Motion estimation using multiple non-overlapping cameras for small unmanned aerial vehicles

An imaging sensor made of multiple light-weight non-overlapping cameras is an effective sensor for a small unmanned aerial vehicle that has strong payload limitation. This paper presents a method for motion estimation by assuming that such a multi-camera system is a spherical imaging system (that is, the cameras share a single optical center). We derive analytically and empirically a condition for a multi-camera system to be modeled as a spherical camera. Interestingly, not only does the spherical assumption simplify the algorithms and calibration procedure, but also motion estimation based on that assumption becomes more accurate.