Want to build some necessary Libraries for feature detection. Got some error. At first, I tried
$ cmake -DOPENCV_EXTRA_MODULES_PATH=~/Desktop/opencv_contrib-master/
and I got error message
FATAL: In-source builds are not allowed. You should create a separate directory for build files.
So, I've followed "In-source builds are not allowed" in cmake
cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/home/Desktop/opencv_contrib-master
but still got error message
CMake Error: The source directory "/home/ryucaps/opencv" does not appear to contain CMakeLists.txt. Specify --help for usage, or press the help button on the CMake GUI.
Can't figure out what's going on. I only wanted to import some libraries that i don't have yet on my code.