Comments on: Dilation with linear structuring elements http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/ 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. Sat, 11 Feb 2012 18:27:50 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Steve http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-23702 Steve Fri, 12 Nov 2010 17:51:52 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-23702 Estelle—I don't understand your question. Can you be more specific about the operation you are trying to achieve? Estelle—I don’t understand your question. Can you be more specific about the operation you are trying to achieve?

]]> By: Estelle http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-23701 Estelle Thu, 11 Nov 2010 22:40:47 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-23701 Hi Steve, I was wondering how it might be possible to erode and dilate based on the value of a grayscale image. I have a segmentation outline and certain grayscale values on that outline. I would like to erode and dilate based on how low or high the grayscale values are. Can you please point me in the right direction here? Thanks!!! Estelle Hi Steve,

I was wondering how it might be possible to erode and dilate based on the value of a grayscale image. I have a segmentation outline and certain grayscale values on that outline. I would like to erode and dilate based on how low or high the grayscale values are. Can you please point me in the right direction here?

Thanks!!!
Estelle

]]> By: Steve http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-22261 Steve Thu, 29 Oct 2009 20:29:39 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-22261 Nazish—The error message suggests that you were trying to use the function erode, which was removed from the toolbox years ago. Try using imerode instead. Nazish—The error message suggests that you were trying to use the function erode, which was removed from the toolbox years ago. Try using imerode instead.

]]> By: Nazish http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-22260 Nazish Thu, 29 Oct 2009 20:22:58 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-22260 when i am using imerode function in .m file it give error as under ?? Error using ==> erode at 12 ERODE has been removed. Use IMERODE instead. when i am using imerode function in .m file it give error as under

?? Error using ==> erode at 12
ERODE has been removed. Use IMERODE instead.

]]> By: Steve http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21998 Steve Fri, 24 Jul 2009 00:33:45 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21998 Sergey—Try using <tt>bitand</tt> and <tt>bitor</tt> instead of <tt>&</tt> and <tt>|</tt>. Sergey—Try using bitand and bitor instead of & and |.

]]> By: Sergey http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21986 Sergey Tue, 21 Jul 2009 10:51:53 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21986 Hi Steve, I use hit-and-miss transform for corner detection. It require a lot of computing time. I want to speed it up by bit packing. How can I do it. initial code: <pre>OBJ_ALL=(imerode(A,B1_1)&imerode(~A,C1_1))|(imerode(A,B1_2)&imerode(~A,C1_2))| ... </pre> final code: <pre>OBJ_ALL=bwunpack(imerode(A_packed,B1_1,'ispacked',A_size),A_size)&bwunpack(imerode(A_packedI,C1_1,'ispacked',A_size),A_size)| ... </pre> Can I execute AND, OR operation without bwunpack and time missing? Thank You. Hi Steve,
I use hit-and-miss transform for corner detection. It require a lot of computing time. I want to speed it up by bit packing. How can I do it.
initial code:

OBJ_ALL=(imerode(A,B1_1)&imerode(~A,C1_1))|(imerode(A,B1_2)&imerode(~A,C1_2))| ...

final code:

OBJ_ALL=bwunpack(imerode(A_packed,B1_1,'ispacked',A_size),A_size)&bwunpack(imerode(A_packedI,C1_1,'ispacked',A_size),A_size)| ...

Can I execute AND, OR operation without bwunpack and time missing?
Thank You.

]]> By: Paul http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21608 Paul Tue, 24 Mar 2009 14:28:12 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21608 Thanks Steve! I was indeed overanalyzing things; you’ve saved my bacon. Hail to you champion! Thanks Steve! I was indeed overanalyzing things; you’ve saved my bacon. Hail to you champion!

]]> By: Steve http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21606 Steve Tue, 24 Mar 2009 12:47:50 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21606 Paul—Maybe you're overanalyzing things? If you pass a 3-D input image to <tt>imdilate</tt>, it does 3-D dilation. For example: <pre> bw_out = imdilate(bw, ones(3,3,3)); </pre> performs 3-D dilation with a 3-by-3-by-3 structuring element. The situation is similar for flood filling. If you want to do 3-D flood filling, just pass a 3-D image to <tt>imfill</tt>. Paul—Maybe you’re overanalyzing things? If you pass a 3-D input image to imdilate, it does 3-D dilation. For example:

bw_out = imdilate(bw, ones(3,3,3));

performs 3-D dilation with a 3-by-3-by-3 structuring element.

The situation is similar for flood filling. If you want to do 3-D flood filling, just pass a 3-D image to imfill.

]]> By: Paul http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21605 Paul Tue, 24 Mar 2009 12:37:51 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21605 Hi Steve Could I please request a blog entry on 3D image (volume) dilation, perhaps as the first steps to a 3D flood filling algorithm? I’ve noticed a number of forum postings asking about 3D dilation and each time you mention that many of the image processing toolbox morphological functions support nD-images. My Matlab skills appear to be lacking as I am unable to puzzle through the strel and imdilate help files to achieve even a simple binary 3D dilation :( Hi Steve
Could I please request a blog entry on 3D image (volume) dilation, perhaps as the first steps to a 3D flood filling algorithm? I’ve noticed a number of forum postings asking about 3D dilation and each time you mention that many of the image processing toolbox morphological functions support nD-images. My Matlab skills appear to be lacking as I am unable to puzzle through the strel and imdilate help files to achieve even a simple binary 3D dilation :(

]]> By: Steve http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21554 Steve Mon, 09 Mar 2009 13:02:15 +0000 http://blogs.mathworks.com/steve/2008/12/31/dilation-with-linear-structuring-elements/#comment-21554 Sunil—Sounds like you face some sort of camera calibration problem in order to determine the distance. Try search for "camera calibration MATLAB". Sunil—Sounds like you face some sort of camera calibration problem in order to determine the distance. Try search for “camera calibration MATLAB”.

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