  We present a novel control strategy for a team of unmanned aerial vehicles
(UAVs) to autonomously achieve a desired formation using only visual feedback
provided by the UAV's onboard cameras. This effectively eliminates the need for
global position measurements. The proposed pipeline is fully distributed and
encompasses a collision avoidance scheme. In our approach, each UAV extracts
feature points from captured images and communicates their pixel coordinates
and descriptors among its neighbors. These feature points are used in our novel
pose estimation algorithm, QuEst, to localize the neighboring UAVs. Compared to
existing methods, QuEst has better estimation accuracy and is robust to feature
point degeneracies. We demonstrate the proposed pipeline in a high-fidelity
simulation environment and show that UAVs can achieve a desired formation in a
natural environment without any fiducial markers.
