環境+工具：
編譯器 : aarch64-linux-gnu-g++ aarch64-linux-gnu-gcc
虛擬機 ：ubuntu16.04
cmake-gui
cd /usr/local
sudo mkdir opencv
將源碼opencv3.4.3 拷貝到此目錄下，並新建兩個opencv_config, opencv-arm-install文件夾，
cmake-gui
點擊configure
Next 如下圖填寫，compilers，c ，c++選項填寫自己要用的交叉編譯工具鏈。Target Root爲檢查編譯工具鏈所在的路徑，根據你的填寫，Finish
選擇你要安裝的路徑；我這裏是安裝在剛剛新建的opencv-arm-install下。以防止將之前在ubuntu下的opencv沖掉，這裏我只改了這一個選項，網上有人將動態鏈接庫的選項也去掉了，但是我生成靜態鏈接庫執行demo出現問題，所以又選回來了，生成動態鏈接庫，反正這裏我只改了這一個地方。
然後點擊configure，Generate。
進入opencv_config文件夾下，
執行
make
make install
完成。
中間make的時候我遇到過兩個問題：
1.在進度到40%多的時候 opencv-3.4.3/3rdparty/libpng/pngstruct.h:30:18: fatal error: zlib.h: No such file or directory
解決方法
在 opencv-3.4.3/CMakeLists.txt，在514行增加以上代碼： ocv_include_directories(./3rdparty/zlib/)下面一行添加，其它類似錯誤一樣的解決方法
......
ocv_include_directories(${OPENCV_CONFIG_FILE_INCLUDE_DIR})
ocv_include_directories(./3rdparty/zlib/)
......
重新cmake一遍，然後在進行make
2.
[ 43%] Building CXX object apps/visualisation/CMakeFiles/opencv_visualisation.dir/opencv_visualisation.cpp.obj
[ 43%] Linking CXX executable ../../bin/opencv_annotation
../../lib/libopencv_core.so: undefined reference to `pthread_mutexattr_destroy'
../../lib/libopencv_imgcodecs.so: undefined reference to `pthread_create'
../../lib/libopencv_core.so: undefined reference to `pthread_key_create'
../..lib/libopencv_imgcodecs.so: undefined reference to `png_init_filter_functions_neon'
../../lib/libopencv_core.so: undefined reference to `pthread_getspecific'
../../lib/libopencv_core.so: undefined reference to `dlopen'
../../lib/libopencv_core.so: undefined reference to `pthread_mutex_trylock'
../../lib/libopencv_core.so: undefined reference to `pthread_key_delete'
../../lib/libopencv_core.so: undefined reference to `dlclose'
../../lib/libopencv_core.so: undefined reference to `dlsym'
../../lib/libopencv_core.so: undefined reference to `pthread_mutexattr_settype'
../../lib/libopencv_imgcodecs.so: undefined reference to `pthread_join'
../../lib/libopencv_core.so: undefined reference to `pthread_setspecific'
../../lib/libopencv_core.so: undefined reference to `pthread_mutexattr_init'
collect2: error: ld returned 1 exit status
解決方法：
如下修改：~/opencv-3.4.3/3rdparty/libpng/pngpriv.h文件。
將128行註釋掉，添加129行內容。
128 /*# if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \*/
129 # if defined(PNG_ARM_NEON) && (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
解決了這兩個問題之後就make通過了
之後將編譯完成的lib include文件夾拷貝到開發板上，網上說拷貝到開發板的/usr/local，但是我拷貝到這個文件夾下執行demo的時候會出現error while loading shared libraries: libopencv_highgui.so.3.4: cannot open shared object file: No such file or directory這個錯誤，後將lib文件裏的.so文件拷貝到lib64文件夾下demo可正常執行。
編譯一個調用攝像頭並且錄像的demo：
#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main()
{
VideoCapture capture(6);//如果是筆記本，0打開的是自帶的攝像頭，1 打開外接的相機
capture.set(3,640);
capture.set(4,480);
Mat img;
VideoWriter vw; //新建一個多媒體文件
int fps = capture.get(CAP_PROP_FPS); //獲取攝像頭的幀率
if (fps <= 0)fps = 16;
//設置視頻的格式
// vw.open("Video.avi", VideoWriter::fourcc('h', '2', '6', '4'), fps, Size(640, 480));
vw.open("1.avi", VideoWriter::fourcc('M', 'J', 'P', 'G'), fps, Size(640, 480));
if (!capture.isOpened()) //判斷攝像頭是否打開
{
cout << "open video faild";
getchar();
}
cout << "open video success" << endl;
if (!vw.isOpened()) //判斷視頻文件是否創建
{
cout << "open vw faild" << endl;
}
cout << "open vw success" << endl;
while (1)
{
capture.read(img); //讀取視頻幀
if (img.empty())
break;
vw.write(img); //將視頻幀寫入文件
}
return 0;
}
將lib和include文件拷貝到交叉編譯的lib和include的文件夾下。並執行以下命令。
aarch64-linux-gnu-g++ camera.cpp -o camera -I/usr/local/opencv/opencv-arm/include -L/usr/local/opencv/opencv-arm/lib -lopencv_highgui -lopencv_core -lopencv_imgproc -lpthread -lrt -ldl -lopencv_imgcodecs -lopencv_videoio
會出現以下警告：
/usr/local/linaro-aarch64-2017.11-gcc7.2/bin/…/lib/gcc/aarch64-linux-gnu/7.2.1/…/…/…/…/aarch64-linux-gnu/bin/ld: warning: …/…/lib/libopencv_imgproc.so, needed by /home/zy/cv22_1.0_rc/cv22_auto_linux_sdk/ambarella/prebuild/third-party/armv8-a/opencv24/usr/lib/libopencv_highgui.so, not found (try using -rpath or -rpath-link)
/usr/local/linaro-aarch64-2017.11-gcc7.2/bin/…/lib/gcc/aarch64-linux-gnu/7.2.1/…/…/…/…/aarch64-linux-gnu/bin/ld: warning: …/…/lib/libopencv_core.so, needed by /home/zy/cv22_1.0_rc/cv22_auto_linux_sdk/ambarella/prebuild/third-party/armv8-a/opencv24/usr/lib/libopencv_highgui.so, not found (try using -rpath or -rpath-link)
這個警告不影響目標代碼的生成，但想去掉的話，其實只需要把找不到的庫放到路徑爲/usr/local/arm/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu/aarch64-linux-gnu/libc/lib/目錄下即可。