How to find circle in an image setting a fixed radius?

[Pier Paolo]

Hallo,

I've an image of a circle. Using "IMAQ find circula edge" I can estimate the circe but I can't force the algorith to use a center I set. Since I already know the center I've just to find the radius of the circle.

Is there any possibilities to modify  "IMAQ find circula edge" to force a fixed center? Is there a "find radius" function?

Thanks

Best regards

Pier Paolo Monticone

[MarcoMauri]

hi Pier Paolo!

From the Lv 2009 help page, one of the inputs of the VI is the following:

Circle or Annulus specifies a circular search area. Center X specifies the x-coordinate of the center of the circle or annulus. Center Y specifies the y-coordinate of the center of the circle or annulus. Inner Radius is the radius (in pixels) of the inner circle defining one edge of the circular strip. Outer Radius is the radius (in pixels) of the outer circle defining the second edge of the circular strip. Start Angle is the first angle of the circular strip. The angle is measured counterclockwise from the x-axis of a coordinate system centered on the center of the circle or annulus. End Angle is the second angle of the circular strip. The angle is measured counterclockwise from the x-axis of a coordinate system centered on the center of the circle or annulus.

Aren't "Center X" and "Center Y" the parameters you are looking for?

Regards,

Marco

[Pier Paolo]

Hi Marco,

Thanks but the center coordinates that you set are for the "area of interest", i.e., where the circle can stay. It does not force the circle to have se same center than the area of interest.

I've been clear?

Thanks

Best regards

Pier Paolo