Orthogonal cameras system for tracking of laparoscopic instruments in training environments.

Introduction: Motion analysis is a valuable tool for assessment of psychomotor skills in laparoscopy. Nonetheless, it requires technologies for tracking the activity of the laparoscopic instruments during training. This paper presents a sensor-free system to track the movements of laparoscopic instruments based on an orthogonal camera system and video image processing. Methods: The movements of the laparoscopic instruments are tracked with two webcams placed in an orthogonal configuration. The position and orientation in the three-dimensional workspace are obtained using color mantes placed on the tip of the instruments. Results: Accuracy tests show a resolution of 0.14 mm for displacement, with 1694 cm(3) of total workspace, and 0.54 degrees in the angular movements. Mean relative errors of the tracking system were <1%. The orthogonal cameras show high precision, linearity, and repeatability of motion recording of the laparoscopic instruments. Conclusion: The proposed system offers unconstrained manipulation of the instruments and a low-cost alternative for traditional tracking technologies.