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AvsFilter_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.
Locates the strongest pair of edges across a given path.
Syntax
void avs::AvsFilter_ScanSingleStripe ( ScanSingleStripeState& ioState, const avl::Image& inImage, const avl::Path& inScanPath, atl::Optional<const avl::CoordinateSystem2D&> inScanPathAlignment, int inScanWidth, avl::InterpolationMethod::Type inImageInterpolation, const avl::StripeScanParams& inStripeScanParams, avl::Selection::Type inStripeSelection, atl::Optional<const avl::LocalBlindness&> inLocalBlindness, atl::Conditional<avl::Stripe1D>& outStripe, atl::Optional<avl::Path&> outAlignedScanPath = atl::NIL, avl::Profile& diagBrightnessProfile, avl::Profile& diagResponseProfile, atl::Array<avl::Path>& diagSamplingPoints )
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 |
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
Remarks
For more information about local coordinate systems please refer to the following article.
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.