Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Hi, does anyone know if there exists an IDL routine for the watershed segmentation algorithm? It's a algorithm, used in digital image processing, for separating overlapping features on a binary picture. Groet, Alrik. ************************************************************ ****************** Alrik van den Brom woonachtig op: De Residentie Hondsrug 184 3524 BV Utrecht 030-2895597 E-mail: a.j.vandenbrom@fys.ruu.nl or a.j.vandenbrom@chem.ruu.nl ************************************************************ ******************
Karsten Rodenacker wrote: > > Alrik van den Brom wrote: >> >> Hi, >> >> does anyone know if there exists an IDL routine for the watershed >> segmentation algorithm? It's a algorithm, used in digital image >> processing, for separating overlapping features on a binary picture. >> >> Groet, >> >> Alrik. >> > Vice versa, I am strongly interested in a 3-D watershed implementation > as well as a quick 3-D distance transformation! > I have an implementation of the 3D watershed operation that I am willing to share. I should warn you of a few things first. My application is in PET imaging and I typically have fltarr(128,128,50) image volumns of rather noisey data. My implementation is NOT a binary implementation. You give it the image volume and a point of interest. To keep with the water shed analogy, the water table is initially set to the value of the point of interest. The water table is then slowly raised (image threshold reduced) until the basin that contains the original point merges with an initially distinct basin. Because I have noisey data, I use a neighborhood operation around the edge of the basin to skip over basins (small puddles) that are only 1 or a few pixels wide. Also, I could not figure out how to implement the algorithm without using nested loops so the code is probably not optimal. If you would like to try the programs, send me email directly. I would very much appriciate users that give me comments to improve my programs and/or programming style. ---- John R. Votaw, Ph.D. Associate Professor of Radiology Emory Center for Positron Emission Tomography votaw@commander.eushc.org voice: (404)712-7954 FAX: (404)712-7962