curvature direction
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i want to find curvature direction in a circle image.can anyone help me with matlab code to find the direction of curvature as clockwise or counterclockwise.
2 Comments
Jan
on 21 Mar 2012
A circle does not have a direction. Please post a picture to explain, how the orientation could be detected.
Accepted Answer
Matt Kindig
on 21 Mar 2012
Is the circle actually part of an image, or do you have the coordinates of the circle? If you have the coordinates, it's just a matter of calculating the sign of the cross product.
cp = cross( [x(2)-x(1), y(2)-y(1), 0], [x(3)-x(1), y(3)-y(1), 0])
direction = sign(cp); %+1 if counterclockwise, -1 if clockwise
4 Comments
Matt Kindig
on 21 Mar 2012
It's not clear to me then how you define clockwise or counterclockwise in your image. Given only an image, how can you tell which direction in which?
More Answers (1)
Matt Kindig
on 22 Mar 2012
It sounds like you mean you want to find the curvature itself (using a technique like shown here: http://en.wikipedia.org/wiki/Curvature. This has nothing to do with the clockwise/counterclockwise direction.
As myself and Jan Simon have requested, can you post an example of your fingerprint image? We can't make code recommendations without knowing what kind of image your are working with.
2 Comments
Jan
on 23 Mar 2012
Just search in this forum. It is explained e.g. in the "Markup help" link on this page, and at http://www.mathworks.com/matlabcentral/answers/243-how-do-i-post-a-picture-with-my-question .
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