diff --git a/include/ITAPropagationModels/Maekawa.h b/include/ITAPropagationModels/Maekawa.h
index b114ab17c91697b5b29be2dbd5a5da044aedb18f..2ce9dcc6ab1534b511d2203012c92402ce71f69f 100644
--- a/include/ITAPropagationModels/Maekawa.h
+++ b/include/ITAPropagationModels/Maekawa.h
@@ -108,8 +108,22 @@ namespace ITAPropagationModels
//! Calculate diffraction filter based on the Maekawa detour method
/**
- * This function calculates the Maekawa diffraction filter based on detour length around a wedge obstacle
- * and the direct path length with and withont any obstacles.
+ * This function calculates the Maekawa diffraction filter coefficient based on detour length around a wedge obstacle
+ * and the direct path length with and without any obstacles.
+ *
+ * @param[in] dPropagationLengthDirect Direct path length [m]
+ * @param[in] dPropagationLengthDetour Detour path length [m]
+ * @param[in] fFrequency Frequency [Hz]
+ * @param[in] fSpeedOfSound Speed of sound [m/s]
+ *
+ */
+ double ITA_PROPAGATION_MODELS_API CalculateDiffractionFilterCoefficient( const double dPropagationLengthDirect, const double dPropagationLengthDetour, const float fFrequency, const float fSpeedOfSound = ITAConstants::SPEED_OF_SOUND_F);
+
+ //! Calculate diffraction factor based on the Maekawa detour method
+ /**
+ * This function calculates the Maekawa diffraction factor based on detour length around a wedge obstacle
+ * and the direct path length with and without any obstacles.
+ * The diffraction factor contains the influence of the wedge without the influence of the propagation path length.
*
* @param[in] dPropagationLengthDirect Direct path length [m]
* @param[in] dPropagationLengthDetour Detour path length [m]
@@ -117,7 +131,7 @@ namespace ITAPropagationModels
* @param[in] fSpeedOfSound Speed of sound [m/s]
*
*/
- float ITA_PROPAGATION_MODELS_API CalculateDiffractionFilterCoefficient( const double dPropagationLengthDirect, const double dPropagationLengthDetour, const float fFrequency, const float fSpeedOfSound = 344.0f );
+ double ITA_PROPAGATION_MODELS_API CalculateDiffractionFactor(const double dPropagationLengthDirect, const double dPropagationLengthDetour, const float fFrequency, const float fSpeedOfSound = ITAConstants::SPEED_OF_SOUND_F);
//! Calculate diffraction filter (frequency domain) based on the Maekawa detour method
@@ -131,7 +145,7 @@ namespace ITAPropagationModels
* @param[in] fSpeedOfSound Speed of sound [m/s]
*
*/
- void ITA_PROPAGATION_MODELS_API CalculateDiffractionFilter( const double dPropagationLengthDirect, const double dPropagationLengthDetour, ITABase::CHDFTSpectrum& oTransferFunction, const float fSpeedOfSound = 344.0f );
+ void ITA_PROPAGATION_MODELS_API CalculateDiffractionFilter( const double dPropagationLengthDirect, const double dPropagationLengthDetour, ITABase::CHDFTSpectrum& oTransferFunction, const float fSpeedOfSound = ITAConstants::SPEED_OF_SOUND_F);
}
}
diff --git a/src/ITAPropagationModels/Maekawa.cpp b/src/ITAPropagationModels/Maekawa.cpp
index 8023b4df40ab4ef60174bcc752670d760e1860dc..146bccc858d9e94a66d173431bf8caf504852dba 100644
--- a/src/ITAPropagationModels/Maekawa.cpp
+++ b/src/ITAPropagationModels/Maekawa.cpp
@@ -36,26 +36,49 @@ double Maekawa::KirchhoffDelta( const double dPropagationLengthDirect, const dou
return dKirchhoffDelta;
}
-void Maekawa::CalculateDiffractionFilter( const double dDirect, const double dDetour, ITABase::CHDFTSpectrum& oTransferFunction, const float fSpeedOfSound /*= 344.0f*/ )
+void Maekawa::CalculateDiffractionFilter( const double dDirect, const double dDetour, ITABase::CHDFTSpectrum& oTransferFunction, const float fSpeedOfSound /*= ITAConstants::SPEED_OF_SOUND_F*/ )
{
assert( fSpeedOfSound > 0.0f );
if( fSpeedOfSound <= 0.0f )
ITA_EXCEPT1( INVALID_PARAMETER, "Speed of sound can't be zero or negative" );
- // Per definition, DC value is real and 1.0
- oTransferFunction.SetCoeffRI( 0, 1.0f, 0.0f );
+ // Per definition, DC value (N = 0) is set to or 10^(5/20) / r_dir (5dB loss as well as loss due to detour length)
+ float fCoefficient = pow(10.0f, 5.0f / 20.0f)/dDirect;
+ oTransferFunction.SetCoeffRI(0, fCoefficient, 0.0f);
+
const int iDFTSize = oTransferFunction.GetSize();
- for( int i = 1; i < iDFTSize - 1; i++ )
+ for( int i = 1; i < iDFTSize; i++ )
{
const float fFrequency = oTransferFunction.GetFrequencyResolution() * i;
- const float fCoefficient = CalculateDiffractionFilterCoefficient( dDirect, dDetour, fFrequency, fSpeedOfSound );
+ fCoefficient = (float) CalculateDiffractionFilterCoefficient( dDirect, dDetour, fFrequency, fSpeedOfSound );
oTransferFunction.SetCoeffRI( i, fCoefficient );
+
+ //Set wave number and phase shift
+ const float k = ITAConstants::TWO_PI_F_L * fFrequency / fSpeedOfSound;
+ oTransferFunction.SetPhasePreserveMagnitude(i, - k * (float) dDetour);
}
}
-float ITA_PROPAGATION_MODELS_API ITAPropagationModels::Maekawa::CalculateDiffractionFilterCoefficient( const double dPropagationLengthDirect, const double dPropagationLengthDetour, const float fFrequency, const float fSpeedOfSound /*= 344.0f */ )
+double Maekawa::CalculateDiffractionFilterCoefficient( const double dPropagationLengthDirect, const double dPropagationLengthDetour, const float fFrequency, const float fSpeedOfSound /*= ITAConstants::SPEED_OF_SOUND_F */ )
{
- // @todo daniel armin
- ITA_EXCEPT_NOT_IMPLEMENTED;
+ //Difference between detour length and direct length
+ const double dDifference = dPropagationLengthDetour - dPropagationLengthDirect;
+
+ //Fresnel number N according to Maekawa //TODO: Equation number
+ const double dN = 2.0 * dDifference / fSpeedOfSound * fFrequency;
+
+ //Calculation of the diffraction filter coefficient according to Kurze, Anderson
+ const double dTemp = sqrt(ITAConstants::TWO_PI_D * dN);
+ const double dFilterCoefficient = pow(pow(10.0, 5.0 / 20.0)* dTemp / tanh(dTemp), -1) / dPropagationLengthDirect;
+
+
+ return dFilterCoefficient;
}
+
+
+double Maekawa::CalculateDiffractionFactor(const double dPropagationLengthDirect, const double dPropagationLengthDetour, const float fFrequency, const float fSpeedOfSound /*= ITAConstants::SPEED_OF_SOUND_F */)
+{
+ //Return the diffraction factor without the influence of the propagation path length
+ return dPropagationLengthDetour * CalculateDiffractionFilterCoefficient(dPropagationLengthDirect, dPropagationLengthDetour, fFrequency, fSpeedOfSound);
+}
\ No newline at end of file
diff --git a/tests/Maekawa/MaekawaTest.cpp b/tests/Maekawa/MaekawaTest.cpp
index 873e8342ad3a6acc5e7527fa81263f421e89e411..0394e18b5bd7f3b7709014a648d4337817491269 100644
--- a/tests/Maekawa/MaekawaTest.cpp
+++ b/tests/Maekawa/MaekawaTest.cpp
@@ -34,7 +34,7 @@ using namespace ITAGeo;
using namespace ITAPropagationModels;
static float g_fSampleRate = 44.1e3f;
-static int g_iFilterLength = 128;
+static int g_iFilterLength = 1280;
//! Tests running the Maekawa model functions
/**
@@ -80,6 +80,11 @@ int main( int, char** )
Maekawa::CalculateDiffractionFilter( dPropLengthDirect, dPropLengthDetour, oDiffractionTF );
cout << "Maekawa filter generation calculation time: " << timeToString( sw.stop() ) << endl;
+ if (Maekawa::IsApplicable(pS->v3InteractionPoint, pR->v3InteractionPoint, pW))
+ {
+ oDiffractionTF.SetZero();
+ }
+
cout << oDiffractionTF.ToString() << endl;
ITAFFTUtils::Export( &oDiffractionTF, "MaekawaTestIR.wav" );
diff --git a/tests/Maekawa/MaekawaTest.m b/tests/Maekawa/MaekawaTest.m
index 72d08a1bd90570c93af62224674ebf0f6affb0ca..cf37fa0ffb006c9706a4f6b5cad89985b782499a 100644
--- a/tests/Maekawa/MaekawaTest.m
+++ b/tests/Maekawa/MaekawaTest.m
@@ -1,6 +1,6 @@
%% Load C++ implementation result
maekawa_ir_cpp = ita_read( 'MaekawaTestIR.wav' );
-
+maekawa_ir_cpp.signalType = 'energy';
%% Run ITA-Toolbox diffraction simulation
n1 = [ -1 1 0 ];
@@ -20,3 +20,7 @@ maekawa_ir.freqData = ita_diffraction_maekawa( w, s, r, maekawa_ir_cpp.freqVecto
%% Combined result
maekawa_eval = ita_merge( maekawa_ir, maekawa_ir_cpp );
+
+%% Plot result
+
+maekawa_eval.pt
\ No newline at end of file