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.