Unobtrusive human height and posture recognition with a capacitive sensor

In pervasive context recognition and user identification applications, unobtrusive recognition of user height and posture is difficult. With the current state of technology, this becomes even harder in environments where cameras are not desired or allowed. This paper answers this problem by presenting a simple, unobtrusive, and low-cost system for measuring height and posture of the user. The measurement method is based on capacitive coupling of low-frequency signals and conductivity of the human body. The designed system was simulated, implemented, and tested with 14 adults. The experimental results show that in 90% of the test cases the height of a person can be measured with 5.2 cm and 14.3 accuracy in standing and all other postures, respectively.