Comments on: Gray scale pixel values in labeled regions http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/ Steve Eddins manages the Image & Geospatial development team at <a href="http://www.mathworks.com/">The MathWorks</a> and coauthored <a href="http://www.mathworks.com/support/books/book5291.html?category=-1&language=-1">Digital Image Processing Using MATLAB</a>. He writes here about image processing concepts, algorithm implementations, and MATLAB.<br><br><img> Mon, 23 Nov 2009 00:55:47 +0000 http://wordpress.org/?v=2.3.1 By: Manju http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22356 Manju Mon, 16 Nov 2009 14:06:56 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22356 well if we have a few ovals within each other like in a cell how do we measure the distance from the center point to the boundary of each region?How do we calculate individual regions? Thanks well if we have a few ovals within each other like in a cell how do we measure the distance from the center point to the boundary of each region?How do we calculate individual regions?
Thanks

]]> By: Steve http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22355 Steve Mon, 16 Nov 2009 12:32:16 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22355 Manju—What do you mean? How is each region defined? Manju—What do you mean? How is each region defined?

]]> By: Manju http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22352 Manju Mon, 16 Nov 2009 03:48:56 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22352 if we have 2-3 regions within each other how do we measure the regions of each one? if we have 2-3 regions within each other how do we measure the regions of each one?

]]> By: Steve http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22190 Steve Tue, 06 Oct 2009 11:16:04 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22190 Opcs—Here's basic assignment: <pre> % Replace element in row 5, col 6 with value 10 A(5, 6) = 10; </pre> You might also want to look at my posts on <a href="http://blogs.mathworks.com/steve/2008/01/28/logical-indexing/" rel="nofollow">logical</a> and <a href="http://blogs.mathworks.com/steve/2008/02/08/linear-indexing/" rel="nofollow">linear indexing</a>. Opcs—Here’s basic assignment:

% Replace element in row 5, col 6 with value 10
A(5, 6) = 10;

You might also want to look at my posts on logical and linear indexing.

]]> By: opcs http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22184 opcs Mon, 05 Oct 2009 21:11:25 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22184 sir,i have an image and want to perform some operations on selective pixels of the image, means to transform an image into different image. how to apply that function on that pixels, leaving remaining pixels unaffected in the resulted image ? I'm in new in matlab and have no more time to complete the assignment so please help me out thanx... sir,i have an image and want to perform some operations on selective pixels of the image, means to transform an image into different image.

how to apply that function on that pixels, leaving remaining pixels unaffected in the resulted image ?

I’m in new in matlab and have no more time to complete the assignment so please help me out

thanx…

]]> By: Steve http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22069 Steve Thu, 20 Aug 2009 16:17:31 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22069 Varun—The convention followed by the Image Processing Toolbox is that gray-scale images represented as floating-point arrays have the range [0, 1], not [0, 255]. I recommend that you take a look at the intro sections in the Image Processing Toolbox users guide that describes the interactions between image type and data type conventions. Note also that the default display range can be overridden when you call <tt>imshow</tt> using this syntax: <pre> imshow(A, [0 255]) </pre> Take a look at the documentation for <tt>imshow</tt> for more details. Varun—The convention followed by the Image Processing Toolbox is that gray-scale images represented as floating-point arrays have the range [0, 1], not [0, 255]. I recommend that you take a look at the intro sections in the Image Processing Toolbox users guide that describes the interactions between image type and data type conventions. Note also that the default display range can be overridden when you call imshow using this syntax:

imshow(A, [0 255])

Take a look at the documentation for imshow for more details.

]]> By: Varun http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22067 Varun Wed, 19 Aug 2009 20:51:40 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22067 Hey, Steve..great post..I have just started using matlab and I stumbled over a problem..i.e If i have an array (NxN..say 100X100) and i store random pixel values into it (in the range of 0-255) and do 'imshow()' should it show the different grey colors..I ran the code but it just showed white for values >0 and black for values=0...Why is it so? and how to I reflect the various greyscale color values of the array onto the image window.. Hey,
Steve..great post..I have just started using matlab and I stumbled over a problem..i.e
If i have an array (NxN..say 100X100) and i store random pixel values into it (in the range of 0-255) and do ‘imshow()’ should it show the different grey colors..I ran the code but it just showed white for values >0 and black for values=0…Why is it so? and how to I reflect the various greyscale color values of the array onto the image window..

]]> By: Steve http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22003 Steve Fri, 24 Jul 2009 01:01:55 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-22003 Marco—Your question is pretty vague. What's stopping you from dividing it in a certain number of parts? Presumably you know how you want to divide it, so divide away. Marco—Your question is pretty vague. What’s stopping you from dividing it in a certain number of parts? Presumably you know how you want to divide it, so divide away.

]]> By: Marco http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-21996 Marco Thu, 23 Jul 2009 10:17:29 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-21996 This technique is very interesting....but what if the image is not oroginally segmented as this one (I mean I have a single entity instead of multiple entities) and you want to divide it in a certain number of parts, and then ask the average value?? This technique is very interesting….but what if the image is not oroginally segmented as this one (I mean I have a single entity instead of multiple entities) and you want to divide it in a certain number of parts, and then ask the average value??

]]> By: Steve http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-21788 Steve Wed, 27 May 2009 18:21:27 +0000 http://blogs.mathworks.com/steve/2007/08/21/gray-scale-pixel-values-in-labeled-regions/#comment-21788 Santosh—Use something like this code to compute the mean of a subimage: <pre> subimage = original_image(r1:r2, c1:c2); average_value = mean2(subimage); </pre> Santosh—Use something like this code to compute the mean of a subimage:

subimage = original_image(r1:r2, c1:c2);
average_value = mean2(subimage);
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