1 /* 2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_COVARIANCE_MATRIX_GENERATOR_H_ 12 #define WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_COVARIANCE_MATRIX_GENERATOR_H_ 13 14 #include "webrtc/modules/audio_processing/beamformer/complex_matrix.h" 15 #include "webrtc/modules/audio_processing/beamformer/array_util.h" 16 17 namespace webrtc { 18 19 // Helper class for Beamformer in charge of generating covariance matrices. For 20 // each function, the passed-in ComplexMatrix is expected to be of size 21 // |num_input_channels| x |num_input_channels|. 22 class CovarianceMatrixGenerator { 23 public: 24 // A uniform covariance matrix with a gap at the target location. WARNING: 25 // The target angle is assumed to be 0. 26 static void UniformCovarianceMatrix(float wave_number, 27 const std::vector<Point>& geometry, 28 ComplexMatrix<float>* mat); 29 30 // The covariance matrix of a source at the given angle. 31 static void AngledCovarianceMatrix(float sound_speed, 32 float angle, 33 size_t frequency_bin, 34 size_t fft_size, 35 size_t num_freq_bins, 36 int sample_rate, 37 const std::vector<Point>& geometry, 38 ComplexMatrix<float>* mat); 39 40 // Calculates phase shifts that, when applied to a multichannel signal and 41 // added together, cause constructive interferernce for sources located at 42 // the given angle. 43 static void PhaseAlignmentMasks(size_t frequency_bin, 44 size_t fft_size, 45 int sample_rate, 46 float sound_speed, 47 const std::vector<Point>& geometry, 48 float angle, 49 ComplexMatrix<float>* mat); 50 }; 51 52 } // namespace webrtc 53 54 #endif // WEBRTC_MODULES_AUDIO_PROCESSING_BEAMFORMER_BF_HELPERS_H_ 55
