Multiparameter Sleep Monitoring Using a Depth Camera - Biomedical Engineering Systems and Technologies - page 286

Multiparameter Sleep Monitoring Using a Depth Camera

Meng-Chieh Yu 1,* , Huan Wu 2 , Jia-Ling Liou 2 , Ming-Sui Lee 1,2 , and Yi-Ping Hung 1,2

1 Graduate Institute of Networking and Multimedia, National Taiwan University,
Roosevelt Road, Taipei, Taiwan
[e-mail], {mslee,hung}@csie.ntu.edu.tw
2 Department of Computer Science and Information Engineering, National Taiwan University,
Roosevelt Road, Taipei, Taiwan
{spidey.wu,jalinliou}@gmail.com

Abstract. In this study, a depth analysis technique was developed to monitor
user's breathing rate, sleep position, and body movement while sleeping
without any physical contact. A cross-section method was proposed to detect
user's head and torso from the sequence of depth images. In the experiment,
eight participants were asked to change the sleep positions (supine and side-
lying) every fifteen breathing cycles on the bed. The results showed that the
proposed method is promising to detect the head and torso with various
sleeping postures and body shapes. In addition, a realistic over-night sleep
monitoring experiment was conducted. The results demonstrated that this
system is promising to monitor the sleep conditions in realistic sleep conditions
and the measurement accuracy was better than the first experiment. This study
is important for providing a non-contact technology to measure multiple sleep
conditions and assist users in better understanding of his sleep quality.

Keywords: Non-contact breath measurement, Sleep position, Sleep cycle, Head
detection, Depth camera.

1 Introduction

Sleep is essential for a person's mental and physical health. Studies indicate that sleep
plays a critical role in immune function [6], metabolism and endocrine function [25],
memory, learning [17], and other vital functions. However, there are some sleep dis-
orders, such as sleep apnea, insomnia, hypersomnia, circadian rhythm disorders,
which might interfere with physical, mental and emotional functioning. For better
understanding of the sleep problems, many sleep centers and research groups are de-
voted to the sleep study. Polysomnography (PSG) is a multi-parametric test used in
the study of sleep and as a diagnostic tool in sleep medicine. It monitors many body
functions including brain activity (EEG), eye movement, muscle activity, heart
rhythm, and breathing while sleeping [9]. In this study, we focus on the research is-
sues in sleep cycle, sleep breathing, and sleep positions. For sleep cycle measurement,
EEG monitoring is the most accurate method to detect user's sleep cycle, including
the period of non-rapid eye movement (NREM) and rapid eye movement (REM).
However, it is not convenient to use. In recent years, the motion sensor and pressure
sensor array are widely used to monitor user's sleep conditions and body movement