comparison AutocorrelationProcessor.cpp @ 25:fe23998968b4

* Added tempogram via autocorrelation feature, using AutocorrelationProcessor
* Moved calculateMax() from NoveltyCurveProcessor to SpectrogramProcessor

+//
+//  AutocorrelationProcessor.cpp
+//  Tempogram
+//
+//  Created by Carl Bussey on 20/08/2014.
+//  Copyright (c) 2014 Carl Bussey. All rights reserved.
+//
+
+#include "AutocorrelationProcessor.h"
+using namespace std;
+
+AutocorrelationProcessor::AutocorrelationProcessor(const size_t &windowLength, const unsigned int &hopSize, const unsigned int &lagIncrement) :
+    m_windowLength(windowLength),
+    m_hopSize(hopSize),
+    m_lagIncrement(lagIncrement)
+{
+    //Nothing to do here
+}
+
+AutoCorrelation AutocorrelationProcessor::process(float * input, const size_t &inputLength) const
+{
+    int readBlockPointerIndex = 0;
+    AutoCorrelation autocorrelation;
+    
+    while(readBlockPointerIndex <= (int)inputLength) {
+        int readPointer = readBlockPointerIndex - m_windowLength/2;
+        
+        autocorrelation.push_back(processBlock(&input[readPointer], min(inputLength-readPointer, m_windowLength)));
+        readBlockPointerIndex += m_hopSize;
+    }
+    
+    return autocorrelation;
+}
+
+vector<float> AutocorrelationProcessor::processBlock(float * blockInput, const size_t &blockLength) const
+{
+    vector<float> autocorrelation;
+    
+    int N = m_windowLength/m_lagIncrement;
+    
+    for (int lag = 0; lag < N; lag++){
+        float sum = 0;
+        int sampleLag = m_lagIncrement*lag;
+        
+        for (int n = sampleLag; n < (int)blockLength; n++){
+            sum += blockInput[n-sampleLag]*blockInput[n];
+        }
+        autocorrelation.push_back(sum/(2*N + 1 - lag));
+    }
+    
+    return autocorrelation;
+}