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ScanMultipleRidges
Header: | FIL.h |
---|---|
Namespace: | fil |
Module: | MetrologyBasic |
Locates multiple dark or bright pixel peaks along a given path.
Applications: Very fast detection of multiple thin structures like wires or scale marks - usually for counting or distance measurements.
Syntax
void fil::ScanMultipleRidges ( const fil::Image& inImage, const ScanMap& inScanMap, const RidgeScanParams& inRidgeScanParams, float inMinDistance, ftl::Optional<float> inMaxDistance, ftl::Optional<const fil::LocalBlindness&> inLocalBlindness, ftl::Array<fil::Ridge1D>& outRidges, ftl::Array<fil::Gap1D>& outGaps, ftl::Optional<fil::Profile&> outBrightnessProfile = ftl::NIL, ftl::Optional<fil::Profile&> outResponseProfile = ftl::NIL )
Parameters
Name | Type | Range | Default | Description | |
---|---|---|---|---|---|
inImage | const Image& | Input image | |||
inScanMap | const ScanMap& | Data precomputed with CreateScanMap | |||
inRidgeScanParams | const RidgeScanParams& | RidgeScanParams ( ProfileInterpolation: Quadratic4 SmoothingStdDev: 0.6f RidgeWidth: 5 RidgeMargin: 2 MinMagnitude: 5.0f RidgePolarity: Dark ) | Parameters controlling the ridge extraction process | ||
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 ridges can be detected in the vicinity of stronger ridges | ||
outRidges | Array<Ridge1D>& | Found ridges | |||
outGaps | Array<Gap1D>& | Gaps between consecutive ridges | |||
outBrightnessProfile | Optional<Profile&> | NIL | Extracted image profile | ||
outResponseProfile | Optional<Profile&> | NIL | Profile of the ridge operator response |
Optional Outputs
The computation of following outputs can be switched off by passing value ftl::NIL
to these parameters: outBrightnessProfile, outResponseProfile.
Read more about Optional Outputs.
Description
The operation scans the image using inScanMap previously generated from a scan path and detects ridges. Depending on the inRidgeScanParams.ridgePolarity parameter, dark, bright or both ridges will be taken into account.
When the number of ridges to be measured is known, one can use the ScanExactlyNRidges filter.
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
- Define inRidgeScanParams.RidgePolarity to detect a particular ridge type, and only that type.
- If too few ridges are found, try decreasing inRidgeScanParams.MinMagnitude. Verify this with the values on the outResponseProfile output.
- If consecutive ridges are very close to each other, change inRidgeScanParams.ProfileInterpolation to Quadratic3.
- Adjust inMinDistance (in pixels) to filter out false ridges that appear in proximity to other ridges.
Examples
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.
- ScanSingleRidge – Locates the strongest dark or bright pixel peak along a given path.
- ScanExactlyNRidges – Locates a specified number of the strongest dark or bright pixel peak along a given path.
- ScanMultipleRidges_Direct – Locates multiple dark or bright pixel peaks along a given path (without a scan map).