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Normalize delay-and-sum mask in Beamformer

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This normalization is done in the Matlab Code but was never ported to the C++ version.

R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/37919004

Cr-Commit-Position: refs/heads/master@{#8279}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8279 4adac7df-926f-26a2-2b94-8c16560cd09d
This commit is contained in:
aluebs@webrtc.org 2015-02-07 02:41:24 +00:00
parent 799e667e9f
commit 2a44be93e8
3 changed files with 19 additions and 1 deletions
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18
webrtc/modules/audio_processing/beamformer/beamformer.cc
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@ -123,6 +123,18 @@ int Round(float x) {
return std::floor(x + 0.5f);
}
// Calculates the sum of absolute values of a complex matrix.
float SumAbs(const ComplexMatrix<float>& mat) {
float sum_abs = 0.f;
const complex<float>* const* mat_els = mat.elements();
for (int i = 0; i < mat.num_rows(); ++i) {
for (int j = 0; j < mat.num_columns(); ++j) {
sum_abs += std::abs(mat_els[i][j]);
}
}
return sum_abs;
}
} // namespace
Beamformer::Beamformer(const std::vector<Point>& array_geometry)
@ -205,6 +217,9 @@ void Beamformer::InitDelaySumMasks() {
complex_f norm_factor = sqrt(
ConjugateDotProduct(delay_sum_masks_[f_ix], delay_sum_masks_[f_ix]));
delay_sum_masks_[f_ix].Scale(1.f / norm_factor);
normalized_delay_sum_masks_[f_ix].CopyFrom(delay_sum_masks_[f_ix]);
normalized_delay_sum_masks_[f_ix].Scale(1.f / SumAbs(
normalized_delay_sum_masks_[f_ix]));
}
}
@ -405,7 +420,8 @@ void Beamformer::ApplyMasks(const complex_f* const* input,
for (int f_ix = 0; f_ix < kNumFreqBins; ++f_ix) {
output_channel[f_ix] = complex_f(0.f, 0.f);
const complex_f* delay_sum_mask_els = delay_sum_masks_[f_ix].elements()[0];
const complex_f* delay_sum_mask_els =
normalized_delay_sum_masks_[f_ix].elements()[0];
for (int c_ix = 0; c_ix < num_input_channels_; ++c_ix) {
output_channel[f_ix] += input[c_ix][f_ix] * delay_sum_mask_els[c_ix];
}

1
webrtc/modules/audio_processing/beamformer/beamformer.h
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@ -136,6 +136,7 @@ class Beamformer : public LappedTransform::Callback {
// Array of length |kNumFreqBins|, Matrix of size |1| x |num_channels_|.
ComplexMatrixF delay_sum_masks_[kNumFreqBins];
ComplexMatrixF normalized_delay_sum_masks_[kNumFreqBins];
// Array of length |kNumFreqBins|, Matrix of size |num_input_channels_| x
// |num_input_channels_|.

1
webrtc/modules/audio_processing/beamformer/covariance_matrix_generator.cc
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@ -143,6 +143,7 @@ void CovarianceMatrixGenerator::PhaseAlignmentMasks(int frequency_bin,
complex<float>* const* mat_els = mat->elements();
for (int c_ix = 0; c_ix < num_input_channels; ++c_ix) {
// TODO(aluebs): Generalize for non-uniform-linear microphone arrays.
float distance = mic_spacing * c_ix * sin_angle * -1.f;
float phase_shift = 2 * M_PI * distance * freq_in_hertz / sound_speed;