A Fundamental Study on an Input Operation of the Communication Aids by Eyeblink Using Image Analysis Methods - Change of the Feature of an Eyeblink Waveforms Resulting from Attributed to Conscious Actions Accompanying Voluntary Eyeblink -

摘要

The input devices for the operation of communication aids and the switches that enable multiple value input are required for disabled at the terminal stage of Amyotrophic Lateral Sclerosis (ALS). We considered the utilization of eyeblink that is relatively less associated with ALS at the terminal stage for the switches. It is known that eyeblink waveforms are different in between voluntary eyeblink and spontaneous eyeblink. Eyeblink waveforms are one-dimensional waveforms obtained by sampling palpebral fissure widths of eye blinking at a constant time interval and by plotting them on a temporal axis. The purpose of this study is to investigate the possibility of categorizing eyeblink data into multiple spaces. We focused on the variations in the shape of eyeblink waveforms attributed to conscious actions accompanying voluntary eyeblink. There was a significant difference in shape feature parameters obtained from eyeblink waveforms between normal voluntary eyeblink and voluntary eyeblink accompanying conscious actions. The results suggest that eyeblink data could be differentiating into six values. The palpebral fissure widths at the time of eyeblink were recorded by the image analysis method, which is a non-contact measurement with fewer burdens. A high-speed video camera with the temporal resolution equivalent to that of EOG is used for the measurements. From the obtained eyeblink waveforms, we extracted six feature points including the starting points of eyelid closure and eyelid opening, shape feature parameters such as eyelid closure time and the mean eyelid opener speed based on these feature points. We made a comparison examination of shape feature parameters of eyeblink waveforms obtained from not only normal voluntary eyeblink but also the following three conscious actions: voluntary eyeblink firmly, lightly; wink; and the combination of the two conscious actions.