134 lines
7.7 KiB
C++
134 lines
7.7 KiB
C++
/** @file
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* @author Edouard DUPIN
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* @author Fatima MARFOUQ
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* @copyright 2011, Edouard DUPIN, all right reserved
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* @license MPL v2.0 (see license file)
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*/
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#pragma once
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#include <etk/types.hpp>
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#include <echrono/Steady.hpp>
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#include <audio/format.hpp>
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#include <ememory/memory.hpp>
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namespace audio {
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namespace algo {
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namespace river {
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class NlmsPrivate;
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/**
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* @brief Least Mean Square (LMS) algorithm "echo canceller"
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* base on publication: http://www.arpapress.com/Volumes/Vol7Issue1/IJRRAS_7_1_05.pdf
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Electronic description:
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/
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o---o /|
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_feedback | |/ |
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>---------------->| | | >~~~~~~~~o
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x(n) | |\ | |
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o---o \| |
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\ o--------0
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| | Environement
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| u(n) | transfert fonction
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| |
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o--------o
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o---o ___ |
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_microphone | |/ \ <~~~~~~o
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<----------------<| | | <~~~~~~~~~~~~< Noise
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d(n) | |\___/ <~~~~~~0
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o---o |
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o~~~~~< Usefull signal
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s(n)
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LMS Algorithm:
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_microphone -----------------------------o
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d(n) |
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o--------o | o-------------o
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o---> filter --------->| | o--->| | _output
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| û(n) | convol-| | d(n) - y(n) |----> e(n) -------> echo-cancelled
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| | -ution |----> y(n) ---->| | |
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| _feedback -----o--->| | o-------------o |
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| x(n) | o--------o |
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| | |
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| | o----------------------------------o |
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| | | | |
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| o-------->| |<-------o
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| | û(n+1) = û(n) |
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| | + mu * e(n) * x(n) |
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| | |
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| o----------------------------------o
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o--------------------------------------------o
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*/
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class Nlms {
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public:
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/**
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* @brief Constructor
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*/
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Nlms();
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/**
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* @brief Destructor
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*/
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virtual ~Nlms();
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public:
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/**
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* @brief Reset algorithm
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*/
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virtual void reset();
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/**
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* @brief Initialize the Algorithm
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* @param[in] _nbChannel Number of channel in the stream.
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* @param[in] _sampleRate Sample rate.
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* @param[in] _format Input/output data format.
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*/
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virtual void init(int8_t _nbChannel, float _sampleRate, enum audio::format _format = audio::format_float);
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/**
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* @brief Get list of format suported in input.
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* @return list of supported format
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*/
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virtual etk::Vector<enum audio::format> getSupportedFormat();
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/**
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* @brief Get list of algorithm format suported. No format convertion.
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* @return list of supported format
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*/
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virtual etk::Vector<enum audio::format> getNativeSupportedFormat();
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/**
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* @brief Main input algo process.
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* @param[in,out] _output Output data.
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* @param[in] _input Input data.
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* @param[in] _inputFeedback Input feedback data (all time MONO).
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* @param[in] _nbChunk Number of chunk in the input buffer.
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* @param[in] _nbChannel Number of channel in the stream.
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*/
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virtual void process(void* _output, const void* _input, const void* _inputFeedback, size_t _nbChunk);
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protected:
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ememory::SharedPtr<NlmsPrivate> m_private; // private data.
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public: // parameter area:
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/**
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* @brief Set filter size with specifing the filter temporal size and his samplerate
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* @param[in] _time Time of the filter size
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*/
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virtual void setFilterTime(echrono::microseconds _time);
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/**
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* @brief Set filter size in number of sample
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* @param[in] _nbSample Sample size of the filter
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*/
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virtual void setFilterSize(size_t _nbSample);
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/**
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* @brief Set Mu value for basic LMS value
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* @param[in] _val new mu value
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*/
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virtual void setMu(double _val);
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};
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}
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}
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}
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