kuh Hough Circle

The Hough Circle tool finds will place a point at the center of the strongest circle within its defined threshold.  This tool can also place a point at all the circles found within the defined threshold.

Using the Hough Circle Tool

The main setup page for the Hough Circle tool is the "Param" page and the "Hough Circle" page.

Hough Circle Page

The Hough Circle page defines the minimum and maximum radius threshold.  

Note: If the circle being inspected goes from dark to light (from the inside out) then the min/max radius numbers should be in positive numbers.  If it goes from light to dark (from the inside out) then the min/max radius should be in negative numbers.  When using negative number be sure that the minimum radius is actually a lower value than the maximum (i.e. -12 min, -10 max will work).

Param Page

Once the radius min/max is defined the "Param" page has several settings that can help isolate the proper circle(s).

Number Smooth Iteration

Number of times the image is smoothed before edge detection is carried out

Differentiation Type
The type of edge finding that is employed.  The 3x3 filter requires a harder edge than the 5x5 filter.

Sensitivity
The minimum edge level.  Increasing sensitivity eliminates weaker edges.

Sort
There are two sorting options:

Strongest - Only the most dominate circle is found.

All - Any circles that fall within the parameters for the tool will be found.

Define Threshold
This is another sensitivity setting.  The higher the theshold the fewer the results.

The coordinate system for the results can be set on the "General" page.