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Software Module
Property
Threshold
Gradient Neg
Threshold Gradient Neg defines the threshold of the negative gradi-
ent.
Note: The gradient represents the change of brightness from pixel to
the next. The higher the contrast of an edge the higher the gradient.
Threshold
Outlier Dis-
tance
Maximum distance to the detected shape which must be maintained
by a point, in order for it to be used in the next iteration. Points which
are farther away than this distance are treated as outliers.
Fitting
Iterations
Number of best-fit calculations which are carried out in order that the
distance of the detected points on the search lines from the circular
line becomes as small as possible. Outliers are not used for subse-
quent best-fit calculations.
Note: The larger the value, the more iteration steps are executed.
Under certain circumstances a shape can be more closely approxi-
mated as a result, but calculation time may be increased as well.
Search Ray
Length
Length of the search rays, along which an edge transition is
searched for.
Search Ray
Interval
Distance between the search rays, along which an edge transition
is searched for. Generally speaking, the use of several search rays
increases accuracy, but also requires more computing time.
Note: Enlarging the interval is especially effective for faster evalua-
tion.
Search Ray
Orientation
The direction of the search ray can be turned 180° with this setting.
Point Usage
[%]
The percentage indicates how many points will be used to ascer-
tain the circle.
Point Usage
Strategy
The points which should be used to ascertain the circle are speci-
fied. Selection can be made between the first and the last points on
the search line. The search direction is made apparent by the direc-
tion of the arrow in the search geometry in the image.
The detected circle is listed under found geometry, and is defined by means of a
center and a diameter.
The following settings/results are displayed under found geometry:
Diameter (px) The circle’s diameter is displayed. The diameter tolerance can
be adjusted so that the circle’s diameter can be linked to an
output.
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