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ScanSingleStripe

Basic

Module: MetrologyBasic

Locates the strongest pair of edges across a given path (without a scan map).

Applications

Very fast detection or measurement of an object defined by a pair of opposite edges.
Name Type Range Description
Input value
 inImage Image Input image
Input value
 inScanPath Path Path along which the scan is performed
Input value
 inScanPathAlignment CoordinateSystem2D* Adjusts the scan path to the position of the inspected object
Input value
 inScanWidth Integer 1 - Width of the scan field in pixels
Input value
 inSamplingParams SamplingParams Parameters controlling the sampling process
Input value
 inStripeScanParams StripeScanParams Parameters controlling the stripe extraction process
Input value
 inStripeSelection Selection Selection mode of the resulting stripe
Input value
 inLocalBlindness LocalBlindness* Defines conditions in which weaker edges can be detected in the vicinity of stronger edges
Output value
 outStripe Stripe1D? Found stripe
Output value
 outAlignedScanPath Path Transformed input path
Output value
 outBrightnessProfile Profile Extracted image profile
Output value
 outResponseProfile Profile Profile of the edge (derivative) operator response
Diagnostic input
 diagSamplingPoints PathArray Array of paths each one containing the sampling points that contributes to a single value of the extracted profile
Diagnostic input
 diagSamplingStep Real Used distance between consecutive sampling points on the scan path

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

  • Connect an input image to the inImage input.
  • Create inScanPath which is more or less perpendicular to the stripes you want to detect. It should be long enough to anticipate all possible stripe locations.
  • Define inStripeScanParams.StripePolarity to detect a particular edge type, and only that type.
  • Use a local coordinate system connected to inScanPathAlignment to automatically adjust the measurement to variable object position (optional).
  • If the noise level is high, try increasing inScanWidth and/or inStripeScanParams.SmoothingStdDev.
  • If no stripe is found, try decreasing inStripeScanParams.MinMagnitude. Verify this with the values on the outResponseProfile output.
  • If consecutive edges are closer than 6 pixels apart, change inStripeScanParams.ProfileInterpolation to Quadratic3.

Examples

Description of usage of this filter can be found in examples and tutorial: Cap (Advanced).

ScanSingleStripe locates the strongest stripe 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.

Complexity Level

This filter is available on Basic Complexity Level.

Filter Group

This filter is member of ScanStripes filter group.

See Also

  • ScanMultipleStripes – Locates multiple pairs of edges across a given path (without a scan map).
  • ScanExactlyNStripes – Locates a specified number of multiple pairs of opposite edges across a given path (without a scan map).
  • ScanSingleStripe – Locates the strongest pair of edges across a given path (without a scan map).