参考博客：
http://blog.csdn.net/u014613745/article/details/78310916
http://blog.csdn.net/public669/article/details/99044895
因为有需要要在tx2安装opencv3.2，然而我这jetpack4.4里的opencv版本是4.1.1，需要卸载重装，但是在catkin_make中遇到了问题，这里说一下如何解决。
一、卸载原有的opencv
sudo apt-get purge libopencv*
sudo apt autoremove
sudo apt-get update
查看opencv版本
pkg-config opencv --modversion
若没有显示说明已经卸载成功
二、安装opencv3.2
1.下载opencv
opencv下载官网：https://opencv.org/releases/
下载source文件然后解压，我这里要在ros的工作的空间里使用。所以放在了catkin_ws/src里
2.安装opencv
1.安装依赖环境
sudo apt-get install build-essential libgtk2.0-dev libavcodec-dev libavformat-dev libjpeg-dev libswscale-dev libtiff5-dev
sudo apt-get install libgtk2.0-dev
sudo apt-get install pkg-config
2.编译并安装
cd opencv
mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local ..
make -j
sudo make install
时间比较漫长耐心等待
安装opencv的时候可能会遇到报错：
Please set them or make sure they are set and tested correctly in the CMake files:
CUDA_nppi_LIBRARY (ADVANCED)
linked by target "opencv_cudev" in directory D:/Cproject/opencv/opencv/sources/modules/cudev
linked by target "opencv_cudev" in directory D:/Cproject/opencv/opencv/sources/modules/cudev
linked by target "opencv_test_cudev" in directory D:/Cproject/opencv/opencv/sources/modules/cudev/test
linked by target "opencv_core" in directory D:/Cproject/opencv/opencv/sources/modules/core
linked by target "opencv_core" in directory D:/Cproject/opencv/opencv/sources/modules/core
linked by target "opencv_test_core" in directory D:/Cproject/opencv/opencv/sources/modules/core
linked by target "opencv_perf_core" in directory D:/Cproject/opencv/opencv/sources/modules/core
linked by target "opencv_test_cudaarithm" in directory D:/Cproject/opencv/opencv/sources/modules/cudaarithm
linked by target "opencv_cudaarithm" in directory D:/Cproject/opencv/opencv/sources/modules/cudaarithm
linked by target "opencv_cudaarithm" in directory D:/Cproject/opencv/opencv/sources/modules/cudaarithm
linked by target "opencv_perf_cudaarithm" in directory D:/Cproject/opencv/opencv/sources/modules/cudaarithm
linked by target "opencv_flann" in directory D:/Cproject/opencv/opencv/sources/modules/flann
linked by target "opencv_flann" in directory D:/Cproject/opencv/opencv/sources/modules/flann
linked by target "opencv_test_flann" in directory D:/Cproject/opencv/opencv/sources/modules/flann
linked by target "opencv_imgproc" in directory D:/Cproject/opencv/opencv/sources/modules/imgproc
linked by target "opencv_imgproc" in directory D:/Cproject/opencv/opencv/sources/modules/imgproc
linked by target "opencv_test_imgproc" in directory D:/Cproject/opencv/opencv/sources/modules/imgproc
linked by target "opencv_perf_imgproc" in directory D:/Cproject/opencv/opencv/sources/modules/imgproc
linked by target "opencv_test_ml" in directory D:/Cproject/opencv/opencv/sources/modules/ml
linked by target "opencv_ml" in directory D:/Cproject/opencv/opencv/sources/modules/ml
linked by target "opencv_ml" in directory D:/Cproject/opencv/opencv/sources/modules/ml
linked by target "opencv_test_video" in directory D:/Cproject/opencv/opencv/sources/modules/video
linked by target "opencv_video" in directory D:/Cproject/opencv/opencv/sources/modules/video
linked by target "opencv_video" in directory D:/Cproject/opencv/opencv/sources/modules/video
linked by target "opencv_perf_video" in directory D:/Cproject/opencv/opencv/sources/modules/video
linked by target "opencv_cudabgsegm" in directory D:/Cproject/opencv/opencv/sources/modules/cudabgsegm
linked by target "opencv_cudabgsegm" in directory D:/Cproject/opencv/opencv/sources/modules/cudabgsegm
linked by target "opencv_test_cudabgsegm" in directory D:/Cproject/opencv/opencv/sources/modules/cudabgsegm
linked by target "opencv_perf_cudabgsegm" in directory D:/Cproject/opencv/opencv/sources/modules/cudabgsegm
linked by target "opencv_cudafilters" in directory D:/Cproject/opencv/opencv/sources/modules/cudafilters
linked by target "opencv_cudafilters" in directory D:/Cproject/opencv/opencv/sources/modules/cudafilters
linked by target "opencv_test_cudafilters" in directory D:/Cproject/opencv/opencv/sources/modules/cudafilters
linked by target "opencv_perf_cudafilters" in directory D:/Cproject/opencv/opencv/sources/modules/cudafilters
linked by target "opencv_cudaimgproc" in directory D:/Cproject/opencv/opencv/sources/modules/cudaimgproc
linked by target "opencv_cudaimgproc" in directory D:/Cproject/opencv/opencv/sources/modules/cudaimgproc
linked by target "opencv_test_cudaimgproc" in directory D:/Cproject/opencv/opencv/sources/modules/cudaimgproc
linked by target "opencv_perf_cudaimgproc" in directory D:/Cproject/opencv/opencv/sources/modules/cudaimgproc
linked by target "opencv_perf_cudawarping" in directory D:/Cproject/opencv/opencv/sources/modules/cudawarping
linked by target "opencv_cudawarping" in directory D:/Cproject/opencv/opencv/sources/modules/cudawarping
linked by target "opencv_cudawarping" in directory D:/Cproject/opencv/opencv/sources/modules/cudawarping
linked by target "opencv_test_cudawarping" in directory D:/Cproject/opencv/opencv/sources/modules/cudawarping
linked by target "opencv_imgcodecs" in directory D:/Cproject/opencv/opencv/sources/modules/imgcodecs
linked by target "opencv_imgcodecs" in directory D:/Cproject/opencv/opencv/sources/modules/imgcodecs
linked by target "opencv_test_imgcodecs" in directory D:/Cproject/opencv/opencv/sources/modules/imgcodecs
linked by target "opencv_perf_imgcodecs" in directory D:/Cproject/opencv/opencv/sources/modules/imgcodecs
linked by target "opencv_perf_photo" in directory D:/Cproject/opencv/opencv/sources/modules/photo
linked by target "opencv_photo" in directory D:/Cproject/opencv/opencv/sources/modules/photo
linked by target "opencv_photo" in directory D:/Cproject/opencv/opencv/sources/modules/photo
linked by target "opencv_test_photo" in directory D:/Cproject/opencv/opencv/sources/modules/photo
linked by target "opencv_test_shape" in directory D:/Cproject/opencv/opencv/sources/modules/shape
linked by target "opencv_shape" in directory D:/Cproject/opencv/opencv/sources/modules/shape
linked by target "opencv_shape" in directory D:/Cproject/opencv/opencv/sources/modules/shape
linked by target "opencv_test_videoio" in directory D:/Cproject/opencv/opencv/sources/modules/videoio
linked by target "opencv_videoio" in directory D:/Cproject/opencv/opencv/sources/modules/videoio
linked by target "opencv_videoio" in directory D:/Cproject/opencv/opencv/sources/modules/videoio
linked by target "opencv_perf_videoio" in directory D:/Cproject/opencv/opencv/sources/modules/videoio
linked by target "opencv_cudacodec" in directory D:/Cproject/opencv/opencv/sources/modules/cudacodec
linked by target "opencv_cudacodec" in directory D:/Cproject/opencv/opencv/sources/modules/cudacodec
linked by target "opencv_perf_cudacodec" in directory D:/Cproject/opencv/opencv/sources/modules/cudacodec
linked by target "opencv_test_cudacodec" in directory D:/Cproject/opencv/opencv/sources/modules/cudacodec
linked by target "opencv_highgui" in directory D:/Cproject/opencv/opencv/sources/modules/highgui
linked by target "opencv_highgui" in directory D:/Cproject/opencv/opencv/sources/modules/highgui
linked by target "opencv_test_highgui" in directory D:/Cproject/opencv/opencv/sources/modules/highgui
linked by target "opencv_perf_objdetect" in directory D:/Cproject/opencv/opencv/sources/modules/objdetect
linked by target "opencv_objdetect" in directory D:/Cproject/opencv/opencv/sources/modules/objdetect
linked by target "opencv_objdetect" in directory D:/Cproject/opencv/opencv/sources/modules/objdetect
linked by target "opencv_test_objdetect" in directory D:/Cproject/opencv/opencv/sources/modules/objdetect
linked by target "opencv_ts" in directory D:/Cproject/opencv/opencv/sources/modules/ts
linked by target "opencv_ts" in directory D:/Cproject/opencv/opencv/sources/modules/ts
linked by target "opencv_test_features2d" in directory D:/Cproject/opencv/opencv/sources/modules/features2d
linked by target "opencv_features2d" in directory D:/Cproject/opencv/opencv/sources/modules/features2d
linked by target "opencv_features2d" in directory D:/Cproject/opencv/opencv/sources/modules/features2d
linked by target "opencv_perf_features2d" in directory D:/Cproject/opencv/opencv/sources/modules/features2d
linked by target "opencv_calib3d" in directory D:/Cproject/opencv/opencv/sources/modules/calib3d
linked by target "opencv_calib3d" in directory D:/Cproject/opencv/opencv/sources/modules/calib3d
linked by target "opencv_test_calib3d" in directory D:/Cproject/opencv/opencv/sources/modules/calib3d
linked by target "opencv_perf_calib3d" in directory D:/Cproject/opencv/opencv/sources/modules/calib3d
linked by target "opencv_cudafeatures2d" in directory D:/Cproject/opencv/opencv/sources/modules/cudafeatures2d
linked by target "opencv_cudafeatures2d" in directory D:/Cproject/opencv/opencv/sources/modules/cudafeatures2d
linked by target "opencv_test_cudafeatures2d" in directory D:/Cproject/opencv/opencv/sources/modules/cudafeatures2d
linked by target "opencv_perf_cudafeatures2d" in directory D:/Cproject/opencv/opencv/sources/modules/cudafeatures2d
linked by target "opencv_cudalegacy" in directory D:/Cproject/opencv/opencv/sources/modules/cudalegacy
linked by target "opencv_cudalegacy" in directory D:/Cproject/opencv/opencv/sources/modules/cudalegacy
linked by target "opencv_test_cudalegacy" in directory D:/Cproject/opencv/opencv/sources/modules/cudalegacy
linked by target "opencv_perf_cudalegacy" in directory D:/Cproject/opencv/opencv/sources/modules/cudalegacy
linked by target "opencv_cudaobjdetect" in directory D:/Cproject/opencv/opencv/sources/modules/cudaobjdetect
linked by target "opencv_cudaobjdetect" in directory D:/Cproject/opencv/opencv/sources/modules/cudaobjdetect
linked by target "opencv_perf_cudaobjdetect" in directory D:/Cproject/opencv/opencv/sources/modules/cudaobjdetect
linked by target "opencv_test_cudaobjdetect" in directory D:/Cproject/opencv/opencv/sources/modules/cudaobjdetect
linked by target "opencv_cudaoptflow" in directory D:/Cproject/opencv/opencv/sources/modules/cudaoptflow
linked by target "opencv_cudaoptflow" in directory D:/Cproject/opencv/opencv/sources/modules/cudaoptflow
linked by target "opencv_test_cudaoptflow" in directory D:/Cproject/opencv/opencv/sources/modules/cudaoptflow
linked by target "opencv_perf_cudaoptflow" in directory D:/Cproject/opencv/opencv/sources/modules/cudaoptflow
linked by target "opencv_perf_cudastereo" in directory D:/Cproject/opencv/opencv/sources/modules/cudastereo
linked by target "opencv_cudastereo" in directory D:/Cproject/opencv/opencv/sources/modules/cudastereo
linked by target "opencv_cudastereo" in directory D:/Cproject/opencv/opencv/sources/modules/cudastereo
linked by target "opencv_test_cudastereo" in directory D:/Cproject/opencv/opencv/sources/modules/cudastereo
linked by target "opencv_test_stitching" in directory D:/Cproject/opencv/opencv/sources/modules/stitching
linked by target "opencv_stitching" in directory D:/Cproject/opencv/opencv/sources/modules/stitching
linked by target "opencv_stitching" in directory D:/Cproject/opencv/opencv/sources/modules/stitching
linked by target "opencv_perf_stitching" in directory D:/Cproject/opencv/opencv/sources/modules/stitching
linked by target "opencv_superres" in directory D:/Cproject/opencv/opencv/sources/modules/superres
linked by target "opencv_superres" in directory D:/Cproject/opencv/opencv/sources/modules/superres
linked by target "opencv_test_superres" in directory D:/Cproject/opencv/opencv/sources/modules/superres
linked by target "opencv_perf_superres" in directory D:/Cproject/opencv/opencv/sources/modules/superres
linked by target "opencv_videostab" in directory D:/Cproject/opencv/opencv/sources/modules/videostab
linked by target "opencv_videostab" in directory D:/Cproject/opencv/opencv/sources/modules/videostab
linked by target "opencv_traincascade" in directory D:/Cproject/opencv/opencv/sources/apps/traincascade
linked by target "opencv_createsamples" in directory D:/Cproject/opencv/opencv/sources/apps/createsamples
linked by target "opencv_annotation" in directory D:/Cproject/opencv/opencv/sources/apps/annotation
linked by target "opencv_visualisation" in directory D:/Cproject/opencv/opencv/sources/apps/visualisation
linked by target "opencv_version" in directory D:/Cproject/opencv/opencv/sources/apps/version
这里的解决方法可以参考博客：http://blog.csdn.net/u014613745/article/details/78310916
3.配置环境，将opencv的库加入路径
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sudo gedit /etc/ld.so.conf
此时在打开的文件中加入/usr/loacl/lib，保存退出
sudo ldconfig
sudo gedit /etc/bash.bashrc
此时在打开的文件末尾加入PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig export PKG_CONFIG_PATH，保存退出
source /etc/bash.bashrc
4.检验
pkg-config opencv --modversion
至此opencv的安装就完成了
三、修改cv_bridge和cmake
本来到上一步就已经结束，但是我在catkin_ws中catkin_make时遇到几个问题，一个是cv_bridge一个是opencv的版本，虽然opencv3,.2已经安装完成，但是catkin_make的时候可以看到opencv被检测的版本是4.1.1以及cv_bridge报错，后来发现opencv安装完成之后在usr/include中出现了opencv，而我们安装的opencv在usr/local/include中并且cv_bridge报错，这里需要修改一下cmake和cv_bridge才能顺利编译下去。
这里是我遇到的错误和解决方法，catkin_make时出现了这个错误
这需要修改cmake
cd opt/ros/melodic/share/cv_bridge/cmake
sudo gedit cv_bridgeConfig.cmake
找到如下的位置。
可以看到cv_bridgeConfig.cmake中引用opencv的路径是/usr/inclde/opencv，到这个路径可以看到文件夹是opencv4不是opencv，所以会按照下面一行的路径去寻找引用，路径同样也是/usr/inclde/opencv，然而之前自己安装的opencv的路径在/usr/local/include中，所以我们下面要对cv_bridgeConfig.cmake中opencv的引用地址进行修改，在cv_bridgeConfig.cmake中把
set(_include_dirs “include;/usr/include;/usr/local/opencv2”)
改成
set(_include_dirs “include;/usr/local/include;/usr/local/include/opencv2”)
如图所示
catkin_make中还可能遇到如下图所示的问题：
这是刚刚安装的opencv版本还没有被系统识别出来，需要进行如下修改：
打开自己安装的opencv的build文件夹，同时打开/usr/lib/aarch64-linux-gnu/cmke/opencv4
把opencv build文件夹中的对应文件复制到opencv4文件夹中，其中OpenCVModules-realease.cmake可能没有，这个好像也没有影响。
再次在catkin_ws中catkin_make就可以了