OpenCV waitKey 無法正常捕捉方向鍵（上下左右），總結和解決方案，可以用waitKeyEx

 在win10+python+opencv3.4.5，測試

while True:
    key = cv2.waitKey(0)
    print('key =', key)

依次按上、下、左、右方向鍵，輸出：

key = 0
key = 0
key = 0
key = 0

 

測試代碼：

while True:
    key = cv2.waitKeyEx(0)
    print('key =', key)

依次按上、下、左、右方向鍵，輸出：

key = 2490368
key = 2621440
key = 2424832
key = 2555904

 

官方說，waitKeyEx和waitKey類似，Key code is implementation specific and depends on used backend: QT/GTK/Win32/etc