Module imagingbook.common

Package imagingbook.common.corners

Class GradientCornerDetector

java.lang.Object

imagingbook.common.corners.GradientCornerDetector

Direct Known Subclasses:

HarrisCornerDetector, MopsCornerDetector, ShiTomasiCornerDetector

public abstract class GradientCornerDetector
extends Object

Abstract super class for all corner detectors based on the local structure matrix (tensor). See Ch. 6 of [1] for details.

[1] W. Burger, M.J. Burge, Digital Image Processing – An Algorithmic Introduction, 3rd ed, Springer (2022).

Version:

2022/03/30

See Also:

• HarrisCornerDetector
• MopsCornerDetector
• ShiTomasiCornerDetector

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	GradientCornerDetector.Parameters

Field Summary

Fields

Modifier and Type	Field	Description
protected final int	M
protected final int	N
protected final GradientCornerDetector.Parameters	params
protected final FloatProcessor	Q
static boolean	RETAIN_TEMPORARY_DATA	For testing/example calculations only!
protected static final float	UndefinedScoreValue

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	GradientCornerDetector(ImageProcessor ip, GradientCornerDetector.Parameters params)

Method Summary

Modifier and Type	Method	Description
FloatProcessor	getA()
FloatProcessor	getB()
FloatProcessor	getC()
List<Corner>	getCorners()
protected abstract 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.
FloatProcessor	getQ()	Returns the corner score function as a FloatProcessor object.

Methods inherited from class java.lang.Object

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

Field Details

RETAIN_TEMPORARY_DATA

public static boolean RETAIN_TEMPORARY_DATA

For testing/example calculations only!

UndefinedScoreValue

protected static final float UndefinedScoreValue

See Also:

• Constant Field Values

M

protected final int M

N

protected final int N

params

protected final GradientCornerDetector.Parameters params

Q

protected final FloatProcessor Q

Constructor Details

GradientCornerDetector

protected GradientCornerDetector(ImageProcessor ip,
 GradientCornerDetector.Parameters params)

Method Details

getCornerScore

protected abstract 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. The method should normalize the score value, such that 100 is returned for the default threshold value. To be implemented by concrete sub-classes.

Parameters:

A - = Ixx(u,v)

B - = Iyy(u,v)

C - = Ixy(u,v)

Returns:

the corner score

See Also:

• HarrisCornerDetector
• ShiTomasiCornerDetector

getQ

public FloatProcessor getQ()

Returns the corner score function as a FloatProcessor object.

Returns:

the score function

getA

public FloatProcessor getA()

getB

public FloatProcessor getB()

getC

public FloatProcessor getC()

getCorners

public List<Corner> getCorners()