樹莓派Python3安裝OpenCV後無法import

開發環境樹莓派4B，使用官方標配系統，系統自帶python3，

pip3 install opencv-python

速度太慢，我就把他下面的鏈接貼到瀏覽器下載了whl文件，用這個安裝的，完事之後報錯下面，心累

pi@raspberrypi:~ $ python3
Python 3.7.3 (default, Apr  3 2019, 05:39:12) 
[GCC 8.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/pi/.local/lib/python3.7/site-packages/cv2/__init__.py", line 3, in <module>
    from .cv2 import *
ImportError: /home/pi/.local/lib/python3.7/site-packages/cv2/cv2.cpython-37m-arm-linux-gnueabihf.so: undefined symbol: __atomic_fetch_add_8

然後我認爲的解決方法，找到報錯信息中的cv2.cpython-37m-arm-linux-gnueabihf.so這個文件，改名cv2.so，用命令複製一份最好，然後

pip3 unistall opencv-python