ubuntu18.04安装opencv 2.4.9，全程手册

一.前言

最近在Ubuntu18.04上成功地安装好了opencv2.4.9版本，过程之艰辛自不必说，发现大多数教程都未能全面讲清楚，所以专门在此把我的安装过程和遇到的所有的坑及解决方法写出来分享

二.安装教程

2.1安装前的准备

        建议先把要安装的opencv2.4.9的源码下载下来，然后再放到虚拟机的Ubuntu上，下载网址：

https://sourceforge.net/projects/opencvlibrary/files/opencv-unix/2.4.9/opencv-2.4.9.zip，当然也可以在Ubuntu上用wget命令下载。这里把下载好的源码解压放到Ubuntu主目录下，会看到一个opencv-2.4.9的文件夹。

2.2依赖的安装

        在安装之前需要要一些依赖需要安装，在Ubuntu终端下执行以下指令：

cd
sudo apt-get install build-essential
sudo apt-get install build-essential cmake libgtk2.0-dev pkg-config python-dev python-numpy libavcodec-dev

        执行上诉指令后可能会报错：errorE: unable to locate libjasper-dev，这是因为没有安装这个依赖报，需要执行以下操作：

sudo apt-get install libjaster-dev
sudo add-apt-repository "deb http://security.ubuntu.com/ubuntu xenial-security main"
sudo apt update
sudo apt install libjasper1 libjasper-dev

2.2正式安装

        首先在终端下进入opencv2.4.9目录，建立一个新文件夹build，并进入这个文件夹目录

cd
cd opencv2.4.9
mkdir build
cd build

         在进行下一步操作前需要先去Ubuntu文件管理器找到OpenCVDetectCXXCompiler.cmake文件，路径为：opencv2.4.9/cmake/OpenCVDetectCXXCompiler.cmake，将文件内容替换如下

# ----------------------------------------------------------------------------
# Detect Microsoft compiler:
# ----------------------------------------------------------------------------
if(CMAKE_CL_64)
    set(MSVC64 1)
endif()

if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
  set(CMAKE_COMPILER_IS_GNUCXX 1)
  set(CMAKE_COMPILER_IS_CLANGCXX 1)
endif()
if(CMAKE_C_COMPILER_ID STREQUAL "Clang")
  set(CMAKE_COMPILER_IS_GNUCC 1)
  set(CMAKE_COMPILER_IS_CLANGCC 1)
endif()
if("${CMAKE_CXX_COMPILER};${CMAKE_C_COMPILER}" MATCHES "ccache")
  set(CMAKE_COMPILER_IS_CCACHE 1)
endif()

# ----------------------------------------------------------------------------
# Detect Intel ICC compiler -- for -fPIC in 3rdparty ( UNIX ONLY ):
#  see  include/opencv/cxtypes.h file for related   ICC & CV_ICC defines.
# NOTE: The system needs to determine if the '-fPIC' option needs to be added
#  for the 3rdparty static libs being compiled.  The CMakeLists.txt files
#  in 3rdparty use the CV_ICC definition being set here to determine if
#  the -fPIC flag should be used.
# ----------------------------------------------------------------------------
if(UNIX)
  if  (__ICL)
    set(CV_ICC   __ICL)
  elseif(__ICC)
    set(CV_ICC   __ICC)
  elseif(__ECL)
    set(CV_ICC   __ECL)
  elseif(__ECC)
    set(CV_ICC   __ECC)
  elseif(__INTEL_COMPILER)
    set(CV_ICC   __INTEL_COMPILER)
  elseif(CMAKE_C_COMPILER MATCHES "icc")
    set(CV_ICC   icc_matches_c_compiler)
  endif()
endif()

if(MSVC AND CMAKE_C_COMPILER MATCHES "icc|icl")
  set(CV_ICC   __INTEL_COMPILER_FOR_WINDOWS)
endif()

# ----------------------------------------------------------------------------
# Detect GNU version:
# ----------------------------------------------------------------------------
if(CMAKE_COMPILER_IS_CLANGCXX)
  set(CMAKE_GCC_REGEX_VERSION "4.2.1")
  set(CMAKE_OPENCV_GCC_VERSION_MAJOR 4)
  set(CMAKE_OPENCV_GCC_VERSION_MINOR 2)
  set(CMAKE_OPENCV_GCC_VERSION 42)
  set(CMAKE_OPENCV_GCC_VERSION_NUM 402)

  execute_process(COMMAND ${CMAKE_CXX_COMPILER} ${CMAKE_CXX_COMPILER_ARG1} -v
                  ERROR_VARIABLE CMAKE_OPENCV_CLANG_VERSION_FULL
                  ERROR_STRIP_TRAILING_WHITESPACE)

  string(REGEX MATCH "version.*$" CMAKE_OPENCV_CLANG_VERSION_FULL "${CMAKE_OPENCV_CLANG_VERSION_FULL}")
  string(REGEX MATCH "[0-9]+\\.[0-9]+" CMAKE_CLANG_REGEX_VERSION "${CMAKE_OPENCV_CLANG_VERSION_FULL}")

elseif(CMAKE_COMPILER_IS_GNUCXX)
  execute_process(COMMAND ${CMAKE_CXX_COMPILER} ${CMAKE_CXX_COMPILER_ARG1} -dumpversion
                OUTPUT_VARIABLE CMAKE_OPENCV_GCC_VERSION_FULL
                OUTPUT_STRIP_TRAILING_WHITESPACE)

  execute_process(COMMAND ${CMAKE_CXX_COMPILER} ${CMAKE_CXX_COMPILER_ARG1} -v
                ERROR_VARIABLE CMAKE_OPENCV_GCC_INFO_FULL
                OUTPUT_STRIP_TRAILING_WHITESPACE)

  # Typical output in CMAKE_OPENCV_GCC_VERSION_FULL: "c+//0 (whatever) 4.2.3 (...)"
  # Look for the version number, major.minor.build
  string(REGEX MATCH "[0-9]+\\.[0-9]+\\.[0-9]+" CMAKE_GCC_REGEX_VERSION "${CMAKE_OPENCV_GCC_VERSION_FULL}")
  if(NOT CMAKE_GCC_REGEX_VERSION)#major.minor
    string(REGEX MATCH "[0-9]+\\.[0-9]+" CMAKE_GCC_REGEX_VERSION "${CMAKE_OPENCV_GCC_VERSION_FULL}")
  endif()

  if(CMAKE_GCC_REGEX_VERSION)
    # Split the parts:
    string(REGEX MATCHALL "[0-9]+" CMAKE_OPENCV_GCC_VERSIONS "${CMAKE_GCC_REGEX_VERSION}")

    list(GET CMAKE_OPENCV_GCC_VERSIONS 0 CMAKE_OPENCV_GCC_VERSION_MAJOR)
    list(GET CMAKE_OPENCV_GCC_VERSIONS 1 CMAKE_OPENCV_GCC_VERSION_MINOR)
  else()#compiler returned just the major version number
    string(REGEX MATCH "[0-9]+" CMAKE_GCC_REGEX_VERSION "${CMAKE_OPENCV_GCC_VERSION_FULL}")
    if(NOT CMAKE_GCC_REGEX_VERSION)#compiler did not return anything reasonable
      set(CMAKE_GCC_REGEX_VERSION "0")
      message(WARNING "GCC version not detected!")
    endif()
    set(CMAKE_OPENCV_GCC_VERSION_MAJOR ${CMAKE_GCC_REGEX_VERSION})
    set(CMAKE_OPENCV_GCC_VERSION_MINOR 0)
  endif()

  set(CMAKE_OPENCV_GCC_VERSION ${CMAKE_OPENCV_GCC_VERSION_MAJOR}${CMAKE_OPENCV_GCC_VERSION_MINOR})
  math(EXPR CMAKE_OPENCV_GCC_VERSION_NUM "${CMAKE_OPENCV_GCC_VERSION_MAJOR}*100 + ${CMAKE_OPENCV_GCC_VERSION_MINOR}")
  message(STATUS "Detected version of GNU GCC: ${CMAKE_OPENCV_GCC_VERSION} (${CMAKE_OPENCV_GCC_VERSION_NUM})")

  if(WIN32)
    execute_process(COMMAND ${CMAKE_CXX_COMPILER} -dumpmachine
              OUTPUT_VARIABLE OPENCV_GCC_TARGET_MACHINE
              OUTPUT_STRIP_TRAILING_WHITESPACE)
    if(OPENCV_GCC_TARGET_MACHINE MATCHES "amd64|x86_64|AMD64")
      set(MINGW64 1)
    endif()
  endif()
endif()

if(MSVC64 OR MINGW64)
  set(X86_64 1)
elseif(MINGW OR (MSVC AND NOT CMAKE_CROSSCOMPILING))
  set(X86 1)
elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "amd64.*|x86_64.*|AMD64.*")
  set(X86_64 1)
elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "i686.*|i386.*|x86.*|amd64.*|AMD64.*")
  set(X86 1)
elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(arm.*|ARM.*)")
  set(ARM 1)
elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(aarch64.*|AARCH64.*)")
  set(AARCH64 1)
endif()

# Workaround for 32-bit operating systems on 64-bit x86_64 processor
if(X86_64 AND CMAKE_SIZEOF_VOID_P EQUAL 4 AND NOT FORCE_X86_64)
  message(STATUS "sizeof(void) = 4 on x86 / x86_64 processor. Assume 32-bit compilation mode (X86=1)")
  unset(X86_64)
  set(X86 1)
endif()

# Similar code exists in OpenCVConfig.cmake
if(NOT DEFINED OpenCV_STATIC)
  # look for global setting
  if(NOT DEFINED BUILD_SHARED_LIBS OR BUILD_SHARED_LIBS)
    set(OpenCV_STATIC OFF)
  else()
    set(OpenCV_STATIC ON)
  endif()
endif()

if(MSVC)
  if(CMAKE_CL_64)
    set(OpenCV_ARCH x64)
  elseif((CMAKE_GENERATOR MATCHES "ARM") OR ("${arch_hint}" STREQUAL "ARM") OR (CMAKE_VS_EFFECTIVE_PLATFORMS MATCHES "ARM|arm"))
    # see Modules/CmakeGenericSystem.cmake
    set(OpenCV_ARCH ARM)
  else()
    set(OpenCV_ARCH x86)
  endif()
  if(MSVC_VERSION EQUAL 1400)
    set(OpenCV_RUNTIME vc8)
  elseif(MSVC_VERSION EQUAL 1500)
    set(OpenCV_RUNTIME vc9)
  elseif(MSVC_VERSION EQUAL 1600)
    set(OpenCV_RUNTIME vc10)
  elseif(MSVC_VERSION EQUAL 1700)
    set(OpenCV_RUNTIME vc11)
  elseif(MSVC_VERSION EQUAL 1800)
    set(OpenCV_RUNTIME vc12)
  elseif(MSVC_VERSION EQUAL 1900)
    set(OpenCV_RUNTIME vc14)
  elseif(MSVC_VERSION EQUAL 1910)
    set(OpenCV_RUNTIME vc15)
  endif()
elseif(MINGW)
  set(OpenCV_RUNTIME mingw)

  if(MINGW64)
    set(OpenCV_ARCH x64)
  else()
    set(OpenCV_ARCH x86)
  endif()
endif()

 这一步操作主要是避免cmake命令后的一些不兼容性报错，如：

        然后进行cmake操作，生成Makefile文件，此时中断是在build目录下，后面加的那条指令是为了避免后面make编译的一个报错

sudo cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D INSTALL_PYTHON_EXAMPLES=ON -D OPENCV_EXTRA_MODULES_PATH=/opencv-2.4.9/modules -D BUILD_EXAMPLES=ON -DENABLE_PRECOMPILED_HEADERS=OFF.. -DENABLE_PRECOMPILED_HEADERS=OFF

一般看到如下图所示的结果输出就是成功了：

         然后进行make操作编译：

sudo make

        期间会遇到一些报错，如下图：

 解决办法：找到opencv-2.4.9/build/modules/contrib/CMakeFiles/opencv_contrib.dir/flags.make文件，删掉-Werror=address，然后重新 sudo make

或者如下报错：error: the compiler can assume that the address of ‘annotate_img’ will never be NULL [-Werror=address]

解决方法：找到opencv-2.4.9/build/modules/contrib/CMakeFiles/opencv_contrib.dir/flags.make文件，删掉-Werror=address，然后重新sudo make

        一般到这就编译好了，接下来就是安装：

sudo make install

安装完成后还需要进行环境变量配置

三.配置lib库路径和环境变量

 3.1配置lib库路径

cd

sudo gedit　/etc/ld.so.conf.d    (在弹出的窗口中添加如下一段文字：/usr/local/lib)

sudo ldconfig (使得配置生效)

 3.2环境变量

sudo gedit /etc/bash.bashrc
(在弹出的窗口中添加 
PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig 
export PKG_CONFIG_PATH 
)

 最后可以在Ubuntu上进入python看看是否成功了。

 如果在python2中可以正常导入，但是python3中不能，执行如下指令：

pip install opencv-python

最最后，如果遇到了本人未提及的问题，可以粘贴错误输出搜索解决方法，一般都能找到