Detect an arc from an image contour or edge

Question

I am trying to detect arcs inside an image. The information that I have for certain with me is the radius of the arc. I can try and maybe get the centre of the circle whose arc I want to identify.

Is there any algorithm in Open CV which can tell us that the detected contour ( or edge from canny edge is an arc or an approximation of an arc)

Any help on how this would be possible in OpenCV with Python or even a general approach would be very helpful

Thanks

Answer 1

If you think that there will not be any change in the shape (i mean arc won't become line or something like this) then you can have a look a Generalized Hough Transform (GHT) which can detect any shape you want.

Cons:

• There is no directly function in openCV library for GHT but you can get several source code at internet.

• It is sometimes slow but can become fast if you set the parameters properly.

• It won't be able to detect if the shape changes. for exmaple, i tried to detect squares using GHT and i got good results but when square were not perfect squares (i.e. rectangle or something like that), it didn't detect.