boofcv.alg.feature.detect.edge

Class HysteresisEdgeTracePoints

java.lang.Object

boofcv.alg.feature.detect.edge.HysteresisEdgeTracePoints

public class HysteresisEdgeTracePoints
extends Object

Given the output from edge non-maximum suppression, perform hysteresis threshold along the edge and constructs a list of pixels belonging to each contour. Points are first connected in direction tangential to the edge's direction, if no matches are found then a match is searched for using an 8-connect rule. The direction image must be the 4-direction type. If multiple points in the local neighborhood can be added to edge then a new edge segment is created.

Author:

Peter Abeles

Constructor Summary

Constructors

Constructor and Description
HysteresisEdgeTracePoints()

Method Summary

Methods

Modifier and Type	Method and Description
List<EdgeContour>	getContours() Returns the found contours.
void	process(ImageFloat32 intensity, ImageSInt8 direction, float lower, float upper) Performs hysteresis thresholding using the provided lower and upper thresholds.
protected void	trace(int x, int y, int indexInten) Traces along object's contour starting at the specified seed.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HysteresisEdgeTracePoints

public HysteresisEdgeTracePoints()

Method Detail

process

public void process(ImageFloat32 intensity,
           ImageSInt8 direction,
           float lower,
           float upper)

Performs hysteresis thresholding using the provided lower and upper thresholds.

Parameters:

intensity - Intensity image after edge non-maximum suppression has been applied. Modified.

direction - 4-direction image. Not modified.

lower - Lower threshold.

upper - Upper threshold.

trace

protected void trace(int x,
         int y,
         int indexInten)

Traces along object's contour starting at the specified seed. As it does so it will set the intensity of points which are below the lower threshold to zero and add points to contour.

Parameters:

x - x-coordinate of seed pixel above threshold

y - y-coordinate of seed pixel above threshold

indexInten - Pixel index in the image array of coordinate (x,y)

getContours

public List<EdgeContour> getContours()

Returns the found contours. Returned data structures are subject to modification next time process is called.

Returns:

List of found contours.