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AVL.ScanExactlyNEdges3D_Direct

Locates a specified number of the strongest changes of surface height along a given path.

Namespace:AvlNet
Assembly:AVL.NET.dll

Syntax

C++
C#
 
public static void ScanExactlyNEdges3D_Direct
(
	AvlNet.Surface inSurface,
	AvlNet.Path inScanPath,
	AvlNet.CoordinateSystem2D? inScanPathAlignment,
	float? inSamplingStep,
	int inScanWidth,
	AvlNet.InterpolationMethod inSurfaceInterpolation,
	AvlNet.EdgeScanParams3D inEdgeScanParams,
	int inEdgeCount,
	AvlNet.Selection inEdgeSelection,
	float inMinDistance,
	float? inMaxDistance,
	AvlNet.LocalBlindness? inLocalBlindness,
	int? inMaxProfileGapWidth,
	INullable<List<AvlNet.SurfaceEdge1D>> outEdges
)

Parameters

Name Type Range Default Description
inSurfaceAvlNet.SurfaceInput surface.
inScanPathAvlNet.PathPath along which the scan is performed.
inScanPathAlignmentAvlNet.CoordinateSystem2D?Adjusts the scan path to the position of the inspected object. Default value: atl::NIL.
inSamplingStepfloat?<0.0f, INF>Distance between consecutive sampling points on the scan path; if Nil, the bigger of surface X and Y scales is chosen. Default value: atl::NIL.
inScanWidthint<1, INF>5Width of the scan field in pixels. Default value: 5.
inSurfaceInterpolationAvlNet.InterpolationMethodBilinearInterpolation method used for extraction of surface points. Default value: Bilinear.
inEdgeScanParamsAvlNet.EdgeScanParams3DEdgeScanParams3D ( ProfileInterpolation: Quadratic4 SmoothingStdDev: 0.6f MinMagnitude: 5.0f EdgeTransition: LowToHigh )Parameters controlling the surface edge extraction process. Default value: EdgeScanParams3D ( ProfileInterpolation: Quadratic4 SmoothingStdDev: 0.6f MinMagnitude: 5.0f EdgeTransition: LowToHigh ).
inEdgeCountint<0, INF>1Number of surface edges to be found. Default value: 1.
inEdgeSelectionAvlNet.SelectionSelection mode of the resulting edges.
inMinDistancefloat<0.0f, INF>0.0fMinimal distance between consecutive edges. Default value: 0.0f.
inMaxDistancefloat?<0.0f, INF>Maximal distance between consecutive edges. Default value: atl::NIL.
inLocalBlindnessAvlNet.LocalBlindness?Defines conditions in which weaker edges can be detected in the vicinity of stronger edges. Default value: atl::NIL.
inMaxProfileGapWidthint?<0, INF>1Maximal number of consecutive not existing profile points. Default value: 1.
outEdgesAvlNet.INullable<System.Collections.Generic.List<AvlNet.SurfaceEdge1D>>Found surface edges. This parameter cannot be null.

Description

The operation scans the surface along inScanPath and finds a set of inEdgeCount surface edges perpendicular to the path. If no subset (of inEdgeCount elements) of detected edges meets the requirements of inEdgeScanParams.minMagnitude, inMinDistance, inEdgeScanParams.edgeTransition 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.

Note that in case of a scan path which is closed, the parameters controlling the distances between consecutive found objects do not control the distance between the first and the last of the found objects (counting from the beginning of the scan path).

The operation is very similar to ScanExactlyNEdges from 1DEdgeDetection category, but there are some substantial differences. One of these is the possibility of absence of information, because some surface points may not exist at all. To detect such edges, where solely change of existence matters, Valid/Invalid options of inEdgeScanParams.EdgeTransition can be used. Outside the surface domain (i.e. rectangle defined by input surface width, height, offsets and scales) there are no valid or invalid points, so no edge can be found in the direct vicinity of the domain border.

Because in the Valid/Invalid mode all edges have equal strength, if inEdgeSelection is set to Best, it will be implicitly substituted with First selection option.

Please note that when the input surface has unequal scales along X and Y axes and the scan path is not parallel to any of the axes, the results may be slightly less accurate because of uneven sampling along axes.

Remarks

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

Function Overrides

See also