| CPC A61B 5/7225 (2013.01) [A61B 5/021 (2013.01); A61B 5/14532 (2013.01); A61B 5/14546 (2013.01); G16H 50/20 (2018.01); G16H 50/30 (2018.01)] | 17 Claims |
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1. An apparatus for estimating blood pressure of a user, the apparatus comprising:
a photoplethysmography (PPG) sensor configured to acquire a PPG signal of the user; and
a processor configured to:
extract, from the acquired PPG signal, a cardiac output (CO) feature value and a total peripheral resistance (TPR) feature value of the user;
adaptively determine a scale factor such that the scale factor varies depending on the CO feature value and the TPR feature value of the user, by
obtaining a first scale control ratio, a second scale control ratio, and a third scale control ratio by applying the CO feature value, the TPR feature value, and a combined feature of the CO feature value and the TPR feature value, to a first scale control ratio decision function, a second scale control ratio decision function, and a third scale control ratio decision function, respectively, and
obtaining the adaptively-determined scale factor based on the first scale control ratio, the second scale control ratio, and the third scale control ratio,
wherein each of the first scale control ratio decision function, the second scale control ratio decision function, and the third scale control ratio decision function has a predetermined low threshold point and a predetermined high threshold point of a threshold feature range, and a predetermined minimum scale control ratio corresponding to a reference feature point located between the predetermined low threshold point and the predetermined high threshold point, and wherein each of the first scale control ratio, the second scale control ratio, and the third scale control ratio decreases from the predetermined low threshold point to the reference feature point, and increases from the reference feature point to the predetermined high threshold point; and
estimate the blood pressure of the user based on the adaptively-determined scale factor and the CO feature value and the TPR feature value of the user.
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