A new optical technique to monitor joint motion using position sensitive detector.

<bold>Background: </bold>Evaluation of joint movements is essential to choose an appropriate rehabilitation protocol for a patient.<bold>Objective: </bold>The aim of this study is to suggest an alternative optical technique for measurement of joint angle which is convenient, inexpensive, and can be operated in real time.<bold>Methods: </bold>According to the principle of the triangulation method, position sensitive detector (PSD) converts reflected light signals into distance-related voltages. Various parameters were investigated to increase detection range and resolution of joint angle measurements.<bold>Results: </bold>The accuracy of the suggested optical sensor was verified by comparing with a commercial goniometer and 3D motion capture system.<bold>Conclusions: </bold>This method can be applied to monitor recovery progress for the patient in rehabilitation and sport science. [ABSTRACT FROM AUTHOR]