m b
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AoA_estimator
Part of a program that estimates the direction of arrival of a signal
AoA_Est.h@11:8574bb5b92b0, 2016-04-28 (annotated)
- Committer:
- mikeb
- Date:
- Thu Apr 28 06:21:10 2016 +0000
- Revision:
- 11:8574bb5b92b0
- Parent:
- 8:aaf5cde0aa0a
- Child:
- 13:d221d9ef6338
New corr;
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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mikeb | 1:4fceb43e2dd3 | 1 | #pragma once |
mikeb | 0:adae25491b93 | 2 | #include "mbed.h" |
mikeb | 0:adae25491b93 | 3 | #include <cmath> |
mikeb | 0:adae25491b93 | 4 | |
mikeb | 8:aaf5cde0aa0a | 5 | /** AoA_Est.h |
mikeb | 8:aaf5cde0aa0a | 6 | * Computes the angle of arrival of an audio signal |
mikeb | 8:aaf5cde0aa0a | 7 | * EXAMPLE: |
mikeb | 8:aaf5cde0aa0a | 8 | @code |
mikeb | 8:aaf5cde0aa0a | 9 | //Find the angle of arrival of a 900Hz audio signal using 3 MBEDS equipped with microphones. |
mikeb | 8:aaf5cde0aa0a | 10 | //Requires an array of phases, found using Phase_Finder and communication between MBEDs. |
mikeb | 8:aaf5cde0aa0a | 11 | //This code begins after phases have been found and communicated to master MBED |
mikeb | 8:aaf5cde0aa0a | 12 | //Sensors are located at (0,0), (150,0), and (150,90). Maximum sensors is 10 including master. Can be changed with parameter MAX_SENSORS |
mikeb | 8:aaf5cde0aa0a | 13 | float angle = 0; |
mikeb | 8:aaf5cde0aa0a | 14 | int x[2] = {150, 150); //Distances from master MBED microphone in milimeters. All distances must be for microphones, not MBED units |
mikeb | 8:aaf5cde0aa0a | 15 | int y[2] = {0, 90); //Do not include master MBED, its microphone is assumed to be 0,0. |
mikeb | 8:aaf5cde0aa0a | 16 | AoA_Est AoA(3, x, y, 900); |
mikeb | 8:aaf5cde0aa0a | 17 | angle = AoA.estimate(phases, phases); |
mikeb | 0:adae25491b93 | 18 | * } |
mikeb | 0:adae25491b93 | 19 | * @endcode |
mikeb | 0:adae25491b93 | 20 | */ |
mikeb | 0:adae25491b93 | 21 | |
mikeb | 8:aaf5cde0aa0a | 22 | const int MAX_SENSORS = 10; //Maxmimum number of sensors |
mikeb | 8:aaf5cde0aa0a | 23 | |
mikeb | 8:aaf5cde0aa0a | 24 | |
mikeb | 8:aaf5cde0aa0a | 25 | |
mikeb | 0:adae25491b93 | 26 | class AoA_Est { |
mikeb | 0:adae25491b93 | 27 | |
mikeb | 0:adae25491b93 | 28 | public: |
mikeb | 8:aaf5cde0aa0a | 29 | /** Create an Angle of Arrival Estimator Object |
mikeb | 8:aaf5cde0aa0a | 30 | * |
mikeb | 8:aaf5cde0aa0a | 31 | * @param numOfSensors Number of sensors including the master |
mikeb | 8:aaf5cde0aa0a | 32 | * @param xPassed[] X coordinates of every sensor EXCEPT the master. Master is assumed (0,0). |
mikeb | 8:aaf5cde0aa0a | 33 | * @param yPassed[] Y coordinates of every sensor EXCEPT the master |
mikeb | 8:aaf5cde0aa0a | 34 | * @param freq frequency of interest in Hz |
mikeb | 8:aaf5cde0aa0a | 35 | * @note Maximum number of supported sensors is 10 |
mikeb | 8:aaf5cde0aa0a | 36 | */ |
mikeb | 8:aaf5cde0aa0a | 37 | AoA_Est(int numOfSensors, int xPassed[], int yPassed[], float freq); |
mikeb | 8:aaf5cde0aa0a | 38 | /** Estimate the angle to the sound source |
mikeb | 8:aaf5cde0aa0a | 39 | * |
mikeb | 8:aaf5cde0aa0a | 40 | * @param phases[] Array of phases, first phase is the master. Must correspond to order of X and Y coordinates. |
mikeb | 8:aaf5cde0aa0a | 41 | * @param amp[] Amplitudes. Not currently used. Repeat the phase array here to prevent errors. |
mikeb | 8:aaf5cde0aa0a | 42 | * @param yPassed[] Y coordinates of every sensor EXCEPT the master |
mikeb | 8:aaf5cde0aa0a | 43 | * @return angle relative to X axis |
mikeb | 8:aaf5cde0aa0a | 44 | */ |
mikeb | 8:aaf5cde0aa0a | 45 | float estimate(float phases[], float amp[]); |
mikeb | 8:aaf5cde0aa0a | 46 | /** Not Used |
mikeb | 0:adae25491b93 | 47 | */ |
mikeb | 0:adae25491b93 | 48 | bool calibrate(); |
mikeb | 8:aaf5cde0aa0a | 49 | /** Confidence level of the output |
mikeb | 8:aaf5cde0aa0a | 50 | * |
mikeb | 8:aaf5cde0aa0a | 51 | * @return number corresponding to the number of angle determinations used in the average |
mikeb | 8:aaf5cde0aa0a | 52 | */ |
mikeb | 0:adae25491b93 | 53 | int confidence; |
mikeb | 0:adae25491b93 | 54 | |
mikeb | 0:adae25491b93 | 55 | private: |
mikeb | 8:aaf5cde0aa0a | 56 | float estimate_Theoretical(float phases[], float amp[]); |
mikeb | 8:aaf5cde0aa0a | 57 | float estimate_Calibrated(float phases[], float amp[]); //Unused |
mikeb | 8:aaf5cde0aa0a | 58 | void comparative_Phases(float phas[]); //Returns the phases relative to the master |
mikeb | 0:adae25491b93 | 59 | float angle_Resolver(); |
mikeb | 0:adae25491b93 | 60 | float distanceFinder(float phase); |
mikeb | 0:adae25491b93 | 61 | int sensors; |
mikeb | 8:aaf5cde0aa0a | 62 | int ITERATIONS; |
mikeb | 0:adae25491b93 | 63 | int x[MAX_SENSORS]; |
mikeb | 0:adae25491b93 | 64 | int y[MAX_SENSORS]; |
mikeb | 0:adae25491b93 | 65 | float phases[MAX_SENSORS - 1]; |
mikeb | 0:adae25491b93 | 66 | float sensorSep[MAX_SENSORS]; |
mikeb | 0:adae25491b93 | 67 | float sensorAngles[MAX_SENSORS]; |
mikeb | 0:adae25491b93 | 68 | float amplitudes[MAX_SENSORS]; |
mikeb | 0:adae25491b93 | 69 | int z[2]; |
mikeb | 1:4fceb43e2dd3 | 70 | float ambigAngles[2][MAX_SENSORS+ITERATIONS]; |
mikeb | 0:adae25491b93 | 71 | float wavelength; |
mikeb | 0:adae25491b93 | 72 | |
mikeb | 0:adae25491b93 | 73 | }; |
mikeb | 0:adae25491b93 | 74 | AoA_Est::AoA_Est(int numOfSensors, int xPassed[], int yPassed[], float freq) : sensors(numOfSensors) |
mikeb | 0:adae25491b93 | 75 | { |
mikeb | 8:aaf5cde0aa0a | 76 | int j = sensors - 1; |
mikeb | 8:aaf5cde0aa0a | 77 | while (j > 0){ |
mikeb | 8:aaf5cde0aa0a | 78 | ITERATIONS += j; |
mikeb | 8:aaf5cde0aa0a | 79 | j--; |
mikeb | 8:aaf5cde0aa0a | 80 | } |
mikeb | 0:adae25491b93 | 81 | wavelength = (338.4 / freq)*1000; |
mikeb | 0:adae25491b93 | 82 | for (short i = 0; i < sensors-1; i++) { |
mikeb | 0:adae25491b93 | 83 | x[i] = xPassed[i]; |
mikeb | 0:adae25491b93 | 84 | y[i] = yPassed[i]; |
mikeb | 0:adae25491b93 | 85 | sensorSep[i] = sqrt(float(xPassed[i] * x[i]) + float(yPassed[i] * y[i])); |
mikeb | 0:adae25491b93 | 86 | sensorAngles[i] = atan2(float(yPassed[i]), float(xPassed[i]))*180/3.1415926535; |
mikeb | 0:adae25491b93 | 87 | } |
mikeb | 0:adae25491b93 | 88 | } |
mikeb | 0:adae25491b93 | 89 | |
mikeb | 0:adae25491b93 | 90 | float AoA_Est::distanceFinder(float phase) { |
mikeb | 0:adae25491b93 | 91 | return phase / 360 * wavelength; |
mikeb | 0:adae25491b93 | 92 | } |
mikeb | 0:adae25491b93 | 93 | |
mikeb | 0:adae25491b93 | 94 | float AoA_Est::estimate_Theoretical(float phases[], float amp[]) { |
mikeb | 0:adae25491b93 | 95 | float distance = 0; |
mikeb | 0:adae25491b93 | 96 | float angle = 0; |
mikeb | 0:adae25491b93 | 97 | |
mikeb | 0:adae25491b93 | 98 | for (int i = 0; i < sensors-1; i++) { |
mikeb | 0:adae25491b93 | 99 | distance = distanceFinder(phases[i]); |
mikeb | 11:8574bb5b92b0 | 100 | distance = (distance > sensorSep[i]) ? distance - 338400/sampleRate : distance; |
mikeb | 0:adae25491b93 | 101 | angle = acos(distance / sensorSep[i])*180/3.1415923535; |
mikeb | 0:adae25491b93 | 102 | ambigAngles[0][i] = sensorAngles[i] - angle; //Potentially swap +/- |
mikeb | 0:adae25491b93 | 103 | ambigAngles[1][i] = sensorAngles[i] + angle; |
mikeb | 11:8574bb5b92b0 | 104 | |
mikeb | 0:adae25491b93 | 105 | ambigAngles[0][i] = (ambigAngles[0][i] < 0) ? ambigAngles[0][i] + 360 : ambigAngles[0][i]; |
mikeb | 0:adae25491b93 | 106 | ambigAngles[1][i] = (ambigAngles[1][i] < 0) ? ambigAngles[1][i] + 360 : ambigAngles[1][i]; |
mikeb | 0:adae25491b93 | 107 | } |
mikeb | 1:4fceb43e2dd3 | 108 | |
mikeb | 1:4fceb43e2dd3 | 109 | float phas_diff = 0; |
mikeb | 1:4fceb43e2dd3 | 110 | float relative_angle = 0; |
mikeb | 1:4fceb43e2dd3 | 111 | float relative_dist = 0; |
mikeb | 8:aaf5cde0aa0a | 112 | /*for (int i = 1; i < sensors - 1; i++) { //for(int i = 1; i<ITERATIONS - sensors+1; i++) |
mikeb | 1:4fceb43e2dd3 | 113 | while (i < sensors - 1) { |
mikeb | 1:4fceb43e2dd3 | 114 | phas_diff = phases[i - 1] - phases[i]; |
mikeb | 1:4fceb43e2dd3 | 115 | if (abs(phas_diff) > 180) { |
mikeb | 1:4fceb43e2dd3 | 116 | phas_diff = (phas_diff < 0) ? phas_diff + 360 : phas_diff - 360; |
mikeb | 1:4fceb43e2dd3 | 117 | } |
mikeb | 1:4fceb43e2dd3 | 118 | distance = distanceFinder(phas_diff); |
mikeb | 1:4fceb43e2dd3 | 119 | relative_angle = atan2(float(y[i - 1] - y[i]), float((x[i - 1] - x[i]))) * 180 / 3.1415926535; |
mikeb | 1:4fceb43e2dd3 | 120 | relative_dist = sqrt(float((x[i - 1] - x[i]) *(x[i - 1] - x[i])) + float((y[i - 1] - y[i]) *(y[i - 1] - y[i]))); |
mikeb | 1:4fceb43e2dd3 | 121 | angle = acos(distance / relative_dist) * 180 / 3.1415923535; |
mikeb | 1:4fceb43e2dd3 | 122 | ambigAngles[0][sensors - 2 + i] = relative_angle - angle; |
mikeb | 1:4fceb43e2dd3 | 123 | ambigAngles[1][sensors - 2 + i] = relative_angle + angle; |
mikeb | 1:4fceb43e2dd3 | 124 | |
mikeb | 1:4fceb43e2dd3 | 125 | ambigAngles[0][sensors - 2 + i] = (ambigAngles[0][sensors - 2 + i] < 0) ? ambigAngles[0][sensors - 2 + i] + 360 : ambigAngles[0][sensors - 2 + i]; |
mikeb | 1:4fceb43e2dd3 | 126 | ambigAngles[1][sensors - 2 + i] = (ambigAngles[1][sensors - 2 + i] < 0) ? ambigAngles[1][sensors - 2 + i] + 360 : ambigAngles[1][sensors - 2 + i]; |
mikeb | 1:4fceb43e2dd3 | 127 | i++; |
mikeb | 1:4fceb43e2dd3 | 128 | } |
mikeb | 6:697b75e941a7 | 129 | }*/ |
mikeb | 0:adae25491b93 | 130 | angle = angle_Resolver(); |
mikeb | 0:adae25491b93 | 131 | return angle; |
mikeb | 0:adae25491b93 | 132 | } |
mikeb | 0:adae25491b93 | 133 | |
mikeb | 0:adae25491b93 | 134 | float AoA_Est::angle_Resolver() { |
mikeb | 0:adae25491b93 | 135 | float angle = ambigAngles[0][0]; |
mikeb | 0:adae25491b93 | 136 | float avg = angle; |
mikeb | 0:adae25491b93 | 137 | bool flag = false; |
mikeb | 0:adae25491b93 | 138 | confidence = 0; |
mikeb | 6:697b75e941a7 | 139 | for (short i = 1; i <= sensors-1; i++) { |
mikeb | 7:25dacf35f4c7 | 140 | if (abs(angle - ambigAngles[0][i]) < abs(angle-ambigAngles[1][i]) && abs(angle-ambigAngles[0][i]) < 40) { |
mikeb | 0:adae25491b93 | 141 | angle = ambigAngles[0][i]; |
mikeb | 0:adae25491b93 | 142 | avg += ambigAngles[0][i]; |
mikeb | 0:adae25491b93 | 143 | confidence++; |
mikeb | 0:adae25491b93 | 144 | } |
mikeb | 7:25dacf35f4c7 | 145 | else if (abs(angle - ambigAngles[1][i]) < abs(angle-ambigAngles[0][i]) && abs(angle - ambigAngles[1][i]) < 40) { |
mikeb | 0:adae25491b93 | 146 | angle = ambigAngles[1][i]; |
mikeb | 0:adae25491b93 | 147 | avg += ambigAngles[1][i]; |
mikeb | 0:adae25491b93 | 148 | confidence++; |
mikeb | 0:adae25491b93 | 149 | } |
mikeb | 0:adae25491b93 | 150 | else if (i == 1 && flag == false) { |
mikeb | 0:adae25491b93 | 151 | angle = ambigAngles[1][0]; |
mikeb | 0:adae25491b93 | 152 | avg = angle; |
mikeb | 0:adae25491b93 | 153 | i = 0; |
mikeb | 0:adae25491b93 | 154 | flag = true; |
mikeb | 0:adae25491b93 | 155 | } |
mikeb | 0:adae25491b93 | 156 | |
mikeb | 0:adae25491b93 | 157 | } |
mikeb | 0:adae25491b93 | 158 | |
mikeb | 7:25dacf35f4c7 | 159 | return avg / (confidence+1);//change when compute the other way |
mikeb | 0:adae25491b93 | 160 | } |
mikeb | 0:adae25491b93 | 161 | |
mikeb | 0:adae25491b93 | 162 | void AoA_Est :: comparative_Phases(float phas[]) { |
mikeb | 0:adae25491b93 | 163 | for (int i = 0; i < sensors - 1; i++) { |
mikeb | 0:adae25491b93 | 164 | phases[i] = phas[0] - phas[i + 1]; |
mikeb | 1:4fceb43e2dd3 | 165 | if (abs(phases[i]) > 180) { |
mikeb | 1:4fceb43e2dd3 | 166 | phases[i] = (phases[i] < 0) ? phases[i] + 360 : phases[i] - 360; |
mikeb | 1:4fceb43e2dd3 | 167 | } |
mikeb | 0:adae25491b93 | 168 | |
mikeb | 0:adae25491b93 | 169 | } |
mikeb | 0:adae25491b93 | 170 | |
mikeb | 0:adae25491b93 | 171 | } |
mikeb | 0:adae25491b93 | 172 | |
mikeb | 0:adae25491b93 | 173 | float AoA_Est::estimate(float phas[], float amplitudes[]) { |
mikeb | 0:adae25491b93 | 174 | float angle; |
mikeb | 0:adae25491b93 | 175 | comparative_Phases(phas); |
mikeb | 0:adae25491b93 | 176 | angle = estimate_Theoretical(phases, amplitudes); |
mikeb | 0:adae25491b93 | 177 | |
mikeb | 0:adae25491b93 | 178 | return angle; |
mikeb | 0:adae25491b93 | 179 | |
mikeb | 0:adae25491b93 | 180 | } |