void cvInRange(//提取图像中在阈值中间的部分  const CvArr* src,//目标图像const CvArr* lower,//阈值下限  const CvArr* upper,//阈值上限  CvArr* dst//结果图像  )

import cv2 as cv

import numpy as np

def video_demo():

    capture = cv.VideoCapture(0)

    while(True):

        #  打开摄像头

        ret,frame = capture.read()

        if ret == False:

            break

        #  转换为hsv图像

        hsv = cv.cvtColor(frame,cv.COLOR_BGR2HSV)

        #  下阈值

        lower_hsv = np.array([37,43,46])

        #  上阈值

        upper_hsv = np.array([77,255,255])

        mask = cv.inRange(hsv,lowerb=lower_hsv,upperb = upper_hsv)

        #  cv.inRange(目标图像，阈值下，阈值上，输出图像)

        cv.imshow ("video",frame)

        cv.imshow ( "mask",mask)

        c = cv.waitKey (50)

        if c == 27:  # 相当于人为退出

            break

video_demo()