#include <EarFilter.h>

Public Member Functions
	EarFilter ()

void	configure (float sampleRate)

std::vector< float >	processSignal (std::vector< float > &inputSignal)

Private Member Functions
std::vector< float >	getLowPassFilterCoefficients (float normalizedFrequency, float qualityFactor)

std::vector< float >	convertToHighPass (const std::vector< float > &lowPassCoefficients)

void	applyIIRFilter (const std::vector< float > &inputSignal, dsp::IIR::Filter< float > &filter, std::vector< float > &filteredSignal)

void	applyFIRFilter (const std::vector< float > &inputSignal, const std::vector< float > &coefficients, std::vector< float > &filteredSignal)

void	calculateTransferFunction (const std::vector< float > b, const std::vector< float > a, int numPoints)

std::vector< float >	elementWiseDivision (const std::vector< float > &vector1, const std::vector< float > &vector2)

std::vector< float >	fir2 (int N, std::vector< float > &freqResponse, const std::vector< float > &gain)

std::vector< float >	linspace (float start, float end, int numPoints)

Private Attributes
float	m_sampleRate {-1.0f}

const float	m_maxFreq {20000.0f}

float	m_hopSizeSec = 0.0058f

float	m_hopSizeSamples

float	m_fc = 680.0f

float	m_q = 0.65f

std::vector< float >	m_magResponse

std::vector< float >	m_normalisedFreqs

std::vector< float >	m_freqResponse

std::vector< float >	m_a

std::vector< float >	m_b

dsp::IIR::Filter< float >	m_filter

std::vector< float >	m_gain

int	N = 50

std::vector< float >	m_firCoeffb

std::vector< float >	m_freqs

std::vector< float >	m_gains

Constructor & Destructor Documentation

◆ EarFilter()

krotos::EarFilter::EarFilter ( )

Constructor

Member Function Documentation

◆ applyFIRFilter()

void krotos::EarFilter::applyFIRFilter	(	const std::vector< float > &	inputSignal,
		const std::vector< float > &	coefficients,
		std::vector< float > &	filteredSignal )

private

Filters the inputSignal using an FIR filter operation, one sample at a time. TODO:: optimise to handle whole block by using SIMD optimisation from JUCE.

Parameters

inputSignal	the input signal in vector form
coefficients	the FIR filter coefficients
filteredSignal	an empty vector initially, contains the filtered afterwards. TODO:: rewrite to operate directly on input

Returns: a vector containing the numerator of the highpass IIR filter coefficients

◆ applyIIRFilter()

void krotos::EarFilter::applyIIRFilter	(	const std::vector< float > &	inputSignal,
		dsp::IIR::Filter< float > &	filter,
		std::vector< float > &	filteredSignal )

private

Filters the inputSignal using an IIR filter and filtering one sample at a time. TODO:: optimize to handle whole block by using SIMD optimisation from JUCE.

Parameters

inputSignal	the input signal in vector form
filter	the IIR filter object performing the filtering
filteredSignal	an empty vector initially, contains the filtered afterwards. TODO:: rewrite to operate directly on input

Returns: a vector containing the numerator of the highpass IIR filter coefficients

◆ calculateTransferFunction()

void krotos::EarFilter::calculateTransferFunction	(	const std::vector< float >	b,
		const std::vector< float >	a,
		int	numPoints )

private

Calculates the transfer function of a filter with coefficients a,b at numPoints.(The equivalent of MATLABs freqz function)

Parameters

b	vector containing the numerator coefficients of the filter
a	vector containing the denominator coefficients of the filter
numPoints	the number of frequencies to calculate on

◆ configure()

void krotos::EarFilter::configure ( float sampleRate )

Configures the filter

Parameters

rate	the audio sampling rate

◆ convertToHighPass()

std::vector< float > krotos::EarFilter::convertToHighPass ( const std::vector< float > & lowPassCoefficients )

private

Calculates the IIR highpass filter coefficients from the lowPass denominator coefficients

Parameters

lowPassCoefficients the vector containing the lowPass Filter coefficients

Returns: a vector containing the numerator of the highpass IIR filter coefficients

◆ elementWiseDivision()

std::vector< float > krotos::EarFilter::elementWiseDivision	(	const std::vector< float > &	vector1,
		const std::vector< float > &	vector2 )

private

Performs element wise division between two vectors

Parameters

vector1	numerator
vector2	denominator

Returns: a vector containing the result of the operation

◆ fir2()

std::vector< float > krotos::EarFilter::fir2	(	int	N,
		std::vector< float > &	freqResponse,
		const std::vector< float > &	gain )

private

FIR arbitrary shape filter design using the frequency sampling method. Designs an Nth order linear phase FIR digital filter, with the frequency response specified by vectors freqResponse and gain and returns the filter coefficients in length N+1 vector. (The equivalent of MATLABs fir2.)

Parameters

N	order of the filter
freqResponse	frequency response we want the FIR filter to have
gain	gain factor of each freq

Returns: a vector containing the filter coefficients

◆ getLowPassFilterCoefficients()

std::vector< float > krotos::EarFilter::getLowPassFilterCoefficients	(	float	normalizedFrequency,
		float	qualityFactor )

private

Calculates the coefficients of an IIR Lowpass filter, with specific cutoff frequency, and quality factor.

Parameters

normalizedFrequency	cutoff in Hz normalized by division with sampleRate
qualityFactor	the filters quality factor

Returns: a vector containing the denominator filter coefficients

◆ linspace()

std::vector< float > krotos::EarFilter::linspace	(	float	start,
		float	end,
		int	numPoints )

inlineprivate

Equivalent of MATLABs linspace.

◆ processSignal()

std::vector< float > krotos::EarFilter::processSignal ( std::vector< float > & inputSignal )

Filter the whole signal

Parameters

x	the sample to filter

Returns: the filtered sample

Member Data Documentation

◆ m_a

std::vector<float> krotos::EarFilter::m_a

private

◆ m_b

std::vector<float> krotos::EarFilter::m_b

private

◆ m_fc

float krotos::EarFilter::m_fc = 680.0f

private

◆ m_filter

dsp::IIR::Filter<float> krotos::EarFilter::m_filter

private

◆ m_firCoeffb

std::vector<float> krotos::EarFilter::m_firCoeffb

private

◆ m_freqResponse

std::vector<float> krotos::EarFilter::m_freqResponse

private

◆ m_freqs

std::vector<float> krotos::EarFilter::m_freqs

private

Initial value:

= {0.0f,
                                      100.0f, 
                                      150.0f,  200.0f,  300.0f,  400.0f,  500.0f,  700.0f,   1000.0f,
                                      1500.0f, 2000.0f, 2500.0f, 3000.0f, 3500.0f, 4000.0f,  4500.0f,
                                      5000.0f, 6000.0f, 7000.0f, 8000.0f, 9000.0f, 10000.0f, 20000.0f}

◆ m_gain

std::vector<float> krotos::EarFilter::m_gain

private

◆ m_gains

std::vector<float> krotos::EarFilter::m_gains

private

Initial value:

= {std::numeric_limits<float>::epsilon(),
                                      0.0363078054770101f,
                                      0.102329299228075f,
                                      0.192752491319094f,
                                      0.407380277804113f,
                                      0.645654229034656f,
                                      0.812830516164099f,
                                      0.944060876285923f,
                                      1.0f,
                                      1.14815362149688f,
                                      1.44543977074593f,
                                      1.86208713666287f,
                                      2.26464430759306f,
                                      2.54097270554930f,
                                      2.54097270554930f,
                                      2.29086765276777f,
                                      1.81970085860998f,
                                      0.954992586021436f,
                                      0.462381021399260f,
                                      0.278612116862977f,
                                      0.229086765276777f,
                                      0.245470891568503f,
                                      0.245470891568503f}

◆ m_hopSizeSamples

float krotos::EarFilter::m_hopSizeSamples

private

◆ m_hopSizeSec

float krotos::EarFilter::m_hopSizeSec = 0.0058f

private

◆ m_magResponse

std::vector<float> krotos::EarFilter::m_magResponse

private

◆ m_maxFreq

const float krotos::EarFilter::m_maxFreq {20000.0f}

private

◆ m_normalisedFreqs

std::vector<float> krotos::EarFilter::m_normalisedFreqs

private

◆ m_q

float krotos::EarFilter::m_q = 0.65f

private

◆ m_sampleRate

float krotos::EarFilter::m_sampleRate {-1.0f}

private

◆ N

int krotos::EarFilter::N = 50

private

The documentation for this class was generated from the following files:

krotos_dsp/utilities/analysis_modules/time_domain_analysis/EarFilter.h
krotos_dsp/utilities/analysis_modules/time_domain_analysis/EarFilter.cpp

Public Member Functions

Private Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ EarFilter()

Member Function Documentation

◆ applyFIRFilter()

◆ applyIIRFilter()

◆ calculateTransferFunction()

◆ configure()

◆ convertToHighPass()

◆ elementWiseDivision()

◆ fir2()

◆ getLowPassFilterCoefficients()

◆ linspace()

◆ processSignal()

Member Data Documentation

◆ m_a

◆ m_b

◆ m_fc

◆ m_filter

◆ m_firCoeffb

◆ m_freqResponse

◆ m_freqs

◆ m_gain

◆ m_gains

◆ m_hopSizeSamples

◆ m_hopSizeSec

◆ m_magResponse

◆ m_maxFreq

◆ m_normalisedFreqs

◆ m_q

◆ m_sampleRate

◆ N