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FisFilter_ScanSingleStripe

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

Header:	FIL.h
Namespace:	fis

Locates the strongest pair of edges across a given path.

Syntax

void fis::FisFilter_ScanSingleStripe
(
	ScanSingleStripeState& ioState,
	const fil::Image& inImage,
	const fil::Path& inScanPath,
	ftl::Optional<const fil::CoordinateSystem2D&> inScanPathAlignment,
	int inScanWidth,
	fil::InterpolationMethod::Type inImageInterpolation,
	const fil::StripeScanParams& inStripeScanParams,
	fil::Selection::Type inStripeSelection,
	ftl::Optional<const fil::LocalBlindness&> inLocalBlindness,
	ftl::Conditional<fil::Stripe1D>& outStripe,
	ftl::Optional<fil::Path&> outAlignedScanPath = ftl::NIL,
	fil::Profile& diagBrightnessProfile,
	fil::Profile& diagResponseProfile,
	ftl::Array<fil::Path>& diagSamplingPoints,
	float& diagSamplingStep
)

Parameters

Name	Type	Range	Default	Description
ioState	ScanSingleStripeState&			Object used to maintain state of the function.
inImage	const Image&			Input image
inScanPath	const Path&			Path along which the scan is performed
inScanPathAlignment	Optional<const CoordinateSystem2D&>		NIL	Adjusts the scan path to the position of the inspected object
inScanWidth	int	1 -	5	Width of the scan field in pixels
inImageInterpolation	InterpolationMethod::Type		Bilinear	Interpolation method used in extraction of image pixel values
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
inStripeSelection	Selection::Type			Selection mode of the resulting stripe
inLocalBlindness	Optional<const LocalBlindness&>		NIL	Defines conditions in which weaker edges can be detected in the vicinity of stronger edges
outStripe	Conditional<Stripe1D>&			Found stripe
outAlignedScanPath	Optional<Path&>		NIL	Path along which the scan is performed; in the image coordinate system
diagBrightnessProfile	Profile&			Extracted image profile
diagResponseProfile	Profile&			Profile of the edge (derivative) operator response
diagSamplingPoints	Array<Path>&			Array of paths each one containing the sampling points that contributed to a single value of the extracted profile
diagSamplingStep	float&			Used distance between consecutive sampling points on the scan path

Optional Outputs

The computation of following outputs can be switched off by passing value ftl::NIL to these parameters: outAlignedScanPath.

Description

The operation scans the image along inScanPath and locates the strongest stripe (i.e. a pair of opposite-polarity edges running across the path) of the given characteristics. If there is no such stripe then the outputs are set to NIL.

The optional parameter inScanPathAlignment defines a transform to be performed on the inScanPath so that the actual scan path (outAlignedScanPath) is adjusted to the position of the object, typically detected by one of Template Matching filters.

Hints

Define inStripeScanParams.StripePolarity to detect a particular edge type, and only that type.
If no stripe is found, try decreasing inStripeScanParams.MinMagnitude. Verify this with the values on the diagResponseProfile output.
If consecutive edges are closer than 6 pixels apart, change inStripeScanParams.ProfileInterpolation to Quadratic3.

Examples

FisFilter_ScanSingleStripe locates the strongest stripe across inScanPath.

Remarks

Read more about Local Coordinate Systems in Machine Vision Guide: Local Coordinate Systems.

This filter is a part of the 1D Edge Detection toolset. For a comprehensive introduction to this technique please refer to 1D Edge Detection and 1D Edge Detection - Subpixel Precision chapters of our Machine Vision Guide.