[CMake] Using different installs/versions of the OpenCV library

[Bart Vandewoestyne]

Hello list,

To compile and link my code with the OpenCV library, I use

find_package( OpenCV REQUIRED )
...
add_executable(framecountertest framecountertest.cpp)
target_link_libraries(framecountertest ${OpenCV_LIBS})

and this works just fine: the OpenCV library that got installed using my 
package management system on Ubuntu 12.10 is being used.

However, under the directory /tmp/opencv_install I have another manual 
installation of a more recent OpenCV library, and I would like to use 
that one instead of the default on my system, or easily switch between 
the two versions.  How should I specify that in my CMakeLists.txt file? 
  I have tried

set(OpenCV_FOUND "1")
set(OpenCV_INCLUDE_DIR 
"/home/bart/Git/Research/fat/inc/TraficonOpenCv/opencv")
set(OpenCV_LIBS 
"opencv_gpu;opencv_contrib;opencv_legacy;opencv_objdetect;opencv_calib3d;opencv_features2d;opencv_video;opencv_highgui;opencv_ml;opencv_imgproc;opencv_flann;opencv_core")
include_directories(${OpenCV_INCLUDE_DIR})
...
add_executable(framecountertest framecountertest.cpp)
target_link_libraries(framecountertest ${OpenCV_LIBS})

but even with these commands, still the default libs on my system are 
being used...

What is the correct way to specify that I want to build with the install 
under /tmp/opencv_install ?  And how can I easily switch between 
versions without needing to remove one or the other version?

Thanks!
Bart