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DetectSegments

Expert

Module: FoundationBasic

Finds segments in an image using Hough Transform.

Name Type Range Description
Input value
 inImage Image Input image
Input value
 inRoi Region* Input region of interest
Input value
 inAngleResolution Real 0.1 - 180.0 Resolution of segments' orientation
Input value
 inMinAngleDelta Real 0.0 - Minimum angle between two segments
Input value
 inMinDistance Real 0.0 - Minimum distance between two segments
Input value
 inMinLength Real 0.0 - Minimum segment length
Input value
 inMinScore Real 0.0 - Minimum matching score
Input value
 inEdgeThreshold Real Minimum accepted edge magnitude
Output value
 outSegments Segment2DArray Output segments
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 straight edges in the inImage using the Hough Transform approach and treats them as segments by tracing gradients along lines. The output array is ordered from best matching to worst matching results.

The parameter inAngleResolution specifies the precision of detected lines' orientations. Value of n means the filter will be able to reliably distinguish lines in n-degree increments.

Parameters inMinAngleDelta and inMinDistance are used for neighbouring results suppression. inMinAngleDelta specifies the minimum angle between two lines while inMinDistance specifies the minimum distance between two parallel lines. Parameter inMinLength limits the length of segments (in pixels), suppressing too short segments.

The orientations of the resulting segments are always between 0 and 180 degrees.

Examples

DetectSegments performed on the sample image with inMinScore = 0.5, inMinLength = 25.

Remarks

Low values of inAngleResolution (under 0.5) may cause high memory consumption and decrease in performance.

Complexity Level

This filter is available on Expert Complexity Level.

See Also

  • DetectLines – Finds lines in an image using Hough Transform.
  • DetectPaths – Finds a specified shape in an image using Hough Transform.