需要用到ｏｐｅｎｃｖ依赖库的CMakeLists注意事项

1、find_package(OpenCV REQUIRED)中的OpenCV一定要遵循该大小写。

　　该句话是根据OpenCV作为前缀自动去/usr/local/share/OpenCV（如果你的opencv安装时，默认前缀设置为：/usr/local时）文件夹中去找OpenCVConfig.cmake，OpenCV-config.cmake 两个文件，进而确定你要引入的opencv头文件和库函数在哪里。

2、自定义引入相应opencv版本

　　如果你有很多的opencv版本，尤其是一个是opencv2.x.x一个是opencv3.x.x，因为2和3在数据结构上有相对较大的变化，所以如果引入错误的版本可能导致程序的无法运行。因为find_package找默认路径下的OpenCV，但是很多时候安装多个版本的库的时候都会make install在opt目录下。、

　　安装在opt的文件中会有share文件夹，这里面就有咱们需要的ＯｐenCV文件夹，所以如果要自己有选择的控制版本，则在find_package这句话前面去设置opencv的ＯpenCV文件夹在哪里，添加set(OpenCV_DIR /opt/opencv-2.4.11/share/OpenCV)这句话。因为我的opencv2.4.11版本install在/opt/opencv-2.4.11文件夹下。这个可以根据你install的位置去变化。

# cmake needs this line
cmake_minimum_required(VERSION 2.8)

# Define project name
project(opencvTest)

# Find OpenCV, you may need to set OpenCV_DIR variable
# to the absolute path to the directory containing OpenCVConfig.cmake file
# via the command line or GUI
find_package(OpenCV REQUIRED)

# If the package has been found, several variables will
# be set, you can find the full list with descriptions
# in the OpenCVConfig.cmake file.
# Print some message showing some of them
message(STATUS "OpenCV library status:")
message(STATUS "    version: ${OpenCV_VERSION}")
message(STATUS "    libraries: ${OpenCV_LIBS}")
message(STATUS "    include path: ${OpenCV_INCLUDE_DIRS}")

# Add OpenCV headers location to your include paths
include_directories(${OpenCV_INCLUDE_DIRS})

# Declare the executable target built from your sources
add_executable(main main.cpp)

# Link your application with OpenCV libraries
target_link_libraries(main ${OpenCV_LIBS})

如果多处编译需要依赖库，则需要给路径，ｓｅｔ一下
# ===================================================================================
#  The OpenCV CMake configuration file
#
#             ** File generated automatically, do not modify **
#
#  Usage from an external project:
#    In your CMakeLists.txt, add these lines:
#
#    FIND_PACKAGE(OpenCV REQUIRED)
#    TARGET_LINK_LIBRARIES(MY_TARGET_NAME ${OpenCV_LIBS})
#
#    Or you can search for specific OpenCV modules:
#
#    FIND_PACKAGE(OpenCV REQUIRED core highgui)
#
#    If the module is found then OPENCV_<MODULE>_FOUND is set to TRUE.
#
#    This file will define the following variables:
#      - OpenCV_LIBS                     : The list of all imported targets for OpenCV modules.
#      - OpenCV_INCLUDE_DIRS             : The OpenCV include directories.
#      - OpenCV_COMPUTE_CAPABILITIES     : The version of compute capability
#      - OpenCV_ANDROID_NATIVE_API_LEVEL : Minimum required level of Android API
#      - OpenCV_VERSION                  : The version of this OpenCV build: "2.4.8"
#      - OpenCV_VERSION_MAJOR            : Major version part of OpenCV_VERSION: "2"
#      - OpenCV_VERSION_MINOR            : Minor version part of OpenCV_VERSION: "4"
#      - OpenCV_VERSION_PATCH            : Patch version part of OpenCV_VERSION: "8"
#      - OpenCV_VERSION_TWEAK            : Tweak version part of OpenCV_VERSION: "0"
#
#    Advanced variables:
#      - OpenCV_SHARED
#      - OpenCV_CONFIG_PATH
#      - OpenCV_INSTALL_PATH  (not set on Windows)
#      - OpenCV_LIB_COMPONENTS
#      - OpenCV_USE_MANGLED_PATHS
#      - OpenCV_HAVE_ANDROID_CAMERA
#
# ===================================================================================