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GCCV7

Overview

Compute angular 2D direction of arrival of audio sources arriving at the mic array

Discussion

This module computes angular 2D direction of arrival of audio sources arriving at the mic array

Input Pins:

Input Pin 1:   Multichannel frequency domain data. Usually output of a WOLA Analysis Module
                      Number of channels must match the number of microphones in the micGeometry argument

Output Pins:

Output Pin 1:   Estimated angular direction of arrival for this WOLA block in degrees. This will be an integer between 0 and 360.

Output Pin 2:    Confidence value for this angle estimate. This will be an integer. Larger values mean more confidence.

Output Pin 3:    Array of 360 floats denoting a histogram of possible angles of arrival for this block. Output pin 1 will be the peak of this histogram.

Module Arguments:

numMics:   number of microphones being used

interpFactor:   Interpolation factor for better angular resolution at the cost of more CPU resources

fftSize:    FFTSize used by WOLA Analysis block preceding the SbDOAV2 module

Fs:    Sampling rate of time domain data entering WOLA Analysis block

LowerBin:    Frequency bin index of lowest WOLA bin entering SbDOAV2 input pin

Inspector Tuning Variables:

BlocksPerHistogram: Each WOLA block we get an angle estimate for each bin. These are accumulated over BlocksPerHistogram
WOLA blocks into a histogram. Then the peak of the histogram is output as the angle estimate. Larger values of
BlocksPerHistogram give more accuracy but slower response time. BlocksPerHistogram value does not affect MIPS.

smoothingCoefficient: The smoothing coefficient, (SC), is a float which takes on values between 0 and 1.
SC operates on the relevant portion of the time domain correlation data between every mic pair. SC performs
exponential smoothing/averaging in time over each point of the correlation functions. The equation is:
state(n) = SC*(new data) + (1-SC)*state(n-1). This smoothing increases the accuracy of the DOA algorithm.
SC allows us to trade off accuracy and responsiveness. The smaller the value of SC, the longer the tail
of our exponential smoothing/averaging.
SC smaller ---> more smoothing more accuracy but less responsiveness
SC larger ---> less smoothing more responsiveness but less accuracy

Module Pack

awe-mod-dspc-vui

ClassID

classID = 16505

Type Definition

typedef struct _ModuleGCCV7
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
INT32 numMics;                                // Number of mics in the array
INT32 interpFactor;                           // Interpolation factor
INT32 fftSize;                                // Size of FFT upstream from this module
INT32 MultiSource;                            // Select single or multiple audio sources reported per block
FLOAT32 Fs;                                   // Time domain sampling rate before WOLA/FFT
INT32 LowerBin;                               // Frequ bin index of lowest frequ component in the WOLA block
FLOAT32 smoothingCoefficient;                 // Smoothing coefficient for exponential smoothing of frequ domain CC data
INT32 BlocksPerHistogram;                     // Number of blocks used to fill histogram before doing smoothing and averaging
INT32 interpBS;                               // Block Size at interpolated rate
FLOAT32 interpSR;                             // Sample rate at interpolated rate
INT32 numDirs;                                // Number of look directions
INT32 maxNumSources;                          // Maximum number of sources to identify
INT32 useInputWeightingPin;                   // Use input weighting pin
INT32 smoothing;                              // 0 No Smoothing  1 Smoothing
INT32 useSmoothingPin;                        // Select use control pin for smoothing coefficient
INT32 combineCongruentMicPairs;               // Select combining congruent mic pairs for MIPS savings
INT32 boxcarDelay;                            // Half length of rectangular window for histogram smoothing
INT32 gaussDelay;                             // Half length of gaussian window for histogram smoothing
FLOAT32 gaussSigma;                           // Standard Deviation for Gaussian window
INT32 NumHistogramStates;                     // Number of full histograms used for temporal averaging
INT32 QCOpt;                                  // Select optimization. DONT CARE, NOT IMPLEMENTED YET
INT32 doHistogramProcessing;                  // Add histogram processing to module outputs
INT32 numBins;                                // Number of bins. This should be the input block size
INT32 numPairs;                               // Number of microphone pairs
INT32 xCorrsZeroSamp;                         // 0th sample index in the xcorr data
INT32 statesSize;                             // Size of states array for frequency domain smoothing
INT32 tdCurrSize;                             // Size of temp td array for time domain smoothing
INT32 maxDelay;                               // Maximum of gaussDelay, boxcarDelay
INT32 HistStatePtr;                           // Index of oldest entry in histogram buffer
INT32 blockCtr;                               // Counter to keep track of number of blocks used to update histogram
INT32 blockCtrReset;                          // Counter to keep track of number of blocks used between reset to zero of avgHistogram
INT32 blockCtrMultiOpt;                       // Counter for multisource/multiblock optimization
INT32 numPairsToUse;                          // Number of non-redunbdant microphone pairs
INT32 NSRMP;                                  // Number of sets of redundant mic pairs
INT32 maxNMPiS;                               // max number of redundant pairs in all sets of redundant pairs
INT32 NNRMP;                                  // Number of non-redundant mic pairs
FLOAT32 epsilon;                              // Small number
FLOAT32 c;                                    // Speed of sound in meters per sec
FLOAT32 windowSize;                           // How much to extend the look window when comparing measured delays with theoretical time delays. This is relative number.
INT32 removalWindowDelta;                     // Number of samples to remove when filtering DOA Peaks
INT32 doHistSmoothing;                        // Specifies whether to do smoothing of histogram
INT32 doHistAveraging;                        // Specifies whether to do temporal smoothing of histogram
FLOAT32 MinPeakThresh;                        // Minimum height of a histogram peak to be eligible to be reported as a DOA
INT32 MinDist;                                // Distance in integer units of degrees, between peaks in histogram to count as a distinct DOA
FLOAT32 noiseFloorDBOffset;                   // Offset, in DB, for noise floor weighting. Higher value will weight noise floor less.
INT32 lookDirLow;                             // Min look direction, in degrees. The low end of the DOA look direction.
INT32 lookDirHigh;                            // Max look direction, in degrees. The high end of the DOA look direction.
INT32 tauMaxMax;                              // Maximum theoretical time delays for all mic pair
INT32 tauMinMin;                              // Minimum theoretical time delays for all mic pair
INT32 tdZeroSamp;                             // windowed xcorr 0 delay sample index
INT32 tdLength;                               // Length of the xcorr vector, after windowing
FLOAT32* micArrayCoords;                      // Microphone geometry in cartesian coordinates and in meters. The vector going from (0,0) to (1,0) is considered 0 degrees.
FLOAT32* noiseFloorVar;                       // Microphone noise floor measurement, in db10 units.
FLOAT32* HistEnergies;                        // Holds energy of sources at each source direction for a data block
FLOAT32* HistAngles;                          // Holds angle for each source for a data block
FLOAT32* HistState;                           // Holds NumHistogramStates histograms
FLOAT32* avgHistogram;                        // Scratch array to hold average histogram
FLOAT32* currentHistogram;                    // Scratch array to hold current histogram
FLOAT32* smoothedHistogram;                   // Scratch array to hold smoothed histogram
FLOAT32* histExt;                             // Scratch array to hold smoothed histogram
FLOAT32* histCnv;                             // Scratch array to hold smoothed histogram
INT32* histSortedAngles;                      // Scratch array for histogram peak picking
FLOAT32* histSortedValues;                    // Scratch array for histogram peak picking
INT32* histAnglesUsed;                        // Scratch array for histogram peak picking
FLOAT32* valuesOutState;                      // Scratch array to hold output histogram counts
INT32* anglesOutState;                        // Scratch array to hold output angles
FLOAT32* GaussianWindow;                      // Gaussian window for smoothing histogram
FLOAT32* BoxcarWindow;                        // Rectangular window for smoothing histogram
INT32* taus;                                  // Theoretical time delays based on the mic geometry and other factors.
FLOAT32* deltaTaus;                           // Difference between taus and taus rounded to nearest sample delay.
FLOAT32* lookDirs;                            // Look directions, in degrees.
INT32* tauMax;                                // Maximum theoretical time delays for each mic pair
INT32* tauMin;                                // Minimum theoretical time delays for each mic pair
FLOAT32* doaValues;                           // Temporary variable from the processing function
FLOAT32* td;                                  // Temporary variable from the processing function
INT32* Map;                                   // Map from pair processed to index of pair in micPairsNR = array of non-redundant mic pairs
FLOAT32* states;                              // Holds current estimate of Rxx
FLOAT32* tdCurr;                              // Temp array for new td data when doing time domain smoothing
INT32* NMPiS;                                 // Array containing number of redundant mic pairs in each set
INT32* CIR;                                   // Array containing channel indices of redundant mic pairs
INT32* CINR;                                  // Array containing channel indices of non-redundant mic pairs
void * ifft_struct_pointer;                   // Points to an instance of an IFFT module
} ModuleGCCV7Class;

Variables

Properties

Name Type Usage isHidden Default Value Range Units
numMics int const 0 4 Unrestricted
interpFactor int const 0 4 Unrestricted
fftSize int const 0 256 Unrestricted
MultiSource int const 0 0 Unrestricted
Fs float const 0 16000 Unrestricted
LowerBin int const 0 0 Unrestricted
smoothingCoefficient float parameter 0 0.2 0:1
BlocksPerHistogram int parameter 0 32 1:200
interpBS int derived 0 512 Unrestricted
interpSR float derived 0 64000 Unrestricted
numDirs int const 1 360 Unrestricted
maxNumSources int const 1 1 Unrestricted
useInputWeightingPin int const 1 0 Unrestricted
smoothing int const 1 2 Unrestricted
useSmoothingPin int const 1 0 Unrestricted
combineCongruentMicPairs int const 1 1 Unrestricted
boxcarDelay int const 1 2 Unrestricted
gaussDelay int const 1 8 Unrestricted
gaussSigma float const 1 3.2 Unrestricted
NumHistogramStates int const 1 4 Unrestricted
QCOpt int const 1 1 Unrestricted
doHistogramProcessing int const 1 1 Unrestricted
numBins int const 1 129 Unrestricted
numPairs int const 1 6 Unrestricted
xCorrsZeroSamp int const 1 64 Unrestricted
statesSize int const 1 1 Unrestricted
tdCurrSize int const 1 1 Unrestricted
maxDelay int const 1 8 Unrestricted
HistStatePtr int state 1 0 Unrestricted
blockCtr int state 1 0 Unrestricted
blockCtrReset int state 1 0 Unrestricted
blockCtrMultiOpt int state 1 0 Unrestricted
numPairsToUse int const 1 6 Unrestricted
NSRMP int const 1 1 Unrestricted
maxNMPiS int const 1 1 Unrestricted
NNRMP int const 1 1 Unrestricted
epsilon float parameter 1 1e-16 Unrestricted
c float parameter 1 343 Unrestricted
windowSize float parameter 1 0 Unrestricted
removalWindowDelta int parameter 1 2 Unrestricted
doHistSmoothing int parameter 1 1 Unrestricted
doHistAveraging int parameter 1 1 Unrestricted
MinPeakThresh float parameter 1 1 0:100
MinDist int parameter 1 10 0:360 degrees
noiseFloorDBOffset float parameter 1 5 -20:20
lookDirLow int parameter 1 0 0:360
lookDirHigh int parameter 1 360 0:360
tauMaxMax int derived 1 0 Unrestricted
tauMinMin int derived 1 0 Unrestricted
tdZeroSamp int derived 1 1 Unrestricted
tdLength int derived 1 1 Unrestricted
micArrayCoords float* parameter 0 [4 x 2] Unrestricted
noiseFloorVar float* parameter 1 [129 x 1] -500:500
HistEnergies float* state 0 [1 x 1] Unrestricted
HistAngles float* state 0 [1 x 1] Unrestricted
HistState float* state 0 [1440 x 1] Unrestricted
avgHistogram float* state 0 [360 x 1] Unrestricted
currentHistogram float* state 0 [360 x 1] Unrestricted
smoothedHistogram float* state 0 [360 x 1] Unrestricted
histExt float* state 0 [376 x 1] Unrestricted
histCnv float* state 0 [392 x 1] Unrestricted
histSortedAngles int* state 0 [360 x 1] Unrestricted
histSortedValues float* state 0 [360 x 1] Unrestricted
histAnglesUsed int* state 0 [360 x 1] Unrestricted
valuesOutState float* state 0 [10 x 1] Unrestricted
anglesOutState int* state 0 [10 x 1] Unrestricted
GaussianWindow float* parameter 1 [17 x 1] Unrestricted
BoxcarWindow float* parameter 1 [5 x 1] Unrestricted
taus int* derived 1 [6 x 360] Unrestricted
deltaTaus float* derived 1 [6 x 360] Unrestricted
lookDirs float* derived 1 [1 x 360] Unrestricted
tauMax int* derived 1 [6 x 1] Unrestricted
tauMin int* derived 1 [6 x 1] Unrestricted
doaValues float* state 0 [360 x 1] Unrestricted
td float* state 0 [1 x 6] Unrestricted
Map int* derived 0 [6 x 1] Unrestricted
states float* state 0 [1 x 1] Unrestricted
tdCurr float* state 0 [1 x 1] Unrestricted
NMPiS int* derived 0 [100 x 1] Unrestricted
CIR int* derived 0 [100 x 1] Unrestricted
CINR int* derived 0 [100 x 1] Unrestricted
ifft_struct_pointer void * state 1 Unrestricted

Pins

Input Pins
Name micIn
Description Microphone array input - in frequency domain
Data type float
Channel range 4
Block size range Unrestricted
Sample rate range Unrestricted
Complex support Complex

Output Pins
Name estDirs
Description Estimated directions, in degrees
Data Type float
Name estEnergy
Description Estimated relative energy for each estimated direction
Data Type float
Name HistValues
Description Histogram output values
Data Type float

Scratch Pins
Channel Count 1
Block size 513
Sample rate 48000
Channel Count 1
Block size 1024
Sample rate 48000
Channel Count 1
Block size 1024
Sample rate 48000

Matlab Usage

File Name: gcc_v7_module.m 
 M = gcc_v7_module(NAME, numMics, interpFactor, fftSize, FS, LOWERBIN) 
 GCCV7 module identifies the 2D angular direction of an audio source received at the mic array.   
 The module takes multichannel frequency domain data as input, (usually the output of a WOLA  
 Analysis module).  The module produces 2 outputs per block:  
 1.)Angle = estimated angular direction of arrival in degrees. This will be an integer between 0 and 360. 
 2.)Confidence value for this angle estimate.  Larger values mean more confidence in the angle estimate.   

 Arguments: 
    NAME - name of the module. 
    numMics - number of microphones in the microphone array 
    interpFactor - how much to interpolate for better estimation at the 
    cost of more MIPS 
    fftSize - Size of the FFT operation done upstream from this module. 
    FS              - Sampling rate of time domain data entering WOLA Analysis block 
    LOWERBIN        - Frequency bin index of lowest WOLA bin entering GCCV7 input pin

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