树莓派脸部追踪

硬件材料

树莓派4B、云台、摄像头

成品展示

思路

1、电脑上显示摄像头拍摄的视频，并得到人脸坐标，将人脸坐标发给树莓派。

2、树莓派来控制舵机旋转

3、电脑和树莓派之间和socket通信

4、树莓派上使用motion将摄像头内容输出到“192.168.6.179:8081”，从而让电脑获取视频源【192.168.6.179是树莓派地址】

注意：

1、树莓派可能需要关掉防火墙：ufw disable

2、树莓派要先启动motion：sudo motion【只用启动一次即可，一直在后台运行】

人脸跟踪的算法

第一种

获得人脸矩阵中心点坐标【x,y】，再获得视频中心坐标，计算两者误差，从而让摄像头旋转相应角度，旋转时要尽量一度一度的转，不要过激，否则容易让抖动。

当然，我写的只是简单的计算两个中心误差再旋转，缺点是旋转不平滑，改进方式是用PID算法

PID算法参考1：https://pyimagesearch.com/2019/04/01/pan-tilt-face-tracking-with-a-raspberry-pi-and-opencv/

PID算法参考2：https://bcxiaobai.eu.org/post/383.html

第二种

参考：https://blog.csdn.net/rikeilong/article/details/126446567

当人脸矩阵左边或右边快要超出视频边界时再旋转，也是要尽量一度一度的转

代码

电脑上

电脑上client.py

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import socket

class connect_Raspberry():
    def __init__(self,host,port):
        print("客户端开启")
        # 套接字接口
        self.mySocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        # 设置ip和端口

        try:
            self.mySocket.connect((host, port))  #连接到服务器
            print("连接到服务器")
        except:  #连接不成功，运行最初的ip
            print('连接RASP不成功')

    def send(self, words):
        # 发送消息
        msg = words
        # 编码发送
        self.mySocket.send(msg.encode("utf-8"))
        # print("成功发送消息")

    def close(self):
        self.mySocket.close()
        print("与树莓派丽连接中断\n")
        exit()


电脑上main.py

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import cv2
import mediapipe as mp
import numpy as np
import client

# 检测脸部
mp_face_detection = mp.solutions.face_detection
mp_drawing = mp.solutions.drawing_utils

# 通信传输
myRaspConnection = client.connect_Raspberry('192.168.6.179', 8888)

if __name__ == "__main__":

    capture = cv2.VideoCapture("http://192.168.6.179:8081")
    ref, frame = capture.read()
    fps = 0.0

    while (True):
        ref, frame = capture.read()
        h, w, _ = np.shape(frame)
        if not ref:
            break
        image = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)

        # 脸部检测
        with mp_face_detection.FaceDetection(model_selection=0, min_detection_confidence=0.8) as face_detection:
            results = face_detection.process(image)

            if results.detections:
                for detection in results.detections:
                    box = detection.location_data.relative_bounding_box
                    # cx,cy,cw,ch=box
                    cx = box.xmin
                    cy = box.ymin
                    cw = box.width
                    ch = box.height

                    cv2.rectangle(image, (int(cx * w), int(cy * h)), (int((cx + cw) * w), int((cy + ch) * h)),
                                  (0, 255, 0), 2)
                # 控制云台
                msg = str(abs(int(cx * w))) + " " + str(abs(int(cy * h))) + " " + str(abs(int((cx + cw) * w))) + " " + str(
                    abs(int((cy + ch) * h)))
                print(msg)
                myRaspConnection.send(msg)

        frame = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)
        # cv2.rectangle(frame, (int(cx*w) , int(cy*h)), (int((cx+cw)*w) , int((cy+ch)*h)),(0, 255, 0), 2)

        cv2.imshow("video", frame)
        c = cv2.waitKey(1) & 0xff

        if c == 27:
            capture.release()
            break
    print("Video Detection Done!")
    capture.release()
    cv2.destroyAllWindows()

​

树莓派上

树莓派上sever.py

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import socket

print("服务开启")
mySocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = "192.168.6.179"
port = 8888 #自己定义的端口号

mySocket.bind((host, port))
mySocket.listen(10)

树莓派上main.py

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import time
import sever
import RPi.GPIO as GPIO
from PCA9685 import PCA9685
import math
pwm=PCA9685()
pwm.setPWMFreq(50)
pwm.setRotationAngle(5,0)


if __name__ == '__main__':
    pid_X_P=0
    pid_Y_P=0
    print("等待连接")
    client,address = sever.mySocket.accept()
    print("新连接")
    print("IP is %s" % address[0])
    print("port is %d\n" % address[1])
    
    beangle = 90 #每个人的初始角度不同，建议先自己测试好角度
    beangle0 = 45

	#舵机插的通道口
    channel1 = 4 #上下
    channel2 = 8 #左右
	
	#变化幅度（这个越大，舵机动的幅度就越大）
    angleFreq = 1
	#超出屏幕范围（这个调大后，脸部离视频边界检测更灵敏）
    changeFreqX = 100
    changeFreqY = 20

    error_x=500            #当前误差值
    last_error_x=100       #上一次误差值
    error_y=250
    last_error_y=50
    wight=900
    height=480
    piv_x=90
    piv_y=45

    step=1
    try:
        print("开始")
        while True:
            msg = client.recv(1024)
            msg = msg.decode("utf-8")
            if msg != "":
                mess = msg.split(' ')
                
                x0 = int(mess[0])#左上角x
                y0 = int(mess[1])#左上角y
                x1 = int(mess[2])#右下角x
                y1 = int(mess[3])#右下角y


				# 方法1：超出中间就偏转
                x_mean=int((x0+x1)/2)
                y_mean=int((y0+y1)/2)
                print("x_mean",x_mean,"y_mean",y_mean)
                error_x=int(x_mean-wight/2)
                error_y=int(y_mean-height/2)
                print("error_x",error_x,"error_y",error_y)

                # 误差大于100,要向左偏
                if error_x<0  and abs(error_x)>100:
                    # temp_x=abs(error_x)/(wight/2)*45
                   
                    step_x=math.exp(abs(error_x)/(wight/2))
                    print(step_x)
                    beangle+=step
                    if beangle >= 180:
                        beangle = 180
                    print("向左偏",beangle)
                    pwm.setRotationAngle(1,beangle)
                # 向右偏
                if error_x>0  and abs(error_x)>100:
                    step_x=math.exp(abs(error_x)/(wight/2))
                    print(step_x)
                    beangle-=step
                    if beangle <=10:
                        beangle = 10
                    print("向右偏",beangle)
                    pwm.setRotationAngle(1,beangle)

                # 误差大于50,要向上偏
                if error_y<0  and abs(error_y)>70:
                    # if abs(error_y)>=100:
                    #     error_y=100
                    # temp_x=abs(error_x)/(wight/2)*45
                    try:
                        step_y=math.exp(abs(error_y)/(height/2))
                    except:
                        step_y=2
                    print(step_y)
                    beangle0-=step
                    if beangle0 <=10:
                        beangle0 = 10
                    print("向上偏",beangle0)
                    pwm.setRotationAngle(0,beangle0)
                # 向下偏
                if error_y>0  and abs(error_y)>70:
                    # if abs(error_y)>=100:
                    #     error_y=100
                    try:
                        step_y=math.exp(abs(error_y)/(height/2))
                    except:
                        step_y=2
                    print(step_y)
                    beangle0+=step
                    if beangle0 >= 85:
                        beangle0 = 95
                    print("向下偏",beangle0)
                    pwm.setRotationAngle(0,beangle0)

                
                
                # 方法2：快超出屏幕时再旋转
                # if x0 < changeFreqX:
                #     beangle += angleFreq
                #     if beangle >= 180:
                #         beangle = 180
                #     pwm.setRotationAngle(1,beangle)
                #     #set_servo_angle(channel1,beangle)
                
                # if y0 < changeFreqY:
                #     beangle0 -= angleFreq
                #     if beangle0 <= 10:
                #         beangle0 = 10
                #     pwm.setRotationAngle(0,beangle0)
                #     #set_servo_angle(channel2,beangle0)

                # if x1 > 640 - changeFreqX: #窗口宽为640
                #     beangle -= angleFreq
                #     if beangle <= 10:
                #         beangle = 10
                #     pwm.setRotationAngle(1,beangle)
                #     #set_servo_angle(channel1,beangle)
                
                # if y1 > 480 - changeFreqY: #窗口高为480
                #     beangle0 += angleFreq
                #     if beangle0 >= 85:
                #         beangle0 = 85
                #     pwm.setRotationAngle(0,beangle0)
                #     set_servo_angle(channel2,beangle0)
                # print("beangle",beangle,"beangle0:",beangle0)
    except ValueError as e:
        pwm.exit_PCA9685()
        print("退出")
        print(e)
        exit()

运行

1、树莓派上先运行main.py

2、电脑上再运行main.py，电脑上可见一个视频窗口，此时摄像头开始追踪人脸

参考

PID算法：https://pyimagesearch.com/2019/04/01/pan-tilt-face-tracking-with-a-raspberry-pi-and-opencv/

思路：https://blog.csdn.net/rikeilong/article/details/126446567?spm=1001.2014.3001.5502