抄録
Mat sensors are used to detect movement of a person who is unable to walk and requires assistance when getting out of bed to keep from falling. Mat sensors are also used to detect a person who might wander the facility unattended. We intoroduced a system which detects the action of getting out of bed using an ultrasonic array sensor to monitor head position. Our previous paper showed the detection rate is 84.6% with an error rate 5.4% and a loss rate of 10.0% for getting out of bed. Though there was only a subject and a bed in this experimental environment, there are various objects and other persons around the actual bed. In actuality, there are objects such as a drip stand and a chair or person, such as a nurse or attendant, around the bed. So, we needed to consider the unwanted ultrasonic reflection from them that might lower the detection rates above. We then created a test environment with products and the person mentioned above around the bed. We used 7 people in 2 test situations in which each person got out of bed 17 differrent ways. We have improved our detection
