Hi,
I am on Ubuntu 16.04 (clean install) following this tutorial . Instead of 3.1.0 I tried to install 3.4.6 which did not work, because the Non-free algorithms are not being included. I again tried with version 3.4.4 which again did not work.
Here is a screenshot of the CMAKE output:
The CMAKE command I use:
cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D INSTALL_C_EXAMPLES=OFF \
-D OPENCV_ENABLE_NONFREE=ON \
-D OPENCV_EXTRA_MODULES_PATH=/home/gertjan/opencv_contrib-3.4.4/modules \
-D BUILD_EXAMPLES=ON ..
I need the non-free algortihms for the use of SIFT.