OpenCV是目前开源项目中最著名的基于机器视觉方向的图像处理的开发包，目前已经有被移植到嵌入式Linux环境上。本文介绍了OpenCV交叉编译的基本步骤。

一、编译环境及库文件

linux环境：ubuntu12.0

交叉编译：4.3.2

arm板子：全志A10

libz:        zlib-1.2.3

libjpeg:       jpegsrc.v7

libpng:       libpng-1.5.10

libyasm:       yasm-1.2.0

opencv:        opencv-2.4.2

libx264:       x264-snapshot-20120608-2245

libxvid:       xvidcore-1.3.2

lffmpeg:       ffmpeg-0.10.3

cmake:         cmake-2.8.8-Linux-i386.tar,gz

二、opencv-2.4.2的移植过程

1、libz的交叉编译：

# ./configure --prefix=/opt/FriendlyARM/toolschain/4.5.1/arm-none-linux-gnueabi --shared

修改makefile

CC=arm-linux-gcc

LDSHARED=arm-linux-gcc

-shared -Wl,-soname,libz.so.1

CPP=arm-linux-gcc

-E

AR=arm-linux-ar

rc

RANLIB=arm-linux-ranlib

#make

#make install

2、libjpeg的交叉编译：

#./configure --host=arm-linux --prefix=/opt/FriendlyARM/toolschain/4.5.1/arm-none-linux-gnueabi --enable-shared --enable-static

#make install

3、libpng的交叉编译

#./configure --host=arm-linux --prefix=/opt/FriendlyARM/toolschain/4.5.1/arm-none-linux-gnueabi --enable-shared --enable-static

#make

#make install

4、yasm的交叉编译:

#./configure --host=arm-linux --prefix=/opt/FriendlyARM/toolschain/4.5.1/arm-none-linux-gnueabi --enable-shared --enable-static

#make

#make install

5、libx264的交叉编译:

#CC=arm-linux-gcc ./configure --enable-shared --host=arm-linux --disable-asm --prefix=/opt/FriendlyARM/toolschain/4.5.1/arm-none-linux-gnueabi

#make

#make install

6、libxvid的交叉编译:

#cd build/generic

#./configure --prefix=/opt/FriendlyARM/toolschain/4.5.1/arm-none-linux-gnueabi --host=arm-linux  --disable-assembly

#make

#make install

7、ffmpeg的交叉编译:

#./configure --prefix=/opt/FriendlyARM/toolschain/4.5.1/arm-none-linux-gnueabi --enable-shared --disable-static --enable-gpl --enable-cross-compile --arch=arm --disable-stripping --target-os=linux --enable-libx264 --enable-libxvid --cc=arm-linux-gcc --enable-swscale

(如果报错libx264 not fount 就--enable-libx264 --enable-libxvid 给去掉继续make)

#make

#make install

8.cmake-gui安装

到官网上下载已经编译好的cmake-2.8.8-Linux-i386.tar.gz，解压就可以了

(若出现cmake-gui:libSM.so:connot open shared objectf file！

安装 sudo apt-get install ia32-libs)

会生成一个图像界面 所以source CRT输入会报错 not connect x server;  要在ubuntu下运行cmake-gui 因为CTR不支持图像界面

9、opencv2.4.2的交叉编译:

用到的主要目录说明：

交叉编译工具链所在目录     /opt/FriendlyARM/toolschain/4.5.1/

安装opencv的目录         /usr/local/

opencv源码所在目录          /home/6410/opencv/opencv-2.4.2/

编译好的opencv库所在目录      /home/6410/opencv/opencv-2.4.2/build

#mkdir build

#cd build

#cmake-gui

选择源代码目录/home/6410/opencv/opencv-2.4.2/

选择Build目录：/home/6410/opencv/opencv-2.4.2/build

点击Configure，保持generator为Unix Makefiles，选择Specify options for cross-compiling，点击Next,

Operating System填写arm-linux

C Compilers填写opt/FriendlyARM/toolschain/4.5.1/bin/arm-linux-gcc

C++ Compilers填写opt/FriendlyARM/toolschain/4.5.1//bin/arm-linux-g++

程序库的Target Root填写opt/FriendlyARM/toolschain/4.5.1/

然后点击Finish。

默认安装目录为/usr/local，点击Generate生成Makefile。

#make

错误一：

Linking CXX executable ../../bin/opencv_createsamples

../../lib/libopencv_core.so: undefined reference to `clock_gettime'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFerrorHandler'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFrealloc'

../../lib/libopencv_core.so: undefined reference to `pthread_key_create

解决方法：

修改CMakeCache.txt，CMAKE_EXE_LINKER_FLAGS原来为空，加上-lpthread -lrt，重新编译，错误消除

错误二：

Linking CXX executable ../../bin/opencv_createsamples

../../lib/libopencv_highgui.so: undefined reference to `_TIFFerrorHandler'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFrealloc'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFmalloc'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFmemcpy'

../../lib/libopencv_highgui.so: undefined reference to `TIFFOpen'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFfree'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFwarningHandler'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFmemcmp'

../../lib/libopencv_highgui.so: undefined reference to `_TIFFmemset'

解决方法：修改CMakeCache.txt，WITH_TIFF:BOOL=ON，改成OFF，重新编译，错误消除。

#make install

三、测试

测试程序：

#include #include #include int main(int argc,char **argv)

{

CvCapture* capture = NULL;

IplImage* frame = NULL;

if(!(capture = cvCaptureFromCAM(-1)))

{

fprintf(stderr, "Can not open camera./n");

return -1;

}

cvNamedWindow("video", 1);

while(frame = cvQueryFrame( capture ) )

{

cvShowImage("video", frame);

}

cvDestroyWindow("video");

cvReleaseCapture(&capture);

return 0;

}

编译：

＃arm-linux-g++ -o opencv_test opencv_test.cpp -I /usr/local/include -L /usr/local/lib -lopencv_core -lopencv_highgui -lpthread -lrt

单个opencv的make就花了大概1个半小时，终于成功了，但是这只是开始，要想运用opecv+qt+x264+ffmpeg做东西，这还需要更长远的学习啊