d@10: /*
d@10:   ==============================================================================
d@10: 
d@10:     SpectralContrast.cpp
d@10:     Created: 14 Aug 2015 12:21:29pm
d@10:     Author:  David
d@10: 
d@10:   ==============================================================================
d@10: */
d@10: 
d@10: #include "SpectralContrast.h"
d@10: #include <algorithm>
d@12: #include <iostream>
d@10: 
d@10: void SpectralContrast::initSpectralContrastVariables(int frameSize, float sampleRate)
d@10: {
d@10: 
d@10: 	int numberBands = 6; //the number of bands in the filter
d@10: 	float lowFrequencyBound = 20; //the lower bound of the lowest band
d@10: 	float highFrequencyBound = sampleRate / 2.0f;
d@10: 	float staticDistribution = 0.15f; //the ratio of the bins to distribute equally [0, 1]
d@10: 	m_neighbourRatio = 0.4f; //the ratio of the bins in the sub band used to calculate the peak and valley", "(0,1]"
d@10: 
d@10: 	// get staticDistribution
d@10: 	float partToScale = 1.0f - staticDistribution;
d@10: 
d@10: 	float binWidth = sampleRate / frameSize;
d@10: 
d@10: 	int lastBins = 0;
d@10: 	m_startAtBin = 0;
d@10: 
d@10: 	m_numberOfBinsInBands.clear();
d@10: 	m_numberOfBinsInBands.resize(numberBands);
d@10: 	lastBins = int(lowFrequencyBound / binWidth);
d@10: 	m_startAtBin = lastBins;
d@10: 
d@10: 	// Determine how many bins are in each band to start with.
d@10: 	// The rest of the bands will be distributed logarithmically.
d@10: 	int  totalNumberOfBins = int(highFrequencyBound / binWidth);
d@10: 	highFrequencyBound = int(partToScale * totalNumberOfBins) * binWidth;
d@10: 	int  staticBinsPerBand = int((1 - partToScale) * totalNumberOfBins) / numberBands;
d@10: 	float ratio = highFrequencyBound / lowFrequencyBound;
d@10: 	float ratioPerBand = pow(ratio, float(1.0 / numberBands));
d@10: 	float currFreq = lowFrequencyBound;
d@10: 
d@10: 	for (int i = 0; i < numberBands; ++i) 
d@10: 	{
d@10: 		currFreq = currFreq * ratioPerBand;
d@10: 		m_numberOfBinsInBands[i] = int(currFreq / binWidth - lastBins + staticBinsPerBand);
d@10: 		lastBins = int(currFreq / binWidth);
d@10: 	}
d@10: 
d@10: }
d@10: 
d@10: void SpectralContrast::computeSpectralContrast(std::vector<float> spectrum, std::vector<float>& spectralContrast, std::vector<float>& valleys)
d@10: {
d@10: 	std::vector<float> spectrumCopy = spectrum; // I want a copy because I'll be transforming it
d@10: 
d@10: 	//substitute minReal for a static value that is the same in all architectures. i.e.: 1e-30
d@12: 	float minFloat = std::numeric_limits<float>::min(); //numeric_limits<Real>::min();
d@10: 
d@10: 	spectralContrast.clear();
d@10: 	valleys.clear();
d@10: 
d@10: 	int specIdx = m_startAtBin;
d@10: 
d@12: 	for (int bandIdx = 0; bandIdx < int(m_numberOfBinsInBands.size()) && specIdx < int(spectrumCopy.size()); ++bandIdx)
d@10: 	{
d@10: 		// get the mean of the band
d@10: 		float bandMean = 0;
d@10: 		for (int i = 0; i < m_numberOfBinsInBands[bandIdx] && specIdx + i < int(spectrumCopy.size()); ++i)
d@10: 		{
d@10: 			bandMean += spectrumCopy[specIdx + i];
d@10: 		}
d@10: 
d@12: 		if (m_numberOfBinsInBands[bandIdx] != 0)
d@10: 		{
d@12: 			bandMean /= m_numberOfBinsInBands[bandIdx];
d@10: 		}
d@10: 
d@12: 		bandMean += minFloat;
d@12: 
d@10: 		// sort the subband (ascending order)
d@10: 		std::sort(spectrumCopy.begin() + specIdx, spectrumCopy.begin() + std::min(specIdx + m_numberOfBinsInBands[bandIdx], int(spectrum.size())));
d@10: 
d@10: 		// number of bins to take the mean of
d@10: 		int neighbourBins = int(m_neighbourRatio * m_numberOfBinsInBands[bandIdx]);
d@12: 		if (neighbourBins < 1)
d@12: 		{		
d@12: 			neighbourBins = 1;
d@12: 		}
d@10: 
d@10: 		// valley (FLT_MIN prevents log(0))
d@10: 		float sum = 0;
d@12: 		for (int i = 0; i < neighbourBins && specIdx + i < int(spectrumCopy.size()); ++i) 
d@10: 		{
d@12: 			sum += spectrumCopy[specIdx + i];
d@10: 		}
d@10: 
d@12: 		float valley = (sum / neighbourBins) + minFloat;
d@10: 
d@10: 		// peak
d@10: 		sum = 0;
d@12: 		for (int i = m_numberOfBinsInBands[bandIdx]; i > m_numberOfBinsInBands[bandIdx] - neighbourBins && specIdx + i - 1 < int(spectrumCopy.size()) && i > 0; --i)
d@10: 		{
d@12: 			sum += spectrumCopy[specIdx + i - 1];
d@10: 		}
d@12: 		
d@10: 
d@12: 		float peak = (sum / neighbourBins) + minFloat;
d@10: 
d@12: 		float ans = (log10(peak / valley)) / (log10(bandMean) + minFloat) ;
d@12: 
d@12: 		spectralContrast.push_back(ans);
d@12: 		valleys.push_back(log10(valley));
d@10: 
d@10: 		specIdx += m_numberOfBinsInBands[bandIdx];
d@10: 	}
d@12: 
d@10: }