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Re: about label regions [message #30600 is a reply to message #30523]

Mon, 06 May 2002 22:53

Xiaoying Jin
Messages: 20
Registered: May 2002

Junior Member

Thanks for your suggestion.

That's what I want to do. I previously thought of this kind of method (label
region after edge detection), but using the normal edge detection we can not
localize the edge to one pixel wide. I think your suggestion is very
helpful. I will try that.

Besides, what is the funciton "Distance"?

Regards,

Xiaoying Jin

"Ted Cary" <tedcary@yahoo.com> wrote in message
news:3CD71905.25D5A98D@yahoo.com...
Thanks for your suggestion.
> If the gray levels of the regions are fairly uniform, do some type of edge
> detection. Mask anything that is not an edge, then you will have a mask
of
> only region interiors. This mask is a bi-level image that you can analyze
with
> one call to LABEL_REGION.
>
> For edge detection of regions of uniform gray level, you might try a
grayscale
> analog of a gradient morph to find the margins. Try something like this
for
> your image:
>
> rad = 1 ; Radius of structuring element. Change for fatter margins.
> disk = Shift(Distance(2*rad+1), rad, rad) LE rad ; Create a disk
structuring
> element.
> imageDilated = Dilate(image, disk, /GRAY) ; Dilate the image with the
disk.
>
> wh = Where(image NE imageDilated) ; Find subscripts of margins.
>
> marginMask = image ; Just create another image of same size as original.
> marginMask[*] = 255 ; Pretend everything is in the interior.
> marginMask[wh] = 0 ; Set margins to 0.
>
> If you TVSCL the marginMask, you should see all regions of white with
black
> borders. This is a bi-level image that can be used with LABEL_REGION.
>
> The disadvantage of this technique is that "brighter" region margins will
> intrude by one pixel into dimmer regions because of the dilation, but at
least
> it illustrates the method. Keep in mind that this assumes your regions
are
> each monotone, as stated in the original post.
>
> Good luck,
>
> TC
>
>
>
>

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[Message index]

		about label regions By: xje4e on Sun, 05 May 2002 21:21
		Re: about label regions By: Ted Cary on Mon, 06 May 2002 22:22
		Re: about label regions By: Xiaoying Jin on Mon, 06 May 2002 22:53
		Re: about label regions By: Ted Cary on Mon, 06 May 2002 17:00
		Re: about label regions By: Xiaoying Jin on Mon, 06 May 2002 14:37
		Re: about label regions By: Ted Cary on Mon, 06 May 2002 14:13
		Re: about label regions By: Xiaoying Jin on Mon, 06 May 2002 12:53
		Re: about label regions By: David Fanning on Mon, 06 May 2002 11:12
		Re: about label regions By: Xiaoying Jin on Mon, 06 May 2002 10:05

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