Remarks on fuzzy reasoning-based brain activity recognition with a compact near infrared spectroscopy device and its application to robot control interface

This paper presents a method for recognizing the state of a user´s brain activity by applying fuzzy reasoning to signals measured by a two-channel compact near-infrared spectroscopy (NIRS) device and investigates its feasibility and characteristics with regards to developing a compact brain-machine interface that utilizes NIRS. Distance-type fuzzy reasoning with membership functions of a singleton fuzzy number in the antecedent/consequence parts is applied to the oxyhaemoglobin concentration change obtained recorded by the compact NIRS device to recognize active and calm brain activity states. In the experiments in which subjects are assigned the tasks of reading silently to themselves, an average recognition rate of 64% can be achieved by the proposed method. As a practical application of the proposed method, experiments to control a robot arm using brain activity recognition result are conducted. Experimental results indicate that a recognition rate of 70% or higher can be achieved by utilizing a feedback interface that allows users to visually understand the state of their own brain activity even when a user is unfamiliar with the system.