Performs a series of 1D edge detections and finds a circle that best matches the detected points.
|inImage||Image||Image to fit the circle to|
|inFittingField||CircleFittingField||Circle fitting field|
|inFittingFieldAlignment||CoordinateSystem2D*||Adjusts the fitting field to the position of the inspected object|
|inScanCount||Integer||3 -||The number of points that will be searched to estimate the position of the circle|
|inScanWidth||Integer||1 -||The width of each scan field (in pixels)|
|inImageInterpolation||InterpolationMethod||Interpolation method used for extraction of image pixel values|
|inEdgeScanParams||EdgeScanParams||Parameters controlling the edge extraction process|
|inEdgeSelection||Selection||Selection mode of edges|
|inLocalBlindness||LocalBlindness*||Defines conditions in which weaker edges can be detected in the vicinity of stronger edges|
|inMaxIncompleteness||Real||0.0 - 0.999||Maximal fraction of edge points not found|
|inFittingMethod||CircleFittingMethod||Method used to fit a circle|
|inOutlierSuppression||MEstimator*||Selects a method for ignoring incorrectly detected points|
|outCircle||Circle2D?||Fitted circle or nothing if the fitting fails|
|outDeviationProfile||Profile?||Profile of distances between the actual circle points and the corresponding reference circle points|
|outAlignedFittingField||CircleFittingField||Fitting field used; in the image coordinate system|
|diagScanSegments||Segment2DArray||Segments along which the scans were run|
|diagSamplingAreas||Rectangle2DArray||Areas from which the input image is sampled|
|diagBrightnessProfiles||ProfileArray||Extracted image profiles|
|diagResponseProfiles||ProfileArray||Profiles of the edge (derivative) operator response|
The operation tries to fit a given circle to edges present in the inImage image. Internally, it performs a series of scans with the ScanSingleEdge filter along inScanCount specific scan segments which length is always equal to the inFittingField width and cannot be less than 4. The found points are then used to determine the actual position of the circle in the image. Only inMaxIncompleteness fraction of these scans may fail. If the fitting according to the given parameters is not possible, outCircle is set to Nil.
- Connect an input image to the inImage input.
- If the object location is variable, connect inFittingFieldAlignment to an appropriate local coordinate system (e.g. from a template matching filter).
- Define the inFittingField input to specify the area in which edge scanning will be performed.
- Define inEdgeScanParams.EdgeTransition to detect a particular edge type, and only that type.
- If the noise level is high, try increasing inScanWidth and/or inEdgeScanParams.SmoothingStdDev.
- If no or too few edge points are found, try decreasing inEdgeScanParams.MinMagnitude.
- If some of the scans may fail, set the inMaxIncompleteness input accordingly.
- If some of the scans may produce false results, try different values of the inOutlierSuppression input.
- Use the diagScanSegments and outEdges outputs to visualize the scanning results.
For more information about local coordinate systems please refer to the following article.
This operation supports automatic parallelization for multicore and multiprocessor systems.
This filter is available on Basic Complexity Level.
This filter is member of FitCircle filter group.