python-2.7 - 使用OpenCV在实时Feed上进行霍夫变换

Question

我一直在尝试找出如何在网络摄像头feed上应用霍夫变换。但是我收到错误消息，它没有适当的格式，即使我对其进行了灰度缩放以检查它是否在uint8中也是如此。

cap = cv2.VideoCapture(1)

while(True):
    ret, frame = cap.read()
    frame = cv2.medianBlur(frame,5)
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    ###
    #HughCircles Detection TEST  
    circles = cv2.HoughCircles(frame,cv2.HOUGH_GRADIENT,1,50,
                               param1=50,param2=30,minRadius=0,maxRadius=0) 
    circles = np.uint16(np.around(circles))
    if circles is None:
        for i in circles[0,:]:
            # draw the outer circle
            cv2.circle(frame,(i[0],i[1]),i[2],(0,255,0),2)
            # draw the center of the circle
            cv2.circle(frame,(i[0],i[1]),2,(0,0,255),3)
    #    
    ###

    # Display the resulting frame
    cv2.imshow('Board',frame)

    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

Answer 1

好吧，在另一篇文章中，我看到圈子在没有可见内容的情况下实际上返回了None，因此必须有一个if，以便它不表示None。

cap = cv2.VideoCapture(1)

while(True):
    ret, frame = cap.read()
    frame = cv2.medianBlur(frame,5)
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

###
#HughCircles Detection TEST  
    circles = cv2.HoughCircles(gray,cv2.HOUGH_GRADIENT,1,50,
                          param1=50,param2=30,minRadius=0,maxRadius=0) 
    circles = np.uint16(np.around(circles))
    if circles != None:
        for i in circles[0,:]:
        # draw the outer circle
            cv2.circle(gray,(i[0],i[1]),i[2],(0,255,0),2)
        # draw the center of the circle
            cv2.circle(gray,(i[0],i[1]),2,(0,0,255),3)
#    
###

# Display the resulting frame
    cv2.imshow('Board',gray)

    if cv2.waitKey(1) & 0xFF == ord('q'):
        break