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AvsFilter_FitCircleToStripe
This is Filter Equivalent. This function may be present in generated code, but should not be used in hand-written code. CreateCircleFittingMap and FitCircleToStripe should be used instead.
Performs a series 1D stripe detections and finds a circle that best matches the detected points.
Syntax
void avs::AvsFilter_FitCircleToStripe ( FitCircleToStripeState& ioState, const avl::Image& inImage, const avl::CircleFittingField& inFittingField, atl::Optional<const avl::CoordinateSystem2D&> inFittingFieldAlignment, int inScanCount, int inScanWidth, const avl::InterpolationMethod::Type inImageInterpolation, const avl::StripeScanParams& inStripeScanParams, avl::Selection::Type inStripeSelection, atl::Optional<const avl::LocalBlindness&> inLocalBlindness, float inMaxIncompleteness, avl::CircleFittingMethod::Type inFittingMethod, atl::Optional<avl::MEstimator::Type> inOutlierSuppression, atl::Conditional<avl::Circle2D>& outCircle, atl::Conditional<avl::Circle2D>& outInnerCircle, atl::Conditional<avl::Circle2D>& outOuterCircle, atl::Array<atl::Conditional<avl::Stripe1D> >& outStripes, atl::Optional<atl::Array<avl::Point2D>&> outStripePoints = atl::NIL, atl::Optional<atl::Conditional<avl::Profile>&> outDeviationProfile = atl::NIL, atl::Optional<avl::CircleFittingField&> outAlignedFittingField = atl::NIL, atl::Array<avl::Segment2D>& diagScanSegments, atl::Array<avl::Rectangle2D>& diagSamplingAreas, atl::Array<avl::Profile>& diagBrightnessProfiles, atl::Array<avl::Profile>& diagResponseProfiles )
Parameters
| Name | Type | Range | Default | Description | |
|---|---|---|---|---|---|
| ioState | FitCircleToStripeState& | Object used to maintain state of the function. | |||
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inImage | const Image& | Image to fit the circle to | ||
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inFittingField | const CircleFittingField& | Circle fitting field | ||
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inFittingFieldAlignment | Optional<const CoordinateSystem2D&> | NIL | Adjusts the fitting field to the position of the inspected object | |
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inScanCount | int | 3 -  |
10 | The number of points that will be searched to estimate the position of the circle |
|
inScanWidth | int | 1 - |
5 | The width of each scan field (in pixels) |
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inImageInterpolation | const InterpolationMethod::Type | Bilinear | Interpolation method used for extraction of image pixel values | |
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inStripeScanParams | const StripeScanParams& | StripeScanParams ( ProfileInterpolation: Quadratic4 SmoothingStdDev: 0.6f MinMagnitude: 5.0f MaxInnerEdgeMagnitude: Nil StripePolarity: Dark MinStripeWidth: 0.0f MaxStripeWidth: Nil ) | Parameters controlling the stripe extraction process | |
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inStripeSelection | Selection::Type | Selection mode of stripe | ||
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inLocalBlindness | Optional<const LocalBlindness&> | NIL | Defines conditions in which weaker edges can be detected in the vicinity of stronger edges | |
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inMaxIncompleteness | float | 0.0 - 0.999 | 0.1f | Maximal fraction of stripe points not found |
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inFittingMethod | CircleFittingMethod::Type | AlgebraicTaubin | Method used to fit a circle | |
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inOutlierSuppression | Optional<MEstimator::Type> | NIL | Selects a method for ignoring incorrectly detected points | |
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outCircle | Conditional<Circle2D>& | Fitted circle in the middle of found stripe | ||
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outInnerCircle | Conditional<Circle2D>& | Fitted inner circle | ||
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outOuterCircle | Conditional<Circle2D>& | Fitted outer circle | ||
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outStripes | Array<Conditional<Stripe1D> >& | Found stripes | ||
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outStripePoints | Optional<Array<Point2D>&> | NIL | Extracted points of middle circle of an image stripe | |
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outDeviationProfile | Optional<Conditional<Profile>&> | NIL | Profile of distances between the actual circle points and the corresponding reference circle points | |
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outAlignedFittingField | Optional<CircleFittingField&> | NIL | Fitting field used; in the image coordinate system | |
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diagScanSegments | Array<Segment2D>& | Segments along which the scans were run | ||
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diagSamplingAreas | Array<Rectangle2D>& | Areas from which the input image is sampled | ||
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diagBrightnessProfiles | Array<Profile>& | Extracted image profiles | ||
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diagResponseProfiles | Array<Profile>& | Profiles of the edge (derivative) operator response |
Description
The operation tries to fit a given circle to stripe present in the inImage image. Internally, it performs a series of scans with the ScanSingleStripe filter along inScanCount specific scan segments which length is always equal to the inFittingField width. 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.
Hints
- Connect an input image to the inImage input.
- Define inStripeScanParams.StripePolarity to detect a particular stripe type, and only that type.
- Adjust inStripeScanParams.MinStripeWidth and inStripeScanParams.MaxStripeWidth to the expected thickness of the stripe (in pixels).
- If no or too few stripe points are found, try decreasing inStripeScanParams.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 outStripePoints outputs to visualize the scanning results.
Examples
Fitting a circle to the dark circular stripe of a washer
(inStripeScanParams.Polarity = Dark).
Remarks
For more information about local coordinate systems please refer to the following article.
This filter is a part of the Shape Fitting toolset. To read more about this technique, one can refer to the Shape Fitting chapter of our Machine Vision Guide
Hardware Acceleration
This operation supports automatic parallelization for multicore and multiprocessor systems.
