JP7010002B2 - Pulse wave analyzer, pulse wave analysis method and program - Google Patents

Pulse wave analyzer, pulse wave analysis method and program Download PDF

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JP7010002B2
JP7010002B2 JP2018001025A JP2018001025A JP7010002B2 JP 7010002 B2 JP7010002 B2 JP 7010002B2 JP 2018001025 A JP2018001025 A JP 2018001025A JP 2018001025 A JP2018001025 A JP 2018001025A JP 7010002 B2 JP7010002 B2 JP 7010002B2
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博光 水上
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Seiko Epson Corp
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本発明は、生体の脈波を解析するための技術に関する。 The present invention relates to a technique for analyzing a pulse wave of a living body.

生体の脈波に関する指標を算定する技術が従来から提案されている。例えば特許文献１には、生体の脈波の大きさに応じた信号（容積脈波）から、心電図のＲ－Ｒ間隔の変動（すなわち心拍変動）に相当するａ－ａ間隔の変動を特定する構成が開示されている。 Conventionally, a technique for calculating an index related to a pulse wave of a living body has been proposed. For example, Patent Document 1 specifies fluctuations in the aa interval corresponding to fluctuations in the RR interval (that is, heart rate variability) of an electrocardiogram from a signal (volumetric pulse wave) corresponding to the magnitude of the pulse wave in a living body. The configuration is disclosed.

特開２０１０－０５１８２２号公報Japanese Unexamined Patent Publication No. 2010-051822

しかし、特許文献１の技術のように、容積脈波から生体の脈波を解析する場合、生体の体動に起因したノイズや装置の回路ノイズの影響を解析結果が受けやすいという問題がある。以上の事情を考慮して、本発明の好適な態様は、脈波信号から高精度に脈波を解析することを目的とする。 However, when analyzing a pulse wave of a living body from a volumetric pulse wave as in the technique of Patent Document 1, there is a problem that the analysis result is easily affected by noise caused by the body movement of the living body and circuit noise of the device. In consideration of the above circumstances, a preferred embodiment of the present invention is to analyze a pulse wave from a pulse wave signal with high accuracy.

以上の課題を解決するために、本発明の好適な態様に係る脈波解析装置は、生体の脈波を表す脈波信号のうち、当該脈波の基本周波数を含む解析帯域内の成分を観測信号として抽出する成分抽出部と、前記基本周波数で変動する第１周期信号を、前記観測信号に乗算することで、同相信号を生成する第１処理部と、前記第１周期信号に直交し、前記基本周波数で変動する第２周期信号を、前記観測信号に乗算することで、直交信号を生成する第２処理部と、前記同相信号および前記直交信号で規定され、時間軸上の第１時点における信号値が示す第１偏角と、前記同相信号および前記直交信号で規定され、前記第１時点とは異なる第２時点における信号値が示す第２偏角との差分を、前記基本周波数に対する周波数の変動を表す周波数変動指標として算定する差分算定部と、前記生体の脈周期に関する周期指標を前記周波数変動指標から算定する指標算定部とを具備する。以上の態様では、脈波信号のうち脈波の基本周波数を含む解析帯域内の成分が観測信号として抽出され、当該観測信号を利用して脈周期に関する周期指標が算定されるから、例えば脈波信号（つまり解析帯域外の成分も含む信号）から周期指標を算定する構成と比較して、生体の体動に起因したノイズや装置の回路ノイズの影響を低減した周期指標を算定することができる。したがって、脈波信号から周波数変動指標を高精度に算定することができる。 In order to solve the above problems, the pulse wave analyzer according to a preferred embodiment of the present invention observes components in the analysis band including the fundamental frequency of the pulse wave among the pulse wave signals representing the pulse waves of a living body. The component extraction unit that extracts as a signal, the first processing unit that generates an in-phase signal by multiplying the observation signal by the first-period signal that fluctuates at the basic frequency, and the first-period signal are orthogonal to each other. , The second processing unit that generates an orthogonal signal by multiplying the observation signal by the second period signal that fluctuates at the fundamental frequency, and the second processing unit defined by the in-phase signal and the orthogonal signal, and the second on the time axis. The difference between the first deviation angle indicated by the signal value at one time point and the second deviation angle indicated by the signal value at the second time point different from the first time point specified by the in-phase signal and the orthogonal signal is described above. It is provided with a difference calculation unit that calculates a frequency fluctuation index representing a frequency fluctuation with respect to a fundamental frequency, and an index calculation unit that calculates a periodic index related to the pulse cycle of the living body from the frequency fluctuation index. In the above embodiment, the components in the analysis band including the fundamental frequency of the pulse wave are extracted as the observation signal from the pulse wave signal, and the periodic index related to the pulse cycle is calculated using the observation signal. Therefore, for example, the pulse wave. Compared with the configuration that calculates the periodic index from the signal (that is, the signal including the components outside the analysis band), it is possible to calculate the periodic index that reduces the influence of noise caused by the body movement of the living body and circuit noise of the device. .. Therefore, the frequency fluctuation index can be calculated with high accuracy from the pulse wave signal.

本発明の好適な態様において、前記脈波信号の解析により前記基本周波数を特定する周波数解析部を具備する。以上の態様では、周波数変動指標の算定に利用される脈波信号の解析により基本周波数が特定されるから、周波数変動指標の算定に利用する脈波信号を基本周波数の特定に流用できるという利点がある。 In a preferred embodiment of the present invention, a frequency analysis unit for specifying the fundamental frequency by analyzing the pulse wave signal is provided. In the above aspect, since the fundamental frequency is specified by the analysis of the pulse wave signal used for calculating the frequency fluctuation index, there is an advantage that the pulse wave signal used for calculating the frequency fluctuation index can be diverted to specify the fundamental frequency. be.

本発明の好適な態様において、前記差分算定部は、前記同相信号の信号値と前記直交信号の信号値との関係を表す複素関数について、前記第１時点と前記第２時点との間における自己相関の偏角を、前記周波数変動指標として算定する。以上の態様では、同相信号の信号値と直交信号の信号値との関係を表す複素関数について、第１時点と第２時点との間における自己相関の偏角が、周波数変動指標として算定されるから、第１偏角と第２偏角とをそれぞれ算定することが不要になる。 In a preferred embodiment of the present invention, the difference calculation unit may use a complex function representing the relationship between the signal value of the in-phase signal and the signal value of the orthogonal signal between the first time point and the second time point. The declination of the autocorrelation is calculated as the frequency fluctuation index. In the above embodiment, the argument of the autocorrelation between the first time point and the second time point is calculated as the frequency fluctuation index for the complex function representing the relationship between the signal value of the in-phase signal and the signal value of the orthogonal signal. Therefore, it is not necessary to calculate the first declination angle and the second declination angle, respectively.

本発明の好適な態様において、前記周期指標に応じて前記解析帯域の帯域幅を制御する帯域制御部を具備する。以上の態様では、周期指標に応じて解析帯域の帯域幅が制御されるから、周期指標の変動する範囲に応じた適切な解析帯域が設定される。 In a preferred embodiment of the present invention, the band control unit for controlling the bandwidth of the analysis band according to the period index is provided. In the above embodiment, since the bandwidth of the analysis band is controlled according to the periodic index, an appropriate analysis band is set according to the fluctuating range of the periodic index.

本発明の好適な態様に係る脈波解析方法は、生体の脈波を表す脈波信号のうち、当該脈波の基本周波数を含む解析帯域内の成分を観測信号として抽出し、前記基本周波数で変動する第１周期信号を、前記観測信号に乗算することで、同相信号を生成し、前記第１周期信号に直交し、前記基本周波数で変動する第２周期信号を、前記観測信号に乗算することで、直交信号を生成し、前記同相信号および前記直交信号で規定され、時間軸上の第１時点における信号値が示す第１偏角と、前記同相信号および前記直交信号で規定され、前記第１時点とは異なる第２時点における信号値が示す第２偏角との差分を、前記基本周波数に対する周波数の変動を表す周波数変動指標として算定し、前記生体の脈周期に関する周期指標を前記周波数変動指標から算定する。 In the pulse wave analysis method according to a preferred embodiment of the present invention, a component in the analysis band including the fundamental frequency of the pulse wave is extracted as an observation signal from the pulse wave signal representing the pulse wave of a living body, and the basic frequency is used. By multiplying the observed signal by the fluctuating first cycle signal, an in-phase signal is generated, and the second cycle signal orthogonal to the first cycle signal and fluctuating at the fundamental frequency is multiplied by the observed signal. By doing so, an orthogonal signal is generated, which is defined by the in-phase signal and the orthogonal signal, and is defined by the first deviation angle indicated by the signal value at the first time point on the time axis, and the in-phase signal and the orthogonal signal. Then, the difference from the second deviation angle indicated by the signal value at the second time point different from the first time point is calculated as a frequency fluctuation index indicating the frequency fluctuation with respect to the fundamental frequency, and the cycle index relating to the pulse cycle of the living body is calculated. Is calculated from the frequency fluctuation index.

本発明の好適な態様に係るプログラムは、生体の脈波を表す脈波信号のうち、当該脈波の基本周波数を含む解析帯域内の成分を観測信号として抽出する成分抽出部、前記基本周波数で変動する第１周期信号を、前記観測信号に乗算することで、同相信号を生成する第１処理部、前記第１周期信号に直交し、前記基本周波数で変動する第２周期信号を、前記観測信号に乗算することで、直交信号を生成する第２処理部、前記同相信号および前記直交信号で規定され、時間軸上の第１時点における信号値が示す第１偏角と、前記同相信号および前記直交信号で規定され、前記第１時点とは異なる第２時点における信号値が示す第２偏角との差分を、前記基本周波数に対する周波数の変動を表す周波数変動指標として算定する差分算定部、および、前記生体の脈周期に関する周期指標を前記周波数変動指標から算定する指標算定部としてコンピューターを機能させる。 The program according to a preferred embodiment of the present invention is a component extraction unit that extracts components in the analysis band including the fundamental frequency of the pulse wave as an observation signal from the pulse wave signals representing the pulse waves of a living body, at the basic frequency. The first processing unit that generates an in-phase signal by multiplying the fluctuating first-period signal by the observation signal, and the second-period signal that is orthogonal to the first-period signal and fluctuates at the fundamental frequency. The second processing unit that generates an orthogonal signal by multiplying the observed signal, the first deviation angle defined by the in-phase signal and the orthogonal signal and indicated by the signal value at the first time point on the time axis, and the same as above. Difference calculated by using the difference from the second deviation angle defined by the phase signal and the orthogonal signal and indicated by the signal value at the second time point different from the first time point as the frequency fluctuation index indicating the frequency fluctuation with respect to the fundamental frequency. The computer functions as a calculation unit and an index calculation unit that calculates a periodic index related to the pulse cycle of the living body from the frequency fluctuation index.

本発明の第１実施形態に係る脈波解析装置の側面図である。It is a side view of the pulse wave analysis apparatus which concerns on 1st Embodiment of this invention. 脈波解析装置の機能に着目した構成図である。It is a block diagram focusing on the function of a pulse wave analysis device. 制御装置の機能に着目した構成図である。It is a block diagram focusing on the function of a control device. 強度スペクトルを示すグラフである。It is a graph which shows the intensity spectrum. 観測周波数の時間変化を表すグラフである。It is a graph which shows the time change of an observation frequency. 制御装置が実行する処理のフローチャートである。It is a flowchart of the process executed by a control device. 第２実施形態に係る脈波解析装置の機能に着目した構成図である。It is a block diagram focusing on the function of the pulse wave analysis apparatus which concerns on 2nd Embodiment. 実製品に付与される検出信号を示すグラフである。It is a graph which shows the detection signal given to the actual product. 第３実施形態に係る脈波解析装置の使用例を示す模式図である。It is a schematic diagram which shows the use example of the pulse wave analysis apparatus which concerns on 3rd Embodiment. 第３実施形態に係る脈波解析装置の他の使用例を示す模式図である。It is a schematic diagram which shows the other use example of the pulse wave analysis apparatus which concerns on 3rd Embodiment. 変形例における脈波解析装置の構成図である。It is a block diagram of the pulse wave analysis apparatus in the modification. 変形例における脈波解析装置の構成図である。It is a block diagram of the pulse wave analysis apparatus in the modification. 変形例における脈波解析装置の構成図である。It is a block diagram of the pulse wave analysis apparatus in the modification.

＜第１実施形態＞
図１は、本発明の第１実施形態に係る脈波解析装置１００の側面図である。第１実施形態の脈波解析装置１００は、被験者の心拍変動（Heart Rate Variability）に関する指標（以下「心拍変動指標」という）を算定する生体測定機器である。心拍変動は、生体の脈波の周期（以下「脈周期」という）の時間的な変動である。第１実施形態の脈波解析装置１００は、被験者の身体のうち特定の部位（以下「測定部位」という）Ｍの脈周期から心拍変動指標を測定する。以下の説明では、被験者の手首または上腕を測定部位Ｍとして例示する。 <First Embodiment>
FIG. 1 is a side view of the pulse wave analysis device 100 according to the first embodiment of the present invention. The pulse wave analysis device 100 of the first embodiment is a biometric device for calculating an index (hereinafter referred to as “heart rate variability index”) relating to the heart rate variability of the subject. Heart rate variability is a temporal variation of the pulse wave cycle of a living body (hereinafter referred to as "pulse cycle"). The pulse wave analysis device 100 of the first embodiment measures the heart rate variability index from the pulse cycle of a specific part (hereinafter referred to as “measurement part”) M in the body of the subject. In the following description, the wrist or upper arm of the subject is exemplified as the measurement site M.

脈波解析装置１００は、測定部位Ｍに装着される。第１実施形態の脈波解析装置１００は、図１に例示される通り、筐体部１２とベルト１４とを具備する腕時計型の携帯機器である。脈波解析装置１００は、測定部位Ｍにベルト１４を巻回することで被験者の身体に装着される。 The pulse wave analysis device 100 is attached to the measurement site M. As illustrated in FIG. 1, the pulse wave analysis device 100 of the first embodiment is a wristwatch-type portable device including a housing portion 12 and a belt 14. The pulse wave analysis device 100 is attached to the body of the subject by winding the belt 14 around the measurement site M.

図２は、脈波解析装置１００の機能に着目した構成図である。図２に例示される通り、第１実施形態の脈波解析装置１００は、制御装置２０と記憶装置２２と表示装置２４と検出装置３０とを具備する。制御装置２０および記憶装置２２は、筐体部１２の内部に設置される。図１に例示される通り、表示装置２４（例えば液晶表示パネル）は、例えば筐体部１２における測定部位Ｍとは反対側の表面に設置され、測定結果を含む各種の画像を制御装置２０による制御のもとで表示する。 FIG. 2 is a configuration diagram focusing on the function of the pulse wave analysis device 100. As illustrated in FIG. 2, the pulse wave analysis device 100 of the first embodiment includes a control device 20, a storage device 22, a display device 24, and a detection device 30. The control device 20 and the storage device 22 are installed inside the housing portion 12. As illustrated in FIG. 1, the display device 24 (for example, a liquid crystal display panel) is installed on the surface of the housing portion 12 opposite to the measurement portion M, and various images including the measurement results are produced by the control device 20. Display under control.

図２の検出装置３０は、測定部位Ｍの状態に応じた検出信号（脈波信号の例示）Ｓa(ｔ)を生成する光学センサーモジュールである。図２に例示される通り、第１実施形態の検出装置３０は、発光部３１と受光部３２と駆動回路３３と出力回路３４とを具備する。発光部３１および受光部３２は、例えば筐体部１２において測定部位Ｍに対向する位置（典型的には測定部位Ｍに接触する表面）に設置される。なお、駆動回路３３および出力回路３４の一方または双方を検出装置３０とは別体の外部回路として設置することも可能である。 The detection device 30 in FIG. 2 is an optical sensor module that generates a detection signal (example of a pulse wave signal) Sa (t) according to the state of the measurement site M. As illustrated in FIG. 2, the detection device 30 of the first embodiment includes a light emitting unit 31, a light receiving unit 32, a drive circuit 33, and an output circuit 34. The light emitting unit 31 and the light receiving unit 32 are installed, for example, at a position facing the measurement portion M (typically, a surface in contact with the measurement portion M) in the housing portion 12. It is also possible to install one or both of the drive circuit 33 and the output circuit 34 as an external circuit separate from the detection device 30.

発光部３１は、測定部位Ｍに光を照射する光源である。第１実施形態の発光部３１は、例えばインコヒーレントな光を出射するＬＥＤ（Light Emitting Diode）等の発光素子が発光部３１として好適に利用される。駆動回路３３は、制御装置２０の制御のもとで発光部３１を発光させる。なお、相異なる波長の光を出射する複数の発光素子で発光部３１を構成してもよい。発光部３１から測定部位Ｍに入射した光は、測定部位Ｍの内部を通過しながら拡散反射を繰返したうえで筐体部１２側に出射する。具体的には、測定部位Ｍの内部に存在する動脈（例えば、上腕動脈、橈骨動脈または尺骨動脈）等の血管と血管内の血液とを通過した光が測定部位Ｍから筐体部１２側に出射する。 The light emitting unit 31 is a light source that irradiates the measurement site M with light. As the light emitting unit 31 of the first embodiment, for example, a light emitting element such as an LED (Light Emitting Diode) that emits incoherent light is suitably used as the light emitting unit 31. The drive circuit 33 causes the light emitting unit 31 to emit light under the control of the control device 20. The light emitting unit 31 may be composed of a plurality of light emitting elements that emit light having different wavelengths. The light incident on the measurement portion M from the light emitting portion 31 is emitted to the housing portion 12 side after repeating diffuse reflection while passing through the inside of the measurement portion M. Specifically, light that has passed through a blood vessel such as an artery existing inside the measurement site M (for example, a brachial artery, a radial artery, or an ulnar artery) and blood in the blood vessel is transmitted from the measurement site M to the housing portion 12 side. Emit.

受光部３２は、測定部位Ｍから到来する光を受光する。第１実施形態の受光部３２は、測定部位Ｍから到達する光の強度の時間変化を表す検出信号（つまり生体を通過した光の強度の時間変化を表す信号）を生成する。例えば、受光部３２は、受光強度に応じた電荷を発生するフォトダイオード（ＰＤ：Photo Diode）等の受光素子を含む。測定部位Ｍの内部の血管は、拍動と同等の周期で反復的に拡張および収縮するから、測定部位Ｍからの受光強度に応じて受光部３２が生成する検出信号は、測定部位Ｍの血管の血流量の変動に対応した周期的な変動成分を含む脈波信号（脈波を表す信号）である。すなわち、検出信号には、脈周期で変動する成分が含まれている。 The light receiving unit 32 receives the light arriving from the measurement site M. The light receiving unit 32 of the first embodiment generates a detection signal (that is, a signal representing a time change in the intensity of light that has passed through the living body) that represents a time change in the intensity of light that arrives from the measurement site M. For example, the light receiving unit 32 includes a light receiving element such as a photodiode (PD) that generates an electric charge according to the light receiving intensity. Since the blood vessels inside the measurement site M repeatedly expand and contract in the same cycle as the pulsation, the detection signal generated by the light receiving unit 32 according to the light receiving intensity from the measurement site M is the blood vessels of the measurement site M. It is a pulse wave signal (a signal representing a pulse wave) containing a periodic fluctuation component corresponding to the fluctuation of the blood vessel volume of. That is, the detection signal contains a component that fluctuates with the pulse cycle.

第１実施形態の検出装置３０は、発光部３１と受光部３２とが測定部位Ｍに対して片側に位置する反射型の光学センサーである。ただし、発光部３１と受光部３２とが測定部位Ｍを挟んで反対側に位置する透過型の光学センサーを検出装置３０として利用してもよい。 The detection device 30 of the first embodiment is a reflection type optical sensor in which the light emitting unit 31 and the light receiving unit 32 are located on one side of the measurement site M. However, a transmissive optical sensor in which the light emitting unit 31 and the light receiving unit 32 are located on opposite sides of the measurement portion M may be used as the detection device 30.

出力回路３４は、受光部３２が受光した光の強度に応じた検出信号Ｓa(ｔ)を生成する。具体的には、出力回路３４は、受光部３２が生成した検出信号を増幅する増幅回路（図示略）と、増幅後の検出信号を所定のサンプリング周期毎にアナログからデジタルに変換することで検出信号Ｓa(ｔ)を生成するＡ/Ｄ変換器（図示略）とを具備する。出力回路３４が生成した検出信号Ｓa(ｔ)は、制御装置２０に供給される。符号ｔは、Ａ/Ｄ変換における時間軸上の任意の１個のサンプリング点を意味する。 The output circuit 34 generates a detection signal Sa (t) according to the intensity of the light received by the light receiving unit 32. Specifically, the output circuit 34 detects an amplifier circuit (not shown) that amplifies the detection signal generated by the light receiving unit 32, and converts the amplified detection signal from analog to digital at predetermined sampling cycles. It includes an A / D converter (not shown) that generates a signal Sa (t). The detection signal Sa (t) generated by the output circuit 34 is supplied to the control device 20. The symbol t means any one sampling point on the time axis in the A / D conversion.

図２の制御装置２０は、ＣＰＵ（Central Processing Unit）またはＦＰＧＡ（Field-Programmable Gate Array）等の演算処理装置であり、脈波解析装置１００の全体を制御する。第１実施形態の制御装置２０は、記憶装置２２に記憶されたプログラム（アプリケーションプログラム）を実行することで、心拍変動指標を算定するための機能（周波数解析部６２，成分抽出部６４，演算処理部６６，変動算定部６８）を実現する。記憶装置２２は、例えば不揮発性の半導体メモリーで構成され、制御装置２０が実行するプログラムと制御装置２０が使用する各種のデータとを記憶する。なお、制御装置２０の機能を複数の集積回路に分散した構成、または、制御装置２０の一部または全部の機能を専用の電子回路で実現した構成も採用され得る。また、図２では制御装置２０と記憶装置２２とを別個の要素として図示したが、記憶装置２２を内包する制御装置２０を例えばＡＳＩＣ（Application Specific Integrated Circuit）等により実現することも可能である。 The control device 20 of FIG. 2 is an arithmetic processing device such as a CPU (Central Processing Unit) or an FPGA (Field-Programmable Gate Array), and controls the entire pulse wave analysis device 100. The control device 20 of the first embodiment has a function (frequency analysis unit 62, component extraction unit 64, arithmetic processing) for calculating a heart rate variability index by executing a program (application program) stored in the storage device 22. Unit 66, fluctuation calculation unit 68) is realized. The storage device 22 is composed of, for example, a non-volatile semiconductor memory, and stores a program executed by the control device 20 and various data used by the control device 20. It should be noted that a configuration in which the functions of the control device 20 are distributed in a plurality of integrated circuits, or a configuration in which some or all of the functions of the control device 20 are realized by a dedicated electronic circuit can also be adopted. Further, although the control device 20 and the storage device 22 are shown as separate elements in FIG. 2, the control device 20 including the storage device 22 can be realized by, for example, an ASIC (Application Specific Integrated Circuit) or the like.

図３は、制御装置２０の機能に着目した構成図である。周波数解析部６２は、検出信号Ｓa(ｔ)の解析により、検出信号Ｓa(ｔ)が表す脈波の基本周波数ｆ0を特定する。基本周波数ｆ0は、被験者の脈拍数に対応する。具体的には、周波数解析部６２は、検出装置３０が生成した検出信号Ｓa(ｔ)から周波数に関する強度スペクトル（例えばパワースペクトル）Ｘを算定し、当該強度スペクトルＸから基本周波数ｆ0を特定する。強度スペクトルＸは、各周波数ｆにおける検出信号Ｓa(ｔ)の信号成分の信号強度（パワーまたは振幅）Ｇ(f)の分布である。強度スペクトルＸの算定には、高速フーリエ変換（ＦＦＴ：Fast Fourier Transform）等の公知の周波数解析が任意に採用され得る。図４は、周波数解析部６２が算定した強度スペクトルＸを示すグラフである。図４に例示される通り、強度スペクトルＸには、脈波を表す複数のピークが含まれる。強度スペクトルＸに含まれる複数のピークのうち、強度Ｇ(f)が最大となるピークの周波数が脈波の基本周波数ｆ0として特定される。図４では、１Ｈｚが基本周波数ｆ0として特定される場合が例示されている。周波数解析部６２による基本周波数ｆ0の特定は、時間軸上の単位期間（フレーム）毎に反復的に実行される。単位期間は、例えば拍動の１拍分に相当する期間より充分に長い時間長（例えば１６秒）である。 FIG. 3 is a configuration diagram focusing on the function of the control device 20. The frequency analysis unit 62 identifies the fundamental frequency f0 of the pulse wave represented by the detection signal Sa (t) by analyzing the detection signal Sa (t). The fundamental frequency f0 corresponds to the pulse rate of the subject. Specifically, the frequency analysis unit 62 calculates an intensity spectrum (for example, a power spectrum) X related to the frequency from the detection signal Sa (t) generated by the detection device 30, and specifies the fundamental frequency f0 from the intensity spectrum X. The intensity spectrum X is a distribution of the signal intensity (power or amplitude) G (f) of the signal component of the detection signal Sa (t) at each frequency f. A known frequency analysis such as Fast Fourier Transform (FFT) may be arbitrarily adopted for the calculation of the intensity spectrum X. FIG. 4 is a graph showing the intensity spectrum X calculated by the frequency analysis unit 62. As illustrated in FIG. 4, the intensity spectrum X includes a plurality of peaks representing pulse waves. Of the plurality of peaks included in the intensity spectrum X, the frequency of the peak having the maximum intensity G (f) is specified as the fundamental frequency f0 of the pulse wave. FIG. 4 illustrates a case where 1 Hz is specified as the fundamental frequency f0. The frequency analysis unit 62 repeatedly executes the specification of the fundamental frequency f0 for each unit period (frame) on the time axis. The unit period is, for example, a time length (for example, 16 seconds) sufficiently longer than the period corresponding to one beat of a beat.

図３の成分抽出部６４は、検出信号Ｓa(ｔ)のうち、脈波の基本周波数ｆ0を含む帯域（以下「解析帯域」という）Ｂ内の成分を観測信号Ｓb(ｔ)として抽出する。図４に例示される通り、解析帯域Ｂは、例えば基本周波数ｆ0を中心周波数とした所定の帯域幅（例えば１Ｈｚ）の通過帯域である。解析帯域Ｂ内の成分を選択的に通過させて、他の成分を除去するような周波数応答を有するバンドパスフィルターが成分抽出部６４として利用される。つまり、解析帯域Ｂ外に存在するノイズ（例えば体動に起因したノイズや脈波解析装置１００の回路ノイズ）の影響を低減した観測信号Ｓb(ｔ)が成分抽出部６４により生成される。 The component extraction unit 64 of FIG. 3 extracts the component in the band (hereinafter referred to as “analysis band”) B including the fundamental frequency f0 of the pulse wave from the detection signal Sa (t) as the observation signal Sb (t). As illustrated in FIG. 4, the analysis band B is, for example, a pass band having a predetermined bandwidth (for example, 1 Hz) with the fundamental frequency f0 as the center frequency. A bandpass filter having a frequency response that selectively passes components in the analysis band B and removes other components is used as the component extraction unit 64. That is, the component extraction unit 64 generates an observation signal Sb (t) that reduces the influence of noise existing outside the analysis band B (for example, noise caused by body movement or circuit noise of the pulse wave analysis device 100).

成分抽出部６４で生成される観測信号Ｓb(ｔ)には、脈周期で変動する成分が含まれる。脈周期は、観測信号Ｓb(ｔ)において相前後する２個のピーク（心臓から測定部位Ｍに到達する進行波に相当するピーク）間の間隔である。被験者の脈周期は、時間軸上で変動し得る。図５は、脈周期の逆数である周波数（以下「観測周波数」）ｆの時間変化を表すグラフである。図５から把握される通り、観測周波数ｆは、脈周期の変動に応じて経時的に変化する。図５には、基本周波数ｆ0に対する観測周波数ｆの変動量Δｆが図示されている。基本周波数ｆ0と観測周波数ｆとの差分が変動量Δｆである。すなわち、周波数解析部６２が特定する基本周波数ｆ0は、観測周波数ｆの変動量Δｆにおける基準値である。時間軸上の任意の時点ｔにおける観測周波数ｆは、基本周波数ｆ0と基本周波数ｆ0に対する変動量Δｆとの和（ｆ0＋Δｆ）で表現されるから、観測信号Ｓb(ｔ)は、以下の数式(1)で表現される。数式(1)から把握される通り、観測信号Ｓb(ｔ)は、観測周波数ｆ(＝ｆ0＋Δｆ)を係数とした正弦関数で表現される。

Figure 0007010002000001
The observation signal Sb (t) generated by the component extraction unit 64 includes a component that fluctuates with the pulse cycle. The pulse cycle is the interval between two peaks (peaks corresponding to the traveling wave arriving at the measurement site M from the heart) that are in phase with each other in the observation signal Sb (t). The subject's pulse cycle can fluctuate on the time axis. FIG. 5 is a graph showing the time change of the frequency (hereinafter referred to as “observed frequency”) f, which is the reciprocal of the pulse cycle. As can be seen from FIG. 5, the observation frequency f changes with time according to the fluctuation of the pulse cycle. FIG. 5 shows the fluctuation amount Δf of the observed frequency f with respect to the fundamental frequency f0. The difference between the fundamental frequency f0 and the observed frequency f is the fluctuation amount Δf. That is, the fundamental frequency f0 specified by the frequency analysis unit 62 is a reference value in the fluctuation amount Δf of the observation frequency f. Since the observed frequency f at an arbitrary time point t on the time axis is expressed by the sum (f0 + Δf) of the fundamental frequency f0 and the fluctuation amount Δf with respect to the fundamental frequency f0, the observed signal Sb (t) is expressed by the following equation (1). ). As can be grasped from the mathematical formula (1), the observation signal Sb (t) is expressed by a sine function having the observation frequency f (= f0 + Δf) as a coefficient.
Figure 0007010002000001

図３の演算処理部６６は、成分抽出部６４が抽出した観測信号Ｓb(ｔ)から、生体の脈周期Ｐを算定する。観測信号Ｓb(ｔ)に対する直交検波により脈周期Ｐを算定する。具体的には、演算処理部６６は、信号処理部９１と第１処理部９３と第２処理部９５と差分算定部９７と指標算定部９８とを具備する。 The arithmetic processing unit 66 of FIG. 3 calculates the pulse cycle P of the living body from the observation signal Sb (t) extracted by the component extraction unit 64. The pulse period P is calculated by orthogonal detection with respect to the observation signal Sb (t). Specifically, the arithmetic processing unit 66 includes a signal processing unit 91, a first processing unit 93, a second processing unit 95, a difference calculation unit 97, and an index calculation unit 98.

信号処理部９１は、基本周波数ｆ0で変動する第１周期信号Ｚi(ｔ)と、基本周波数ｆ0で変動する第２周期信号Ｚq(ｔ)とを生成する。第１周期信号Ｚi(ｔ)と第２周期信号Ｚq(ｔ)とは相互に直交する。具体的には、第１周期信号Ｚi(ｔ)は、以下の数式(2)の余弦関数で表現され、第２周期信号Ｚq(ｔ)は、以下の数式(3)の正弦関数で表現される。具体的には、信号処理部９１は、第１周期信号Ｚi(ｔ)を生成する発振器と、第１周期信号Ｚi(ｔ)を９０°だけ移相することで第２周期信号Ｚq(ｔ)を生成する移相器とを含んで構成される。

Figure 0007010002000002
Figure 0007010002000003
 The signal processing unit 91 generates a first period signal Zi (t) that fluctuates at the fundamental frequency f0 and a second period signal Zq (t) that fluctuates at the fundamental frequency f0. The first period signal Zi (t) and the second period signal Zq (t) are orthogonal to each other. Specifically, the first period signal Zi (t) is expressed by the cosine function of the following equation (2), and the second period signal Zq (t) is expressed by the sine function of the following equation (3). To. Specifically, the signal processing unit 91 shifts the phase of the oscillator that generates the first period signal Zi (t) by 90 ° to the second period signal Zq (t). Consists of including a phase shifter to produce.
Figure 0007010002000002
Figure 0007010002000003

第１処理部９３は、信号処理部９１が生成した第１周期信号Ｚi(ｔ)を観測信号Ｓb(ｔ)に乗算することで、同相信号Ｓi(ｔ)を生成する。第１実施形態の第１処理部９３は、乗算部９３１と低域通過部９３３とを具備する。乗算部９３１は、数式(1)で表現される観測信号Ｓb(ｔ)と、数式(2)で表現される第１周期信号Ｚi(ｔ)とを乗算する。乗算部９３１による乗算結果（数式(1)と数式(2)との積で表現される信号）には、基本周波数ｆ0と変動量Δｆとの和成分(ｆ0＋Δｆ＋ｆ0)および差成分(ｆ0＋Δｆ－ｆ0)が含まれる。低域通過部９３３は、乗算部９３１の乗算結果から、以下の数式(4)で表現される同相信号Ｓi(ｔ)を生成する。数式(4)から理解される通り、同相信号Ｓi(ｔ)は、変動量Δｆを係数とした余弦関数で表現される。乗算部９３１の乗算結果のうち、同相信号Ｓi(ｔ)を表す成分を通過させ、同相信号Ｓi(ｔ)を表す成分よりも高域側の成分を除去するローパスフィルターが低域通過部９３３として利用される。具体的には、乗算部９３１の乗算結果から和成分(ｆ0＋Δｆ＋ｆ0)が低域通過部９３３により除去される。

Figure 0007010002000004
The first processing unit 93 generates an in-phase signal Si (t) by multiplying the observation signal Sb (t) by the first period signal Zi (t) generated by the signal processing unit 91. The first processing unit 93 of the first embodiment includes a multiplication unit 931 and a low frequency passage unit 933. The multiplication unit 931 multiplies the observation signal Sb (t) expressed by the equation (1) and the first period signal Zi (t) expressed by the equation (2). The multiplication result by the multiplication unit 931 (the signal expressed by the product of the equation (1) and the equation (2)) includes the sum component (f0 + Δf + f0) and the difference component (f0 + Δf−f0) of the fundamental frequency f0 and the fluctuation amount Δf. Is included. The low-pass passage unit 933 generates an in-phase signal Si (t) expressed by the following equation (4) from the multiplication result of the multiplication unit 931. As understood from the equation (4), the common mode signal Si (t) is expressed by a cosine function with the fluctuation amount Δf as a coefficient. Of the multiplication results of the multiplication unit 931, a low-pass filter that passes the component representing the in-phase signal Si (t) and removes the component on the higher frequency side than the component representing the common-mode signal Si (t) is the low-pass filter. It is used as 933. Specifically, the sum component (f0 + Δf + f0) is removed from the multiplication result of the multiplication unit 931 by the low frequency passage unit 933.
Figure 0007010002000004

第２処理部９５は、信号処理部９１が生成した第２周期信号Ｚq(ｔ)を観測信号Ｓb(ｔ)に乗算することで、直交信号Ｓq(ｔ)を生成する。第１実施形態の第２処理部９５は、乗算部９５１と低域通過部９５３とを具備する。乗算部９５１は、数式(1)で表現される観測信号Ｓb(ｔ)と、数式(3)で表現される第２周期信号Ｚq(ｔ)とを乗算する。乗算部９５１による乗算結果（数式(1)と数式(3)との積で表現される信号）には、基本周波数ｆ0と変動量Δｆとの和成分(ｆ0＋Δｆ＋ｆ0)および差成分(ｆ0＋Δｆ－ｆ0)が含まれる。低域通過部９５３は、乗算部９５１の乗算結果から、以下の数式(5)で表現される直交信号Ｓq(ｔ)を生成する。数式(5)から理解される通り、直交信号Ｓq(ｔ)は、変動量Δｆを係数とした正弦関数で表現される。乗算部９５１の乗算結果のうち、直交信号Ｓq(ｔ)を表す成分を通過させ、直交信号Ｓq(ｔ)を表す成分よりも高域側の成分を除去するローパスフィルターが低域通過部９５３として利用される。具体的には、乗算部９５１の乗算結果から和成分(ｆ0＋Δｆ＋ｆ0)が低域通過部９５３により除去される。

Figure 0007010002000005
The second processing unit 95 generates an orthogonal signal Sq (t) by multiplying the observation signal Sb (t) by the second period signal Zq (t) generated by the signal processing unit 91. The second processing unit 95 of the first embodiment includes a multiplication unit 951 and a low frequency passage unit 953. The multiplication unit 951 multiplies the observation signal Sb (t) expressed by the equation (1) and the second period signal Zq (t) expressed by the equation (3). The multiplication result by the multiplication unit 951 (the signal expressed by the product of the equation (1) and the equation (3)) includes the sum component (f0 + Δf + f0) and the difference component (f0 + Δf−f0) of the fundamental frequency f0 and the fluctuation amount Δf. Is included. The low-pass passage unit 953 generates an orthogonal signal Sq (t) expressed by the following mathematical formula (5) from the multiplication result of the multiplication unit 951. As can be understood from the equation (5), the orthogonal signal Sq (t) is expressed by a sine function having the fluctuation amount Δf as a coefficient. Among the multiplication results of the multiplication unit 951, a low-pass filter that passes a component representing the orthogonal signal Sq (t) and removes a component on the higher frequency side than the component representing the orthogonal signal Sq (t) is used as the low-pass filter section 953. It will be used. Specifically, the sum component (f0 + Δf + f0) is removed from the multiplication result of the multiplication unit 951 by the low frequency passage unit 953.
Figure 0007010002000005

差分算定部９７は、同相信号Ｓi(ｔ)と直交信号Ｓq(ｔ)とから、基本周波数ｆ0に対する観測周波数ｆの変動を表す指標（以下「周波数変動指標」という）を算定する。具体的には、差分算定部９７は、同相信号Ｓi(ｔ)および直交信号Ｓq(ｔ)で規定され、時間軸上の第１時点ｔ1における信号値が示す第１偏角θ1と、同相信号Ｓi(ｔ)および直交信号Ｓq(ｔ)で規定され、第１時点ｔ1とは異なる第２時点ｔ2における信号値が示す第２偏角θ2との差分を周波数変動指標として算定する。第１時点ｔ1は、Ａ／Ｄ変換器のサンプリング周期Ｔのｎ個分に相当する時間だけ時点ｔ0よりも後方の時点（ｔ0＋ｎＴ）である。第２時点ｔ2は、サンプリング周期Ｔの（ｎ＋１）個分に相当する時間だけ時点ｔ0よりも後方の時点（ｔ0＋(ｎ＋１)Ｔ）である。すなわち、第１時点ｔ1と第２時点ｔ2とは、時間軸上で相前後するサンプリング点である。時点ｔ0は時間軸上の特定の時点である。 The difference calculation unit 97 calculates an index (hereinafter referred to as “frequency fluctuation index”) representing the fluctuation of the observed frequency f with respect to the fundamental frequency f0 from the in-phase signal Si (t) and the orthogonal signal Sq (t). Specifically, the difference calculation unit 97 is defined by the in-phase signal Si (t) and the orthogonal signal Sq (t), and is the same as the first deviation angle θ1 indicated by the signal value at the first time point t1 on the time axis. The difference from the second deviation angle θ2 indicated by the signal value at the second time point t2, which is defined by the phase signal Si (t) and the orthogonal signal Sq (t) and is different from the first time point t1, is calculated as the frequency fluctuation index. The first time point t1 is a time point (t0 + nT) behind the time point t0 by the time corresponding to n sampling cycles T of the A / D converter. The second time point t2 is a time point (t0 + (n + 1) T) after the time point t0 by a time corresponding to (n + 1) pieces of the sampling cycle T. That is, the first time point t1 and the second time point t2 are sampling points that are in phase with each other on the time axis. The time point t0 is a specific time point on the time axis.

ここで、数式(4)の同相信号Ｓi(ｔ)の信号値と数式(5)の直交信号Ｓq(ｔ)の信号値とは、以下の数式(6)の複素関数で表現することが可能である（オイラーの公式）。数式(6)は、時点ｔにおける偏角が２πΔｆｔで表現される複素関数である。

Figure 0007010002000006
第１実施形態の差分算定部９７は、数式(6)で表現される複素関数について、第１時点ｔ1における第１偏角θ1と、第２時点ｔ2における第２偏角θ2との差分を周波数変動指標として算定する。具体的には、数式(6)で表現される複素関数について、第１時点ｔ1と第２時点ｔ2との間における自己相関Ｃ(ｔ)の偏角ＡrgＣ(ｔ)が周波数変動指標として算定される。自己相関Ｃ(ｔ)は、以下の数式(7)で表現される。数式(7)の２πΔｆｔ1が第１偏角θ1であり、数式(7)の２πΔｆｔ2が第２偏角θ2である。数式(7)における自己相関Ｃ(ｔ)の偏角ＡrgＣ(ｔ)である２πΔｆＴが、第１偏角θ1と第２偏角θ2との差分を表す。
Figure 0007010002000007
 Here, the signal value of the in-phase signal Si (t) in the equation (4) and the signal value of the orthogonal signal Sq (t) in the equation (5) can be expressed by the complex function of the following equation (6). It is possible (Euler's formula). Equation (6) is a complex function in which the argument at time point t is expressed by 2πΔft.
Figure 0007010002000006
 The difference calculation unit 97 of the first embodiment determines the difference between the first argument θ1 at the first time point t1 and the second argument θ2 at the second time point t2 for the complex function expressed by the mathematical formula (6). Calculated as a fluctuation index. Specifically, for the complex function expressed by the mathematical formula (6), the argument ArgC (t) of the autocorrelation C (t) between the first time point t1 and the second time point t2 is calculated as a frequency fluctuation index. To. The autocorrelation C (t) is expressed by the following mathematical formula (7). The 2πΔft1 of the equation (7) is the first argument θ1, and the 2πΔft2 of the equation (7) is the second argument θ2. 2πΔfT, which is the argument ArgC (t) of the autocorrelation C (t) in the equation (7), represents the difference between the first argument θ1 and the second argument θ2.
Figure 0007010002000007

図３の指標算定部９８は、差分算定部９７が算定した周波数変動指標（ＡrgＣ(ｔ)）から脈周期Ｐを算定する。脈周期Ｐは、数式(7)の関係を考慮すると、以下の数式(8)の演算により算定される。

Figure 0007010002000008
数式(8)から理解さる通り、脈周期Ｐは、基本周波数ｆ0に対する変動量Δｆの割合で表現される。指標算定部９８は、検出信号Ｓa(ｔ)のサンプリング周期Ｔ毎に脈周期Ｐを算定する。つまり、指標算定部９８は、時間軸上の相異なる時点に対応する複数の脈周期Ｐの時系列（すなわち心拍変動）を特定する。 The index calculation unit 98 in FIG. 3 calculates the pulse cycle P from the frequency fluctuation index (ArgC (t)) calculated by the difference calculation unit 97. The pulse cycle P is calculated by the following formula (8) in consideration of the relation of the formula (7).
Figure 0007010002000008
 As can be understood from the equation (8), the pulse period P is expressed by the ratio of the fluctuation amount Δf to the fundamental frequency f0. The index calculation unit 98 calculates the pulse cycle P for each sampling cycle T of the detection signal Sa (t). That is, the index calculation unit 98 specifies a time series (that is, heart rate variability) of a plurality of pulse cycles P corresponding to different time points on the time axis.

変動算定部６８は、指標算定部９８が特定した心拍変動から心拍変動指標を算定する。例えば心拍変動の標準偏差を表すＳＤＮＮ(standard deviation of NN intervals)や、交感神経のバランスを表したＬＦ(Low Frequency)／ＨＦ（High Frequency）比が心拍変動指標として例示される。ＳＤＮＮおよびＬＦ／ＨＦ比の算定には、公知の技術が任意に採用される。表示装置２４は、変動算定部６８が算定した心拍変動指標を表示する。 The fluctuation calculation unit 68 calculates the heart rate variability index from the heart rate variability specified by the index calculation unit 98. For example, SDNN (standard deviation of NN intervals), which represents the standard deviation of heart rate variability, and the LF (Low Frequency) / HF (High Frequency) ratio, which represents the balance of sympathetic nerves, are exemplified as heart rate variability indexes. Known techniques are optionally employed in the calculation of SDNN and LF / HF ratios. The display device 24 displays the heart rate variability index calculated by the fluctuation calculation unit 68.

図６は、制御装置２０が実行する処理（以下「脈波解析処理」という）のフローチャートである。例えば、被験者からの指示を契機として脈波解析処理が実行される。図６の脈波解析処理は、周波数解析部６２による基本周波数ｆ0の特定後に、時間軸上のサンプリング周期Ｔ毎に実行される。脈波解析処理を開始すると、成分抽出部６４は、検出信号Ｓa(ｔ)のうち脈波の基本周波数ｆ0を含む解析帯域Ｂ内の成分を観測信号Ｓb(ｔ)として抽出する（Ｓ1）。すなわち、検出信号Ｓa(ｔ)のうち解析帯域Ｂ外に存在するノイズの影響を低減した観測信号Ｓb(ｔ)が生成される。信号処理部９１は、数式(1)で表現される第１周期信号Ｚi(ｔ)と、数式(2)で表現される第２周期信号Ｚq(ｔ)とを生成する（Ｓ2）。第１処理部９３は、第１周期信号Ｚi(ｔ)を観測信号Ｓb(ｔ)に乗算することで、前述の数式(4)で表現される同相信号Ｓi(ｔ)を生成する（Ｓ3）。第２処理部９５は、第２周期信号Ｚq(ｔ)を観測信号Ｓb(ｔ)に乗算することで、前述の数式(5)で表現される直交信号Ｓq(ｔ)を生成する（Ｓ4）。なお、ステップＳ3とステップＳ4との順番の先後は不問である。差分算定部９７は、同相信号Ｓi(ｔ)と直交信号Ｓq(ｔ)とから周波数変動指標を算定する（Ｓ5）。数式(4)の同相信号Ｓi(ｔ)の信号値と数式(5)の直交信号Ｓq(ｔ)の信号値との関係を表す数式(6)の複素関数について、第１時点ｔ1と第２時点ｔ2との間における自己相関Ｃ(ｔ)の偏角ＡrgＣ(ｔ)が周波数変動指標として算定される。自己相関Ｃ(ｔ)は、前述の数式(7)で表現される。指標算定部９８は、周波数変動指標から脈周期Ｐを算定する。脈周期Ｐの算定には、前述の数式(8)が利用される。 FIG. 6 is a flowchart of a process (hereinafter referred to as “pulse wave analysis process”) executed by the control device 20. For example, the pulse wave analysis process is executed triggered by an instruction from the subject. The pulse wave analysis process of FIG. 6 is executed every sampling period T on the time axis after the frequency analysis unit 62 specifies the fundamental frequency f0. When the pulse wave analysis process is started, the component extraction unit 64 extracts the component in the analysis band B including the fundamental frequency f0 of the pulse wave from the detection signal Sa (t) as the observation signal Sb (t) (S1). That is, the observation signal Sb (t) in which the influence of noise existing outside the analysis band B in the detection signal Sa (t) is reduced is generated. The signal processing unit 91 generates a first period signal Zi (t) expressed by the equation (1) and a second period signal Zq (t) expressed by the equation (2) (S2). The first processing unit 93 multiplies the observation signal Sb (t) by the first period signal Zi (t) to generate the common mode signal Si (t) expressed by the above equation (4) (S3). ). The second processing unit 95 generates an orthogonal signal Sq (t) expressed by the above equation (5) by multiplying the observation signal Sb (t) by the second period signal Zq (t) (S4). .. It should be noted that the order of step S3 and step S4 does not matter. The difference calculation unit 97 calculates the frequency fluctuation index from the in-phase signal Si (t) and the orthogonal signal Sq (t) (S5). Regarding the complex function of the equation (6) representing the relationship between the signal value of the in-phase signal Si (t) of the equation (4) and the signal value of the orthogonal signal Sq (t) of the equation (5), the first time point t1 and the first The deviation angle ArgC (t) of the autocorrelation C (t) between the two time points t2 is calculated as a frequency fluctuation index. The autocorrelation C (t) is expressed by the above-mentioned mathematical formula (7). The index calculation unit 98 calculates the pulse cycle P from the frequency fluctuation index. The above-mentioned mathematical formula (8) is used to calculate the pulse cycle P.

以上の説明から理解される通り、第１実施形態では、検出信号Ｓa(ｔ)のうち脈波の基本周波数ｆ0を含む解析帯域Ｂ内の成分が観測信号Ｓb(ｔ)として抽出され、当該観測信号Ｓb(ｔ)を利用して脈周期Ｐが算定される。以上の構成によれば、例えば検出信号Ｓa(ｔ)から（つまり解析帯域Ｂ以外の成分も含む信号から）脈周期Ｐを算定する構成と比較して、生体の体動に起因したノイズや装置の回路ノイズの影響を低減した脈周期Ｐを算定することができる。したがって、検出信号Ｓa(ｔ)から脈周期Ｐを高精度に算定することができる。ひいては、脈周期Ｐから高精度に周波数変動指標を算定することが可能である。 As can be understood from the above description, in the first embodiment, the component in the analysis band B including the fundamental frequency f0 of the pulse wave is extracted as the observation signal Sb (t) from the detection signal Sa (t), and the observation is performed. The pulse cycle P is calculated using the signal Sb (t). According to the above configuration, noise and devices caused by the body movement of the living body are compared with the configuration in which the pulse period P is calculated from, for example, the detection signal Sa (t) (that is, from the signal including the components other than the analysis band B). It is possible to calculate the pulse period P in which the influence of the circuit noise of the above is reduced. Therefore, the pulse period P can be calculated with high accuracy from the detection signal Sa (t). As a result, it is possible to calculate the frequency fluctuation index with high accuracy from the pulse period P.

また、上述の通り、周波数解析部６２による基本周波数ｆ0の特定と、成分抽出部６４による観測信号Ｓb(ｔ)の抽出には共通の検出信号Ｓa(ｔ)が利用される。すなわち、周波数変動指標の算定に利用される検出信号Ｓa(ｔ)の解析により基本周波数ｆ0が特定される。以上の構成によれば、周波数変動指標の算定に利用する検出信号Ｓa(ｔ)を基本周波数ｆ0の特定に流用できるという利点がある。 Further, as described above, the common detection signal Sa (t) is used for the frequency analysis unit 62 to specify the fundamental frequency f0 and the component extraction unit 64 to extract the observation signal Sb (t). That is, the fundamental frequency f0 is specified by the analysis of the detection signal Sa (t) used for calculating the frequency fluctuation index. According to the above configuration, there is an advantage that the detection signal Sa (t) used for calculating the frequency fluctuation index can be diverted to specify the fundamental frequency f0.

＜第２実施形態＞
本発明の第２実施形態を説明する。なお、以下に例示する各形態において作用または機能が第１実施形態と同様である要素については、第１実施形態の説明で使用した符号を流用して各々の詳細な説明を適宜に省略する。 <Second Embodiment>
A second embodiment of the present invention will be described. For the elements whose actions or functions are the same as those of the first embodiment in each of the embodiments exemplified below, the reference numerals used in the description of the first embodiment will be diverted and detailed description of each will be omitted as appropriate.

第１実施形態では、成分抽出部６４における解析帯域Ｂの帯域幅は固定である。それに対して、第２実施形態では、成分抽出部６４における解析帯域Ｂの帯域幅は可変である。図７は、第２実施形態に係る制御装置２０の機能に着目した構成図である。第２実施形態の制御装置２０は、第１実施形態の制御装置２０が実現した機能（周波数解析部６２，成分抽出部６４，演算処理部６６，変動算定部６８）に加えて、帯域制御部６９の機能を実現する。 In the first embodiment, the bandwidth of the analysis band B in the component extraction unit 64 is fixed. On the other hand, in the second embodiment, the bandwidth of the analysis band B in the component extraction unit 64 is variable. FIG. 7 is a configuration diagram focusing on the function of the control device 20 according to the second embodiment. The control device 20 of the second embodiment has a band control unit in addition to the functions (frequency analysis unit 62, component extraction unit 64, arithmetic processing unit 66, fluctuation calculation unit 68) realized by the control device 20 of the first embodiment. Achieve 69 functions.

帯域制御部６９は、指標算定部９８が算定した脈周期Ｐに応じて、成分抽出部６４における解析帯域Ｂの帯域幅を制御する。具体的には、脈周期Ｐの時系列（つまり心拍変動）の散布度（脈周期Ｐのバラツキを表す指標）に応じて、解析帯域Ｂの帯域幅が制御される。心拍変動の散布度が大きい場合には帯域幅が広くなるように制御され、心拍変動の散布度が小さい場合には帯域幅が狭くなるように制御される。成分抽出部６４は、帯域制御部６９により設定された帯域幅の解析帯域Ｂを利用して、検出信号Ｓa(ｔ)から観測信号Ｓb(ｔ)を抽出する。 The band control unit 69 controls the bandwidth of the analysis band B in the component extraction unit 64 according to the pulse cycle P calculated by the index calculation unit 98. Specifically, the bandwidth of the analysis band B is controlled according to the degree of dispersion of the time series of the pulse cycle P (that is, the heart rate variability) (an index showing the variation of the pulse cycle P). When the degree of spread of heart rate variability is large, the bandwidth is controlled to be wide, and when the degree of spread of heart rate variability is small, the bandwidth is controlled to be narrow. The component extraction unit 64 extracts the observation signal Sb (t) from the detection signal Sa (t) by using the analysis band B having the bandwidth set by the band control unit 69.

第２実施形態においても第１実施形態と同様の効果が実現される。第２実施形態では、脈周期Ｐに応じて、成分抽出部６４における解析帯域Ｂの帯域幅が制御されるから、解析帯域Ｂの帯域幅が固定である第１実施形態の構成と比較して、脈周期Ｐの変動する範囲に応じた適切な解析帯域Ｂが設定される。 The same effect as that of the first embodiment is realized in the second embodiment. In the second embodiment, since the bandwidth of the analysis band B in the component extraction unit 64 is controlled according to the pulse cycle P, the bandwidth of the analysis band B is fixed as compared with the configuration of the first embodiment. , An appropriate analysis band B is set according to the fluctuation range of the pulse cycle P.

第１実施形態および第２実施形態では、周波数解析部６２が１個の単位期間について特定した基本周波数ｆ0を、成分抽出部６４における解析帯域Ｂの設定と、同相信号Ｓi(ｔ)および直交信号Ｓq(ｔ)の周波数の設定とに適用する構成を便宜的に例示した。実際には、時間軸上の単位期間毎に周波数解析部６２が基本周波数ｆ0を反復的に特定し、基本周波数ｆ0の特定毎に、成分抽出部６４における解析帯域Ｂの設定と、第１周期信号Ｚi(ｔ)および第２周期信号Ｚq(ｔ)の生成とに当該基本周波数ｆ0が適用される。すなわち、基本周波数ｆ0は順次に更新される。 In the first embodiment and the second embodiment, the fundamental frequency f0 specified by the frequency analysis unit 62 for one unit period is set to the analysis band B in the component extraction unit 64, and the in-phase signal Si (t) and orthogonal to each other. The configuration applied to the setting of the frequency of the signal Sq (t) is exemplified for convenience. Actually, the frequency analysis unit 62 repeatedly specifies the fundamental frequency f0 for each unit period on the time axis, and each time the fundamental frequency f0 is specified, the analysis band B is set in the component extraction unit 64 and the first cycle is set. The fundamental frequency f0 is applied to the generation of the signal Zi (t) and the second period signal Zq (t). That is, the fundamental frequency f0 is sequentially updated.

以上に説明した通り、本発明の好適な態様においては、検出信号Ｓa(ｔ)から順次に特定される基本周波数ｆ0に応じて成分抽出部６４の解析帯域Ｂを設定する構成（以下「構成Ａ」という）を採用する。構成Ａを採用することで実際の脈波解析装置（以下「実製品」という）から観測できる挙動を以下に説明する。 As described above, in the preferred embodiment of the present invention, the analysis band B of the component extraction unit 64 is set according to the fundamental frequency f0 sequentially specified from the detection signal Sa (t) (hereinafter, “configuration A”). ") Is adopted. The behavior that can be observed from an actual pulse wave analysis device (hereinafter referred to as "actual product") by adopting the configuration A will be described below.

図８に例示される通り、信号値が周期的に変動する検出信号Ｓa(ｔ)を実製品に付与した場合を想定する。検出信号Ｓa(ｔ)の周波数は、時点ｔa1まで１Ｈｚに維持され、時点ｔa1において１Ｈｚから２Ｈｚに不連続に変化し、時点ｔa1の後の時点ｔb1において２Ｈｚから１Ｈｚに不連続に変化する。 As illustrated in FIG. 8, it is assumed that the detection signal Sa (t) whose signal value fluctuates periodically is applied to the actual product. The frequency of the detection signal Sa (t) is maintained at 1 Hz until time point ta1, changes discontinuously from 1 Hz to 2 Hz at time point ta1, and discontinuously changes from 2 Hz to 1 Hz at time point tb1 after time point ta1.

実製品では、所定長の単位期間毎に基本周波数ｆ0が更新される。したがって、検出信号Ｓa(ｔ)の周波数が１Ｈｚから２Ｈｚに変動する時点ｔa1では基本周波数ｆ0は未だ更新されず、時点ｔa1から時間が経過した時点ｔa2（すなわち単位期間の端点）が到来することで基本周波数ｆ0が更新される。したがって、時点ｔa1から時点ｔa2までの期間内においては、検出信号Ｓa(ｔ)の周波数は２Ｈｚであるけれども、成分抽出部６４の解析帯域Ｂの中心周波数は依然として１Ｈｚに維持されるという状況になる。すなわち、観測信号Ｓb(ｔ)は、本来の周期的な変動である２Ｈｚの成分は低減されてノイズが優勢な信号となる。したがって、実製品Ａにおいては、指標算定部９８が算定する脈周期Ｐは、ノイズに起因した異常値となる。同様の理由により、図８から理解される通り、時点ｔb1から時点ｔb2の間においても脈周期Ｐは異常値となる。なお、検出信号Ｓa(ｔ)は、実際には生体の脈波を表す信号であるから、周波数が不連続に変動することはない。したがって、実際の測定の場面では、図８に例示したようなノイズは観測されず、脈周期Ｐを高精度に測定できるという所期の効果は実現される。 In the actual product, the fundamental frequency f0 is updated every unit period of a predetermined length. Therefore, at the time point ta1 where the frequency of the detection signal Sa (t) fluctuates from 1 Hz to 2 Hz, the fundamental frequency f0 is not yet updated, and the time point ta2 (that is, the end point of the unit period) when time has passed from the time point ta1 arrives. The fundamental frequency f0 is updated. Therefore, within the period from the time point ta1 to the time point ta2, the frequency of the detection signal Sa (t) is 2 Hz, but the center frequency of the analysis band B of the component extraction unit 64 is still maintained at 1 Hz. .. That is, the observation signal Sb (t) becomes a signal in which noise is predominant by reducing the component of 2 Hz, which is the original periodic fluctuation. Therefore, in the actual product A, the pulse cycle P calculated by the index calculation unit 98 is an abnormal value due to noise. For the same reason, as can be understood from FIG. 8, the pulse cycle P becomes an abnormal value even between the time point tb1 and the time point tb2. Since the detection signal Sa (t) is actually a signal representing a pulse wave of a living body, the frequency does not fluctuate discontinuously. Therefore, in the actual measurement scene, the noise as illustrated in FIG. 8 is not observed, and the desired effect that the pulse cycle P can be measured with high accuracy is realized.

他方、構成Ａを採用することなく脈周期Ｐを測定する構成（例えば成分抽出部６４を省略した構成）では、検出信号Ｓa(ｔ)の周波数の変化には迅速に追従して脈周期Ｐが測定される。したがって、時点ｔa1や時点ｔb1の直後の期間において脈周期Ｐは異常値とならない。以上の説明から理解される通り、検出信号Ｓa(ｔ)の周波数が不連続に変化した直後に脈周期Ｐが異常値となる場合、実製品は構成Ａを採用している可能性が高いと言える。なお、構成Ａを採用しない構成において、検出信号Ｓa(ｔ)の周波数が不連続に変化する時点の直後において異常値の発生を回避できるとは言っても、構成Ａを採用していない以上、脈周期Ｐの測定値にはノイズに起因した誤差が発生する。したがって、脈周期Ｐの高精度な測定という観点からすると、構成Ａを採用した構成が、構成Ａを採用しない構成と比較して有利であるという事情は変わらない。なお、実製品に付与する検出信号Ｓa(ｔ)は、図８の例示に限定されない。例えば周波数が経時的に変化するチャープ信号を検出信号Ｓa(ｔ)として利用してもよい。 On the other hand, in the configuration in which the pulse cycle P is measured without adopting the configuration A (for example, the configuration in which the component extraction unit 64 is omitted), the pulse cycle P rapidly follows the change in the frequency of the detection signal Sa (t). Be measured. Therefore, the pulse cycle P does not become an abnormal value in the period immediately after the time point ta1 or the time point tb1. As can be understood from the above explanation, if the pulse cycle P becomes an abnormal value immediately after the frequency of the detection signal Sa (t) changes discontinuously, it is highly possible that the actual product adopts the configuration A. I can say. Although it is possible to avoid the occurrence of an abnormal value immediately after the time when the frequency of the detection signal Sa (t) changes discontinuously in the configuration in which the configuration A is not adopted, as long as the configuration A is not adopted, the configuration A is not adopted. An error due to noise occurs in the measured value of the pulse cycle P. Therefore, from the viewpoint of highly accurate measurement of the pulse cycle P, the situation that the configuration adopting the configuration A is advantageous as compared with the configuration not adopting the configuration A does not change. The detection signal Sa (t) given to the actual product is not limited to the example shown in FIG. For example, a chirp signal whose frequency changes with time may be used as a detection signal Sa (t).

なお、以上の説明では、脈周期Ｐに着目したが、実製品が構成Ａを採用しているか否かを判断するための指標は、脈周期Ｐに限定されない。脈周期Ｐが異常値を取る場合は、脈周期Ｐの時系列（心拍変動）から算定される心拍変動指標も異常値をとり得る。したがって、心拍変動指標を利用して構成Ａを採用しているか否かを判断してもよい。具体的には、時点ｔa1から時点ｔa2までの期間や時点ｔb1から時点ｔb2までの期間において心拍変動指標が異常値となる場合には構成Ａを採用している可能性が高い。 In the above description, the pulse cycle P has been focused on, but the index for determining whether or not the actual product adopts the configuration A is not limited to the pulse cycle P. When the pulse cycle P takes an abnormal value, the heart rate variability index calculated from the time series (heart rate variability) of the pulse cycle P can also take an abnormal value. Therefore, it may be determined whether or not the configuration A is adopted by using the heart rate variability index. Specifically, if the heart rate variability index becomes an abnormal value in the period from the time point ta1 to the time point ta2 or the time point tb1 to the time point tb2, it is highly possible that the configuration A is adopted.

＜第３実施形態＞
図９は、第３実施形態における脈波解析装置１００の使用例を示す模式図である。図９に例示される通り、脈波解析装置１００は、相互に別体で構成された検出ユニット７１と表示ユニット７２とを具備する。検出ユニット７１は、前述の各形態で例示した検出装置３０を具備する。図１０には、被験者の上腕に装着される形態の検出ユニット７１が例示されている。図１０に例示される通り、被験者の手首に装着される形態の検出ユニット７１も好適である。 <Third Embodiment>
FIG. 9 is a schematic diagram showing a usage example of the pulse wave analysis device 100 in the third embodiment. As illustrated in FIG. 9, the pulse wave analysis device 100 includes a detection unit 71 and a display unit 72 that are configured as separate bodies from each other. The detection unit 71 includes the detection device 30 exemplified in each of the above-described embodiments. FIG. 10 illustrates a detection unit 71 in a form worn on the upper arm of a subject. As illustrated in FIG. 10, a detection unit 71 worn on the wrist of the subject is also suitable.

表示ユニット７２は、前述の各形態で例示した表示装置２４を具備する。例えば携帯電話機またはスマートフォン等の情報端末が表示ユニット７２の好適例である。ただし、表示ユニット７２の具体的な形態は任意である。例えば、被験者が携帯可能な腕時計型の情報端末、または、脈波解析装置１００の専用の情報端末を表示ユニット７２として利用してもよい。 The display unit 72 includes the display device 24 exemplified in each of the above-described embodiments. For example, an information terminal such as a mobile phone or a smartphone is a suitable example of the display unit 72. However, the specific form of the display unit 72 is arbitrary. For example, a wristwatch-type information terminal that can be carried by the subject, or a dedicated information terminal of the pulse wave analysis device 100 may be used as the display unit 72.

検出信号Ｓa(ｔ)から心拍変動指標を算定するための要素（以下「演算部」という）は、例えば表示ユニット７２に搭載される。演算部は、図３に例示された要素（周波数解析部６２，成分抽出部６４，演算処理部６６，変動算定部６８）を包含する。演算部は、例えば表示ユニット７２に搭載される。検出ユニット７１の検出装置３０が生成した検出信号Ｓa(ｔ)が有線または無線で表示ユニット７２に送信される。表示ユニット７２の演算部は、検出信号Ｓa(ｔ)から心拍変動指標を算定して表示装置２４に表示する。 An element for calculating the heart rate variability index from the detection signal Sa (t) (hereinafter referred to as “calculation unit”) is mounted on the display unit 72, for example. The arithmetic unit includes the elements exemplified in FIG. 3 (frequency analysis unit 62, component extraction unit 64, arithmetic processing unit 66, variation calculation unit 68). The calculation unit is mounted on the display unit 72, for example. The detection signal Sa (t) generated by the detection device 30 of the detection unit 71 is transmitted to the display unit 72 by wire or wirelessly. The calculation unit of the display unit 72 calculates the heart rate variability index from the detection signal Sa (t) and displays it on the display device 24.

なお、演算部を検出ユニット７１に搭載してもよい。演算部は、検出装置３０が生成した検出信号Ｓa(ｔ)から心拍変動指標を算定し、当該心拍変動指標を表示するためのデータを表示ユニット７２に有線または無線で送信する。表示ユニット７２の表示装置２４は、検出ユニット７１から受信したデータが示す心拍変動指標を表示する。 The calculation unit may be mounted on the detection unit 71. The calculation unit calculates a heart rate variability index from the detection signal Sa (t) generated by the detection device 30, and transmits data for displaying the heart rate variability index to the display unit 72 by wire or wirelessly. The display device 24 of the display unit 72 displays the heart rate variability index indicated by the data received from the detection unit 71.

＜変形例＞
以上に例示した各形態は多様に変形され得る。具体的な変形の態様を以下に例示する。以下の例示から任意に選択された２以上の態様を適宜に併合することも可能である。 <Modification example>
Each of the above-exemplified forms can be variously modified. Specific modes of modification are illustrated below. It is also possible to appropriately merge two or more embodiments arbitrarily selected from the following examples.

（１）前述の各形態の脈波解析装置１００は変動算定部６８を具備する構成を例示したが、変動算定部６８を脈波解析装置１００から省略してもよい。例えば指標算定部９８が算定した脈周期Ｐが表示装置２４に表示される。また、脈波解析装置１００が算定した脈周期Ｐを脈波解析装置１００とは別体の情報端末（例えば携帯電話機またはスマートフォン）に送信して、当該情報端末が脈周期Ｐから心拍変動指標を算定してもよい。 (1) Although the configuration of each of the above-mentioned pulse wave analysis devices 100 including the fluctuation calculation unit 68 is illustrated, the fluctuation calculation unit 68 may be omitted from the pulse wave analysis device 100. For example, the pulse cycle P calculated by the index calculation unit 98 is displayed on the display device 24. Further, the pulse cycle P calculated by the pulse wave analysis device 100 is transmitted to an information terminal (for example, a mobile phone or a smartphone) separate from the pulse wave analysis device 100, and the information terminal outputs a heart rate variability index from the pulse cycle P. You may calculate.

（２）前述の各形態では、指標算定部９８は、生体の脈周期Ｐを算定したが、指標算定部９８が算定する指標は脈周期Ｐに限定されない。例えば脈周期Ｐの段階を複数の候補（例えば、異常／高目／通常、など）から特定して被験者に報知することも可能である。または、基準となる脈周期Ｐ（例えば基本周波数ｆ0の逆数に相当する周期）からの変動量を算定して被験者に報知してもよい。以上の説明から理解される通り、指標算定部９８が算定する指標は、生体の脈周期Ｐに関する周期指標として包括的に表現される。 (2) In each of the above-mentioned forms, the index calculation unit 98 calculates the pulse cycle P of the living body, but the index calculated by the index calculation unit 98 is not limited to the pulse cycle P. For example, it is also possible to identify the stage of the pulse cycle P from a plurality of candidates (for example, abnormal / high / normal, etc.) and notify the subject. Alternatively, the fluctuation amount from the reference pulse cycle P (for example, the cycle corresponding to the reciprocal of the fundamental frequency f0) may be calculated and notified to the subject. As understood from the above explanation, the index calculated by the index calculation unit 98 is comprehensively expressed as a periodic index relating to the pulse cycle P of the living body.

（３）前述の各形態では、数式(6)の複素関数について、第１時点ｔ1と第２時点ｔ2との間における自己相関Ｃ(ｔ)の偏角ＡrgＣ(ｔ)を周波数変動指標として算定したが、周波数変動指標の算定方法は以上の例示に限定されない。数式(6)の複素関数について、第１偏角θ1と第２偏角θ2とをそれぞれ算定し、当該第１偏角θ1と第２偏角θ2との差分を周波数変動指標として算定してもよい。ただし、自己相関Ｃ(ｔ)の偏角ＡrgＣ(ｔ)を周波数変動指標として算定する前述の各形態によれば、第１偏角θ1と第２偏角θ2とをそれぞれ算定することが不要になる。 (3) In each of the above-mentioned forms, for the complex function of the equation (6), the argument ArgC (t) of the autocorrelation C (t) between the first time point t1 and the second time point t2 is calculated as the frequency fluctuation index. However, the calculation method of the frequency fluctuation index is not limited to the above examples. For the complex function of equation (6), the first argument θ1 and the second argument θ2 can be calculated respectively, and the difference between the first argument θ1 and the second argument θ2 can be calculated as the frequency fluctuation index. good. However, according to each of the above-mentioned forms in which the declination ArgC (t) of the autocorrelation C (t) is calculated as a frequency fluctuation index, it is not necessary to calculate the first declination θ1 and the second declination θ2, respectively. Become.

（４）前述の各形態では、周波数解析部６２による基本周波数ｆ0の特定と、成分抽出部６４による観測信号Ｓb(ｔ)の抽出とに共通の検出信号Ｓa(ｔ)を利用したが、周波数解析部６２による基本周波数ｆ0の特定と、成分抽出部６４による観測信号Ｓb(ｔ)の抽出とに別個の検出信号Ｓa(ｔ)を利用してもよい。検出装置３０を利用しない方法で基本周波数ｆ0を取得してもよい。例えば、脈波解析装置１００とは別体の情報端末から基本周波数ｆ0を取得して周期指標の特定に利用してもよい。 (4) In each of the above-described embodiments, the detection signal Sa (t) common to the identification of the fundamental frequency f0 by the frequency analysis unit 62 and the extraction of the observation signal Sb (t) by the component extraction unit 64 is used. A separate detection signal Sa (t) may be used for the identification of the fundamental frequency f0 by the analysis unit 62 and the extraction of the observation signal Sb (t) by the component extraction unit 64. The fundamental frequency f0 may be acquired by a method that does not use the detection device 30. For example, the fundamental frequency f0 may be acquired from an information terminal separate from the pulse wave analysis device 100 and used for specifying the periodic index.

（５）前述の各形態では、単体の機器として構成された脈波解析装置１００を例示したが、以下の例示の通り、脈波解析装置１００の複数の要素は相互に別体の装置として実現され得る。なお、以下の説明では、検出信号Ｓa(ｔ)から心拍変動指標を算定する要素を「演算部２７」と表記する。演算部２７は、例えば、図３に例示された要素（周波数解析部６２，成分抽出部６４，演算処理部６６，変動算定部６８）を包含する。なお、第２実施形態の構成では、帯域制御部６９も演算部２７に含まれる。 (5) In each of the above-described embodiments, the pulse wave analysis device 100 configured as a single device is exemplified, but as shown in the following example, the plurality of elements of the pulse wave analysis device 100 are realized as separate devices from each other. Can be done. In the following description, the element for calculating the heart rate variability index from the detection signal Sa (t) is referred to as "calculation unit 27". The calculation unit 27 includes, for example, the elements exemplified in FIG. 3 (frequency analysis unit 62, component extraction unit 64, calculation processing unit 66, fluctuation calculation unit 68). In the configuration of the second embodiment, the band control unit 69 is also included in the calculation unit 27.

前述の各形態では、検出装置３０を具備する脈波解析装置１００を例示したが、図１１に例示される通り、検出装置３０を脈波解析装置１００とは別体とした構成も想定される。検出装置３０は、例えば被験者の手首や上腕等の測定部位Ｍに装着される可搬型の光学センサーモジュールである。脈波解析装置１００は、例えば携帯電話機またはスマートフォン等の情報端末で実現される。腕時計型の情報端末で脈波解析装置１００を実現してもよい。検出装置３０が生成した検出信号Ｓa(ｔ)が有線または無線で脈波解析装置１００に送信される。脈波解析装置１００の演算部２７は、検出信号Ｓa(ｔ)から心拍変動指標を算定して表示装置２４に表示する。以上の説明から理解される通り、検出装置３０は脈波解析装置１００から省略され得る。 In each of the above-described embodiments, the pulse wave analysis device 100 including the detection device 30 is exemplified, but as illustrated in FIG. 11, a configuration in which the detection device 30 is separate from the pulse wave analysis device 100 is also assumed. .. The detection device 30 is a portable optical sensor module mounted on a measurement site M such as a subject's wrist or upper arm. The pulse wave analysis device 100 is realized by an information terminal such as a mobile phone or a smartphone. The pulse wave analysis device 100 may be realized by a wristwatch type information terminal. The detection signal Sa (t) generated by the detection device 30 is transmitted to the pulse wave analysis device 100 by wire or wirelessly. The calculation unit 27 of the pulse wave analysis device 100 calculates a heart rate variability index from the detection signal Sa (t) and displays it on the display device 24. As understood from the above description, the detection device 30 may be omitted from the pulse wave analysis device 100.

前述の各形態では、表示装置２４を具備する脈波解析装置１００を例示したが、図１２に例示される通り、表示装置２４を脈波解析装置１００とは別体とした構成も想定される。脈波解析装置１００の演算部２７は、検出信号Ｓa(ｔ)から心拍変動指標を算定し、当該心拍変動指標を表示するためのデータを表示装置２４に送信する。表示装置２４は、専用の表示機器であってもよいが、例えば、携帯電話機もしくはスマートフォン等の情報端末、または、被験者が携帯可能な腕時計型の情報端末に搭載されてもよい。脈波解析装置１００の演算部２７が算定した心拍変動指標は、有線または無線により表示装置２４に送信される。表示装置２４は、脈波解析装置１００から受信した心拍変動指標を表示する。以上の説明から理解される通り、表示装置２４は脈波解析装置１００から省略され得る。 In each of the above-described embodiments, the pulse wave analysis device 100 including the display device 24 is illustrated, but as illustrated in FIG. 12, a configuration in which the display device 24 is separate from the pulse wave analysis device 100 is also assumed. .. The calculation unit 27 of the pulse wave analysis device 100 calculates a heart rate variability index from the detection signal Sa (t), and transmits data for displaying the heart rate variability index to the display device 24. The display device 24 may be a dedicated display device, but may be mounted on, for example, an information terminal such as a mobile phone or a smartphone, or a wristwatch-type information terminal that can be carried by a subject. The heart rate variability index calculated by the calculation unit 27 of the pulse wave analysis device 100 is transmitted to the display device 24 by wire or wirelessly. The display device 24 displays the heart rate variability index received from the pulse wave analysis device 100. As understood from the above description, the display device 24 may be omitted from the pulse wave analysis device 100.

図１３に例示される通り、検出装置３０および表示装置２４を脈波解析装置１００（演算部２７）とは別体とした構成も想定される。例えば、脈波解析装置１００（演算部２７）が、携帯電話機やスマートフォン等の情報端末に搭載される。 As illustrated in FIG. 13, it is assumed that the detection device 30 and the display device 24 are separate from the pulse wave analysis device 100 (calculation unit 27). For example, the pulse wave analysis device 100 (calculation unit 27) is mounted on an information terminal such as a mobile phone or a smartphone.

（６）前述の各形態では、筐体部１２とベルト１４とを具備する腕時計型の脈波解析装置１００を例示したが、脈波解析装置１００の具体的な形態は任意である。例えば、被験者の身体に貼付可能なパッチ型、被験者の耳部に装着可能な耳装着型、被験者の指先に装着可能な指装着型（例えば着爪型）、または、被験者の頭部に装着可能な頭部装着型など、任意の形態の脈波解析装置１００が採用され得る。 (6) In each of the above-described embodiments, the wristwatch-type pulse wave analysis device 100 including the housing portion 12 and the belt 14 is exemplified, but the specific form of the pulse wave analysis device 100 is arbitrary. For example, a patch type that can be attached to the subject's body, an ear-mounted type that can be attached to the subject's ear, a finger-mounted type that can be attached to the subject's fingertips (for example, a nail-attached type), or a subject's head that can be attached. Any form of pulse wave analysis device 100, such as a head-mounted type, can be adopted.

（７）前述の各形態では、被験者の心拍変動指標を表示装置２４に表示したが、心拍変動指標を被験者に報知するための構成は以上の例示に限定されない。例えば、心拍変動指標を音声で被験者に報知することも可能である。被験者の耳部に装着可能な耳装着型の脈波解析装置１００においては、心拍変動指標を音声で報知する構成が特に好適である。また、心拍変動指標を被験者に報知することは必須ではない。例えば、脈波解析装置１００が算定した心拍変動指標を通信網から他の通信装置に送信してもよい。また、脈波解析装置１００の記憶装置２２や脈波解析装置１００に着脱可能な可搬型の記録媒体に心拍変動指標を格納してもよい。 (7) In each of the above-described embodiments, the heart rate variability index of the subject is displayed on the display device 24, but the configuration for notifying the subject of the heart rate variability index is not limited to the above examples. For example, it is also possible to notify the subject of the heart rate variability index by voice. In the ear-worn pulse wave analysis device 100 that can be worn on the selvage of the subject, a configuration in which the heart rate variability index is notified by voice is particularly suitable. In addition, it is not essential to notify the subject of the heart rate variability index. For example, the heart rate variability index calculated by the pulse wave analysis device 100 may be transmitted from the communication network to another communication device. Further, the heart rate variability index may be stored in a portable recording medium that can be attached to and detached from the storage device 22 of the pulse wave analysis device 100 or the pulse wave analysis device 100.

（８）前述の各形態に係る脈波解析装置１００は、前述の例示の通り、制御装置２０とプログラムとの協働により実現される。本発明の好適な態様に係るプログラムは、コンピューターが読取可能な記録媒体に格納された形態で提供されてコンピューターにインストールされ得る。また、配信サーバーが具備する記録媒体に格納されたプログラムを、通信網を介した配信の形態でコンピューターに提供することも可能である。記録媒体は、例えば非一過性（non-transitory）の記録媒体であり、ＣＤ-ＲＯＭ等の光学式記録媒体（光ディスク）が好例であるが、半導体記録媒体または磁気記録媒体等の公知の任意の形式の記録媒体を包含し得る。なお、非一過性の記録媒体とは、一過性の伝搬信号（transitory, propagating signal）を除く任意の記録媒体を含み、揮発性の記録媒体を除外するものではない。 (8) The pulse wave analysis device 100 according to each of the above-mentioned embodiments is realized by the cooperation between the control device 20 and the program as in the above-mentioned example. The program according to a preferred embodiment of the present invention may be provided and installed in a computer in a form stored in a computer-readable recording medium. It is also possible to provide a program stored in a recording medium included in a distribution server to a computer in the form of distribution via a communication network. The recording medium is, for example, a non-transitory recording medium, and an optical recording medium (optical disc) such as a CD-ROM is a good example, but a known arbitrary such as a semiconductor recording medium or a magnetic recording medium. Can include recording media in the form of. The non-transient recording medium includes any recording medium other than the transient propagation signal (transitory, propagating signal), and does not exclude the volatile recording medium.

１００…脈波解析装置、１２…筐体部、１４…ベルト、２０…制御装置、２２…記憶装置、２４…表示装置、３０…検出装置、３１…発光部、３２…受光部、３３…駆動回路、３４…出力回路、６２…周波数解析部、６４…成分抽出部、６６…演算処理部、６８…変動算定部、６９…帯域制御部、９１…信号処理部、９３…第１処理部、９５…第２処理部、９７…差分算定部、９８…指標算定部、９３１，９５１…乗算部、９３３，９５３…低域通過部。



100 ... pulse wave analysis device, 12 ... housing unit, 14 ... belt, 20 ... control device, 22 ... storage device, 24 ... display device, 30 ... detection device, 31 ... light emitting unit, 32 ... light receiving unit, 33 ... drive Circuit, 34 ... Output circuit, 62 ... Frequency analysis unit, 64 ... Component extraction unit, 66 ... Arithmetic processing unit, 68 ... Fluctuation calculation unit, 69 ... Band control unit, 91 ... Signal processing unit, 93 ... First processing unit, 95 ... 2nd processing unit, 97 ... difference calculation unit, 98 ... index calculation unit, 931,951 ... multiplication unit, 933, 953 ... low frequency passage unit.

Claims (8)

生体の脈波を表す脈波信号のうち、当該脈波の基本周波数を含む解析帯域内の成分を観測信号として抽出する成分抽出部と、
前記基本周波数で変動する第１周期信号を、前記観測信号に乗算することで、同相信号を生成する第１処理部と、
前記第１周期信号に直交し、前記基本周波数で変動する第２周期信号を、前記観測信号に乗算することで、直交信号を生成する第２処理部と、
前記同相信号および前記直交信号で規定され、時間軸上の第１時点における信号値が示す第１偏角と、前記同相信号および前記直交信号で規定され、前記第１時点とは異なる第２時点における信号値が示す第２偏角との差分を、前記基本周波数に対する周波数の変動を表す周波数変動指標として算定する差分算定部と、
前記生体の脈周期に関する周期指標を前記周波数変動指標から算定する指標算定部と
を具備する脈波解析装置。 Of the pulse wave signals representing the pulse waves of a living body, a component extraction unit that extracts components in the analysis band including the fundamental frequency of the pulse wave as an observation signal, and a component extraction unit.
A first processing unit that generates an in-phase signal by multiplying the observed signal by a first-period signal that fluctuates at the fundamental frequency.
A second processing unit that generates an orthogonal signal by multiplying the observed signal by a second period signal that is orthogonal to the first period signal and fluctuates at the fundamental frequency.
The first deviation angle defined by the in-phase signal and the orthogonal signal and indicated by the signal value at the first time point on the time axis, and the first deviation angle defined by the in-phase signal and the orthogonal signal and different from the first time point. A difference calculation unit that calculates the difference from the second deviation angle indicated by the signal value at two time points as a frequency fluctuation index showing the frequency fluctuation with respect to the fundamental frequency.
A pulse wave analysis device including an index calculation unit that calculates a cycle index related to the pulse cycle of a living body from the frequency fluctuation index. 前記脈波信号の解析により前記基本周波数を特定する周波数解析部を具備する
請求項１の脈波解析装置。 The pulse wave analysis device according to claim 1, further comprising a frequency analysis unit that identifies the fundamental frequency by analyzing the pulse wave signal. 前記差分算定部は、前記同相信号の信号値と前記直交信号の信号値との関係を表す複素関数について、前記第１時点と前記第２時点との間における自己相関の偏角を、前記周波数変動指標として算定する
請求項１または請求項２の脈波解析装置。 The difference calculation unit determines the argument of the autocorrelation between the first time point and the second time point for the complex function representing the relationship between the signal value of the in-phase signal and the signal value of the orthogonal signal. The pulse wave analysis device according to claim 1 or 2, which is calculated as a frequency fluctuation index. 前記周期指標に応じて前記解析帯域の帯域幅を制御する帯域制御部を具備する
請求項１から請求項３の何れかの脈波解析装置。 The pulse wave analysis apparatus according to any one of claims 1 to 3, further comprising a band control unit that controls the bandwidth of the analysis band according to the periodic index. 前記第１時点と前記第２時点とは、時間軸上で相前後するサンプリング点である The first time point and the second time point are sampling points that are in phase with each other on the time axis.
請求項１から請求項４の何れかの脈波解析装置。 The pulse wave analysis apparatus according to any one of claims 1 to 4. 前記第１処理部は、前記第１周期信号と前記観測信号との積で表現される信号から高域側の振動成分を除去することで前記同相信号を生成し、前記第２処理部は、前記第２周期信号と前記観測信号との積で表現される信号から高域側の振動成分を除去することで前記直交信号を生成する The first processing unit generates the in-phase signal by removing the vibration component on the high frequency side from the signal represented by the product of the first period signal and the observation signal, and the second processing unit generates the in-phase signal. , The orthogonal signal is generated by removing the vibration component on the high frequency side from the signal expressed by the product of the second period signal and the observed signal.
請求項５の脈波解析装置。 The pulse wave analysis device according to claim 5. 生体の脈波を表す脈波信号のうち、当該脈波の基本周波数を含む解析帯域内の成分を観測信号として抽出し、
前記基本周波数で変動する第１周期信号を、前記観測信号に乗算することで、同相信号を生成し、
前記第１周期信号に直交し、前記基本周波数で変動する第２周期信号を、前記観測信号に乗算することで、直交信号を生成し、
前記同相信号および前記直交信号で規定され、時間軸上の第１時点における信号値が示す第１偏角と、前記同相信号および前記直交信号で規定され、前記第１時点第２時点における信号値が示す第２偏角との差分を、前記基本周波数に対する周波数の変動を表す周波数変動指標として算定し、
前記生体の脈周期に関する周期指標を前記周波数変動指標から算定する
脈波解析方法。 Of the pulse wave signals representing the pulse wave of a living body, the components in the analysis band including the fundamental frequency of the pulse wave are extracted as observation signals.
By multiplying the observed signal by the first period signal that fluctuates at the fundamental frequency, an in-phase signal is generated.
An orthogonal signal is generated by multiplying the observation signal by a second period signal orthogonal to the first period signal and fluctuating at the fundamental frequency.
The first deviation angle defined by the in-phase signal and the orthogonal signal and indicated by the signal value at the first time point on the time axis, and defined by the in-phase signal and the orthogonal signal, at the second time point of the first time point. The difference from the second deviation angle indicated by the signal value is calculated as a frequency fluctuation index showing the frequency fluctuation with respect to the fundamental frequency.
A pulse wave analysis method for calculating a cycle index relating to the pulse cycle of a living body from the frequency fluctuation index. 生体の脈波を表す脈波信号のうち、当該脈波の基本周波数を含む解析帯域内の成分を観測信号として抽出する成分抽出部、
前記基本周波数で変動する第１周期信号を、前記観測信号に乗算することで、同相信号を生成する第１処理部、
前記第１周期信号に直交し、前記基本周波数で変動する第２周期信号を、前記観測信号に乗算することで、直交信号を生成する第２処理部、
前記同相信号および前記直交信号で規定され、時間軸上の第１時点における信号値が示す第１偏角と、前記同相信号および前記直交信号で規定され、前記第１時点第２時点における信号値が示す第２偏角との差分を、前記基本周波数に対する周波数の変動を表す周波数変動指標として算定する差分算定部、および、
前記生体の脈周期に関する周期指標を前記周波数変動指標から算定する指標算定部
としてコンピューターを機能させるプログラム。 A component extraction unit that extracts components in the analysis band including the fundamental frequency of the pulse wave as an observation signal from the pulse wave signals representing the pulse waves of a living body.
A first processing unit that generates an in-phase signal by multiplying the observed signal by a first-period signal that fluctuates at the fundamental frequency.
A second processing unit that generates an orthogonal signal by multiplying the observed signal by a second period signal that is orthogonal to the first period signal and fluctuates at the fundamental frequency.
The first deviation angle defined by the in-phase signal and the orthogonal signal and indicated by the signal value at the first time point on the time axis, and defined by the common-mode signal and the orthogonal signal, at the second time point of the first time point. A difference calculation unit that calculates the difference from the second deviation angle indicated by the signal value as a frequency fluctuation index indicating frequency fluctuation with respect to the fundamental frequency, and
A program that makes a computer function as an index calculation unit that calculates a cycle index related to the pulse cycle of a living body from the frequency fluctuation index.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001137201A (en) 1999-11-12 2001-05-22 Matsushita Electric Ind Co Ltd Bloodless continuous sphygmomanometer
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