Cooperative Targeting: Detection and Tracking of Small Objects with a Dual Camera System

Surveillance of a scene with computer vision faces the challenge of meeting two competing design objectives simultaneously: maintain a sufficient field-of-view coverage and provide adequate details of a target object if and when it appears in the scene. In this paper we propose a dual-camera system for tracking small objects based on a stationary camera and a pantilt- zoom (PTZ) camera. The utilization of two cameras enables us to detect a small object with the stationary camera while tracking it with the second moving camera. We present a method for modeling the dual-camera system and demonstrate how the model can be used in object detection and tracking applications. The main contribution of this paper is that we provide a model for explicitly computing the extrinsic parameters of the PTZ camera with respect to the stationary camera in order to target the moving camera at an object that has been detected by the stationary camera. Our mathematical model combines stereo calibration and hand-eye calibration algorithms as well as the kinematics of the pan-tilt unit, in order for the two cameras to collaborate. We present experimental results of our model in indoor and outdoor applications. The results prove that our dual camera system is an effective solution to the problem of detecting and tracking a small object with both excellent scene coverage and object details.