Pulse detector and pulse detection method

• US 9,049,997 B2
• Filed: 10/06/2010
• Issued: 06/09/2015
• Est. Priority Date: 10/27/2009
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Takahashi, Yusuke, Urano, Osamu
• Primary Examiner(s): Natnithithadha, Navin
• Assistant Examiner(s): WEARE, MEREDITH H
• Application Number:
  US12/898,966
• Publication Number:
  US 20110098582A1
• Time in Patent Office: 1,707 Days
• Field of Search: 600323-340, 600500-503
• US Class Current: 1/1
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: A61B 5/7257 using Fourier transforms

Abstract

A pulse detector that detects a pulse signal originating from the pulse of a human body includes: a pulse wave sensor that detects and outputs a first pulse wave signal in which the pulse signal and a noise signal are mixed; and a first filtering unit that generates an adaptive spectral line enhancer based on the first pulse wave signal, divides the first pulse wave signal into a first signal and a second signal, and outputs a second pulse wave signal including at least the first signal.

Claims

1. A pulse detector that detects a pulse signal originating from the pulse of a human body, comprising:

a pulse wave sensor that outputs a first pulse wave signal in which the pulse signal and a noise signal are mixed, wherein the noise signal includes a normal signal having a high autocorrelation and an abnormal noise signal having a low autocorrelation;

a motion sensor that outputs a motion signal in response to a motion of the human body;

a first filtering unit that outputs a second pulse wave signal including the pulse signal and the normal noise signal extracted from the first pulse wave signal;

a second filtering unit that outputs a third pulse wave signal which the normal noise signal has been suppressed using the second pulse wave signal and the motion signal; and

an analyzing unit that analyzes the third pulse wave signal to obtain a frequency information corresponding to the third pulse wave signal;

wherein the first filtering unit outputs the second pulse wave signal using the first pulse wave signal and the third pulse wave signal.

2. The pulse detector according to claim 1, wherein

the first filtering unit generates a first component signal including the pulse signal and the normal noise signal, and a second component signal including the abnormal noise signal based on the first pulse wave signal and the third pulse wave signal, and combines the first component signal and the second component signal with a weight factor to output the second pulse wave signal.

3. The pulse detector according to claim 2, wherein

the weight factor is a set of gain coefficient of the first filtering unit which includes gain coefficients corresponding to the first component signal and the second component signal and is switched to a second set of gain coefficient from a first set of gain coefficient when an amplitude of the first pulse signal has increased over the predetermined threshold.

4. The pulse detector according to claim 2, wherein

the first component signal includes a heartbeat signal component and the normal signal which contains changes in the bloodstream caused by swinging motion of an arm during walking or jogging, and

the second component signal includes an abnormal signal which contains changes in the bloodstream caused by a motion of a finger or a wrist and changes in the bloodstream caused by a touch on a finger or a wrist.

5. The pulse detector according to claim 1, further comprising a band member configured and arranged to be attached to the human body, wherein the pulse wave sensor is coupled to the band member so that the pulse wave sensor is configured and arranged to be attached the human body by attaching the band member to the human body.

6. The pulse detector according to claim 1, further comprising

a display section configured and arranged to display a pulse rate obtained based on analysis of the frequency information corresponding to the third pulse wave signal by the analyzing unit.

7. The pulse detector according to claim 1, further comprising:

a timer circuit; and

a display section configured and arranged to display time based on a signal outputted from the timer circuit.