High Frequency 3D Reconstruction from Unsynchronized Multiple Cameras

Stereo reconstruction generally requires image correspondence such as point and line correspondences in multiple images. Cameras need to be synchronized to obtain corresponding points of time-varying shapes. However, the image information obtained from synchronized multiple cameras is redundant, and has limitations with resolution. In this paper, we show that by using a set of unsynchronized cameras instead of synchronized one, we can obtain much more information on 3D motions, and can reconstruct higher frequency 3D motions than that with the standard synchronized cameras. As a result, we can attain super resolution 3D reconstruction from unsynchronized cameras. In the standard reconstruction with multiple cameras, the cameras are synchronized, and observe the same set of M sequential points in 3D space as shown in Fig. 1 (a). Thus, the maximum frequency fS of 3D motion, which can be recovered from camera images, is fS < 1 2 M. If we observe the same 3D motion by using K unsynchronized cameras, we observe K×M different points in the 3D space as shown in Fig. 1 (b). As a result, all the 2KM observations from K cameras are independent of one another, unlike those from the synchronized cameras. Thus, we have a possibility of reconstructing 3D points up to 2 3 KM. Therefore, the maximum frequency fU of recoverable 3D motion is fU < 1 3 KM. Thus, we find that the unsynchronized cameras have a possibility of reconstructing 3 K times higher frequency 3D motion than the synchronized cameras as follows: