The CircleHoughTool searches for a circle in the set region that best matches the given parameters, within a given search interval.


The following parameters are available for configuration:

  1. Magnitude Scale: For this purpose, edge information is derived from the input image using a “Sobel filter”. The Magnitude Scale parameter is used for edge enhancement.

  2. Smoothness: The transformation result of the edge information into Hough space is smoothed using Gaussian filter. The smoothness parameter describes the strength of the smoothing.

  3. Radius Start: Default value of the radius start value in pixels

  4. Radius Step: Step size by which the radius is increased in pixels.

  5. Radius Count: Number of steps by which the start value of the radius is incremented by the step size.

  6. Minimum Houghmax: The accumulator value in Hough space must exceed a minimum value for each radius traversed. The Minimum Houghmax parameter is specified here as a percentage of the circumference of the associated circle.

  7. Blobthreshold (Stretch Gauss): The position (center) of the circle is obtained by a blob evaluation, where the Blob Threshold parameter is to be specified as a percentage of the Hough maximum.

  8. Maximum Hougharea: In order to really detect a clear, as pointed as possible expression of the “Hough response”, the parameter Maximum HoughArea is used to check that the associated blob area does not exceed the specified limit.

  9. EmbeddingEnabled: With this checkbox an “averaging” (Average over all Houghaccu) over all Hough accumulators (for all passed radii) is additionally selectable.

  10. Determine best blob by:

  • DistHoughMaxToBlobBoundary

  • DistHoughMaxToBlobCenterOfMass

  • DistHoughMaxToWeightedMidpoint

  • MaxBlobArea

  1. Get best circle of best blob by:

  • HoughMax

  • CenterOfMass

  • WeightedMidpoint

  1. Enabled: Checkbox enables averaging over all Hough results for all radii traversed.

  2. Blob Threshold: Percentage gray value specification related to the maximum smoothing.

  3. Min Blobarea: Default minimum blob area in pixels

  4. Intermediary images: Checkbox activates the saving of recordings under the specified path.

  5. InputImage is edge image: By activating the checkbox, an edge image can already be provided as InputImage for evaluation.

  6. Mutlithreading: Checkbox parallelizes processes within the CircleHoughTool for runtime optimization.


The following result values are available:

  1. ID

  2. Radius in pixel

  3. Radius

  4. CenterMassX

  5. CenterMassY

  6. WeightedMidpointX

  7. WeightedMidpointY

  8. Area

  9. ConnectivityLabel

  10. Acircularity

  11. DistToBoundary

  12. DistToCenterOfMass

  13. DistToWeightedMidpoint