opencv在ubuntu下的安装

主要参照：http://www.samontab.com/web/2010/04/installing-opencv-2-1-in-ubuntu/

www.samontab.com/web/2011/06/installing-opencv-2-2-in-ubuntu-11-04/

装opencv之前先要装一些软件：

sudo apt-get install build-essential libgtk2.0-dev libavcodec-dev libavformat-dev libjpeg62-dev libtiff4-dev cmake libswscale-dev libjasper-dev

在官网下载opencv源码，解压后进入目录，执行（注意有个“.”，作为cmake的参数表示当前目录）

cmake .

然后

makesudo make install

下面配置library，打开/etc/ld.so.conf.d/opencv.conf，在末尾加入/usr/local/lib    (有可能是个空文件，没关系)

然后 

sudo ldconfig

然后编辑/etc/bash.bashrc

加入

PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfigexport PKG_CONFIG_PATH

至此，opencv安装配置完毕，下面开始测试

---------------------------------------------------------------------------------------------
将opencv源码包下的example/c拷贝出来，执行./build_all.sh
编译完后试一个人脸检测的程序：

./facedetect --cascade="/usr/local/share/OpenCV/haarcascades/haarcascade_frontalface_alt.xml" --scale=1.5 lena.jpg

结果如下：

 

注意：
1.关于编译方法，参照opencv源码下example/c/build_all.sh
2.有些路径的OpenCV注意大小写，如example/c下facedetect运行时的路径

安装过程中可能碰到一些问题:

CMake Warning at 3rdparty/ippicv/downloader.cmake:54 (message):
  ICV: Local copy of ICV package has invalid MD5 hash:
  0103b909e19ca9c6497a7ae696c16480 (expected:
  8b449a536a2157bcad08a2b9f266828b)
Call Stack (most recent call first):
  3rdparty/ippicv/downloader.cmake:108 (_icv_downloader)
  cmake/OpenCVFindIPP.cmake:235 (include)
  cmake/OpenCVFindLibsPerf.cmake:12 (include)
  CMakeLists.txt:526 (include)


-- ICV: Downloading ippicv_linux_20141027.tgz...
CMake Error at 3rdparty/ippicv/downloader.cmake:71 (file):
  file DOWNLOAD HASH mismatch


    for file: [/home/jason/program/opencv-3.0.0/3rdparty/ippicv/downloads/linux-8b449a536a2157bcad08a2b9f266828b/ippicv_linux_20141027.tgz]
      expected hash: [8b449a536a2157bcad08a2b9f266828b]
        actual hash: [0103b909e19ca9c6497a7ae696c16480]


Call Stack (most recent call first):
  3rdparty/ippicv/downloader.cmake:108 (_icv_downloader)
  cmake/OpenCVFindIPP.cmake:235 (include)
  cmake/OpenCVFindLibsPerf.cmake:12 (include)
  CMakeLists.txt:526 (include)

问题的原因是文件下载失败， ippicv_linux_20151201.tgz文件是36M多，失败的时候是只有几M，解决方法：用root权限删掉未下载完的文件，从压缩包拷贝opencv-3.2.0.zip\opencv-3.2.0\3rdparty\ippicv文件夹，重新运行

cmake .

cmake -D WITH_TBB=ON -D BUILD_NEW_PYTHON_SUPPORT=ON -D WITH_V4L=OFF -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON -D BUILD_EXAMPLES=ON .

命令，网速好的情况下多试几次就可以了。

cmake .的时候，出现问题，编译失败，查看错误日志，发现是缺少videodev.h 文件，解决方法：安装libv4后执行

sudo ln -s /usr/include/libv4l1-videodev.h /usr/include/linux/videodev.h