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zizi21

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Maths sign

Hi,

I am trying to understand scale space article at http://en.wikipedia.org/wiki/Scale_space

I don't understand a maths sign that is used by the article. Attached is the print screen of that maths sign. It is the E sign at L and derivative. Thus it mean sum ?

Thanks a lot.
Zizi
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Mohammed Khawaja
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I believe you are talking about the upside down triangle which is the laplace operator.  Refer to wikipedia for more:

http://en.wikipedia.org/wiki/Laplace_operator
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zizi21

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Sorry, that is not it.

It is the curly E that becomes the subscript for L and derivative. Please refer to the attached sum.jpg.
I don't see attached sum.jpg, but are you referring to the normalized derivatives?
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Sorry, thought i had uploaded it. just uploaded it.. could you please take a look at it. yes,i am referring to L and derivatives..
sum.jpg
It looks liks Lindberg's ° normalized derivative operator http://www.itu.dk/people/stud3154/Assignment2_1/Lindeberg98a.pdf.
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I am referring to Edge Detection and ridge detection with automatic scale selection paper by the same author (Tony Lindeberg).
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ozo
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As mentioned by ozo, it is Lindberg's normalized derivative operator and is part of formula used in scaling algorithms.
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Thanks all for your help. Apologies for coming late as something happened which prevented me frm accessing the computer