环境

操作系统：Ubuntu 18.04

OpenCv版本：4.6.0

交叉工具链：arm-linux-gnueabihf-gcc-5.3.1

下载OpenCV源代码

这里推荐大家到网上找OpenCV的Linux版本安装包（.tar.gz结尾），不要github上clone（clone下来的没编译通过）

https://github.com/opencv/opencv/releases/tag/4.6.0

选择tar.gz源码

下载 Opencv Contrib

https://gitcode.net/mirrors/opencv/opencv_contrib 下载在Tags里找到相应版本下载，

注意版本要与opencv一致
下载好解压后，将opencv_contrib放在opencv文件夹里面。

创建一个交叉编译参数文件

lu@DESKTOP-UJNM808:/WorkSpace/opencv-4.6.0$ cat arm-linux-gnueabihf.toolchain.cmake
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR arm)

set(CMAKE_C_COMPILER "/opt/ext-toolchain/bin/arm-linux-gnueabihf-gcc")
set(CMAKE_CXX_COMPILER "/opt/ext-toolchain/bin/arm-linux-gnueabihf-g++")

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

set(CMAKE_C_FLAGS "-march=armv7-a -mfloat-abi=hard -mfpu=neon")
set(CMAKE_CXX_FLAGS "-march=armv7-a -mfloat-abi=hard -mfpu=neon")

# cache flags
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS}" CACHE STRING "c flags")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}" CACHE STRING "c++ flags")
lu@DESKTOP-UJNM808:/WorkSpace/opencv-4.6.0$

创建一个编译脚本

lu@DESKTOP-UJNM808:/WorkSpace/opencv-4.6.0$ cat make.sh
cmake -DCMAKE_TOOLCHAIN_FILE=../arm-linux-gnueabihf.toolchain.cmake \
-DCMAKE_INSTALL_PREFIX=./install_arm \
-DBUILD_opencv_world=OFF \
-DBUILD_SHARED_LIBS=ON \
-DWITH_OPENEXR=OFF \
-DWITH_PNG=OFF \
-DBUILD_JAVA=OFF \
-DWITH_OPENJPEG=OFF \
-DENABLE_NEON=ON \
-DENABLE_VFPV3=ON \
-DENABLE_VFPV4=ON \
-DCMAKE_BUILD_TYPE=RELEASE \
-DENABLE_PRECOMPILED_HEADERS=OFF \
-DENABLE_FAST_MATH=ON \
-DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-4.6.0/modules ..
lu@DESKTOP-UJNM808:/WorkSpace/opencv-4.6.0$

安装依赖库

#安装cmake
$ sudo apt-get install -y cmake

编译源代码

# 新建build_arm目录
$ cd opencv4.6.0/

# 创建build_arm目录用于存放编译好的配置文件等信息 
$ mkdir build_arm   

# 将make.sh脚本移到build_arm/下
$ mv make.sh build_arm/

# 执行编译脚本
$ ./make.sh

等待编译完成。