cv2.VideoCapture（0）不适用于rasberrypi相机

Question

下面是在Ubuntu中运行良好的代码。但是，当我在Raspberry Pi和Raspberry Pi相机上使用它时，却没有任何结果。

import cv2
import numpy as np

video = cv2.VideoCapture(0)

while True:
    ret, orig_frame = video.read()
    if not ret:
        video = cv2.VideoCapture(0)
        continue

    frame = cv2.GaussianBlur(orig_frame, (5, 5), 0)
    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
    low_yellow = np.array([18, 94, 140])
    up_yellow = np.array([48, 255, 255])    
    mask = cv2.inRange(hsv, low_yellow, up_yellow)    
    edges = cv2.Canny(mask, 75, 150)
    lines = cv2.HoughLinesP(edges, 1, np.pi/180, 50, maxLineGap=50)     
    if lines is not None:
        print 'yellow'

    low_black=np.array([0, 0, 0])
    up_black=np.array([180, 255, 30])
    maskB= cv2.inRange(hsv, low_black, up_black)    
    edgesB = cv2.Canny(maskB, 75, 150)
    linesB=cv2.HoughLinesP(edgesB, 1, np.pi/180, 50, maxLineGap=50)
    if linesB is not None:
        print 'Black'


    key = cv2.waitKey(25)
    if key == 27:
        break
video.release()
cv2.destroyAllWindows()