在linux中安装好opencv包之后，导入cv2报如下错误：
ImportError: libgthread-2.0.so.0: cannot open shared object file: No such file or directory
import cv2
File "/usr/local/lib/python3.9/site-packages/cv2/__init__.py", line 181, in <module>
bootstrap()
File "/usr/local/lib/python3.9/site-packages/cv2/__init__.py", line 153, in bootstrap
native_module = importlib.import_module("cv2")
File "/usr/local/lib/python3.9/importlib/__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
ImportError: libgthread-2.0.so.0: cannot open shared object file: No such file or directory
针对这个错误可以重新安装opencv包：
pip uninstall opencv-python
pip install opencv-python-headless
安装完成后，可以正常导入
