IPToolEdgeCircle

Description

determining the largest and smallest radius and edge points.  The edge circle finding tool locates edge pixels and does a best fit circle to them. The method employed is directional and sub pixel edges are found. The number of points found depends on the parameters settings.

The Edge Circle Tool

The tool employs a donut ROI ROI

Parameters

WhichEdge

The Edge of interest. By default the brightest edge is found.  Alternatly, the 1st through nth edge can be selected

EdgePolarity

The polarity of the edge being sort, either
 dark to light (1)
 light to dark(-1)
 don't care (0)

Smoothing

The amount of averaging in determining the edge. Units are pixels.

Leniency

This is a measure of edge steepness. The bigger the number the more likely the edge finder will detect more gradual edges. Units are pixels.

MinContrast

The minimum difference in intensity for an edge to be regarded as an edge. This is a measure of greylevel differences. Note that typically for a greylevel image 0 is black and 255 is white. The 255 is the the maximum contrast.

ROIWidth

The number of pixels / size of the internal sub ROI used to determine an edge. The larger the number the less sensitive the edge points are to small edge changes. Units are pixels.

ROIStep

The number of pixels between consecutive edge points. Together with the ROI Width this determines the number of edge points found. Units are pixels.

FitMethod

Best Fit: determine strongest (best fit) circle
PointsDiameter:
The points calculated represent points on opposite sides of the circle.
The is a two pass approach with the first pass re-centering the ROI.
The points in alternately 180 degrees apart.
Max Inscribed Circle: Bubble use a bible technique the smallest circle
Max Inscribed Circle: Concave the smallest circle
more accurate than the bubble technique but susceptible to noise
Min Circumscribed Circle: the largest circle
HoughHough transform to fit circle

MaxNumberIterations
MaxError

this is a filter that once a circle has been fitted points exceeding the max error are removed. This is repeated until either the Max Error is not exceeded or we have exceeded the max number iterations
Only applies when set to best fit fitting

PointCount

Output: The number of points found