Module imagingbook.common

Package imagingbook.common.corners

Class SubpixelMaxInterpolator.Quartic

java.lang.Object

imagingbook.common.corners.SubpixelMaxInterpolator

imagingbook.common.corners.SubpixelMaxInterpolator.Quartic

Enclosing class:

SubpixelMaxInterpolator

public static class SubpixelMaxInterpolator.Quartic
extends SubpixelMaxInterpolator

2D interpolator based on fitting a 'quartic' (i.e., 4th-order) polynomial

 f(x,y) = c_0 + c_1 x + c_2 y + c_3 x^2 + c_4 y^2 + c_5 x y + c_6 x^2 y + c_7 x y^2 + c_8 x^2 y^2

to the supplied sample values. The interpolation function passes through all sample values. The local maximum cannot be found in closed form but is found iteratively, which is not guaranteed to succeed. See Appendix E.2.4 (Alg. E.3, 'FindMaxQuartic') of [1] for additional details.

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

Nested Class Summary

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

SubpixelMaxInterpolator.Method, SubpixelMaxInterpolator.QuadraticLeastSquares, SubpixelMaxInterpolator.QuadraticTaylor, SubpixelMaxInterpolator.Quartic

Field Summary

Fields

Modifier and Type	Field	Description
static final double	DefaulMaxDelta
static final int	DefaultMaxIterations
static final double	DefaultMaxRad

Method Summary

Modifier and Type	Method	Description
static SubpixelMaxInterpolator.Quartic	getInstance()
static SubpixelMaxInterpolator.Quartic	getInstance(int maxIterations, double maxDelta, double maxRad)
float[]	getMax(float[] s)	Tries to locate the sub-pixel maximum from the 9 discrete sample values (s0,...,s8) taken from a 3x3 neighborhood, arranged in the following order:

Methods inherited from class java.lang.Object

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

Field Details

DefaultMaxIterations

public static final int DefaultMaxIterations

See Also:

• Constant Field Values

DefaulMaxDelta

public static final double DefaulMaxDelta

See Also:

• Constant Field Values

DefaultMaxRad

public static final double DefaultMaxRad

See Also:

• Constant Field Values

Method Details

getInstance

public static SubpixelMaxInterpolator.Quartic getInstance()

getInstance

public static SubpixelMaxInterpolator.Quartic getInstance(int maxIterations,
 double maxDelta,
 double maxRad)

getMax

public float[] getMax(float[] s)

Description copied from class: SubpixelMaxInterpolator

Tries to locate the sub-pixel maximum from the 9 discrete sample values (s0,...,s8) taken from a 3x3 neighborhood, arranged in the following order:

 s4 s3 s2
 s5 s0 s1
 s6 s7 s8
 

The center value (s0) is associated with position (0,0).

Specified by:

getMax in class SubpixelMaxInterpolator

Parameters:

s - a vector containing 9 sample values in the order described above

Returns:

a 3-element array [x,y,z], with the estimated maximum position (x,y) and the associated max. value (z). This position is relative to the center coordinate (0,0). null is returned if the maximum position could not be located.