ESTIMATION DEVICE, VIBRATION STATE ESTIMATION METHOD, AND RECORDING MEDIUM

• US 20160310044A1
• Filed: 01/14/2016
• Published: 10/27/2016
• Est. Priority Date: 04/23/2015
• Status: Active Grant

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: MAENO, Kurato, YAMAMOTO, Kohei
• Granted Patent: US 10,485,455 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0507 using microwaves or terahertz waves
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: A61B 8/488 involving Doppler signals

Abstract

An estimation device includes a first converting unit configured to convert a beat signal to a one-dimensional first candidate signal on the basis of a two-dimensional distribution of the beat signal, a second converting unit configured to convert the beat signal to a one-dimensional second candidate signal on the basis of a two-dimensional position change of the beat signal, and a signal deciding unit configured to decide a one-dimensional signal on the basis of the first candidate signal and the second candidate signal.

Claims

1. An estimation device comprising:

a first converting unit configured to convert a beat signal to a one-dimensional first candidate signal on the basis of a two-dimensional distribution of the beat signal;

a second converting unit configured to convert the beat signal to a one-dimensional second candidate signal on the basis of a two-dimensional position change of the beat signal; and

a signal deciding unit configured to decide a one-dimensional signal on the basis of the first candidate signal and the second candidate signal.

2. The estimation device according to claim 1, wherein

the signal deciding unit decides an evaluation value by comparing a feature value of the first candidate signal and a feature value of the second candidate signal, and selects the first candidate signal and/or the second candidate signal as the one-dimensional signal on the basis of the evaluation value.

3. The estimation device according to claim 2, wherein

the feature value is a frequency.

4. The estimation device according to claim 1, wherein

a center of the distribution of the beat signal is estimated on the basis of the two-dimensional distribution of the beat signal, and

the signal deciding unit decides an evaluation value on the basis of an amount of change of a rotation angle of the beat signal with respect to the center of the distribution, and selects the first candidate signal and/or the second candidate signal as the one-dimensional signal on the basis of the evaluation value.

5. The estimation device according to claim 2, wherein

when selecting both of the first candidate signal and the second candidate signal as the one-dimensional signal, the signal deciding unit decides the one-dimensional signal by weighting the first candidate signal and the second candidate signal on the basis of the evaluation value.

6. The estimation device according to claim 1, wherein

when the signal deciding unit selects one of the first candidate signal and the second candidate signal, and then selects the other of the first candidate signal and the second candidate signal, the signal deciding unit adjusts a phase of the one of the first candidate signal and the second candidate signal to a phase of the other of the first candidate signal and the second candidate signal.

7. The estimation device according to claim 1, wherein

when selecting both of the first candidate signal and the second candidate signal, the signal deciding unit adjusts a phase of one of the first candidate signal and the second candidate signal to a phase of the other of the first candidate signal and the second candidate signal.

8. The estimation device according to claim 1, wherein

the first converting unit calculates an inner product of a two-dimensional vector expressing the beat signal and an eigenvector corresponding to a maximum eigenvalue of a covariance matrix of the beat signal, and

a result of the calculation corresponds to the first candidate signal.

9. The estimation device according to claim 1, wherein

a center of the distribution of the beat signal is estimated on the basis of the two-dimensional distribution of the beat signal, and

the second converting unit multiplies a distance from the center of the distribution to a position of the beat signal, by an amount of change of a rotation angle of the beat signal with respect to the center of the distribution, and

a result of the multiplication corresponds to the second candidate signal.

10. The estimation device according to claim 1, further comprising:

a frequency estimating unit configured to estimate a frequency of the one-dimensional signal;

a reference position estimating unit configured to estimate a plurality of reference positions of the one-dimensional signal on the basis of the frequency, and

a cycle calculating unit configured to calculate a cycle of the one-dimensional signal;

wherein

the cycle of the one-dimensional signal is an interval between one reference position and another reference position estimated by the reference position estimating unit, and

the one reference position and the other reference position are continuous.

11. The estimation device according to claim 1, wherein

the beat signal is a beat signal detected by a Doppler sensor in response to vibration caused by respiration of a living body.

12. An estimation method comprising:

a first conversion step for converting a beat signal to a one-dimensional first candidate signal on the basis of a two-dimensional distribution of the beat signal;

a second conversion step for converting the beat signal to a one-dimensional second candidate signal on the basis of a two-dimensional position change of the beat signal; and

a decision step for deciding a one-dimensional signal on the basis of the first candidate signal and the second candidate signal.

13. A non-transitory computer readable recording medium comprising instructions for execution by a control portion of an estimation device, the instructions including:

converting a beat signal to a one-dimensional first candidate signal on the basis of a two-dimensional distribution of the beat signal;

converting the beat signal to a one-dimensional second candidate signal on the basis of a two-dimensional position change of the beat signal; and

deciding a one-dimensional signal on the basis of the first candidate signal and the second candidate signal.