title: A Novel Earphone Type Sensor for Measuring Mealtime: Consideration of the Method to Distinguish between Running and Meals.
abstract: In this study, we describe a technique for estimating meal times using an earphone-type wearable sensor. A small optical sensor composed of a light-emitting diode and phototransistor is inserted into the ear hole of a user and estimates the meal times of the user from the time variations in the amount of light received. This is achieved by emitting light toward the inside of the ear canal and receiving light reflected back from the ear canal. This proposed technique allowed "meals" to be differentiated from having conversations, sneezing, walking, ascending and descending stairs, operating a computer, and using a smartphone. Conventional devices worn on the head of users and that measure food intake can vibrate during running as the body is jolted more violently than during walking; this can result in the misidentification of running as eating by these devices. To solve this problem, we used two of our sensors simultaneously: one in the left ear and one in the right ear. This was based on our finding that measurements from the left and right ear canals have a strong correlation during running but no correlation during eating. This allows running and eating to be distinguished based on correlation coefficients, which can reduce misidentification. Moreover, by using an optical sensor composed of a semiconductor, a small and lightweight device can be created. This measurement technique can also measure body motion associated with running, and the data obtained from the optical sensor inserted into the ear can be used to support a healthy lifestyle regarding both eating and exercise.
authors.affiliation: Graduate School of Information Sciences, Hiroshima City University, 3-4-1 Ozukahigashi, Asaminami-ku, Hiroshima 731-3194, Japan. taniguti@hiroshima-cu.ac.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Taniguchi
authors.affiliation: Graduate School of Information Sciences, Hiroshima City University, 3-4-1 Ozukahigashi, Asaminami-ku, Hiroshima 731-3194, Japan. hikaru-chiaki@robotics.info.hiroshima-cu.ac.jp.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Chiaki
authors.affiliation: Graduate School of Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, Japan. 15fm314h@shinshu-u.ac.jp.
authors.forename: Mami
authors.initials: M
authors.lastname: Kurosawa
authors.affiliation: Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, Japan. nishikawa@shinshu-u.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nishikawa
mesh_terms: D004424:Ear Canal; D004435:Eating; D012420:Running; D016138:Walking
keywords: body vibration on running; dietary support; ear canal; meal time estimation; wearable device