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DetectPaths

Expert

Module: FoundationBasic

Finds a specified shape in an image using Hough Transform.

Applications

This is an old algorithm for template matching. Quite slow.
Name Type Range Description
Input value
 inImage Image Input image
Input value
 inRoi Region* Input region of interest
Input value
 inPath Path Input path
Input value
 inMinScore Real 0.0 - Minimum matching score
Input value
 inEdgeThreshold Real Minimum accepted edge magnitude
Output value
 outPaths PathArray Output paths
Output value
 outScores RealArray Output scores
Diagnostic input
 diagGradientMagnitudeImage Image Visualized gradients magnitude of an input image
Diagnostic input
 diagScoreImage Image Calculated score for each pixel of an input image

Description

The operation detects paths in the inImage using the Generalized Hough Transform approach. The output array is ordered from best matching to worst matching results.

Examples

A sample path (scaled for convenience).

DetectPaths performed on the sample images with inMinScore = 0.7.

Remarks

DetectPaths is not scale- or rotation-invariant (slightly scaled or rotated paths are, however, detected properly).

Long inPaths cause long computation time.

Errors

This filter can throw an exception to report error. Read how to deal with errors in Error Handling.

List of possible exceptions:

Error type Description
DomainError Degenerate path in DetectPaths.

Complexity Level

This filter is available on Expert Complexity Level.

See Also

  • DetectLines – Finds lines in an image using Hough Transform.
  • DetectSegments – Finds segments in an image using Hough Transform.