  The use of autonomous UAVs for surveillance purposes and other reconnaissance
tasks is increasingly becoming popular and convenient.These tasks requires the
ability to successfully ingress through the rectangular openings or windows of
the target structure.In this paper, a method to robustly detect the window in
the surrounding using basic image processing techniques and efficient distance
measure, is proposed.Furthermore, a navigation scheme which incorporates this
detection method for performing navigation task has also been proposed.The
whole navigation task is performed and tested in the simulation environment
GAZEBO.
