Exploiting HD camcorders for close-up human movement applications

Abstract

Lately, the cost of HD video camcorders has decreased greatly and the inclusion of an internal hard disk in many models has eased the bother of downloading video clips from cumbersome tape devices. These factors have increased their potential as 3D recording devices and measurement tools for the health monitoring of patients by practitioners. This investigation determined: (1) the 3D measurement quality of off-the-shelf high definition camcorders for human-movement-related medical applications; (2) the suitability of a low-cost LED synchronisation device for multi-camcorder tracking; and (3) the suitability of these imaging sensors for practitioners. The results show that a four-camcorder system is capable of measuring a 3D distance in a static setting to better than 0Æ050mm; it can track a moving calibrated square-wave signal of 0Æ5 and 1 Hz to better than 0Æ3 and 0Æ2mm, respectively. Using a calibrated scale bar mounted on a moving human leg, the error produced as a result of frame disparity using a low-cost LED frame-synchronising device was under 0Æ3mm for a four-, three- and two-camcorder configuration.