OpenCV - Ubuntu编译opencv（以全志V851s为例）

1.主要参考教程《使用CMake-gui编译OpenCV3源码的详细过程》，实际操作结合多个教程。

2.放从OPENCV RELEASE 下载的解压出来的文件，里面还要放对应版本的contribute 解压文件

/root/opencv-4.5.4

/root/opencv-4.5.4/build6

  

在这里要找到三个地方进行修改;

1、勾选上BUILD_opencv_world
2、在CMAKE_BUILD_TYPE后填上：RELEASE

3、在OPENCV_EXTRA_MODULES_PATH后填上opencv-contrib/modules的路径

比如我是：/home/wsx/opencv/opencv/opencv_contrib/modules
完成之后再次点击Configure按钮，稍等片刻，之后在点击Generate按钮
（所有红色报错，全部关掉即可）

交叉编译工具链地址：

/root/tina-v853-docker/prebuilt/rootfsbuilt/arm/toolchain-sunxi-musl-gcc-830/toolchain/bin/arm-openwrt-linux-gcc

/root/tina-v853-docker/prebuilt/rootfsbuilt/arm/toolchain-sunxi-musl-gcc-830/toolchain/bin/arm-openwrt-linux-g++

/root/tina-v853-docker/prebuilt/rootfsbuilt/arm/toolchain-sunxi-musl-gcc-830/bin/

注意：

• 取消WITH_GTK
  取消WITH_TIFF , PNG ,JPG
  所有红色报错的功能，都不要勾选，或者自己搞定。

• 如果点击configure提示处理器未识别
  那么执行vi /root/opencv-4.5.4/cmake/OpenCVDetectCXXCompiler.cmake
  可以在第47行，写入 set(CMAKE_SYSTEM_PROCESSOR arm)
  （一定会提示，一定要这么做。）

4、 如果要修改默认的install文件夹，要在点击Generate之前修改，修改方式如下
vi /root/opencv-4.5.4/build6/CMakeCache.txt
修改CMAKE_INSTALL_PREFIX:PATH=/root/opencv-4.5.4/build6

5、进入目录
/root/opencv-4.5.4/build6/

执行 cmake .
执行 export STAGING_DIR=/root/tina-v853-docker/prebuilt/rootfsbuilt/arm/toolchain-sunxi-musl-gcc-830/toolchain/bin
执行 make -j20

(看自己的线程数，设定）

到此编译成功

6、编译出来的文件
动态库文件 /usr/local/lib/
文件库 /usr/local/include/opencv4/

注意下面步骤中成功编译出来的固件，是不含动态库的，所以还需要编译时所用的动态库，同步复制到板子的/usr/lib/ 里面去。否则报错找不到动态库

7、编译一个opencv example

首先 执行

export STAGING_DIR=/root/tina-v853-docker/prebuilt/rootfsbuilt/arm/toolchain-sunxi-musl-gcc-830/toolchain/bin

任意目录下创建3个文件

1.CMakeLists.txt

cmake_minimum_required(VERSION 3.10)

set (ARM_LINUX_GCC_PATH /root/tina-v853-docker/prebuilt/rootfsbuilt/arm/toolchain-sunxi-musl-gcc-830/toolchain/bin/) # 改成你的路径
set (CMAKE_C_COMPILER ${ARM_LINUX_GCC_PATH}arm-openwrt-linux-gcc)
set (CMAKE_CXX_COMPILER ${ARM_LINUX_GCC_PATH}arm-openwrt-linux-g++)

project(Test_OpenCV_Mobile)
set(CMAKE_CXX_STANDARD 11)
set(OpenCV_DIR "/root/opencv-4.5.4/") # 改成你的路径
find_package(OpenCV REQUIRED)
FIND_PACKAGE(OpenMP REQUIRED)
add_executable(Test_OpenCV_Mobile main.cpp)
target_link_libraries(Test_OpenCV_Mobile pthread)
target_link_libraries(Test_OpenCV_Mobile dl)
target_link_libraries(Test_OpenCV_Mobile -fopenmp)
target_link_libraries(Test_OpenCV_Mobile ${OpenCV_LIBS})

2.makefile

OPENCV_DIR := /root/opencv-4.5.4/
THIRD_PART_INCLUDE := -I$(OPENCV_DIR)include/opencv4 -I$(OPENCV_DIR)include/opencv4/opencv2
THIRD_PART_LIBRARY := $(OPENCV_DIR)lib/libopencv_highgui.a $(OPENCV_DIR)lib/libopencv_features2d.a $(OPENCV_DIR)lib/libopencv_imgproc.a $(OPENCV_DIR)lib/libopencv_photo.a $(OPENCV_DIR)lib/libopencv_video.a $(OPENCV_DIR)lib/libopencv_core.a

TARGET = Test_OpenCV_Mobile
START:
    @echo START
    rm -rf $(TARGET)
    /root/tina-v853-docker/prebuilt/rootfsbuilt/arm/toolchain-sunxi-musl-gcc-830/toolchain/bin/arm-openwrt-linux-g++ -O2 -std=c++11 -lpthread -fopenmp -ldl $(CFLAGS) $(THIRD_PART_INCLUDE) -o $(TARGET) ./main.cpp $(THIRD_PART_LIBRARY)

.PHONY:clean

clean:
    rm -rf $(BINDIR)

3.main.cpp

#include <opencv2/opencv.hpp>
#include <iostream>
int main()
{
    cv::Mat mat = cv::Mat::zeros(256,256, CV_8UC1);
    {
        cv::rectangle(mat, cv::Rect(40, 45, 51, 65), cv::Scalar(255), -1, cv::LINE_8, 0);//绘制填充矩形
        cv::rectangle(mat, cv::Rect(180, 180, 85, 21), cv::Scalar(255), -1, cv::LINE_8, 0);//绘制填充矩形
        std::cout << "mat.rows = " << mat.rows << std::endl;
        std::cout << "mat.cols = " << mat.cols << std::endl;
    }
    return 0;
}

8.编译 opencv example
在创建的目录里面，执行

cmake .
make

9、将文件推进板子，并添加权限执行

10、推送相应的动态库进入 /usr/lib
比如 world,core….

11、最后终端执行，推送进来的文件。
./Test_OpenCV/example

到此 opencv 4.5.4 编译成功，并运行opencv example成功。