A Collection of existing apriltag library
apriltag_mit - a c++ library from http://people.csail.mit.edu/kaess/apriltags/
apriltag_umich - a c library from http://april.eecs.umich.edu/wiki/index.php/AprilTags
apriltag_ros - a ros node for detecting apriltag. Requires Ubuntu 14 and ROS Indigo or higher.
All of them are catkin pacakges, simply do
catkin_make