NONCONTACT MONITORING OF RESPIRATION BASED ON AN ULTRASONIC PHASE-SHIFT RECONSTRUCTION METHOD

摘要

We have developed a novel noncontact respiration monitoring that utilized an ultrasonic phase-shift reconstruction method for measuring the normal vibration of chest-wall. In this paper, a simple but efficient method for vibration measurement is adopted for the sleep apnea syndrome. The instrument consists of a pair of 40 kHz ultrasonic transducers which are used in a transmit-receive mode to get the motion of a point on a vibration object. The relative motion of the object modulates the phase angle between transmitted and received ultrasound signals. We have also developed an ingenious method to reconstruct the relative motion of an object from the acquired data of the phase angle changes. The measurement accuracy of the system in the reported experiments is within +/- 0.07 mm. The main advantages of this vibration measurement system are high resolution, low cost, and noncontact measurement.