Spherical approximation for multiple cameras in motion estimation: Its applicability and advantages
Estimating motions of a multi-camera system which may not have overlapping fields of view is generally complex and computationally expensive because of the non-zero offset between each cameras center. It is conceivable that if we can assume that multiple cameras share a single optical center, and thus can be modeled as a spherical imaging system, motion estimation and calibration of this system would become simpler and more efficient. In this paper, we analytically and empirically derive the conditions under which a multi-camera system can be modeled as a single spherical camera. Various analyses and experiments using simulated and real images show that spherical approximation is applicable to a surprisingly larger extent than currently expected. Moreover, we show that, when applicable, this approximation even results in improvements in accuracy and stability of estimated motion over the exact algorithm.
spherical approximation multiple cameras camera motion estimation camera calibration structure from motion