I. Introduction
Sleep is among the most important pervasive characteristics affecting human well-being. Sleep quality is a proven biometric that plays an eminent role in health status evaluation of patients with mental or physical disorders. The quality of sleep is highly correlated with the severity of many illnesses, such as cardiovascular and chronic obstructive pulmonary diseases [1]. The pattern of in-bed postures during sleep is one of the key indicators of sleep quality and can be beneficial for several medical diagnosis or treatment plans such as ones in sleep apnea [2]. For instance, lateral postures are recommended for reducing sleep disorders for mild to moderate sleep apnea, according to [3].