Module imagingbook.common

Package imagingbook.common.corners

Class HarrisCornerDetector

java.lang.Object

imagingbook.common.corners.GradientCornerDetector

imagingbook.common.corners.HarrisCornerDetector

public class HarrisCornerDetector
extends GradientCornerDetector

This is an implementation of the Harris/Stephens corner detector, as described in [1]. See Sec. 6.2 of [2] for additional details. This class extends GradientCornerDetector (where most of the work is done) by defining a specific corner score function.

[1] C. G. Harris and M. Stephens. A combined corner and edge detector. In C. J. Taylor, editor, 4th Alvey Vision Conference, pp. 147–151, Manchester (1988).
[2] W. Burger, M.J. Burge, Digital Image Processing – An Algorithmic Introduction, 3rd ed, Springer (2022).

Version:

2022/03/30

Nested Class Summary

Nested classes/interfaces inherited from class imagingbook.common.corners.GradientCornerDetector

GradientCornerDetector.Parameters

Field Summary

Fields

Modifier and Type	Field	Description
static final double	DefaultAlpha

Fields inherited from class imagingbook.common.corners.GradientCornerDetector

M, N, params, Q, RETAIN_TEMPORARY_DATA, UndefinedScoreValue

Constructor Summary

Constructors

Constructor	Description
HarrisCornerDetector(ImageProcessor ip, GradientCornerDetector.Parameters params)

Method Summary

Modifier and Type	Method	Description
protected float	getCornerScore(float a, float b, float c)	Calculates the corner response score for a single image position (u,v) from the elements A, B, C of the local structure matrix.
void	setAlpha(double alpha)	Set the sensitivity parameter α (alpha) for the corner score function.

Methods inherited from class imagingbook.common.corners.GradientCornerDetector

getA, getB, getC, getCorners, getQ

Methods inherited from class java.lang.Object

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

Field Details

DefaultAlpha

public static final double DefaultAlpha

See Also:

• Constant Field Values

Constructor Details

HarrisCornerDetector

public HarrisCornerDetector(ImageProcessor ip,
 GradientCornerDetector.Parameters params)

Method Details

setAlpha

public void setAlpha(double alpha)

Set the sensitivity parameter α (alpha) for the corner score function.

Parameters:

alpha - sensitivity parameter (default is 0.05)

getCornerScore

protected float getCornerScore(float a,
 float b,
 float c)

Description copied from class: GradientCornerDetector

Calculates the corner response score for a single image position (u,v) from the elements A, B, C of the local structure matrix. The method should normalize the score value, such that 100 is returned for the default threshold value. To be implemented by concrete sub-classes.

Specified by:

getCornerScore in class GradientCornerDetector

Parameters:

a - = Ixx(u,v)

b - = Iyy(u,v)

c - = Ixy(u,v)

Returns:

the corner score

See Also:

• HarrisCornerDetector
• ShiTomasiCornerDetector