cv2.waitkey（1）OpenCV的蟒蛇

Question

未運行，我需要了解在python cv2.waitkey（）與CV2

faceCascade = cv2.CascadeClassifier(cascPath) 

video_capture = cv2.VideoCapture(0) 

while True: 
    # Capture frame-by-frame 
ret, frame = video_capture.read() 

gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) 

faces = faceCascade.detectMultiScale(
    gray, 
    scaleFactor=1.1, 
    minNeighbors=8, 
    minSize=(40, 40), 
    #flags=cv2.cv.CV_HAAR_SCALE_IMAGE 
    flags = 0 
) 

# Draw a rectangle around the faces 
for (x, y, w, h) in faces: 
    cv2.rectangle(gray, (x, y), (x+w, y+h), (0, 255, 0), 2) 

# Display the resulting frame 
cv2.imshow('Video', gray) 
if cv2.waitKey(1) & 0xFF == ord('q'): 
    break 
if cv2.waitKey(1) & 0xFF == ord('b'): 
    cv2.imwrite('example.png',gray) 

cv2.waitKey()當我按b鍵不保存圖片，但按q作品。請幫忙！

Answer 1

您正在調用waitKey（）兩次。用您的密碼，按任意鍵，然後按b，然後保存圖像。

只有調用waitKey（1）一次，並將結果保存在一個變量，然後測試該變量，例如：

keypress = cv2.waitKey(1) 
if keypress & 0xFF == ord('q'): 
    break 
if keypress & 0xFF == ord('b'): 
    cv2.imwrite('example.png',gray)