cmake find_package（OpenCV）总是使用OpenCV 2.4，即使我指定PATHS到OpenCV 3.3

Question

我想通过CMakeLists.txt使用OpenCV 3，CMakeLists.txt如下：

set(OpenCV_ROOT /usr/local/opencv3)
set(OpenCV_INCLUDE_DIRS ${OpenCV_ROOT}/include)
set(OpenCV_LIBRARIES "${OpenCV_ROOT}/lib")
message("find ${OpenCV_INCLUDE_DIRS}")
.....
include_directories(${OpenCV_INCLUDE_DIRS}) 
target_link_libraries(main ${OpenCV_LIBRARIES})

    在以下位置找到OpenCV：/ usr / local / include / opencv; / usr / local / include

但是OpenCV 3的路径是/ usr / local / opencv3。看起来 指定的路径不起作用，CMakeLists.txt使用默认的opencv 2.4而不是OpenCV 3.

 如何解决这个问题呢？我整天都在努力。