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Re: Image Analysis: identifying objects with Mathematica 7.0

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  • Subject: [mg114133] Re: Image Analysis: identifying objects with Mathematica 7.0
  • From: Matthias Odisio <matthias at>
  • Date: Wed, 24 Nov 2010 07:01:34 -0500 (EST)


Mathematica 8 sheds new light on this old thread:

On 4/15/09 9:04 AM, Matthias Odisio wrote:
> Gideon,
> 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.
> Yes, it is possible.
> You can use ImageCorrelate; if the appearance of the dimmers varies a 
> lot in the image, this approach may not be good. You can then revert to 
> ImageFilter with a more robust template matching function.

As of Mathematica 8, ImageCorrelate is equipped with most of these
robust template matching functions, e.g. as used in (J.P. Lewis,
"Fast Normalized Cross-Correlation"), etc.
Moreover, as a convenience the second argument of ImageCorrelate may
now be an image, ie. the template or pattern you want to find matches
of. See the documentation at:

That being said, if my memory does not fail me, Gideon's specific
problem is perhaps better solved using various morphological
functions followed by queries to ComponentMeasurements.

Matthias Odisio
Wolfram Research

> We could probably be more specific if we could see one of your images.
> Matthias Odisio
> Wolfram Research
>> 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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