5.0 | 2 ratings Rate this file 233 downloads (last 30 days) File Size: 747.79 KB File ID: #21376

ISLANDS

08 Sep 2008 (Updated 23 Sep 2008)

Finds all "islands" which are 4-connected components in a matrix.

File Information
Description	ISLANDS finds all "islands" which are 4-connected components in a matrix. The function will return three output arguments, including the largest connected island in the input matrix. See the detailed help for all descriptions. Inspired by a recent puzzler posted here: http://blogs.mathworks.com/pick/2008/08/18/puzzler-find-largest-connected-island/ and by the submission from Tim Davis. Also included is a MEX-File version which runs faster than the M-File version. Tested on 2007a and 2007b. Please email me about bugs and other concerns. Thanks.
Acknowledgements	The author wishes to acknowledge the following in the creation of this submission: find_components
MATLAB release	MATLAB 7.5 (R2007b)
Zip File Content
Other Files	Islands/humor.mat, Islands/islands.m, Islands/islandsmx.cpp, Islands/islandsmx.m, Islands/islandsmx.mexw32

Tags for This File
Everyone's Tags	4connected, connected component, mex, morphology, pixel connectivity, puzzler, segmentation
Tags I've Applied
Add New Tags	Please login to tag files.

Comments and Ratings (2)
15 Sep 2008	Richard B.	It took me a while to get the humor, I am slow though. Nicely done.
31 Oct 2008	Tim Davis	Nice work!

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Updates
11 Sep 2008	Added more input checking.
18 Sep 2008	Faster mex-file.
19 Sep 2008	M-File now twice as fast.
23 Sep 2008	Now 3 times faster for a large binary matrix.

Tag Activity for this File
Tag	Applied By	Date/Time
morphology	Matt Fig	22 Oct 2008 10:18:22
segmentation	Matt Fig	22 Oct 2008 10:18:22
4connected	Matt Fig	22 Oct 2008 10:18:22
puzzler	Matt Fig	22 Oct 2008 10:18:22
pixel connectivity	Matt Fig	22 Oct 2008 10:18:22
connected component	Matt Fig	22 Oct 2008 10:18:22
mex	Matt Fig	22 Oct 2008 10:18:22

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