Employing an Incentive Spirometer to Calibrate Tidal Volumes Estimated from a Smartphone Camera
- Authors
- Reyes, Bersain A.; Reljin, Natasa; Kong, Youngsun; Nam, Yunyoung; Ha, Sangho; Chon, Ki H.
- Issue Date
- Mar-2016
- Publisher
- Multidisciplinary Digital Publishing Institute (MDPI)
- Keywords
- breathing monitor; smartphone camera; incentive spirometer; calibration; tidal volume
- Citation
- Sensors, v.16, no.3
- Journal Title
- Sensors
- Volume
- 16
- Number
- 3
- URI
- https://scholarworks.bwise.kr/sch/handle/2021.sw.sch/9301
- DOI
- 10.3390/s16030397
- ISSN
- 1424-8220
1424-3210
- Abstract
- A smartphone-based tidal volume (V-T) estimator was recently introduced by our research group, where an Android application provides a chest movement signal whose peak-to-peak amplitude is highly correlated with reference V-T measured by a spirometer. We found a Normalized Root Mean Squared Error (NRMSE) of 14.998% +/- 5.171% (mean +/- SD) when the smartphone measures were calibrated using spirometer data. However, the availability of a spirometer device for calibration is not realistic outside clinical or research environments. In order to be used by the general population on a daily basis, a simple calibration procedure not relying on specialized devices is required. In this study, we propose taking advantage of the linear correlation between smartphone measurements and V-T to obtain a calibration model using information computed while the subject breathes through a commercially-available incentive spirometer (IS). Experiments were performed on twelve (N = 12) healthy subjects. In addition to corroborating findings from our previous study using a spirometer for calibration, we found that the calibration procedure using an IS resulted in a fixed bias of -0.051 L and a RMSE of 0.189 +/- 0.074 L corresponding to 18.559% +/- 6.579% when normalized. Although it has a small underestimation and slightly increased error, the proposed calibration procedure using an IS has the advantages of being simple, fast, and affordable. This study supports the feasibility of developing a portable smartphone-based breathing status monitor that provides information about breathing depth, in addition to the more commonly estimated respiratory rate, on a daily basis.
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Collections - College of Engineering > Department of Computer Science and Engineering > 1. Journal Articles
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