前言

本系统主要以STM32C8T6作为微控制器，以LCD屏为人机交互窗口，以openMV4摄像头为图像采集设备。利用STM32C8T6通过串口通信发送数据给Openmv，让Openmv进行人脸识别，并且将识别结果返回给STM32，并且发送数据给语音模块，进行语音播报；同时STM32IO口控制继电器，给电磁锁通入电压打开门。

一、Openmv程序源码

这部分代码包括Openmv与STM32的串口通信，人脸识别，人脸特征存储。
串口通信

uart = UART(3, 115200)
uart.init(115200, bits=8, parity=None, stop=1)  #8位数据位，无校验位，1位停止位
num1 = 6
#============串口发送======================
def send_data_packet(c):temp = struct.pack("<bb",                #格式为俩个字符俩个整型0xAA,                       #帧头1c)                          #人脸识别 01
#                   x, # up sample by 4    #数据1
#                   y) # up sample by 4    #数据2uart.write(temp)                           #串口发送

人脸识别

#==============人脸识别====================
def face_recognition():sensor.reset() # Initialize the camera sensor.sensor.set_pixformat(sensor.GRAYSCALE) # or sensor.GRAYSCALEsensor.set_framesize(sensor.LCD) # or sensor.QQVGA (or others)sensor.skip_frames(10) #  Let new settings take affect.sensor.skip_frames(time = 1000) #等待5slcd.init() # Initialize the lcd screen.NUM_SUBJECTS = 1              #图像库中不同人数，一共6人NUM_SUBJECTS_IMGS = 10        #每人有20张样本图片# 拍摄当前人脸。img = sensor.snapshot()#img = image.Image("face/%s/1.pgm"%(SUB))lcd.display(img)pyb.LED(RED_LED_PIN).on()sensor.skip_frames(time = 2000) # Give the user time to get ready.等待3s，pyb.LED(RED_LED_PIN).off()     #拍照指示灯d0 = img.find_lbp((0, 0, img.width(), img.height()))#d0为当前人脸的lbp特征img = Nonepmin = 999999num=0for s in range(1, NUM_SUBJECTS+1):dist = 0for i in range(2, NUM_SUBJECTS_IMGS+1):img = image.Image("singtown/s%d/%d.pgm"%(s, i))d1 = img.find_lbp((0, 0, img.width(), img.height()))#d1为第s文件夹中的第i张图片的lbp特征dist += image.match_descriptor(d0, d1)#计算d0 d1即样本图像与被检测人脸的特征差异度。print("Average dist for subject %d: %d"%(s, dist/NUM_SUBJECTS_IMGS))#pmin = min(pmin, dist/NUM_SUBJECTS_IMGS, s)#特征差异度越小，被检测人脸与此样本更相似更匹配。if (dist/NUM_SUBJECTS_IMGS)<pmin:pmin=(dist/NUM_SUBJECTS_IMGS)num=sprint(pmin)lcd.display(img)if(pmin > 10000):print("未能识别,请再次尝试")send_data_packet(0x02)else:send_data_packet(0x01)print("欢迎")
#        if(num == 2):
#           send_data_packet(0x03)
#           print("识别成功")print("发送成功")

人脸拍照特征存储

#========拍照并保存到识别库的程序代码=====================
def take_photos():sensor.reset() # Initialize the camera sensor.sensor.set_pixformat(sensor.GRAYSCALE) # or sensor.GRAYSCALEsensor.set_framesize(sensor.LCD) # or sensor.QQVGA (or others)sensor.skip_frames(10) # Let new settings take affect.sensor.skip_frames(time = 2000)lcd.init() # Initialize the lcd screen.num2 = 1 #设置被拍摄者序号，第一个人的图片保存到s1文件夹，第二个人的图片保存到s2文件夹，以此类推。每次更换拍摄者时，修改num值。n = 10 #设置每个人拍摄图片数量。#连续拍摄n张照片，每间隔3s拍摄一次。while(n):#红灯亮pyb.LED(RED_LED_PIN).on()sensor.skip_frames(time = 2000) # Give the user time to get ready.等待3s，准备一下表情。#红灯灭，蓝灯亮pyb.LED(RED_LED_PIN).off()pyb.LED(BLUE_LED_PIN).on()#保存截取到的图片到SD卡print(n)sensor.snapshot().save("singtown/s%s/%s.pgm" % (num2, n) ) # or "example.bmp" (or others)lcd.display(sensor.snapshot())n -= 1pyb.LED(BLUE_LED_PIN).off()print("拍照并保存成功！进行下一张")if n==0:send_data_packet(0x03)  #发送完成