ACCURACY OF THE SOFTWARE GENLOCK WITH DIGITAL CAMCORDERS

Abstract

Recently, digital camcorders have gained popularity as a viable means of recording movements in video motion analysis, mainly due to the ease of use and reasonably high image resolution. Digital camcorders, however, suffer from a major drawback, lack of the hardware genlock capability. Camcorders thus operate independently from each other and introduce time offsets among themselves. These time offsets in turn violate the requirement of simultaneous observations from multiple cameras in the 3·D analysis, producing erroneous real-life coordinates of the markers. This is especially true in fast motions, in which a small time offset can be translated into a large spatial error, and the time offsets must be corrected before the 3-D reconstruction. The genlock (synchronization) of the cameras can be potentially achieved by a software-based strategy, the software genlock. The purpose of this stUdy was to investigate the accuracy of the software genlock using digital camcorders.