Camera and IR Sensor-Based Sleep Apnea Diagnosis Device

The number of patients with sleep apnea (SA), which may cause heart disease or stroke, is increasing worldwide. Polysomnography (PSG) is the most reliable diagnostic method. However, it is expensive, and an accurate diagnosis is difficult because various sensors attached to the body can cause insomnia for sensitive patients. Several home diagnosis methods have been proposed to overcome these problems, but the accuracy is not guaranteed. In this article, we propose a method for diagnosing hypopnea as well as SA comfortably at home using an infrared (IR) camera. The proposed method requires the patients to wear a mask, which enables easy tracking and measurement of breathing even though they are lying on their sides 90° apart from the front. The diagnostic program converts the temperature changes of the mask surface received from the IR camera into the breathing waveform and calculates breathing cycles. Also, it defines five states and six events for state transition and makes the final diagnosis by calculating the duration and occurrence of apnea during the sleep period. As information, including thermal images and/or breathing waveforms, can be transmitted in real time via the Internet, it is also possible to analyze the patient’s symptoms in a hospital or specialized care facility. The usefulness of the proposed device is verified by observing the breathing cycle and the duration of apnea according to various situations, including the type of mask, the number of subjects, and the angle and distance between the camera and the subject.