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Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry
Calculation of peripheral capillary oxygen saturation [Formula: see text] levels in humans is often made with a pulse oximeter, using photoplethysmography (PPG) waveforms. However, measurements of PPG waveforms are susceptible to motion noise due to subject and sensor movements. In this study, we co...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer Netherlands
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8286955/ https://www.ncbi.nlm.nih.gov/pubmed/32556842 http://dx.doi.org/10.1007/s10877-020-00539-2 |
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author | Alkhoury, Ludvik Choi, Ji-won Wang, Chizhong Rajasekar, Arjun Acharya, Sayandeep Mahoney, Sean Shender, Barry S. Hrebien, Leonid Kam, Moshe |
author_facet | Alkhoury, Ludvik Choi, Ji-won Wang, Chizhong Rajasekar, Arjun Acharya, Sayandeep Mahoney, Sean Shender, Barry S. Hrebien, Leonid Kam, Moshe |
author_sort | Alkhoury, Ludvik |
collection | PubMed |
description | Calculation of peripheral capillary oxygen saturation [Formula: see text] levels in humans is often made with a pulse oximeter, using photoplethysmography (PPG) waveforms. However, measurements of PPG waveforms are susceptible to motion noise due to subject and sensor movements. In this study, we compare two [Formula: see text] -level calculation techniques, and measure the effect of pre-filtering by a heart-rate tuned comb peak filter on their performance. These techniques are: (1) “Red over Infrared,” calculating the ratios of AC and DC components of the red and infrared PPG signals,[Formula: see text] , followed by the use of a calibration curve to determine the [Formula: see text] level Webster (in: Design of pulse oximeters, CRC Press, Boca Raton, 1997); and (2) a motion-resistant algorithm which uses the Discrete Saturation Transform (DST) (Goldman in J Clin Monit Comput 16:475–83, 2000). The DST algorithm isolates individual “saturation components” in the optical pathway, which allows separation of components corresponding to the [Formula: see text] level from components corresponding to noise and interference, including motion artifacts. The comparison we provide here (employing the two techniques with and without pre-filtering) addresses two aspects: (1) accuracy of the [Formula: see text] calculations; and (2) computational complexity. We used both synthetic data and experimental data collected from human subjects. The human subjects were tested at rest and while exercising; while exercising, their measurements were subject to the impacts of motion. Our main conclusion is that if an uninterrupted high-quality heart rate measurement is available, then the “Red over Infrared” approach preceded by a heart-rate tuned comb filter provides the preferred trade-off between [Formula: see text] -level accuracy and computational complexity. A modest improvement in [Formula: see text] estimate accuracy at very low SNR environments may be achieved by switching to the pre-filtered DST-based algorithm (up to 6% improvement in [Formula: see text] level accuracy at −10 dB over unfiltered DST algorithm and the filtered “Red over Infrared” approach). However, this improvement comes at a significant computational cost. |
format | Online Article Text |
id | pubmed-8286955 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Springer Netherlands |
record_format | MEDLINE/PubMed |
spelling | pubmed-82869552021-07-20 Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry Alkhoury, Ludvik Choi, Ji-won Wang, Chizhong Rajasekar, Arjun Acharya, Sayandeep Mahoney, Sean Shender, Barry S. Hrebien, Leonid Kam, Moshe J Clin Monit Comput Original Research Calculation of peripheral capillary oxygen saturation [Formula: see text] levels in humans is often made with a pulse oximeter, using photoplethysmography (PPG) waveforms. However, measurements of PPG waveforms are susceptible to motion noise due to subject and sensor movements. In this study, we compare two [Formula: see text] -level calculation techniques, and measure the effect of pre-filtering by a heart-rate tuned comb peak filter on their performance. These techniques are: (1) “Red over Infrared,” calculating the ratios of AC and DC components of the red and infrared PPG signals,[Formula: see text] , followed by the use of a calibration curve to determine the [Formula: see text] level Webster (in: Design of pulse oximeters, CRC Press, Boca Raton, 1997); and (2) a motion-resistant algorithm which uses the Discrete Saturation Transform (DST) (Goldman in J Clin Monit Comput 16:475–83, 2000). The DST algorithm isolates individual “saturation components” in the optical pathway, which allows separation of components corresponding to the [Formula: see text] level from components corresponding to noise and interference, including motion artifacts. The comparison we provide here (employing the two techniques with and without pre-filtering) addresses two aspects: (1) accuracy of the [Formula: see text] calculations; and (2) computational complexity. We used both synthetic data and experimental data collected from human subjects. The human subjects were tested at rest and while exercising; while exercising, their measurements were subject to the impacts of motion. Our main conclusion is that if an uninterrupted high-quality heart rate measurement is available, then the “Red over Infrared” approach preceded by a heart-rate tuned comb filter provides the preferred trade-off between [Formula: see text] -level accuracy and computational complexity. A modest improvement in [Formula: see text] estimate accuracy at very low SNR environments may be achieved by switching to the pre-filtered DST-based algorithm (up to 6% improvement in [Formula: see text] level accuracy at −10 dB over unfiltered DST algorithm and the filtered “Red over Infrared” approach). However, this improvement comes at a significant computational cost. Springer Netherlands 2020-06-17 2021 /pmc/articles/PMC8286955/ /pubmed/32556842 http://dx.doi.org/10.1007/s10877-020-00539-2 Text en © The Author(s) 2020 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Original Research Alkhoury, Ludvik Choi, Ji-won Wang, Chizhong Rajasekar, Arjun Acharya, Sayandeep Mahoney, Sean Shender, Barry S. Hrebien, Leonid Kam, Moshe Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry |
title | Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry |
title_full | Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry |
title_fullStr | Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry |
title_full_unstemmed | Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry |
title_short | Heart-rate tuned comb filters for processing photoplethysmogram (PPG) signals in pulse oximetry |
title_sort | heart-rate tuned comb filters for processing photoplethysmogram (ppg) signals in pulse oximetry |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8286955/ https://www.ncbi.nlm.nih.gov/pubmed/32556842 http://dx.doi.org/10.1007/s10877-020-00539-2 |
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