Improvement of Detection Accuracy of Pulse Beat in Non-Contact Unobtrusive Multi-Vital Measurement Using Unitized In-Bed Sheet Electrode Sensor

Abstract

We report on improvement in detection accuracy (DA) of pulse beet (PB) measured unobtrusively with unitized in-bed sheet electrode sensor (SES). The SES placed under the bed sheet includes two strip electrodes for electrocardiogram (ECG) measurement. The SES also comprises driven shield and ground (GND) plane surrounding the ECG electrodes, and has two primary strip sensors for PB detection on the upper and lower edges of the SES. GND for ECG measurement also functions secondary strip sensor for PB detection. Since initial prototype of the SES revealed low DA of PB due to poor coupling area to the body surface, we introduced additional secondary strip sensor between the two ECG electrodes. The DA after the introduction of additional strip sensor were 17.7, 30.7 or 77.5 % for 10, 30 or 50 mm wide additional strip at the upper back, whereas 13.2, 35.6 or 53.2 % at the lower back.