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AvsFilter_FitCircleToRidges

This is Filter Equivalent. This function may be present in generated code, but should not be used in hand-written code. CreateCircleFittingMap and FitCircleToRidges should be used instead.

Performs a series of 1D ridge detections and finds a circle that best matches the detected points.

Syntax

void avs::AvsFilter_FitCircleToRidges
(
	FitCircleToRidgesState& 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::RidgeScanParams& inRidgeScanParams,
	avl::Selection::Type inRidgeSelection,
	atl::Optional<const avl::LocalBlindness&> inLocalBlindness,
	float inMaxIncompleteness,
	avl::CircleFittingMethod::Type inFittingMethod,
	atl::Optional<avl::MEstimator::Type> inOutlierSuppression,
	atl::Conditional<avl::Circle2D>& outCircle,
	atl::Optional<atl::Array<atl::Conditional<avl::Ridge1D> >&> outRidges = 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	FitCircleToRidgesState&			Object used to maintain state of the function.
inImage	const Image&			Image to fit the circle to
inFittingField	const CircleFittingField&			Circle fitting field
inFittingFieldAlignment	Optional<const CoordinateSystem2D&>		NIL	Adjusts the fitting field to the position of the inspected object
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)
inImageInterpolation	const InterpolationMethod::Type		Bilinear	Interpolation method used for extraction of image pixel values
inRidgeScanParams	const RidgeScanParams&		RidgeScanParams ( ProfileInterpolation: Quadratic4 SmoothingStdDev: 1.0f RidgeWidth: 5 RidgeMargin: 2 MinMagnitude: 5.0f RidgePolarity: Dark )	Parameters controlling the ridge extraction process
inRidgeSelection	Selection::Type			Selection mode of ridges
inLocalBlindness	Optional<const LocalBlindness&>		NIL	Defines conditions in which weaker ridges can be detected in the vicinity of stronger ridges
inMaxIncompleteness	float	0.0 - 0.999	0.1f	Maximal fraction of ridge points not found
inFittingMethod	CircleFittingMethod::Type		AlgebraicTaubin	Method used to fit a circle
inOutlierSuppression	Optional<MEstimator::Type>		NIL	Selects a method for ignoring incorrectly detected points
outCircle	Conditional<Circle2D>&			Fitted circle or nothing if the fitting fails
outRidges	Optional<Array<Conditional<Ridge1D> >&>		NIL	Found ridges
outDeviationProfile	Optional<Conditional<Profile>&>		NIL	Profile of distances between the actual circle points and the corresponding reference circle points
outAlignedFittingField	Optional<CircleFittingField&>		NIL	Fitting field used; in the image coordinate system
diagScanSegments	Array<Segment2D>&			Segments along which the scans were run
diagSamplingAreas	Array<Rectangle2D>&			Areas from which the input image is sampled
diagBrightnessProfiles	Array<Profile>&			Extracted image profiles
diagResponseProfiles	Array<Profile>&			Profiles of the ridge operator response

Description

The operation tries to fit a given circle to ridges present in the inImage image. Internally, it performs a series of scans with the ScanSingleRidge 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 inRidgeScanParams.RidgePolarity to detect a particular ridge type, and only that type.
Adjust inRidgeScanParams.RidgeWidth to the expected thickness of the ridge (in pixels).
If no or too few ridge points are found, try decreasing inRidgeScanParams.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 outRidges outputs to visualize the scanning results.

Examples

Fitting a circle to a wall of a plastic capsule
(inRidgeScanParams.Polarity = Dark, inRidgeScanParams.RidgeWidth = 3).

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.