Module imagingbook.common

Package imagingbook.common.corners

Class SubpixelMaxInterpolator.QuadraticTaylor

java.lang.Object

imagingbook.common.corners.SubpixelMaxInterpolator

imagingbook.common.corners.SubpixelMaxInterpolator.QuadraticTaylor

Enclosing class:

SubpixelMaxInterpolator

public static class SubpixelMaxInterpolator.QuadraticTaylor
extends SubpixelMaxInterpolator

2D interpolator using second-order Taylor expansion to find the coefficients of the quadratic interpolating polynomial

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

The resulting function fits exactly the 5 on-axis samples (s[0], s[1], s[3], s[5], s[7]) but in general does not pass through the outer diagonal samples (s[2], s[4], s[6], s[8]). See Appendix E.2.2 (Alg. E.1, 'FindMaxQuadraticTaylor') 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.QuadraticTaylor	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.QuadraticTaylor 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.