The library itself is independent of ROS, so it is built outside ROS catkin. There are wrappers for ROS (https://github.com/strands-project/v4r_ros_wrappers), which can then be placed inside the normal catkin workspace.

stated in package.xml There are two options to use the SIFT recognizer:

• Use V4R third party library SIFT GPU (this requires a decent GPU - see www.cs.unc.edu/~ccwu/siftgpu) [default]
• Use OpenCV non-free SIFT implementation (this requires the non-free module of OpenCV - can be installed from source). This option is enabled if BUILD_SIFTGPU is disabled in cmake.

In order to use V4R in ROS, use the v4r_ros_wrappers.

simply install sudo apt-get install ros-indigo-v4r after enabling the STRANDS repositories.

cd ~/somewhere
git clone 'https://github.com/strands-project/v4r'
cd v4r
mkdir build
cd build
cmake ..
make
sudo make install (optional)