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AvsFilter_ScanSingleRidge


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

Header:AVL.h
Namespace:avs

Locates the strongest dark or bright pixel peak along a given path.

Syntax

void avs::AvsFilter_ScanSingleRidge
(
	ScanSingleRidgeState& ioState,
	const avl::Image& inImage,
	const avl::Path& inScanPath,
	atl::Optional<const avl::CoordinateSystem2D&> inScanPathAlignment,
	int inScanWidth,
	avl::InterpolationMethod::Type inImageInterpolation,
	const avl::RidgeScanParams& inRidgeScanParams,
	avl::Selection::Type inRidgeSelection,
	atl::Optional<const avl::LocalBlindness&> inLocalBlindness,
	atl::Conditional<avl::Ridge1D>& outRidge,
	atl::Optional<avl::Path&> outAlignedScanPath = atl::NIL,
	avl::Profile& diagBrightnessProfile,
	avl::Profile& diagResponseProfile,
	atl::Array<avl::Path>& diagSamplingPoints,
	float& diagSamplingStep
)

Parameters

Name Type Range Default Description
ioState ScanSingleRidgeState& 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
inRidgeScanParams const RidgeScanParams& RidgeScanParams ( ProfileInterpolation: Quadratic4 SmoothingStdDev: 0.6f RidgeWidth: 5 RidgeMargin: 2 MinMagnitude: 5.0f RidgePolarity: Dark ) Parameters controlling the ridge extraction process
inRidgeSelection Selection::Type Selection mode of the resulting ridge
inLocalBlindness Optional<const LocalBlindness&> NIL Defines conditions in which weaker edges can be detected in the vicinity of stronger edges
outRidge Conditional<Ridge1D>& Found ridge
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 ridge 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 atl::NIL to these parameters: outAlignedScanPath.

Read more about Optional Outputs.

Description

The operation scans the image along inScanPath and locates the strongest ridge of the given characteristics. If there is no such ridge 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

  • Adjust inRidgeScanParams.RidgeWidth to the expected thickness of the ridge (in pixels).
  • Define inRidgeScanParams.RidgePolarity to detect a particular ridge type, and only that type.
  • If no ridge is found, try decreasing inRidgeScanParams.MinMagnitude.
  • For difficult cases try different settings of the inRidgeScanParams.RidgeOperator parameter.

Examples

AvsFilter_ScanSingleRidge locates the strongest ridge 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.

See Also

  • CreateScanMap – Precomputes a data object that is required for fast 1D edge detection.