A low-cost system for capturing and analyzing the motion of aquatic organisms

Capture and quantitative analysis of the motion of organisms is a powerful tool that can be used in diverse biological. fields including physiology, behavior, kinematics, and ecology. A number of high-end commercial motion capture and analysis systems that offer a wide array of features and image capture and analysis capabilities are available. However, few, if any, such systems are low cost and could be used for projects with small budgets or by researchers interested in collecting pilot data before upgrading to an expensive motion capture and analysis system. Our paper describes a low-cost (<$US1000, not including the cost of the computer) motion capture and analysis system that simultaneously captures live video from 5 digital video cameras (Unibrain Fire-i FireWire [IEEE 1394]) using standard security camera software (SecuritySpy 1.3.1). The video analyses are carried out using a combination of standard spreadsheet software (Microsoft Excel) and a freeware image-analysis program (NIH Image J), with one of the available particle-tracking plugins. Tests using New Zealand mudsnails (Potamopyrgus antipodarum) demonstrated that the system could record and accurately track the movement of small (4 mm) targets. Recommendations for designing similar project-specific systems are provided.