A Two-Layer 3-D Reconstruction Method and Calibration for Multicamera-Based Volumetric Positioning and Characterization

A 3-D reconstruction method and multicamera calibration using multiple artificial reference markers have been used for precise volumetric surveillance of fast-flying objects. The method uses a two-layer 3-D reconstruction that integrates two multicamera stereo nodes. The fields of view of stereo nodes are directed at an acute angle to each other to provide greater coverage with the given constraints and to determine the flight characteristics of objects in 3-D. The object's flight reconstruction includes a “rough” estimation of its positions relative to selected artificial reference points in both stereo nodes separately and subsequent “refinement” of calculated positions. In this article, we describe the proposed method and calibration technique using a multicamera system to measure the object characteristics in 3-D. The proposed method applies to volumetric surveillance in situations where it is necessary to count, track, and analyze the activities of flying objects, especially birds, using high spatial resolution.