Simultaneous Optimization of Structure and Motion in Dynamic Scenes Using Unsynchronized Stereo Cameras

Akihito Seki, Masatoshi Okutomi

Abstract: In this paper, we propose a simultaneous estimation method of structure and motion in dynamic scenes. Usual methods for obtaining structure and motion using stereo cameras require two kinds of operations: stereo correspondence and tracking. Therefore, we must separately determine the correspondence between stereo images and sequential images. This necessity complicates the algorithm and increases the possibility of mismatches because of the object's motion and visibility change in the images. Our proposed method makes two contributions. The first contribution is the method of corresponding all stereo images and sequential images at once. Therefore, we can obtain the structure and motion simultaneously and more accurately. On the other hand, most stereo correspondence algorithms are limited to use under a synchronized status. In a stereo rig using unsynchronized cameras, as are most commercially available cameras, the structure cannot be obtained by stereo correspondence and triangulation because of the unknown time offset between cameras. Therefore, our second contribution is a method of estimating structure, motion, and time offset simultaneously using unsynchronized stereo cameras. This latter task is accomplished by taking advantage of the first contribution scheme. Additionally, our method requires no preprocessing such as motion segmentation for separating identical-motion objects and advance calibration of the time offset. Finally, we present the experimental results using both synthetic and real images.