用python识别红绿灯

导入包：

import cv2
import numpy as np

接着导入视频：

cap = cv2.VideoCapture('test.mp4')

因为视频是一帧一帧的图像，所以需要遍历：

while True:
    ret,frame = cap.read()#按帧读取，这是读取一帧
    if ret == False:
        break

紧接着截取rio区域：

    roiColor = frame[100:500,300:800]

转换hsv颜色空间：

    hsv = cv2.cvtColor(roiColor,cv2.COLOR_BGR2HSV)

        #红色

    lower_hsv_red = np.array([157,177,122])
    upper_hsv_red = np.array([179,255,255])
    mask_red = cv2.inRange(hsv,lowerb=lower_hsv_red,upperb=upper_hsv_red)

        #中值滤波

    red_blur = cv2.medianBlur(mask_red, 7)

        #绿色

    lower_hsv_green = np.array([49,79,137])
    upper_hsv_green = np.array([90,255,255])
    mask_green = cv2.inRange(hsv,lowerb=lower_hsv_green,upperb=upper_hsv_green)
    green_blur = cv2.medianBlur(mask_green, 7)

因为图像是二值的图像，所以如果图像出现白点，也就是255，那么就取他的max最大值255：
    red_color = np.max(red_blur)
    green_color = np.max(green_blur)

在red_color中判断二值图像如果数值等于255，那么就判定为red，在green_color中判断二值图像如果数值等于255，那么就判定为green：

    if red_color == 255:
        print('red')
        cv2.rectangle(frame,(660,420),(400,300),(0,0,255),2) #按坐标画出矩形框
        cv2.putText(frame, "red", (500, 280), cv2.FONT_HERSHEY_COMPLEX, 1, (0, 0, 255),2)#显示red文本信息

    elif green_color == 255:
        print('green')
        cv2.rectangle(frame, (660, 420), (400, 300), (0, 0, 255), 2)
        cv2.putText(frame, "green", (500, 280), cv2.FONT_HERSHEY_COMPLEX, 1, (0, 255, 0),2)

收尾：

    cv2.imshow('frame',frame)#输出
    c = cv2.waitKey(10)#延迟
    if c==27:
        break

总结：

import cv2
import numpy as np

cap = cv2.VideoCapture('test.mp4')
while True:
    ret,frame = cap.read()
    if ret == False:
        break
    frame = cv2.resize(frame,(1620,900))
    #截取roi区域
    roiColor = frame[100:500,300:800]
    #转换hsv颜色空间
    hsv = cv2.cvtColor(roiColor,cv2.COLOR_BGR2HSV)

    #red
    lower_hsv_red = np.array([157,177,122])#红上
    upper_hsv_red = np.array([179,255,255])#红下
    mask_red = cv2.inRange(hsv,lowerb=lower_hsv_red,upperb=upper_hsv_red)#过滤出红色部分
    #中值滤波
    red_blur = cv2.medianBlur(mask_red, 7)
    #green
    lower_hsv_green = np.array([49,79,137])
    upper_hsv_green = np.array([90,255,255])
    mask_green = cv2.inRange(hsv,lowerb=lower_hsv_green,upperb=upper_hsv_green)
    #中值滤波
    green_blur = cv2.medianBlur(mask_green, 7)

    #因为图像是二值的图像，所以如果图像出现白点，也就是255，那么就取他的max最大值255
    red_color = np.max(red_blur)
    green_color = np.max(green_blur)
    #在red_color中判断二值图像如果数值等于255，那么就判定为red
    if red_color == 255:
        print('red')
        cv2.rectangle(frame,(660,420),(400,300),(0,0,255),2) #按坐标画出矩形框
        cv2.putText(frame, "red", (500, 280), cv2.FONT_HERSHEY_COMPLEX, 1, (0, 0, 255),2)#显示red文本信息
    #在green_color中判断二值图像如果数值等于255，那么就判定为green
    elif green_color == 255:
        print('green')
        cv2.rectangle(frame, (660, 420), (400, 300), (0, 0, 255), 2)
        cv2.putText(frame, "green", (500, 280), cv2.FONT_HERSHEY_COMPLEX, 1, (0, 255, 0),2)

    cv2.imshow('frame',frame)#输出
    c = cv2.waitKey(10)
    if c==27:
        break