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Re: Image Analysis: identifying objects with Mathematica 7.0

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  • Subject: [mg98714] Re: Image Analysis: identifying objects with Mathematica 7.0
  • From: dh <dh at>
  • Date: Thu, 16 Apr 2009 04:20:09 -0400 (EDT)
  • References: <grupo8$m7$>

Hi Gideon,

if I understand correctly, you want to find where a "subpicture" occurs 

in a larger picture.

If you consider the picture as a numerrical array, then the correlation 

is large at places ahere the subpicture appears.

Here is a simple example where we place a subpicture in the middle of a 

larger array:

m1 = SparseArray[{{10, 10} -> 1, {10, 11} -> 1, {11, 10} ->

      1, {11, 11} -> 1}, {20, 20}];

m2 = {{1, 1}, {1, 1}};

ListCorrelate[m2, m1] // MatrixForm

hope this helps, Daniel

GidiL wrote:

> Hi All!


> I would appreciate any input on the following problem:


> After scanning my samples with TEM, I get images (JPEG or TIFF) which

> contain many  dimmers, e.g. gold nanoparticles connected via some

> other molecule.

> Approximately half of the popoulation is that of dimmers, while the

> other half contains trimmers, monomers, etc. I would like to run some

> statistics on the samples.

> I read Theodore Gray's post in the Wolfram Blog about the new

> capabilities of image processing in Mathematica 7.0.1 and I would like

> to ask if it is possible to do the following in Mathematica:


> Pick out a square that contains the dimmers, define that square as a

> new image, and then let Mathematica search for such an image within

> the original image.


> I know that Mathematica has a new function MorphologicalComponents

> that is apparently the key to getting this done, but I don't really

> understand how to use it. It is also supposed to return the

> coordinates of the located images, but I don't know how to extract

> this output from the function.


> Thanks,


> Gideon


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