2020 Fiscal Year Research-status Report
Development of dynamics preserving method for extraction of imaging photoplethysmogram signal from a conventional camera's video recordings.
| Project/Area Number |
19K14589
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
スヴィリドヴァ ニーナ 東京理科大学, 工学部情報工学科, 助教 (70782829)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | photoplethysmogram / nonlinear dynamics / time series analysis / chaos theory |
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| Outline of Annual Research Achievements |
Starting from the previous year, the main focus of this research was to deepen understanding of the PPG dynamics itself and how various factors affect its parameters. Therefore, this FY's first aim was to improve understanding of dynamics changes due to age. Secondly, the effects of the presence of hypertension conditions, a widely spread cardiovascular system disorder, on PPG dynamics were investigated. Results obtained by the recurrence quantification analysis (RQA) clearly demonstrated that the determinism property remains unchanged despite age and hypertension condition, while other dynamical characteristics indicated changes in complexity and predictability with aging or in presence of hypertension conditions. However, the applied analysis could reveal this reliably only in the case of high-quality data measured over a long time. In many cases, contact and especially imaging PPGs can be measured with a good quality only during a short time. Therefore, the effect of data length was additionally investigated to identify indexes useable not only for long but also for short-measured time series. It was detected that certain methods of RQA are applicable even to very short PPG recordings.
Additional attention was paid to the transition of the RQA indexes in different dynamical systems with the change of applied methods parameters. Certain differences in determinism parameter transition was found for chaotic systems compared with noisy periodic systems, which makes it important to confirm PPG analysis results transition with variable parameters.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Various dynamical properties and their dependence on commonly changing conditions were carefully investigated, this creates a solid background for the progress of this research project.
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| Strategy for Future Research Activity |
Investigate consistency of the properties investigated in FY2020 in photoplethysmograms extracted from video by different common extraction techniques.
Investigate properties transition with variable parameters in analysis methods.
Identify which technique of time series extraction from video provides dynamical characteristics the closest to the contact photoplethysmograms.
Quantify which dynamical properties differ most significantly between contact and imaging photoplethysmograms, and based on the results proceed with extraction method modifications with aim of the observed differences decrease.
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| Causes of Carryover |
Due to the travel restriction and academic conference cancellations because of the novel coronavirus 2019, significant funds reserved for participation in academic conferences remained unused. Funds transferred from FY2020 will be used in FY 2021 for participation in academic conferences onsite and for open access articles publication-related costs.
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