US 12,114,964 B2
Biological information measuring apparatus, non-transitory computer-readable recording medium having stored therein a program for causing a computer to execute a process for measuring biological information, and method for measuring biological information
Makoto Yoshizawa, Sendai (JP); and Norihiro Sugita, Sendai (JP)
Assigned to TOHOKU UNIVERSITY, Sendai (JP)
Filed by TOHOKU UNIVERSITY, Sendai (JP)
Filed on May 26, 2020, as Appl. No. 16/883,387.
Application 16/883,387 is a continuation of application No. PCT/JP2018/043004, filed on Nov. 21, 2018.
Claims priority of application No. 2017-230362 (JP), filed on Nov. 30, 2017.
Prior Publication US 2020/0288996 A1, Sep. 17, 2020
Int. Cl. A61B 5/021 (2006.01); A61B 5/00 (2006.01); A61B 5/024 (2006.01); A61B 5/347 (2021.01); A61B 5/374 (2021.01)
CPC A61B 5/02116 (2013.01) [A61B 5/02416 (2013.01); A61B 5/347 (2021.01); A61B 5/374 (2021.01); A61B 5/7257 (2013.01); A61B 5/7278 (2013.01); A61B 5/7435 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A biological information measuring apparatus comprising;
a video camera configured to obtain a video signal of a predetermined part of a subject;
a memory;
a processor having processor circuitry coupled to the memory; and
a display configured to display information processed by the processor and information to be stored in the memory, wherein:
the processor circuitry in the processor comprises a video signal obtainer, a video pulse wave extractor, a distortion calculator, and a measurer;
the video camera is configured to output the video signal to the video signal obtainer;
the video pulse wave extractor is configured to extract video pulse wave information representing a temporal change in a brightness value included in the video signal;
the distortion calculator is configured to calculate, based on a heartbeat basic component and a second component, a waveform distortion being a change due to fluctuations in blood pressure, wherein the heartbeat basic component is obtained by filtering the extracted video pulse wave information using a filter of the distortion calculator in which the filter is set to a band corresponding to a frequency of a heartbeat of the subject and included within a range of 0.7-3.5 Hz, and the second component contains a frequency component of a frequency band higher than the heartbeat frequency band included in the video pulse information;
the measurer is configured to measure an increase of the waveform distortion as a decline of the blood pressure and measures a decrease of the waveform distortion as a rise of the blood pressure;
the distortion calculator comprises either:
an element A in a case where the waveform distortion is expressed as a difference in time between the heartbeat basic component and the second component, the element A comprising:
a feature point detector configured to detect a feature point of the heartbeat basic component;
a vertex detector configured to detect, from the video pulse wave information, a vertex of an end diastolic segment of the video pulse wave; and
a difference calculator configured to calculate, as the difference in time, a time difference between the feature point and the vertex, the feature point being obtained by applying a bandpass filter to a time series signal corresponding to the video pulse wave information stored in the memory; or
an element B in a case where the waveform distortion is expressed as a ratio between the heartbeat basic component and the second component in a frequency domain; the element B comprising:
a convertor configured to obtain a sum of Fourier coefficients of each of the heartbeat basic component and the second component; and
a ratio calculator configured to calculate, as the ratio in the frequency domain, a ratio of the sum of the Fourier coefficients of the second component to the sum of the Fourier coefficients of the heartbeat basic component;
the predetermined part is a part in which an arteriole increases a peripheral vascular resistance by being innervated by a sympathetic nerve when the blood pressure rises; and
the display is configured to display the video of the video signal obtained by the video signal obtainer, the waveform distortion calculated by the distortion calculator, and the fluctuations in the blood pressure of the subject measured by the measurer.