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Thread Subject:
defining search regions in Image

Subject: defining search regions in Image

From: ben

Date: 13 Dec, 2010 13:53:05

Message: 1 of 3

Hi all,

I have 3 points on an image that are relatively spaced far apart. As usual, these points are represented as (x,y) pixels.

I want to create a "region" around each point where each point will be a center.

To do this I plan to use Area of a circle to specify the region where the size of the region depends on the radius I set.

I tried this for one these these point I'm talking about, that is , Area = pi*Radius^2.
In Matlab, of course when I computed this I got a single value of 'Area' size.

Is there any functions in image toolbox maybe that can help me relate this 'Area' value and the (x, y) coordinate of the point in which I want to set as the center of the region?

I am creating this regions as a sort of Buffer search regions to search for points that would potentially lie inside this circular search region. If anyone can suggest how I may approach this I would appreciate it.

best regards,
ben

Subject: defining search regions in Image

From: Sean de

Date: 13 Dec, 2010 16:11:05

Message: 2 of 3

"ben " <cloader41@gmail.com> wrote in message <ie58g1$okf$1@fred.mathworks.com>...
> Hi all,
>
> I have 3 points on an image that are relatively spaced far apart. As usual, these points are represented as (x,y) pixels.
>
> I want to create a "region" around each point where each point will be a center.
>
> To do this I plan to use Area of a circle to specify the region where the size of the region depends on the radius I set.
>
> I tried this for one these these point I'm talking about, that is , Area = pi*Radius^2.
> In Matlab, of course when I computed this I got a single value of 'Area' size.
>
> Is there any functions in image toolbox maybe that can help me relate this 'Area' value and the (x, y) coordinate of the point in which I want to set as the center of the region?
>
> I am creating this regions as a sort of Buffer search regions to search for points that would potentially lie inside this circular search region. If anyone can suggest how I may approach this I would appreciate it.
>
> best regards,
> ben

This thread should be of interest to you:
http://www.mathworks.co.kr/matlabcentral/newsreader/view_thread/291115

-Sean

Subject: defining search regions in Image

From: ImageAnalyst

Date: 13 Dec, 2010 17:53:37

Message: 3 of 3

I added Sean's fine code to the FAQ:
http://matlab.wikia.com/wiki/FAQ#How_do_I_create_a_circle.3F

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