1 /*
2 * Copyright (c) 2015 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 #include "webrtc/modules/audio_processing/beamformer/array_util.h"
12
13 #include <algorithm>
14 #include <limits>
15
16 #include "webrtc/base/checks.h"
17
18 namespace webrtc {
19 namespace {
20
21 const float kMaxDotProduct = 1e-6f;
22
23 } // namespace
24
GetMinimumSpacing(const std::vector<Point> & array_geometry)25 float GetMinimumSpacing(const std::vector<Point>& array_geometry) {
26 RTC_CHECK_GT(array_geometry.size(), 1u);
27 float mic_spacing = std::numeric_limits<float>::max();
28 for (size_t i = 0; i < (array_geometry.size() - 1); ++i) {
29 for (size_t j = i + 1; j < array_geometry.size(); ++j) {
30 mic_spacing =
31 std::min(mic_spacing, Distance(array_geometry[i], array_geometry[j]));
32 }
33 }
34 return mic_spacing;
35 }
36
PairDirection(const Point & a,const Point & b)37 Point PairDirection(const Point& a, const Point& b) {
38 return {b.x() - a.x(), b.y() - a.y(), b.z() - a.z()};
39 }
40
DotProduct(const Point & a,const Point & b)41 float DotProduct(const Point& a, const Point& b) {
42 return a.x() * b.x() + a.y() * b.y() + a.z() * b.z();
43 }
44
CrossProduct(const Point & a,const Point & b)45 Point CrossProduct(const Point& a, const Point& b) {
46 return {a.y() * b.z() - a.z() * b.y(), a.z() * b.x() - a.x() * b.z(),
47 a.x() * b.y() - a.y() * b.x()};
48 }
49
AreParallel(const Point & a,const Point & b)50 bool AreParallel(const Point& a, const Point& b) {
51 Point cross_product = CrossProduct(a, b);
52 return DotProduct(cross_product, cross_product) < kMaxDotProduct;
53 }
54
ArePerpendicular(const Point & a,const Point & b)55 bool ArePerpendicular(const Point& a, const Point& b) {
56 return std::abs(DotProduct(a, b)) < kMaxDotProduct;
57 }
58
GetDirectionIfLinear(const std::vector<Point> & array_geometry)59 rtc::Optional<Point> GetDirectionIfLinear(
60 const std::vector<Point>& array_geometry) {
61 RTC_DCHECK_GT(array_geometry.size(), 1u);
62 const Point first_pair_direction =
63 PairDirection(array_geometry[0], array_geometry[1]);
64 for (size_t i = 2u; i < array_geometry.size(); ++i) {
65 const Point pair_direction =
66 PairDirection(array_geometry[i - 1], array_geometry[i]);
67 if (!AreParallel(first_pair_direction, pair_direction)) {
68 return rtc::Optional<Point>();
69 }
70 }
71 return rtc::Optional<Point>(first_pair_direction);
72 }
73
GetNormalIfPlanar(const std::vector<Point> & array_geometry)74 rtc::Optional<Point> GetNormalIfPlanar(
75 const std::vector<Point>& array_geometry) {
76 RTC_DCHECK_GT(array_geometry.size(), 1u);
77 const Point first_pair_direction =
78 PairDirection(array_geometry[0], array_geometry[1]);
79 Point pair_direction(0.f, 0.f, 0.f);
80 size_t i = 2u;
81 bool is_linear = true;
82 for (; i < array_geometry.size() && is_linear; ++i) {
83 pair_direction = PairDirection(array_geometry[i - 1], array_geometry[i]);
84 if (!AreParallel(first_pair_direction, pair_direction)) {
85 is_linear = false;
86 }
87 }
88 if (is_linear) {
89 return rtc::Optional<Point>();
90 }
91 const Point normal_direction =
92 CrossProduct(first_pair_direction, pair_direction);
93 for (; i < array_geometry.size(); ++i) {
94 pair_direction = PairDirection(array_geometry[i - 1], array_geometry[i]);
95 if (!ArePerpendicular(normal_direction, pair_direction)) {
96 return rtc::Optional<Point>();
97 }
98 }
99 return rtc::Optional<Point>(normal_direction);
100 }
101
GetArrayNormalIfExists(const std::vector<Point> & array_geometry)102 rtc::Optional<Point> GetArrayNormalIfExists(
103 const std::vector<Point>& array_geometry) {
104 const rtc::Optional<Point> direction = GetDirectionIfLinear(array_geometry);
105 if (direction) {
106 return rtc::Optional<Point>(Point(direction->y(), -direction->x(), 0.f));
107 }
108 const rtc::Optional<Point> normal = GetNormalIfPlanar(array_geometry);
109 if (normal && normal->z() < kMaxDotProduct) {
110 return normal;
111 }
112 return rtc::Optional<Point>();
113 }
114
AzimuthToPoint(float azimuth)115 Point AzimuthToPoint(float azimuth) {
116 return Point(std::cos(azimuth), std::sin(azimuth), 0.f);
117 }
118
119 } // namespace webrtc
120