ubuntu opencv的使用

博客转载自：https://blog.csdn.net/u012816621/article/details/51732932

CMakeLists.txt

# 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
#set(OpenCV_DIR *****)
find_package(OpenCV REQUIRED)
add_definitions(${OpenCV_DEFINITIONS})
 
# 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})

【注意事项】

1、find_package(OpenCV REQUIRED)中的OpenCV一定要遵循该大小写。 
因为该句话是根据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。