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Diffstat (limited to 'webrtc/modules/audio_processing/beamformer/array_util.cc')
-rw-r--r-- | webrtc/modules/audio_processing/beamformer/array_util.cc | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/webrtc/modules/audio_processing/beamformer/array_util.cc b/webrtc/modules/audio_processing/beamformer/array_util.cc new file mode 100644 index 0000000000..8aaeee9f59 --- /dev/null +++ b/webrtc/modules/audio_processing/beamformer/array_util.cc @@ -0,0 +1,118 @@ +/* + * Copyright (c) 2015 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. + */ + +#include "webrtc/modules/audio_processing/beamformer/array_util.h" + +#include <algorithm> +#include <limits> + +#include "webrtc/base/checks.h" + +namespace webrtc { +namespace { + +const float kMaxDotProduct = 1e-6f; + +} // namespace + +float GetMinimumSpacing(const std::vector<Point>& array_geometry) { + RTC_CHECK_GT(array_geometry.size(), 1u); + float mic_spacing = std::numeric_limits<float>::max(); + for (size_t i = 0; i < (array_geometry.size() - 1); ++i) { + for (size_t j = i + 1; j < array_geometry.size(); ++j) { + mic_spacing = + std::min(mic_spacing, Distance(array_geometry[i], array_geometry[j])); + } + } + return mic_spacing; +} + +Point PairDirection(const Point& a, const Point& b) { + return {b.x() - a.x(), b.y() - a.y(), b.z() - a.z()}; +} + +float DotProduct(const Point& a, const Point& b) { + return a.x() * b.x() + a.y() * b.y() + a.z() * b.z(); +} + +Point CrossProduct(const Point& a, const Point& b) { + return {a.y() * b.z() - a.z() * b.y(), a.z() * b.x() - a.x() * b.z(), + a.x() * b.y() - a.y() * b.x()}; +} + +bool AreParallel(const Point& a, const Point& b) { + Point cross_product = CrossProduct(a, b); + return DotProduct(cross_product, cross_product) < kMaxDotProduct; +} + +bool ArePerpendicular(const Point& a, const Point& b) { + return std::abs(DotProduct(a, b)) < kMaxDotProduct; +} + +rtc::Maybe<Point> GetDirectionIfLinear( + const std::vector<Point>& array_geometry) { + RTC_DCHECK_GT(array_geometry.size(), 1u); + const Point first_pair_direction = + PairDirection(array_geometry[0], array_geometry[1]); + for (size_t i = 2u; i < array_geometry.size(); ++i) { + const Point pair_direction = + PairDirection(array_geometry[i - 1], array_geometry[i]); + if (!AreParallel(first_pair_direction, pair_direction)) { + return rtc::Maybe<Point>(); + } + } + return first_pair_direction; +} + +rtc::Maybe<Point> GetNormalIfPlanar(const std::vector<Point>& array_geometry) { + RTC_DCHECK_GT(array_geometry.size(), 1u); + const Point first_pair_direction = + PairDirection(array_geometry[0], array_geometry[1]); + Point pair_direction(0.f, 0.f, 0.f); + size_t i = 2u; + bool is_linear = true; + for (; i < array_geometry.size() && is_linear; ++i) { + pair_direction = PairDirection(array_geometry[i - 1], array_geometry[i]); + if (!AreParallel(first_pair_direction, pair_direction)) { + is_linear = false; + } + } + if (is_linear) { + return rtc::Maybe<Point>(); + } + const Point normal_direction = + CrossProduct(first_pair_direction, pair_direction); + for (; i < array_geometry.size(); ++i) { + pair_direction = PairDirection(array_geometry[i - 1], array_geometry[i]); + if (!ArePerpendicular(normal_direction, pair_direction)) { + return rtc::Maybe<Point>(); + } + } + return normal_direction; +} + +rtc::Maybe<Point> GetArrayNormalIfExists( + const std::vector<Point>& array_geometry) { + const rtc::Maybe<Point> direction = GetDirectionIfLinear(array_geometry); + if (direction) { + return Point(direction->y(), -direction->x(), 0.f); + } + const rtc::Maybe<Point> normal = GetNormalIfPlanar(array_geometry); + if (normal && normal->z() < kMaxDotProduct) { + return normal; + } + return rtc::Maybe<Point>(); +} + +Point AzimuthToPoint(float azimuth) { + return Point(std::cos(azimuth), std::sin(azimuth), 0.f); +} + +} // namespace webrtc |