Tracking Rotation and Translation of Laser Microsurgical Instruments

An accurate optical sensing system has been developed to measure the position and orientation of a laser beam in two dimensions. The system is useful for evaluation of the accuracy of hand-held laser microsurgical instruments. The apparatus uses a lens and a beam-splitter to receive the incoming laser beam. Two position sensitive detectors placed at different distances from the beam splitter make it possible to rapidly and accurately calculate the position and orientation of the axis of the laser. II. METHODOLOGY A. System development Keywords—Microsurgery, accuracy, optical sensing, position sensitive detector, angular measurement, tremor The primary elements in MADRID are optical sensors to track the laser beam. While CCD cameras could be used, this option is costly due to the two high-frame-rate and highresolution digital cameras and frame grabbers needed. As an alternative, PSDs offer high accuracy, high frequency response, and lower cost. They provide analog output, thus avoiding issues of pixel resolution, and are best suited to tracking a single light spot, such as in this application.