Comments on: Neighbor indexing http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/ 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. Wed, 01 Feb 2012 13:58:45 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Ferenc http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-24725 Ferenc Sun, 04 Dec 2011 13:37:04 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-24725 Thanks a lot Steve, this was xtremely useful. Thanks a lot Steve, this was xtremely useful.

]]> By: Steve http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-23503 Steve Fri, 17 Sep 2010 12:36:42 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-23503 Stefano—Your code idx(east_neighbors) is a mistake. I didn't do that in my post, and I'm not sure why you are doing that. You already extracted the east neighbors in the line: <pre class="code"> east_neighbors = B(east_idx) </pre> Stefano—Your code idx(east_neighbors) is a mistake. I didn’t do that in my post, and I’m not sure why you are doing that. You already extracted the east neighbors in the line:

east_neighbors = B(east_idx)
]]> By: stefano http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-23499 stefano Fri, 17 Sep 2010 06:21:59 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-23499 Steve, I dont think so. I used as you say: B=[0 0 0 0 0;0 24 1 8 0;0 5 7 14 0;0 6 13 20 0;0 0 0 0 0] east_idx=idx+east_offset east_neighbors=B(east_idx) but.. >> idx(east_neighbors) ??? Subscript indices must either be real positive integers or logicals. I dont know why get that error message. and the matrix has nonzero elements on the borders. what can it be? Steve, I dont think so. I used as you say: B=[0 0 0 0 0;0 24 1 8 0;0 5 7 14 0;0 6 13 20 0;0 0 0 0 0]
east_idx=idx+east_offset
east_neighbors=B(east_idx)
but..

>> idx(east_neighbors)
??? Subscript indices must either be real positive integers or logicals.

I dont know why get that error message. and the matrix has
nonzero elements on the borders. what can it be?

]]> By: Steve http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-23480 Steve Tue, 14 Sep 2010 00:18:26 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-23480 Stefano—It doesn't have anything to do with whether the matrix is logical or not. It has to do whether it has nonzero elements on the borders. See the "Note" in the next-to-last paragraph. Stefano—It doesn’t have anything to do with whether the matrix is logical or not. It has to do whether it has nonzero elements on the borders. See the “Note” in the next-to-last paragraph.

]]> By: stefano http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-23479 stefano Mon, 13 Sep 2010 22:18:49 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-23479 when using no logical matrix , it doesnt work. for example A=[17 24 1 8 15;23 5 .....; 11 18 25 2 9] >>idx(east_neighbors) ??? Index exceeds matrix dimensions. when using no logical matrix , it doesnt work. for example A=[17 24 1 8 15;23 5 .....; 11 18 25 2 9]

>>idx(east_neighbors)

??? Index exceeds matrix dimensions.

]]> By: Neha http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-15087 Neha Fri, 16 Nov 2007 17:02:41 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-15087 I was trying to find run lengths in diagonal directions, so wanted to use the neighbor offset to find that, but I found another solution, merely logical to it. Thanks! I was trying to find run lengths in diagonal directions, so wanted to use the neighbor offset to find that, but I found another solution, merely logical to it.
Thanks!

]]> By: Steve http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-15076 Steve Fri, 16 Nov 2007 12:02:47 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-15076 Reena—Use imshow. Pay attention to data type issues. For example, it matters whether your data is uint8 or double. Please read the introductory chapters of the Image Processing Toolbox Users Guide. Reena—Use imshow. Pay attention to data type issues. For example, it matters whether your data is uint8 or double. Please read the introductory chapters of the Image Processing Toolbox Users Guide.

]]> By: Reena http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-15074 Reena Fri, 16 Nov 2007 10:27:25 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-15074 Hello steave , I have follwing image data,How I display image using it? <em>[image data deleted from comment by Steve]</em> Thank you Hello steave ,

I have follwing image data,How I display image using it?

[image data deleted from comment by Steve]

Thank you

]]> By: Steve http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-15003 Steve Thu, 15 Nov 2007 06:21:29 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-15003 Neha—Tell me a little bit more specifically about what you are trying to do, what you have tried, and why it didn't work. Neha—Tell me a little bit more specifically about what you are trying to do, what you have tried, and why it didn’t work.

]]> By: Neha http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-14989 Neha Wed, 14 Nov 2007 21:25:09 +0000 http://blogs.mathworks.com/steve/2007/03/28/neighbor-indexing/#comment-14989 Steve, I'm facing similar problems. Can you suggest a solution to Xunkai's problem? Thanks! Steve,

I’m facing similar problems. Can you suggest a solution to Xunkai’s problem?

Thanks!

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