以下代码为在Python3环境下利用OpenCV 抓取摄像头的实时图像, 通过OpenCV的 calHist函数计算直方图, 并显示在3个不同窗口中.

import cv2

import numpy as np

from matplotlib import pyplot as plt

import time

cap  = cv2.VideoCapture(0)

for i in range(0, 19):
     print(cap.get(i))

while(1):
     ret, frame = cap.read()
     # color = ('b', 'g', 'r')
     color = ((255,0,0), (0,255,0), (0,0,255))

for i, col in enumerate(color):
         hist = cv2.calcHist([frame], [i], None, [256], [0, 256])
         minVal, maxVal,minPos,maxPos = cv2.minMaxLoc(hist)
         # print(minVal, maxVal,minPos,maxPos)
         histImage = np.zeros([256,256,3], np.uint8)
         for x in range(256):
             cv2.line(histImage, (x,256), (x, 256-(hist[x]/maxVal)*250), col)
         cv2.imshow("Hist{}".format(i), histImage)
    
     cv2.imshow("Capture", frame)
     # time.sleep(0.01)

key = cv2.waitKey(1)
     if key & 0xff == ord('q') or key == 27:
         print(frame.shape,ret)
         break

cap.release()

cv2.destroyAllWindows()