math
Class Correlation

java.lang.Object
  math.Correlation

public class Correlation
extends java.lang.Object

User: lyon Date: Nov 18, 2007 Time: 9:48:44 AM Copyright DocJava, Inc. 2005.

Constructor Summary

Correlation()

Method Summary

static double	dot(double[] a, double[] b, int j) Calculate the dot product of two vectors.
static java.awt.Image	extractTemplate(java.awt.Image img)
static double[]	getMovingNormalizedCrossCorrelation(double[] signal, double[] kernel)
static float[][]	getSIBB(ShortImageBean sib)
static float[][]	getSIBG(ShortImageBean sib)
static float[][]	getSIBR(ShortImageBean sib)
static void	main(java.lang.String[] args)
static void	main2(java.lang.String[] args)
static double	moravec(double[] x, double[] y)
static java.awt.Image	NCCTry2(java.awt.Image img1, java.awt.Image img2)
static double	normalizedCrossCorrelation(double[] x, double[] y)
static java.awt.Image	normalizedCrossCorrelation(java.awt.Image img1, java.awt.Image img2)
static java.awt.Image	normalizedCrossCorrelationFFT(java.awt.Image img1, java.awt.Image img2)
static double	nssd(double[] x, double[] y)
static double	nzssd(double[] x, double[] y)
static void	oldVersion(java.lang.String[] args)
static double[]	padOutWithZeros(double[] b, int length) This method will pad out a new array of length length and return it.
static double	sad(double[] x, double[] y)
static double	simpleCrossCorrelation(double[] x, double[] y)
static void	speedTestCorrelation(int n)
static double	ssd(double[] x, double[] y)
static void	testCorrelation()
static void	timeTest(java.lang.Runnable r, java.lang.String title)
static double	zeroMeanNormalizedCrossCorrelation(double[] x, double[] y, int period, int startpoint) Calculate the Pearson product-moment correlation between the two variables.
static double[]	zeroPadCorrelate(double[] a, double[] b) Zero pads a non-cyclic cross correlation between the signal and the template.
static java.awt.Image	zeroPadImage(java.awt.Image template, java.awt.Image img1)
static void	zeroPadImage(ShortImageBean sibImage, ShortImageBean sibTemplate)
static double	zsad(double[] x, double[] y)

Methods inherited from class java.lang.Object

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

Constructor Detail

Correlation

public Correlation()

Method Detail

main2

public static void main2(java.lang.String[] args)

speedTestCorrelation

public static void speedTestCorrelation(int n)

oldVersion

public static void oldVersion(java.lang.String[] args)

timeTest

public static void timeTest(java.lang.Runnable r,
                            java.lang.String title)

ssd

public static double ssd(double[] x,
                         double[] y)

sad

public static double sad(double[] x,
                         double[] y)

zsad

public static double zsad(double[] x,
                          double[] y)

nzssd

public static double nzssd(double[] x,
                           double[] y)

nssd

public static double nssd(double[] x,
                          double[] y)

moravec

public static double moravec(double[] x,
                             double[] y)

normalizedCrossCorrelation

public static double normalizedCrossCorrelation(double[] x,
                                                double[] y)

simpleCrossCorrelation

public static double simpleCrossCorrelation(double[] x,
                                            double[] y)

testCorrelation

public static void testCorrelation()

getMovingNormalizedCrossCorrelation

public static double[] getMovingNormalizedCrossCorrelation(double[] signal,
                                                           double[] kernel)

zeroMeanNormalizedCrossCorrelation

public static double zeroMeanNormalizedCrossCorrelation(double[] x,
                                                        double[] y,
                                                        int period,
                                                        int startpoint)

Calculate the Pearson product-moment correlation between the two variables. This will return a correlation co-efficient which is in the range of -1 (negative correlation) through to (no correlation) through to 1 (perfect correlation.

The correlation co-efficient is calculated as follows:

 r = sum(Zx * Zy)
     ------------
         N - 1
 

 Where Zx = X - E(X)
            --------
              Sx
 

Where E(X) is the mean of X and Sx is the standard deviation of X.

Simillarly for Zy. Zero Mean Normalized Cross-correlation zncc

Parameters:

x - values to test against

y - values to detect correlation against x

period - number of days to analyse

Returns:

the correlation co-efficient

normalizedCrossCorrelationFFT

public static java.awt.Image normalizedCrossCorrelationFFT(java.awt.Image img1,
                                                           java.awt.Image img2)

normalizedCrossCorrelation

public static java.awt.Image normalizedCrossCorrelation(java.awt.Image img1,
                                                        java.awt.Image img2)

NCCTry2

public static java.awt.Image NCCTry2(java.awt.Image img1,
                                     java.awt.Image img2)

zeroPadImage

public static java.awt.Image zeroPadImage(java.awt.Image template,
                                          java.awt.Image img1)

zeroPadImage

public static void zeroPadImage(ShortImageBean sibImage,
                                ShortImageBean sibTemplate)

getSIBR

public static float[][] getSIBR(ShortImageBean sib)

getSIBG

public static float[][] getSIBG(ShortImageBean sib)

getSIBB

public static float[][] getSIBB(ShortImageBean sib)

extractTemplate

public static java.awt.Image extractTemplate(java.awt.Image img)

zeroPadCorrelate

public static double[] zeroPadCorrelate(double[] a,
                                        double[] b)

Zero pads a non-cyclic cross correlation between the signal and the template.

Parameters:

a - vector signal for the cross correlation

b - template vector for the cross correlation

Returns:

non-normalized cross correlation

padOutWithZeros

public static double[] padOutWithZeros(double[] b,
                                       int length)

This method will pad out a new array of length length and return it.

Parameters:

b - prepended to the output array

length - of the new array

Returns:

new array with b at the beginning and zeros on the tail.

dot

public static double dot(double[] a,
                         double[] b,
                         int j)

Calculate the dot product of two vectors.

Parameters:

a - the first vector

b - the second vector

Returns:

the dot product

main

public static void main(java.lang.String[] args)