安装Ubuntu版opencv
在 https://github.com/opencv/opencv 下载源码，在源码根目录下打开终端
mkdir build
cd build
cmake ..
make -j
sudo make install
mkdir catkin_ws && cd catkin_ws
mkdir src && cd src
catkin_init_workspace
catkin_make
方法2：（只安装python版本）
pip install opencv-python --user
方法3：（失败）
apt-cache search opencv
可以看到依赖库大全：
查看依赖库
cl-opencv-apps
gstreamer1.0-opencv
gyoto-bin
libcv-bridge-dev
libcv-bridge1d
libgstreamer-opencv1.0-0
libimage-geometry-dev
libimage-geometry0d
libopencv-apps-dev
libopencv-apps1d
libopencv-calib3d-dev
libopencv-calib3d4.2
libopencv-contrib-dev
libopencv-contrib4.2
libopencv-core-dev
libopencv-core4.2
libopencv-dev
libopencv-dnn-dev
libopencv-dnn4.2
libopencv-features2d-dev
libopencv-features2d4.2
libopencv-flann-dev
libopencv-flann4.2
libopencv-highgui-dev
libopencv-highgui4.2
libopencv-imgcodecs-dev
libopencv-imgcodecs4.2
libopencv-imgproc-dev
libopencv-imgproc4.2
libopencv-ml-dev
libopencv-ml4.2
libopencv-objdetect-dev
libopencv-objdetect4.2
libopencv-photo-dev
libopencv-photo4.2
libopencv-shape-dev
libopencv-shape4.2
libopencv-stitching-dev
libopencv-stitching4.2
libopencv-superres-dev
libopencv-superres4.2
libopencv-ts-dev
libopencv-video-dev
libopencv-video4.2
libopencv-videoio-dev
libopencv-videoio4.2
libopencv-videostab-dev
libopencv-videostab4.2
libopencv-viz-dev
libopencv-viz4.2
libopencv4.2-java
libopencv4.2-jni
node-opencv
opencv-data
opencv-doc
python-willow-doc
python3-cv-bridge
python3-gyoto
python3-image-geometry
python3-opencv
python3-opencv-apps
python3-willow
ros-opencv-apps
ros-noetic-aruco-opencv
ros-noetic-aruco-opencv-dbgsym
ros-noetic-aruco-opencv-msgs
ros-noetic-checkerboard-detector
ros-noetic-cv-bridge
ros-noetic-cv-camera
ros-noetic-grid-map-cv
ros-noetic-image-geometry
ros-noetic-opencv-apps
ros-noetic-opencv-apps-dbgsym
ros-noetic-slic
ros-noetic-swri-opencv-util
ros-noetic-swri-opencv-util-dbgsym
ros-noetic-video-stream-opencv
ros-noetic-video-stream-opencv-dbgsym
ros-noetic-vision-opencv
sudo apt-get install libopencv-dev
sudo apt-get install 以下的东西
node-opencv opencv-data opencv-doc python-willow-doc python3-cv-bridge python3-gyoto python3-image-geometrypython3-opencvpython3-opencv-apps python3-willowros-opencv-apps ros-noetic-aruco-opencv ros-noetic-aruco-opencv-dbgsym ros-noetic-aruco-opencv-msgs ros-noetic-checkerboard-detector ros-noetic-cv-bridge ros-noetic-cv-camera ros-noetic-grid-map-cv ros-noetic-image-geometry ros-noetic-opencv-apps ros-noetic-opencv-apps-dbgsym ros-noetic-slic ros-noetic-swri-opencv-util ros-noetic-swri-opencv-util-dbgsym ros-noetic-video-stream-opencv ros-noetic-video-stream-opencv-dbgsym ros-noetic-vision-opencv
cl-opencv-appsgstreamer1.0-opencv gyoto-bin libcv-bridge-dev libcv-bridge1d libgstreamer-opencv1.0-0 libimage-geometry-dev libimage-geometry0d libopencv-apps-dev libopencv-apps1d libopencv-calib3d-dev libopencv-calib3d4.2 libopencv-contrib-dev libopencv-contrib4.2 libopencv-core-dev libopencv-core4.2 libopencv-dev libopencv-dnn-dev libopencv-dnn4.2 libopencv-features2d-dev libopencv-features2d4.2 libopencv-flann-dev libopencv-flann4.2 libopencv-highgui-dev libopencv-highgui4.2 libopencv-imgcodecs-dev libopencv-imgcodecs4.2 libopencv-imgproc-dev libopencv-imgproc4.2 libopencv-ml-dev libopencv-ml4.2 libopencv-objdetect-dev libopencv-objdetect4.2 libopencv-photo-dev libopencv-photo4.2 libopencv-shape-dev libopencv-shape4.2 libopencv-stitching-dev libopencv-stitching4.2 libopencv-superres-dev libopencv-superres4.2 libopencv-ts-dev libopencv-video-dev libopencv-video4.2 libopencv-videoio-dev libopencv-videoio4.2 libopencv-videostab-dev libopencv-videostab4.2 libopencv-viz-dev libopencv-viz4.2 libopencv4.2-java libopencv4.2-jni
报错：
cl-opencv-appsgstreamer1.0-opencv: command not found
E: Unable to locate package python3-image-geometrypython3-opencvpython3-opencv-apps
E: Unable to locate package python3-willowros-opencv-apps
E: Unable to locate package ros-noetic-vision-opencv
remove以后又报错：
E: Unable to locate package python3-image-geometrypython3-opencvpython3-opencv-apps
E: Unable to locate package python3-willowros-opencv-apps
E: Unable to locate package ros-noetic-vision-opencv cl-opencv-appsgstreamer1.0-opencv
E: Unable to locate package libopencv4.2-jni