to >> convert thick raster lines into single-pixel-width lines. >> Does anyone know of one? Are there any programs out there that >> performs line thinning? (Skeletonizing) >> >You might check out Theo Pavlidis' 1982 book. I think the title is is >_Algorithms for Computer Graphics and Image Processing_. This is the only place >I recall seeing line thinning discussed explicitly. I have sent mail to the original poster, BUT: Thinning produces a skeleton that is 1 pixel wide from an image containing lines of arbitrary raster width. This is usually done using small masks and simple morphological operations, and can result in good skeletons for simple images. Often, artifacts are generated that are hard to remove automatically. Some book references are: Rosenfeld&Kak, 'Digital Picture Processing', vol 2. Academic Press, 1982, pg 232-240. Pratt, W.K., 'Digital image Processing', Wiley, 1978. Pg 517- Fairhurst, M.C., 'Computer Vision for Robotic Systems', Prentice- Hall, 1988. Pg 48- Gonzalez&Wintz, 'Digital Image Processing', Addison Wesley, 1987. Pg 398-402. I feel that Gonzalez is the best of the above. There are hundreds of papers on the subject. For journals try IEEE PAMI, Pattern Recognition, IEEE Systems,Man and Cybernetics. Even Communications of the ACM. Personally, I find local area methods to be unsatisfactory. The skeleton has a non-local character. Best of those methods is possibly by Holt et al. Jim Parker Space Information Science Group (403) 220-6784 Department of Computer Science (403) 220-6015 University of Calgary (403) 284-4707 [FAX] Calgary, Alberta, CANADA parker@cpsc.ucalgary.ca [internet] T2N-1N4 ----------------------------------------------------------------------------