Comments on: Connected component labeling – Part 6 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/ Steve Eddins manages the Image & Geospatial development team at The MathWorks and coauthored Digital Image Processing Using MATLAB. He writes here about image processing concepts, algorithm implementations, and MATLAB. Fri, 10 Feb 2012 18:55:59 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Yang http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-24041 Yang Tue, 22 Mar 2011 11:33:03 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-24041 OK, thanks for your reply! ^_^ OK, thanks for your reply! ^_^

]]> By: Steve http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-24038 Steve Mon, 21 Mar 2011 17:38:43 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-24038 Yang—dmperm was already available as a fast, built-in MATLAB operation. Also, bwlabel is based the idea of labeling runs of pixels instead of labeling individual pixels, so the equivalence-class determination step is a relatively small fraction of the overall performance picture of bwlabel. Yang—dmperm was already available as a fast, built-in MATLAB operation. Also, bwlabel is based the idea of labeling runs of pixels instead of labeling individual pixels, so the equivalence-class determination step is a relatively small fraction of the overall performance picture of bwlabel.

]]> By: Yang http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-24037 Yang Sun, 20 Mar 2011 14:45:27 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-24037 Hi Steve: I am a little confused. Do you use disjoint sets in bwlabel? I have read the source code, and it seems that you use dmperm instead. Why? Is dmperm faster than disjoint sets? Yang Hi Steve:

I am a little confused. Do you use disjoint sets in bwlabel? I have read the source code, and it seems that you use dmperm instead. Why? Is dmperm faster than disjoint sets?

Yang

]]> By: Steve http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-23305 Steve Wed, 21 Jul 2010 17:40:39 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-23305 Hilda—No, I doubt that it is feasible. Hilda—No, I doubt that it is feasible.

]]> By: Hilda http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-23304 Hilda Wed, 21 Jul 2010 17:13:17 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-23304 Hello, I have a set of code here that I need to translate to C by using the RTW. Most of it adheres to the Embedded MatLab subset, but the function bwlabel is included. In RTW C code generation you can insert functions already written in C. So my question is, is it feasible to include the .cpps in the image toolbox/private folder that perform most of the bwlabel operations to bypass having to write the algorithm with embedded matlab compliant functions? Hello,
I have a set of code here that I need to translate to C by using the RTW. Most of it adheres to the Embedded MatLab subset, but the function bwlabel is included. In RTW C code generation you can insert functions already written in C. So my question is, is it feasible to include the .cpps in the image toolbox/private folder that perform most of the bwlabel operations to bypass having to write the algorithm with embedded matlab compliant functions?

]]> By: Steve http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-22410 Steve Fri, 04 Dec 2009 18:48:16 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-22410 Evan—See the pseudocode and external links on <a href="http://en.wikipedia.org/wiki/Disjoint-set_data_structure" rel="nofollow">this page</a>. Evan—See the pseudocode and external links on this page.

]]> By: Evan http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-22386 Evan Mon, 30 Nov 2009 01:18:08 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-22386 Hi, I am currently working on writing my own connected components code in MATLAB. I have read through all of your posts and find them very helpful in the theory part of the code. I have tried searching online for a example of the algorithm that I can implement in MATLAB but i cant find any example of the equivalence matrix or union find codes. My question is what the pseudocode for doing the union-find/equivalence matrix. I have also not had any luck in getting my hands on any of the recommended books through interlibrary loan. Any help would be awesome! Thanks. Hi,
I am currently working on writing my own connected components code in MATLAB. I have read through all of your posts and find them very helpful in the theory part of the code. I have tried searching online for a example of the algorithm that I can implement in MATLAB but i cant find any example of the equivalence matrix or union find codes. My question is what the pseudocode for doing the union-find/equivalence matrix. I have also not had any luck in getting my hands on any of the recommended books through interlibrary loan. Any help would be awesome! Thanks.

]]> By: Steve http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-22000 Steve Fri, 24 Jul 2009 00:36:22 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-22000 Anand—Connected-component labeling will probably be useful to you, but you don't need to implement the algorithm yourself. Just use <tt>bwlabel</tt> (or <tt>bwconncomp</tt> if you already have the R2009a release) from the Image Processing Toolbox. Anand—Connected-component labeling will probably be useful to you, but you don’t need to implement the algorithm yourself. Just use bwlabel (or bwconncomp if you already have the R2009a release) from the Image Processing Toolbox.

]]> By: anand http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-21988 anand Tue, 21 Jul 2009 11:02:11 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-21988 Hi, I need to detect text (font) region in a image (a high resolution text imgae).. I just want to know , will this algo help me out? thanks Anand Hi,
I need to detect text (font) region in a image (a high resolution text imgae).. I just want to know , will this algo help me out?

thanks
Anand

]]> By: Steve http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-21915 Steve Thu, 25 Jun 2009 15:03:36 +0000 http://blogs.mathworks.com/steve/2007/05/25/connected-component-labeling-part-6/#comment-21915 Ardy—There is a lot information available online about the union find algorithm. I can also recommend Sedgewick, Algorithms in C, 3rd ed, Parts 1-4, pp. 10-23. Ardy—There is a lot information available online about the union find algorithm. I can also recommend Sedgewick, Algorithms in C, 3rd ed, Parts 1-4, pp. 10-23.

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