2019 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 / deterministinc chaos / filtering / nonlinear dynamics |
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| Outline of Annual Research Achievements |
The photoplethysmogram (PPG) extracted from the video (imaging PPG, iPPG) has great potential for applications in the health monitoring area. However, the iPPG unavoidably contains a significant amount of noise due to the surrounding light interference, equipment noises, subject movements, etc., which limits iPPG signal applicability. This makes noise filtering an important issue. However, due to the complexity of the PPG dynamics, the choice of the appropriate filter is a challenging task. Therefore during the research period (FY2019), various PPG filtration techniques and its parameters were studied for the contact type green light PPG signals. Methods of nonlinear time series analysis, including the possible attraction reconstruction, recurrence plot and its quantitative analysis, predictability and the largest Lyapunov exponent estimation, were applied to the raw and filtered PPG data to investigate the effect of these filters on the PPG dynamics. A comparison of the results obtained from the analysis of differently processed time series demonstrated that filters conventionally applied to the PPG can significantly alter its dynamics. Thus qualitative and quantitative results have demonstrated shifts in the chaotic dynamics of original data towards regularity in filtered PPG signals. Based on the obtained dynamical characteristics filters with minimized impact on the PPG's chaotic dynamics were identified. This contributes to further applied studies on both PPG and iPPG signals.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
Effect of filtration on complex photoplethysmogram (PPG) dynamics was investigated on a large number of reference PPG datasets. Qualitative and quantitative changes in dynamical characteristics were successfully obtained and analyzed. However, due to the extended hospitalization of the principal investigator, processing and analysis of data collected by the video camera was slightly delayed.
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| Strategy for Future Research Activity |
The following steps to be implemented in further study.
1. Filtration techniques that demonstrated the best performance in terms of the minimum impact on the dynamics of reference PPG signals to be applied to the PPG data extracted from a video recording.
2. Dynamical characteristics of the raw and filtered PPG extracted from video to be studied.
3. After confirmation of the suitable filtering technique for the PPG extracted from video with conventional extraction applied, the next extraction method modification will be conducted based on the results of the analysis of the signals dynamics.
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| Causes of Carryover |
Due to the extended hospitalization of principal investigator purchase of goods necessary for the experiment implementation was delayed. Amount unused in fiscal year 2019 will be used in the current fiscal year for purchase of experiment related goods.
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