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AvsFilter_ScanExactlyNRidges
This is Filter Equivalent. This function may be present in generated code, but should not be used in hand-written code. CreateScanMap and ScanExactlyNRidges should be used instead.
Locates a specified number of the strongest dark or bright pixel peak along a given path.
Syntax
void avs::AvsFilter_ScanExactlyNRidges ( ScanExactlyNRidgesState& 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, int inRidgeCount, avl::Selection::Type inRidgeSelection, float inMinDistance, atl::Optional<float> inMaxDistance, atl::Optional<const avl::LocalBlindness&> inLocalBlindness, atl::Conditional<atl::Array<avl::Ridge1D> >& outRidges, atl::Conditional<atl::Array<avl::Gap1D> >& outGaps, 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 | ScanExactlyNRidgesState& | Object used to maintain state of the function. | |||
inImage | const Image& | Input image to be measured | |||
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 | ||
inRidgeCount | int | 0 - | 1 | Number of ridges to be found | |
inRidgeSelection | Selection::Type | Selection mode of the resulting ridges | |||
inMinDistance | float | 0.0 - | 0.0f | Minimal distance between consecutive ridges | |
inMaxDistance | Optional<float> | 0.0 - | NIL | Maximal distance between consecutive ridges | |
inLocalBlindness | Optional<const LocalBlindness&> | NIL | Defines conditions in which weaker edges can be detected in the vicinity of stronger edges | ||
outRidges | Conditional<Array<Ridge1D> >& | Found ridges | |||
outGaps | Conditional<Array<Gap1D> >& | Gaps between consecutive edges | |||
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 |
Description
The operation scans the image along inScanPath and finds a set of inRidgeCount image ridges perpendicular to the path. If no subset (of inRidgeCount elements) of detected ridges meets the requirements of inRidgeScanParams.minMagnitude, inMinDistance, inRidgeScanParams.ridgePolarity 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.
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).
Hints
- Set inRidgeCount to the number of ridges that are to be found (the N number).
- Define inEdgeScanParams.RidgePolarity to detect a particular ridge type, and only that type.
- If the expected number of ridges cannot be found, try decreasing inRidgeScanParams.MinMagnitude. Verify this with the values on the diagResponseProfile output.
- If consecutive ridges are very close to each other, change inEdgeScanParams.ProfileInterpolation to Quadratic3.
- Adjust inMinDistance (in pixels) to filter out false ridges that appear in proximity to other ridges.
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.