| Presentation | 2023-03-16 Calculation of Lyapunov Exponent for Imaging Photoplethysmogram Hirofumi Nakayama, Nina Sviridova, Tohru Ikeguchi, |
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| PDF Download Page |  PDF download Page Link |
| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | Photoplethysmogram is a biological signal of the cardiovascular system that measures changes in the amount of light reflected when light irradiates skin surface, and provides information such as heart rate, blood pressure, and blood oxygen saturation. It has been suggested that photoplethysmograms have nonlinear, possibly chaotic, dynamical characteristics by applying nonlinear time series analysis to photoplethysmogram. The results also suggests that physiological and mental health indicators can be extracted. On the other hand, a method called imaging photoplethysmography, in which LED light is used as a light source and a camera as a receiver, has recently been introduced to estimate pulse waves from video images taken from the skin surface. Although the imaging photoplethysmography is used to calculate heart rates and blood pressures in a similar way to the photoplethysmogram, it requires only simple and commercially available camera devices such as smartphones for measurement. In this report, we investigate whether the imaging photoplethysmogram can capture nonlinear, possibly chaotic, dynamical characteristics of the photoplethysmogram. First, we measured the photoplethysmogram and the imaging photoplethysmogram simultaneously. These trajectories in the phase space were reconstructed in the time delay coordinate system. Next, the largest Lyapunov exponent was estimated to quantitatively evaluate orbit instability, or one of the essential characteristics of deterministic chaos. The results showed that the reconstructed trajectories of the photoplethysmogram and imaging photoplethysmogram have recurrence structure and that the largest Lyapunov exponents of the imaging photoplethysmogram exhibit the positive value which indicates that the imaging photoplethysmogram has orbital instability. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | Nonlinear dynamics / Lyapunov exponent / Photoplethysmogram / Imaging Photoplethysmogram |
| Paper # | MSS2022-81,NLP2022-126 |
| Date of Issue | 2023-03-08 (MSS, NLP) |
| Conference Information | |
| Committee | NLP / MSS |
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| Conference Date | 2023/3/15(3days) |
| Place (in Japanese) | (See Japanese page) |
| Place (in English) | |
| Topics (in Japanese) | (See Japanese page) |
| Topics (in English) | |
| Chair | Akio Tsuneda(Kumamoto Univ.) / Atsuo Ozaki(Osaka Inst. of Tech.) |
| Vice Chair | Hiroyuki Torikai(Hosei Univ.) / Shingo Yamaguchi(Yamaguchi Univ.) |
| Secretary | Hiroyuki Torikai(Sojo Univ.) / Shingo Yamaguchi(Gifu Univ.) |
| Assistant | Yuichi Yokoi(Nagasaki Univ.) / Yoshikazu Yamanaka(Utsunomiya Univ.) / Masato Shirai(Shimane Univ.) |
| Paper Information | |
| Registration To | Technical Committee on Nonlinear Problems / Technical Committee on Mathematical Systems Science and its Applications |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Calculation of Lyapunov Exponent for Imaging Photoplethysmogram |
| Sub Title (in English) | |
| Keyword(1) | Nonlinear dynamics |
| Keyword(2) | Lyapunov exponent |
| Keyword(3) | Photoplethysmogram |
| Keyword(4) | Imaging Photoplethysmogram |
| 1st Author's Name | Hirofumi Nakayama |
| 1st Author's Affiliation | Tokyo University of Science(TUS) |
| 2nd Author's Name | Nina Sviridova |
| 2nd Author's Affiliation | Tokyo University of Science(TUS) |
| 3rd Author's Name | Tohru Ikeguchi |
| 3rd Author's Affiliation | Tokyo University of Science(TUS) |
| Date | 2023-03-16 |
| Paper # | MSS2022-81,NLP2022-126 |
| Volume (vol) | vol.122 |
| Number (no) | MSS-435,NLP-436 |
| Page | pp.pp.95-99(MSS), pp.95-99(NLP), |
| #Pages | 5 |
| Date of Issue | 2023-03-08 (MSS, NLP) |