qt.qpa.plugin: Could not load the Qt platform plugin “xcb” in “$HOME/venv/lib/python3.8/site-packages/cv2/qt/plugins” even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
Available platform plugins are: xcb, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl.

安装 opencv-python-headless

pip install -i https://pypi.tuna.tsinghua.edu.cn/simple opencv-python-headless