Module imagingbook.common

Package imagingbook.common.corners

Class SubpixelMaxInterpolator.QuadraticLeastSquares

java.lang.Object

imagingbook.common.corners.SubpixelMaxInterpolator

imagingbook.common.corners.SubpixelMaxInterpolator.QuadraticLeastSquares

Enclosing class:

SubpixelMaxInterpolator

public static class SubpixelMaxInterpolator.QuadraticLeastSquares
extends SubpixelMaxInterpolator

2D interpolator based on least-squares fitting a quadratic polynomial

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

to the supplied sample values. See Sec. E.2.3 (Alg. E2, 'FindMaxQuadraticLeastSquares') 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

Method Summary

Modifier and Type	Method	Description
static SubpixelMaxInterpolator.QuadraticLeastSquares	getInstance()
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

Method Details

getInstance

public static SubpixelMaxInterpolator.QuadraticLeastSquares getInstance()

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.