opencv - CMake搜索OpenCV库

Question

我已经安装了Opencv-3.2，可以看到bin和lib文件

$ ls /share/apps/computer/opencv-3.2.0/built/bin/opencv_
opencv_annotation     opencv_createsamples  opencv_traincascade     opencv_version        opencv_visualisation
$ ls /share/apps/computer/opencv-3.2.0/built/lib/
libopencv_calib3d.so           libopencv_imgcodecs.so.3.2.0   libopencv_stitching.so.3.2
libopencv_calib3d.so.3.2       libopencv_imgproc.so           libopencv_stitching.so.3.2.0
libopencv_calib3d.so.3.2.0     libopencv_imgproc.so.3.2       libopencv_superres.so
libopencv_core.so              libopencv_imgproc.so.3.2.0     libopencv_superres.so.3.2
libopencv_core.so.3.2          libopencv_ml.so                libopencv_superres.so.3.2.0
libopencv_core.so.3.2.0        libopencv_ml.so.3.2            libopencv_videoio.so
libopencv_features2d.so        libopencv_ml.so.3.2.0          libopencv_videoio.so.3.2
libopencv_features2d.so.3.2    libopencv_objdetect.so         libopencv_videoio.so.3.2.0
libopencv_features2d.so.3.2.0  libopencv_objdetect.so.3.2     libopencv_video.so
libopencv_flann.so             libopencv_objdetect.so.3.2.0   libopencv_video.so.3.2
libopencv_flann.so.3.2         libopencv_photo.so             libopencv_video.so.3.2.0
libopencv_flann.so.3.2.0       libopencv_photo.so.3.2         libopencv_videostab.so
libopencv_highgui.so           libopencv_photo.so.3.2.0       libopencv_videostab.so.3.2
libopencv_highgui.so.3.2       libopencv_shape.so             libopencv_videostab.so.3.2.0
libopencv_highgui.so.3.2.0     libopencv_shape.so.3.2         pkgconfig/
libopencv_imgcodecs.so         libopencv_shape.so.3.2.0
libopencv_imgcodecs.so.3.2     libopencv_stitching.so

现在，根据 tutorial，我编写了一个简单的程序。问题是， cmake出现一些错误，似乎无法找到该库。

CMake Error at CMakeLists.txt:3 (find_package):
  By not providing "FindOpenCV.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "OpenCV", but
  CMake did not find one.

  Could not find a package configuration file provided by "OpenCV" with any
  of the following names:

    OpenCVConfig.cmake
    opencv-config.cmake

  Add the installation prefix of "OpenCV" to CMAKE_PREFIX_PATH or set
  "OpenCV_DIR" to a directory containing one of the above files.  If   "OpenCV"
  provides a separate development package or SDK, be sure it has been
  installed.

我不知道如何设置 CMAKE_PREFIX_PATH或 OpenCV_DIR。我该如何解决？

CMakeLists.txt的内容是

cmake_minimum_required(VERSION 2.8)
project( DisplayImage )
find_package( OpenCV REQUIRED )
add_executable( DisplayImage DisplayImage.cpp )
target_link_libraries( DisplayImage ${OpenCV_LIBS} )

Answer 1

这取决于您是否具有OpenCVConfig.cmake脚本，该脚本随OpenCV的安装一起提供(即，在安装目录/share/apps/computer/opencv-3.2.0/built/下)。

如果您安装的OpenCV 缺少OpenCVConfig.cmake脚本的，则需要使用脚本FindOpenCV.cmake运送您的项目(查找并从网上复制它，几乎任何一种都适用)，并将带有此脚本的目录添加到CMAKE_MODULE_PATH变量中:

list(APPEND CMAKE_MODULE_PATH <directory-with-find-script>)

提示CMake有关您的OpenCV安装的可能方法:

如果您具有OpenCVConfig.cmake脚本，请将OpenCV_DIR变量设置为包含此脚本的目录:

cmake -DOpenCV_DIR=/share/apps/computer/opencv-3.2.0/built/<...>

将CMAKE_PREFIX_PATH变量设置为OpenCV的安装前缀:

cmake -DCMAKE_PREFIX_PATH=/share/apps/computer/opencv-3.2.0/built

这适用于OpenCVConfig.cmake和FindOpenCV.cmake脚本。另请参见该问题:Hinting Find<name>.cmake Files with a custom directory。