Android Open Source - CopresenceDataCollector X Corr And Dist From Wav

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Back to project page CopresenceDataCollector.

License

The source code is released under:

Copyright (c) 2014, Xiang Gao All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Re...

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Java Source Code

package org.sesy.coco.datacollector.audio;
import org.apache.commons.math3.stat.StatUtils;
import com.musicg.wave.Wave;
/*w ww  .j ava2  s  .co m*/
import edu.emory.mathcs.jtransforms.fft.DoubleFFT_1D;


public class XCorrAndDistFromWav {
  private double maxCorr;
  private double dist, timeDist, freqDist;
  private double[] timeSignal1, timeSignal2;
  private double[] freqSignal1, freqSignal2;
  private int N;  // number of samples (Note: 16bit/s means 2 bytes as 1 sample)
  
  
  public XCorrAndDistFromWav(Wave wave1, Wave wave2){
    
    N = Math.min(wave1.size()/2, wave2.size()/2);
    timeSignal1 = normalize(wave1.getSampleAmplitudes(), N);
    timeSignal2 = normalize(wave2.getSampleAmplitudes(), N);
    double[] ccf = new double[2*N-1];
    new CrossCorrelation(timeSignal1, timeSignal2).getCCF(ccf);
    maxCorr = StatUtils.max(ccf);
    timeDist = 1 - maxCorr;
    
    freqSignal1 = normalize(harmonics(timeSignal1), 0);
    freqSignal2 = normalize(harmonics(timeSignal2), 0);
    
    double freqSum = 0;
    for(int i=0; i<freqSignal1.length; i++){
      double diff = freqSignal1[i] - freqSignal2[i];
      freqSum += diff * diff; 
    }
    freqDist = Math.sqrt(freqSum);
    
    dist = Math.sqrt(freqSum + timeDist * timeDist); 
  }
  
  public double getMaxCorr(){    
    return maxCorr;
  }
  
  public double getDist(){
    return dist;
  }
  
  public double[] harmonics(double[] timeSignal){
    int windowSize = timeSignal.length;
    double[] tmpTimeSignal = new double[2*windowSize];
    for(int i=0; i<windowSize; i++){
      double hamWindow = 0.54 - 0.46*Math.cos(2*Math.PI*i/windowSize);
      tmpTimeSignal[i] = timeSignal[i] * hamWindow;
    }
    DoubleFFT_1D fft = new DoubleFFT_1D(windowSize); 
        fft.realForwardFull(tmpTimeSignal);
        double[] fullFFTList = tmpTimeSignal;
        
        int vector_end = Math.round((float)windowSize/2);
        double[] fftValues = new double[vector_end];
        for(int j=0; j<vector_end; j++){
          fftValues[j] = Math.sqrt(fullFFTList[2*j]*fullFFTList[2*j] + fullFFTList[2*j+1]*fullFFTList[2*j+1]);
        }
        return fftValues;
  }
  
  public double[] normalize(short[] amps, int n){
    int size = 0;
    if(n == 0){
      size = amps.length;
    }else{
      size = n;
    }
    double sum_energy = 0;
    for(int i=0; i<size; i++){
      sum_energy += (double) amps[i] * ((double) amps[i]);
    }
    double avg_energy = Math.sqrt(sum_energy);
    double[] normalizedAmps = new double[size];
    for(int j=0; j<size; j++){
      normalizedAmps[j] = ((double) amps[j])/avg_energy ;
    }
    return normalizedAmps;
  }
  
  public double[] normalize(double[] amps, int n){
    int size = 0;
    if(n == 0){
      size = amps.length;
    }else{
      size = n;
    }
    double sum_energy = 0;
    for(int i=0; i<size; i++){
      sum_energy += amps[i] * amps[i];
    }
    double avg_energy = Math.sqrt(sum_energy);
    double[] normalizedAmps = new double[size];
    for(int j=0; j<size; j++){
      normalizedAmps[j] = ((double) amps[j])/avg_energy ;
    }
    return normalizedAmps;
  }
  
}

Java Source Code List