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/*
* Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_COVARIANCE_MATRIX_GENERATOR_H_
#define WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_COVARIANCE_MATRIX_GENERATOR_H_
#include "webrtc/modules/audio_processing/beamformer/complex_matrix.h"
#include "webrtc/modules/audio_processing/beamformer/array_util.h"
namespace webrtc {
// Helper class for Beamformer in charge of generating covariance matrices. For
// each function, the passed-in ComplexMatrix is expected to be of size
// |num_input_channels| x |num_input_channels|.
class CovarianceMatrixGenerator {
public:
// A uniform covariance matrix with a gap at the target location. WARNING:
// The target angle is assumed to be 0.
static void UniformCovarianceMatrix(float wave_number,
const std::vector<Point>& geometry,
ComplexMatrix<float>* mat);
// The covariance matrix of a source at the given angle.
static void AngledCovarianceMatrix(float sound_speed,
float angle,
size_t frequency_bin,
size_t fft_size,
size_t num_freq_bins,
int sample_rate,
const std::vector<Point>& geometry,
ComplexMatrix<float>* mat);
// Calculates phase shifts that, when applied to a multichannel signal and
// added together, cause constructive interferernce for sources located at
// the given angle.
static void PhaseAlignmentMasks(size_t frequency_bin,
size_t fft_size,
int sample_rate,
float sound_speed,
const std::vector<Point>& geometry,
float angle,
ComplexMatrix<float>* mat);
};
} // namespace webrtc
#endif // WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_BF_HELPERS_H_
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