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0、前言

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前段时间参加了一个比赛，需要完成ROS机器人的语音定位功能，但由于种种原因，未能完成该功能，现将整体思路整理如下。

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1、硬件简介

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首先需要说明的是，本博客目的不是打广告，只是为了完成功能所需。
这里用到的硬件是麦克风阵列ReSpeaker Mic array V2.0，该麦克风阵列集成了四个麦克风，分别位于十字的四个点上，因此可以轻易的获取声源以麦克风阵列为中心的方位角；同时支持USB口，支持现有的操作系统如Windows，Linux，MacOS等。基于以上两个特点，可以使用该麦克风阵列实现语音定位。该麦克风阵列的详细信息请参考：该麦克风阵列详细资料 该阵列结合树莓派制作智能音箱的教程：智能音箱

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2、语音定位

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接下来讲解使用ReSpeaker Mic array V2.0进行语音定位的思路。
就像上面说的，该麦克风阵列可实时获取声源的方位角，但不能直接获取声源到该麦克风阵列的距离，因此想到的解决办法就是使用两个麦克风阵列，分别命名为阵1和阵2，通过一边两角可构建三角形定理构建一个三角形并求出三角形的边长，从而获取声源到机器人中心的距离，示意图如下：

图中，R已知，为两个麦克风阵列的距离；θ1为麦克风阵列1求得的角度，并且麦克风阵列1的中心对齐ROS机器人的中心；θ2为麦克风阵列2求得的角度。因此r1即为要求的声源到ROS机器人的距离。
由三角形正弦定理求得该距离：r1=R*sin(θ2)/sin(180-θ1-θ2)
求得距离后，可根据该距离与机器人中心坐标求得声源在地图上的坐标。设机器人中心的坐标为(x1,y1)，已知；声源的坐标为(x2,y2)，待求。如图：

根据三角形勾股定理得：
此时便可获得声源在地图上的位置(x2,y2)。以(x1,y1)作为起点，以(x2,y2)作为终点即可完成语音定位功能。

这种方法虽然可以实现ROS下的语音定位功能，但实现的成本还是有点高的，而且不易小型化，轻型化，可以作为一个参考方法。如果各位大佬有更好的解决方法，欢迎在下方留言讨论。
单个麦克风阵列获取声源角度的程序如下(Linux系统)：

# -*- coding: utf-8 -*-import sys
import struct
import usb.core
import usb.utilUSAGE = """Usage: python {} -h-p      show all parameters-r      read all parametersNAME    get the parameter with the NAMENAME VALUE  set the parameter with the NAME and the VALUE
"""# parameter list
# name: (id, offset, type, max, min , r/w, info)
PARAMETERS = {'AECFREEZEONOFF': (18, 7, 'int', 1, 0, 'rw', 'Adaptive Echo Canceler updates inhibit.', '0 = Adaptation enabled', '1 = Freeze adaptation, filter only'),'AECNORM': (18, 19, 'float', 16, 0.25, 'rw', 'Limit on norm of AEC filter coefficients'),'AECPATHCHANGE': (18, 25, 'int', 1, 0, 'ro', 'AEC Path Change Detection.', '0 = false (no path change detected)', '1 = true (path change detected)'),'RT60': (18, 26, 'float', 0.9, 0.25, 'ro', 'Current RT60 estimate in seconds'),'HPFONOFF': (18, 27, 'int', 3, 0, 'rw', 'High-pass Filter on microphone signals.', '0 = OFF', '1 = ON - 70 Hz cut-off', '2 = ON - 125 Hz cut-off', '3 = ON - 180 Hz cut-off'),'RT60ONOFF': (18, 28, 'int', 1, 0, 'rw', 'RT60 Estimation for AES. 0 = OFF 1 = ON'),'AECSILENCELEVEL': (18, 30, 'float', 1, 1e-09, 'rw', 'Threshold for signal detection in AEC [-inf .. 0] dBov (Default: -80dBov = 10log10(1x10-8))'),'AECSILENCEMODE': (18, 31, 'int', 1, 0, 'ro', 'AEC far-end silence detection status. ', '0 = false (signal detected) ', '1 = true (silence detected)'),'AGCONOFF': (19, 0, 'int', 1, 0, 'rw', 'Automatic Gain Control. ', '0 = OFF ', '1 = ON'),'AGCMAXGAIN': (19, 1, 'float', 1000, 1, 'rw', 'Maximum AGC gain factor. ', '[0 .. 60] dB (default 30dB = 20log10(31.6))'),'AGCDESIREDLEVEL': (19, 2, 'float', 0.99, 1e-08, 'rw', 'Target power level of the output signal. ', '[−inf .. 0] dBov (default: −23dBov = 10log10(0.005))'),'AGCGAIN': (19, 3, 'float', 1000, 1, 'rw', 'Current AGC gain factor. ', '[0 .. 60] dB (default: 0.0dB = 20log10(1.0))'),'AGCTIME': (19, 4, 'float', 1, 0.1, 'rw', 'Ramps-up / down time-constant in seconds.'),'CNIONOFF': (19, 5, 'int', 1, 0, 'rw', 'Comfort Noise Insertion.', '0 = OFF', '1 = ON'),'FREEZEONOFF': (19, 6, 'int', 1, 0, 'rw', 'Adaptive beamformer updates.', '0 = Adaptation enabled', '1 = Freeze adaptation, filter only'),'STATNOISEONOFF': (19, 8, 'int', 1, 0, 'rw', 'Stationary noise suppression.', '0 = OFF', '1 = ON'),'GAMMA_NS': (19, 9, 'float', 3, 0, 'rw', 'Over-subtraction factor of stationary noise. min .. max attenuation'),'MIN_NS': (19, 10, 'float', 1, 0, 'rw', 'Gain-floor for stationary noise suppression.', '[−inf .. 0] dB (default: −16dB = 20log10(0.15))'),'NONSTATNOISEONOFF': (19, 11, 'int', 1, 0, 'rw', 'Non-stationary noise suppression.', '0 = OFF', '1 = ON'),'GAMMA_NN': (19, 12, 'float', 3, 0, 'rw', 'Over-subtraction factor of non- stationary noise. min .. max attenuation'),'MIN_NN': (19, 13, 'float', 1, 0, 'rw', 'Gain-floor for non-stationary noise suppression.', '[−inf .. 0] dB (default: −10dB = 20log10(0.3))'),'ECHOONOFF': (19, 14, 'int', 1, 0, 'rw', 'Echo suppression.', '0 = OFF', '1 = ON'),'GAMMA_E': (19, 15, 'float', 3, 0, 'rw', 'Over-subtraction factor of echo (direct and early components). min .. max attenuation'),'GAMMA_ETAIL': (19, 16, 'float', 3, 0, 'rw', 'Over-subtraction factor of echo (tail components). min .. max attenuation'),'GAMMA_ENL': (19, 17, 'float', 5, 0, 'rw', 'Over-subtraction factor of non-linear echo. min .. max attenuation'),'NLATTENONOFF': (19, 18, 'int', 1, 0, 'rw', 'Non-Linear echo attenuation.', '0 = OFF', '1 = ON'),'NLAEC_MODE': (19, 20, 'int', 2, 0, 'rw', 'Non-Linear AEC training mode.', '0 = OFF', '1 = ON - phase 1', '2 = ON - phase 2'),'SPEECHDETECTED': (19, 22, 'int', 1, 0, 'ro', 'Speech detection status.', '0 = false (no speech detected)', '1 = true (speech detected)'),'FSBUPDATED': (19, 23, 'int', 1, 0, 'ro', 'FSB Update Decision.', '0 = false (FSB was not updated)', '1 = true (FSB was updated)'),'FSBPATHCHANGE': (19, 24, 'int', 1, 0, 'ro', 'FSB Path Change Detection.', '0 = false (no path change detected)', '1 = true (path change detected)'),'TRANSIENTONOFF': (19, 29, 'int', 1, 0, 'rw', 'Transient echo suppression.', '0 = OFF', '1 = ON'),'VOICEACTIVITY': (19, 32, 'int', 1, 0, 'ro', 'VAD voice activity status.', '0 = false (no voice activity)', '1 = true (voice activity)'),'STATNOISEONOFF_SR': (19, 33, 'int', 1, 0, 'rw', 'Stationary noise suppression for ASR.', '0 = OFF', '1 = ON'),'NONSTATNOISEONOFF_SR': (19, 34, 'int', 1, 0, 'rw', 'Non-stationary noise suppression for ASR.', '0 = OFF', '1 = ON'),'GAMMA_NS_SR': (19, 35, 'float', 3, 0, 'rw', 'Over-subtraction factor of stationary noise for ASR. ', '[0.0 .. 3.0] (default: 1.0)'),'GAMMA_NN_SR': (19, 36, 'float', 3, 0, 'rw', 'Over-subtraction factor of non-stationary noise for ASR. ', '[0.0 .. 3.0] (default: 1.1)'),'MIN_NS_SR': (19, 37, 'float', 1, 0, 'rw', 'Gain-floor for stationary noise suppression for ASR.', '[−inf .. 0] dB (default: −16dB = 20log10(0.15))'),'MIN_NN_SR': (19, 38, 'float', 1, 0, 'rw', 'Gain-floor for non-stationary noise suppression for ASR.', '[−inf .. 0] dB (default: −10dB = 20log10(0.3))'),'GAMMAVAD_SR': (19, 39, 'float', 1000, 0, 'rw', 'Set the threshold for voice activity detection.', '[−inf .. 60] dB (default: 3.5dB 20log10(1.5))'),# 'KEYWORDDETECT': (20, 0, 'int', 1, 0, 'ro', 'Keyword detected. Current value so needs polling.'),'DOAANGLE': (21, 0, 'int', 359, 0, 'ro', 'DOA angle. Current value. Orientation depends on build configuration.')
}class Tuning:TIMEOUT = 100000def __init__(self, dev):self.dev = devdef write(self, name, value):try:data = PARAMETERS[name]except KeyError:returnif data[5] == 'ro':raise ValueError('{} is read-only'.format(name))id = data[0]# 4 bytes offset, 4 bytes value, 4 bytes typeif data[2] == 'int':payload = struct.pack(b'iii', data[1], int(value), 1)else:payload = struct.pack(b'ifi', data[1], float(value), 0)self.dev.ctrl_transfer(usb.util.CTRL_OUT | usb.util.CTRL_TYPE_VENDOR | usb.util.CTRL_RECIPIENT_DEVICE,0, 0, id, payload, self.TIMEOUT)def read(self, name):try:data = PARAMETERS[name]except KeyError:returnid = data[0]cmd = 0x80 | data[1]if data[2] == 'int':cmd |= 0x40length = 8response = self.dev.ctrl_transfer(usb.util.CTRL_IN | usb.util.CTRL_TYPE_VENDOR | usb.util.CTRL_RECIPIENT_DEVICE,0, cmd, id, length, self.TIMEOUT)response = struct.unpack(b'ii', response.tostring())if data[2] == 'int':result = response[0]else:result = response[0] * (2.**response[1])return resultdef set_vad_threshold(self, db):self.write('GAMMAVAD_SR', db)def is_voice(self):return self.read('VOICEACTIVITY')@propertydef direction(self):return self.read('DOAANGLE')@propertydef version(self):return self.dev.ctrl_transfer(usb.util.CTRL_IN | usb.util.CTRL_TYPE_VENDOR | usb.util.CTRL_RECIPIENT_DEVICE,0, 0x80, 0, 1, self.TIMEOUT)[0]def close(self):"""close the interface"""usb.util.dispose_resources(self.dev)def find(vid=0x2886, pid=0x0018):dev = usb.core.find(idVendor=vid, idProduct=pid)if not dev:returnreturn Tuning(dev)def main():if len(sys.argv) > 1:if sys.argv[1] == '-p':print('name\t\t\ttype\tmax\tmin\tr/w\tinfo')print('-------------------------------')for name in sorted(PARAMETERS.keys()):         #打印所有参数data = PARAMETERS[name]print('{:16}\t{}'.format(name, b'\t'.join([str(i) for i in data[2:7]])))for extra in data[7:]:print('{}{}'.format(' '*60, extra))else:dev = find()            #在Linux上查找麦克风阵列设备if not dev:print('No device found')sys.exit(1)if sys.argv[1] == '-r':        #从设备获取所有参数设置print('{:24} {}'.format('name', 'value'))print('-------------------------------')for name in sorted(PARAMETERS.keys()):print('{:24} {}'.format(name, dev.read(name)))else:name = sys.argv[1].upper()if name in PARAMETERS:if len(sys.argv) > 2:# 获取角度，命令行输入应该为(前提是去到该文件根目录)： tuning.py DOAANGLEdev.write(name, sys.argv[2])        print('{}: {}'.format(name, dev.read(name)))else:print('{} is not a valid name'.format(name))dev.close()else:print(USAGE.format(sys.argv[0]))if __name__ == '__main__':main()