Development of an Angle Measurement System Using Monocular Camera and Moiré Patterns

This paper describes the development of an angle measurement system using a monocular camera. In recent years, the measurement of the angle of a human joint has played an important role in various fields. Particularly, in the area of rehabilitation, measurement results are applied to make a diagnosis based on the condition of the patient; therefore, high accuracy is required. However, the use of such results is limited because systems with sufficient accuracy are expensive and bulky. In the proposed method, we introduce a Moiré pattern that magnifies small angular displacements to compensate for the poor resolution of the camera. We experimentally verified the robustness of the measurement results’ assuming practical use.