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Re: Erosion/Dilation Operators [message #8213 is a reply to message #8201]

Wed, 19 February 1997 00:00

Christian Soeller
Messages: 46
Registered: August 1996

Member

Achim Hein <hein@nv.et-inf.uni-siegen.de> writes:

> These functions are a very fast way to clean up data due to special
> expectation but think about the border of dilated/eroded areas - you
> shift the border of the eroded area and so you can lost information you
> are interested in.

Not necessarily true. You normally do an erosion (or several erosions) followed
by the same number of dilations with the same structuring elements. That will
remove small areas and smooth boundaries of remaining areas without shifting
them too much.

Typical structuring elements for 2D images:

s = replicate(1,3,3)

or the cross

+
+++
+

(3x3 array with indicated elements equal to one). You should experiment a
bit. Standard textbooks on image processing will have a section on
morphological image processing.

An alternative approach to reject 'noise ice' which might be characterised by
having a very small area is to delete all 'connected' areas that are smaller
than a given threshold. See the example of the 'label_region' function on how
to do something like that.

Christian

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[Message index]

		Re: Erosion/Dilation Operators By: Kirt Schaper on Wed, 19 February 1997 00:00
		Re: Erosion/Dilation Operators By: djackson on Wed, 19 February 1997 00:00
		Re: Erosion/Dilation Operators By: Christian Soeller on Wed, 19 February 1997 00:00
		Re: Erosion/Dilation Operators By: Achim Hein on Wed, 19 February 1997 00:00
		Re: Erosion/Dilation Operators By: Christian Soeller on Wed, 19 February 1997 00:00
		Re: Erosion/Dilation Operators By: Achim Hein on Tue, 18 February 1997 00:00

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