下载源码：

Releases - OpenCV

我这里是下载最新版本4.7.0

编译源码

1、把下载的源码包上传到开发板，解压后在opencv下面新建一个build文件压，并进行入build文件夹。
2、执行：
sudo cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..
3、然后执行编译：
sudo make -j8
4、然而到最后是编译通不过的：

make[1]: *** Waiting for unfinished jobs....
[ 92%] Building CXX object modules/gapi/CMakeFiles/opencv_test_gapi.dir/test/cpu/gapi_imgproc_tests_fluid.cpp.o
c++: fatal error: Killed signal terminated program cc1plus
compilation terminated.
make[2]: *** [modules/gapi/CMakeFiles/opencv_perf_gapi.dir/build.make:128: modules/gapi/CMakeFiles/opencv_perf_gapi.dir/perf/cpu/gapi_core_perf_tests_fluid.cpp.o] Error 1
[ 92%] Building CXX object modules/gapi/CMakeFiles/opencv_test_gapi.dir/test/cpu/gapi_ocv_stateful_kernel_tests.cpp.o
c++: fatal error: Killed signal terminated program cc1plus
compilation terminated.
make[2]: *** [modules/gapi/CMakeFiles/opencv_perf_gapi.dir/build.make:63: modules/gapi/CMakeFiles/opencv_perf_gapi.dir/perf/common/gapi_core_perf_tests.cpp.o] Error 1
[ 92%] Building CXX object modules/gapi/CMakeFiles/opencv_test_gapi.dir/test/cpu/gapi_operators_tests_cpu.cpp.o
c++: fatal error: Killed signal terminated program cc1plus
compilation terminated.
make[2]: *** [modules/gapi/CMakeFiles/opencv_test_gapi.dir/build.make:76: modules/gapi/CMakeFiles/opencv_test_gapi.dir/test/common/gapi_core_tests.cpp.o] Error 1
make[2]: *** Waiting for unfinished jobs....
c++: fatal error: Killed signal terminated program cc1plus
compilation terminated.
make[2]: *** [modules/gapi/CMakeFiles/opencv_perf_gapi.dir/build.make:141: modules/gapi/CMakeFiles/opencv_perf_gapi.dir/perf/cpu/gapi_imgproc_perf_tests_cpu.cpp.o] Error 1
c++: fatal error: Killed signal terminated program cc1plus
compilation terminated.
make[2]: *** [modules/gapi/CMakeFiles/opencv_test_gapi.dir/build.make:180: modules/gapi/CMakeFiles/opencv_test_gapi.dir/test/cpu/gapi_imgproc_tests_cpu.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:3611: modules/gapi/CMakeFiles/opencv_perf_gapi.dir/all] Error 2
make[1]: *** [CMakeFiles/Makefile2:3653: modules/gapi/CMakeFiles/opencv_test_gapi.dir/all] Error 2
make: *** [Makefile:163: all] Error 2

所以后面还是退回了4.5.4才能安装好。
mak 好后，执行sudo make install

配置环境：

1.添加路径
（1）打开文件：
sudo vim /etc/ld.so.conf.d/opencv.conf
在文件后面添加如下内容：
/usr/loacal/lib

2.修改etc/bash.bashrc

我们之前安装的时候 OPENCV_GENERATE_PKGCONFIG=ON 所以在/usr/local/lib/pkgconfig下生成了opencv4.pc文件，里面记录了OpenCV头文件、库文件的路經。需要进行如下配置：
`sudo vim /etc/bash.bashrc

`

加截：
sudo ldconfig

#文件末尾添加以下内容 并保存
PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig
export PKG_CONFIG_PATH

然后的要安装 sudo apt install mlocate
要不会报错sudo: updatedb: command not found
#更新
sudo updatedb
source /etc/bash.bashrc

检查是否安装好：

#终端输入以下两命令，显示正常则安装成功
pkg-config --modversion opencv4 #查看版本号
pkg-config --libs opencv4 #查看libs库

然后报错：

forlinx@ok3588:~/opencv-4.5.4/build$ pkg-config opencv --modversion
Package opencv was not found in the pkg-config search path.
Perhaps you should add the directory containing `opencv.pc'
to the PKG_CONFIG_PATH environment variable
No package 'opencv' found

处理：

经过网上详细查询资料后，是缺失了opencv.pc这个配置信息文件，故解决方法就是添加这个文件然后将其导入到环境变量中，具体操作如下：

首先创建opencv.pc文件，这里要注意它的路径信息：

cd /usr/local/lib
sudo mkdir pkgconfig
cd pkgconfig
sudo touch opencv.pc

然后在opencv.pc中添加以下信息，注意这些信息需要与自己安装opencv时的库路径对应：

prefix=/usr/local
exec_prefix=${prefix}
includedir=${prefix}/include
libdir=${exec_prefix}/lib

Name: opencv
Description: The opencv library
Version:4.5.4
Cflags: -I${includedir}/opencv4
Libs: -L${libdir} -lopencv_shape -lopencv_stitching -lopencv_objdetect -lopencv_superres -lopencv_videostab -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_video -lopencv_photo -lopencv_ml -lopencv_imgproc -lopencv_flann  -lopencv_core

保存后再执行版本查看OK了：

forlinx@ok3588:/usr/local/lib/pkgconfig$ pkg-config opencv --modversion
4.5.4

验证：

进入opencv/samples/cpp/example_cmake目录下，终端打开，依次输入：

forlinx@ok3588:~/opencv-4.5.4/samples/cpp/example_cmake$ cmake .
-- The C compiler identification is GNU 9.3.0
-- The CXX compiler identification is GNU 9.3.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found OpenCV: /usr/local (found version "4.5.4")
-- OpenCV library status:
--     config: /usr/local/lib/cmake/opencv4
--     version: 4.5.4
--     libraries: opencv_calib3d;opencv_core;opencv_dnn;opencv_features2d;opencv_flann;opencv_highgui;opencv_imgcodecs;opencv_imgproc;opencv_ml;opencv_objdetect;opencv_photo;opencv_stitching;opencv_video;opencv_videoio
--     include path: /usr/local/include/opencv4
-- Configuring done
-- Generating done
-- Build files have been written to: /home/forlinx/opencv-4.5.4/samples/cpp/example_cmake
forlinx@ok3588:~/opencv-4.5.4/samples/cpp/example_cmake$ make
Scanning dependencies of target opencv_example
[ 50%] Building CXX object CMakeFiles/opencv_example.dir/example.cpp.o
[100%] Linking CXX executable opencv_example
[100%] Built target opencv_example
forlinx@ok3588:~/opencv-4.5.4/samples/cpp/example_cmake$

然后在桌面打开 ./example
./opencv_example
然后就可以生成opencv图像

填坑

1、3688有8核，编译时前面可以开8核编译，但到93%会报错：

fatal error: Killed signal terminated program cc++: fatal error: Killed signal terminated program cc1plus

经查资料，是交换空间太小导致的，我重复编了好多编，最后解决方法是只开2个线程编译，才通过。
2、opencv版本太新，可能会出现不兼容的情况。