Conics-enhanced vision approach for easy and low-cost 3D tracking

Abstract

This paper presents a conics-enhanced vision approach for low-cost and easy-to-operate 3D tracking. The idea is to use paper disks as markers and recover the 3D positions of these paper disks by a property of conics: the 3D rotation and translation information of a planar circle with known radius could be recovered from its elliptic projection in one image (Int. J. Comput. Vision 10(1) (1993) 7). This property implies that tracking a paper disk in 3D could be done by tracking its elliptic projection in a sequence of 2D images. Since ellipse tracking has to consider many factors such as occlusion, background, light and so on, it is difficult to develop a general algorithm that works for all situations. In this paper, we discuss algorithms for two types of ellipse tracking: real-time tracking of single, non-occluded ellipse and off-line tracking of multiple ellipses. They are used to develop a real-time tracker to control the camera movement in a virtual environment and a multiple-tracker system that works off-line to acquire human motion data to animate a 3D human model. Implementation details and experimental results of the tracking systems are presented. The proposed 3D tracking approach is valuable for applications where accuracy and speed are not very critical but affordability and operational ease are most concerned, e.g., the educational-purpose virtual environments for kids.