opencv3在CMakeLists.txt中的调用问题

在cmake工程中使用opencv需要在CMakeLists.txt文件中加以调用，在opencv2.xx版本，可以用以下语句

# 寻找OpenCV库
find_package( OpenCV REQUIRED )
 
# 添加头文件
include_directories(  ${OpenCV_INCLUDE_DIRS}  )

add_executable( xxx xxx.cpp )

# 链接OpenCV库
target_link_libraries( xxx ${OpenCV_LIBS}  )

但如果你使用的是OpenCV 3.x版本，再用上面的方法就会报错

CMake Warning at /home/zn/opencv-3.1.0/cmake/OpenCVConfig.cmake:166 (message):
  Found OpenCV Windows Pack but it has no binaries compatible with your
  configuration.

  You should manually point CMake variable OpenCV_DIR to your build of OpenCV
  library.
Call Stack (most recent call first):
  CMakeLists.txt:11 (find_package)


CMake Error at CMakeLists.txt:11 (find_package):
  Found package configuration file:

    /home/zn/opencv-3.1.0/cmake/OpenCVConfig.cmake

  but it set OpenCV_FOUND to FALSE so package "OpenCV" is considered to be
  NOT FOUND.


-- Configuring incomplete, errors occurred!

从上面的报错可以看出在OpenCVConfig.cmake文件中设置OpenCV_FOUND to FALSE，故find_package( OpenCV REQUIRED )是不可用的。我认为这是opencv3.x版本对opencv2.x版本的屏蔽，以防混用。要使用opencv3.x需要用如下语句

# 寻找OpenCV库  我的版本的opencv3.1.0
find_package( OpenCV 3.1  REQUIRED ) 
 
# 添加头文件
include_directories(  ${OpenCV_INCLUDE_DIRS}  )

add_executable( xxx xxx.cpp )

# 链接OpenCV库
target_link_libraries( xxx ${OpenCV_LIBS}  )

也就是要加上opencv对应的版本号就可以解决报错了。