An inexpensive stereo-image capture tool for motion study

Abstract

This paper discusses the evaluation of a video stereo-image capture tool for photogrammetric applications. The 'NuView Adapter', a commonly available video-image splitting device, and a digital video camera (DV) could be used to capture stereoscopic video footage for many photogrammetric applications in which low-cost near-simultaneous stereo-images are required for 3D viewing or for 3D spatial data capture. Relevant photogrammetric applications might include: aerial surveillance, human/animal motion study (tracking), bank/security surveillance and precise 3D animation. The device permits two distinct views (left and right perspective views) to enter a single lens DV. A single convergence control in the device allows the user to obtain a stereo view of near and far objects. The system is easy to operate and the stereo-images give a good visual 3D effect. Research was carried out to determine the quality of the stereo-image for 3D measurement. The investigation involved: (1) the calibration of a customised system for optimum close range photogrammetric application; and (2) a case study involving motion tracking. A semi-automated monodigitising photogrammetric technique was used to determine the accuracy of the system. The results show that this system could achieve a spatial data accuracy of better than 13 mm at an object distance of 9 m. The horizontal and vertical accuracies are similar to those obtained by the conventional stereoscopic camera technique using a ''normal case'' configuration with 86% overlap