WO2011086644A1

WO2011086644A1 - Biometric information measuring device and method for same

Info

Publication number: WO2011086644A1
Application number: PCT/JP2010/007368
Authority: WO
Inventors: 謙治蛤
Original assignee: コニカミノルタセンシング株式会社
Priority date: 2010-01-18
Filing date: 2010-12-20
Publication date: 2011-07-21

Abstract

In the disclosed biometric information measuring device (SA) and method for the same, a histogram based on measurement data related to measured predetermined physiological phenomena of a living being is acquired by a histogram calculation unit (35); predetermined statistical parameters in the acquired histogram are acquired by a statistical parameter calculation unit (40); predetermined information for acquiring biometric information of the living body, such as a pv value, is acquired by a pv calculation unit (41) by using a model prepared beforehand representing a relationship between the predetermined information and the statistical parameters; and then, on the basis of the acquired predetermined information, which is the pv value in this example, the predetermined biometric information, which is the SpO2 value in this example, is obtained by an SpO2 calculation unit (42).

Description

Biological information measuring apparatus and method

The present invention relates to a biological information measuring apparatus that measures biological information related to a living body by measuring physiological phenomena of the living body, and in particular, even when noise occurs due to, for example, body movement of the living body, for example, blood oxygen saturation or pulse rate The present invention relates to a biological information measuring device and a biological information measuring method capable of suitably measuring numbers and the like.

As is well known, the significance of monitoring the oxygen concentration in living tissue is extremely great in clinical practice. Oxygen is the most important substance for maintaining life activity, and the parameters relating to oxygen supply are important because biological tissue cells are seriously damaged when the supply of oxygen is cut off. For this reason, when oxygen supply can become unstable, for example, when treating patients with anesthesia, post-surgery, respiratory failure and circulatory failure, monitor whether or not oxygen is being supplied appropriately This is very important. Oxygen supply to the living tissue is performed by arterial blood. Therefore, in order to grasp whether or not oxygen supply to the living tissue is appropriately performed, living body information such as a pulse rate and blood oxygen saturation is monitored.

Conventionally, a biological information measuring device called a pulse oximeter has been known as a device for measuring biological information such as pulse rate and blood oxygen saturation. This biological information measuring device uses a fluctuation component in the amount of transmitted or reflected light of living tissue caused by pulsation of arterial blood, and measures the attenuation of pulsation with two different wavelengths of light, and calculates the oxygen saturation from the ratio. It is a device to seek. This biological information measuring device has a feature that it can be easily measured in a non-invasive manner, and is disclosed in Patent Document 1, for example.

In the apparatus disclosed in Patent Document 1, the received light signal of the red light transmitted through the living tissue is filtered by a plurality of relatively narrow bandpass filters, and the received light of the infrared light transmitted through the living tissue. The signal is also filtered by a plurality of band-pass filters having relatively narrow bands, and the ratio of the red light signal to the infrared light signal (red light signal / infrared light signal) from each of the filtered signals. ) And the blood oxygen saturation is obtained from the histogram of this ratio.

In Patent Document 1, as described above, a relatively clear double peak in which noise is suppressed is obtained by filtering each of the received light signal of red light and the received light signal of infrared light with a plurality of bandpass filters. The histogram which has is obtained (for example, refer to FIG. 22 of Patent Document 1). However, when each of the received light signal of red light and the received light signal of infrared light is filtered by a single filter, for example, it has a relatively clear double peak as in Patent Document 1 due to noise such as body movement of a living body. In many cases, a histogram cannot be obtained. For this reason, it is difficult to obtain biological information such as a pulse rate and blood oxygen saturation with relatively high accuracy.

US Pat. No. 7,509,154

The present invention is an invention made in view of the above-described circumstances, and its object is to provide a biological information measuring device capable of measuring biological information more accurately even when noise occurs due to, for example, body movement of the living body, and the like. It is to provide a biological information measurement method.

In the biological information measuring device and the biological information measuring method according to the present invention, a histogram is obtained based on the measured measurement data relating to a predetermined physiological phenomenon of the living body, and predetermined statistical parameters in the obtained histogram are obtained. The predetermined information is obtained by using a model prepared in advance representing the relationship between the predetermined information for obtaining the biological information of the biological body and the statistical parameter, and the obtained predetermined information is included in the obtained predetermined information. Based on this, the predetermined biological information is obtained. For this reason, the living body information measuring device and the living body information measuring method having such a configuration can measure living body information with higher accuracy even when noise occurs due to, for example, body movement of the living body.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

It is a figure which shows the structure of the biometric information measuring apparatus in 1st Embodiment. It is a flowchart which shows operation | movement of the biometric information measuring apparatus of 1st Embodiment in the case of calculating | requiring oxygen saturation. It is a flowchart which shows operation | movement of the biometric information measuring apparatus of 1st Embodiment in the case of calculating | requiring a pulse rate. It is a figure which shows the histogram of 3rd ratio P in a 1st case. It is a figure which shows the histogram of 3rd ratio P in a 2nd case. It is a figure which shows the histogram of 3rd ratio P in a 3rd case. It is a figure which shows the structure of the biometric information measuring apparatus in 2nd Embodiment. It is a flowchart which shows operation | movement of the biometric information measuring apparatus of 2nd Embodiment in the case of calculating | requiring oxygen saturation.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of a biological information measurement apparatus according to the first embodiment. The biological information measuring device SA in the first embodiment is a device that measures biological information related to a living body by measuring a physiological phenomenon of the living body that is a measurement target. The biological information is, for example, a pulse rate and blood oxygen saturation. Such biological information can be obtained by using a fluctuation component in the amount of transmitted or reflected light of biological tissue caused by pulsation of arterial blood, and the basic principle thereof is a well-known conventional means. -0264437 and the like.

For example, as shown in FIG. 1, the biological information measuring apparatus SA has a sensor unit 1 that measures a predetermined physiological phenomenon of a living body and outputs measurement data, and measurement data measured by the sensor unit 1. Based on, for example, a calculation control unit 3A that measures biological information such as a pulse rate and blood oxygen saturation, and a display unit 6 that displays the biological information measured by the calculation control unit 3A so as to be recognized from the outside. The

The sensor unit 1 is connected to the arithmetic control unit 3A, and in this embodiment, is a device that measures information related to blood in a living tissue as a physiological phenomenon of the living body. More specifically, the sensor unit 1 is a device that measures a fluctuation component in the amount of transmitted or reflected light of living tissue caused by arterial blood pulsation due to a heartbeat as a physiological phenomenon of the living body.

Examples of a method for measuring a physiological phenomenon of such a living body include a method using the light absorption characteristics of hemoglobin in a living tissue. Oxygen is transported to each cell of the living body by hemoglobin, but hemoglobin combines with oxygen in the lung to become oxygenated hemoglobin, and returns to hemoglobin (reduced hemoglobin) when oxygen is consumed in the cells of the living body. Blood oxygen saturation is defined as the percentage of oxyhemoglobin in the blood (in the blood). The absorbance of each of these hemoglobin and oxyhemoglobin has a wavelength dependency, and hemoglobin absorbs more light than oxyhemoglobin for red light (red wavelength region light), for example, while infrared light (infrared light) Less light is absorbed than oxyhemoglobin. In other words, when hemoglobin is oxidized to oxygenated hemoglobin, the absorption of red light decreases and the absorption of infrared light increases. Conversely, when it is reduced to return to hemoglobin, the absorption of red light increases and the absorption of infrared light increases. It has an optical property that absorption is reduced. The living body information measuring apparatus SA of the present embodiment uses such a difference in light absorption characteristics of hemoglobin and oxidized hemoglobin with respect to red light and infrared light, for example, a living body such as a pulse rate and blood oxygen saturation. It seeks information.

Due to such a method, the sensor unit 1 according to the present embodiment includes, for example, a first sensor unit 11 that measures the light absorption characteristics in the biological tissue with respect to red light, and a first sensor that measures the light absorption characteristics in the biological tissue with respect to infrared light. 2 sensor unit 12 and is connected to arithmetic control unit 3A. The first sensor unit 11 includes, for example, an R light emitting element such as a light emitting diode that irradiates the biological tissue with red light having a wavelength λ1, and red light that is irradiated by the R light emitting element and transmitted or reflected by the biological tissue. For example, the second sensor unit 12 is configured to irradiate the living tissue with infrared light having a wavelength λ2 different from the wavelength λ1, for example, a light-emitting diode. An IR light emitting element and an IR light receiving element such as a silicon photodiode that receives infrared light irradiated by the IR light emitting element and transmitted or reflected by the living tissue are configured. The sensor unit 1 can use such a transmission type or reflection type sensor.

The sensor unit 1 is set in a predetermined biological tissue such as a finger, an earlobe, or the back of the hand, wrist, or foot of an infant, and measured by the first and second measuring units 11 and 12. Data is output to the arithmetic control unit 3A. More specifically, in the first sensor unit 11 having such a configuration, the R light emitting element emits red light to the living tissue, and the R light receiving element is applied to the living tissue by the R light emitting element. The red light R that is transmitted or reflected by the irradiated red light through the living tissue is received, and the received red light is photoelectrically converted, so that an electric signal corresponding to the amount of received light is used as the measurement data in the arithmetic control unit 3A. Output to. Similarly, in the second sensor unit 12, the IR light emitting element irradiates the biological tissue with infrared light, and the IR light receiving element emits infrared light irradiated onto the biological tissue by the IR light emitting element. By receiving infrared light transmitted or reflected through the living tissue and photoelectrically converting the received infrared light, an electrical signal corresponding to the amount of received light is output to the arithmetic control unit 3A as the measurement data.

The arithmetic control unit 3A is connected to the display unit 6 and obtains biological information based on measurement data measured by the sensor unit 1 and controls the entire biological information measuring device SA. The arithmetic control unit 3A acquires time series data of measurement data from the sensor unit 1 by sampling the measurement data measured by the sensor unit 1 at a predetermined sampling period (for example, a frequency of 37.5 Hz, for example). is there. Further, for example, the arithmetic control unit 3A acquires measurement data from the sensor unit 1 as time-series data by driving the sensor unit 1 with a predetermined cycle, that is, by causing each operation of light emission and light reception to be performed. Further, for example, the sensor unit 1 samples the measurement data as time-series data by sampling at a predetermined sampling period, and outputs the measurement data of the time-series data to the arithmetic control unit 3A. This measurement data may be analog data, but in the present embodiment, it is digital data, and conversion from analog data to digital data (AD conversion) is performed by the sensor unit 1 or the arithmetic control unit 3A. Further, if necessary, the sensor unit 1 or the calculation control unit 3A may further include an amplification unit that amplifies the measurement data before AD conversion.

More specifically, the arithmetic control unit 3A obtains a histogram based on the measurement data measured by the sensor unit 1, obtains a predetermined statistical parameter in the obtained histogram, and obtains a predetermined living body related to the living body to be measured. When a predetermined information for obtaining information is an output variable and the predetermined statistical parameter is an input variable, a model representing a relationship between the output variable and the input variable is stored in advance, and the obtained The predetermined information is obtained by using a statistical parameter in the model, and the predetermined biological information is obtained based on the obtained predetermined information. For example, a micro that includes a microprocessor, a memory, and its peripheral circuit Consists of a computer. The memory includes various programs such as a biological information calculation program for obtaining biological information based on measurement data measured by the sensor unit 1, a control program for controlling the entire biological information measuring device SA, and a sensor unit. For example, EEPROM (Electrically Erasable Programmable Read Only Memory) or non-volatile storage that stores various data such as the measurement data measured in step 1 and data necessary for execution of the program The device includes a ROM (Read Only Memory) that is an element and a RAM (Random Access Memory) that is a volatile storage element that serves as a so-called working memory of the microprocessor. Central Processing Unit) etc., by executing the program Functionally, for example, a first preprocessing unit 31, a second preprocessing unit 32, a first bandpass filter unit (first BPF unit) 33, and a second bandpass filter unit (second BPF unit) 34, , Histogram calculation unit 35, ratio calculation unit 36, cross-correlation calculation unit 37, first autocorrelation calculation unit 38, second autocorrelation calculation unit 39, statistical parameter calculation unit 40, pv calculation unit 41, , An SpO2 calculation unit 42, a pulse rate calculation unit 43, and a reliability calculation unit 44.

The first and

second preprocessing units

31 and 32 perform predetermined preprocessing on the measurement data input from the sensor unit 1. More specifically, the first preprocessing unit 31 performs so-called dark processing for correcting dark current in the R light receiving element on the measurement data related to red light input from the first sensor unit 11. Then, a first ratio (red light _AC / DC ratio) R (= R _AC / R _DC ) of the _AC component R _AC to the DC component R _DC is calculated, and the first BPF unit 33 is notified (output). To do. The second preprocessing unit 32 performs a so-called dark process for correcting dark current in the IR light receiving element on the measurement data related to the infrared light input from the second sensor unit 12, and A second ratio (infrared light _AC / DC ratio) IR (= IR _AC / IR _DC ) of the _AC component IR _AC with respect to the DC component IR _DC is calculated, and the second ratio IR is notified (output) to the first BPF unit 33. For the dark process, a known method is used. For example, an output value (dark current value) Rdark output from the R light receiving element in a light-shielded state is subtracted from the measurement data related to the red light, and the infrared light is subtracted from the infrared light. This is performed by subtracting the output value (dark current value) IRdark output from the IR light receiving element in the light shielding state from the measurement data concerned. The output values Rdark and IRdark output from the light-receiving R light-receiving element and the IR light-receiving element are measured in advance.

The first and

second BPF units

33 and 34 are filters that remove a predetermined noise component from the measurement data measured by the sensor unit 1, and are usually included as fluctuation components in the amount of transmitted or reflected light of living tissue caused by pulsation of arterial blood. The frequency components other than the frequency components to be removed are removed. The first BPF unit 33 is, for example, a filter having a predetermined frequency band including a frequency component that is normally included as a fluctuation component in the amount of transmitted or reflected light of biological tissue caused by pulsation of arterial blood with respect to red light. The ratio R is filtered (filtered), and the first ratio R after the filter processing is notified to each of the ratio calculator 36, the cross-correlation calculator 37, the first autocorrelation calculator 38, and the pulse rate calculator 43. . The second BPF unit 34 is, for example, a filter having a predetermined frequency band including a frequency component normally included as a fluctuation component in the amount of transmitted or reflected light of living tissue caused by pulsation of arterial blood with respect to infrared light as a pass band. Filter the 2 ratio IR (filtering), and notify the second ratio IR after the filter process to each of the ratio calculator 36, the cross-correlation calculator 37, the second autocorrelation calculator 39, and the pulse rate calculator 43. To do. In the biological information measuring apparatus SA of the present embodiment, there is one band pass filter for the measurement data related to the light of one wavelength, and there is not a plurality as in the technique disclosed in Patent Document 1. Further, in Patent Document 1, it is disclosed that, in a histogram relating to oxygen saturation, the maximum or minimum oxygen saturation at which a peak occurs or the frequency in the histogram is not zero is obtained. However, a model such as a first order polynomial, a rational expression, and an irrational expression related to the statistical parameters is not used from a plurality of statistical parameters as in the present embodiment.

The ratio calculation unit 36 calculates a third ratio (two-wavelength variation ratio) P (= R / IR) of the first ratio R with respect to the second ratio IR, and notifies the histogram calculation unit 35 of the third ratio P. It is.

The histogram calculation unit 35 calculates a histogram (frequency distribution) of the third ratio P obtained from the measurement data measured by the sensor unit 1 within a predetermined time range, and uses the histogram of the third ratio as a statistical parameter calculation unit. 40 is notified. The predetermined time range is a time range in which the number of pieces of measurement data for which the histogram is statistically significant can be acquired, and the number of pieces of measurement data is, for example, 300, 400, 500, or the like. The histogram calculation unit 35 classifies a predetermined range assumed as a numerical range that can be taken by the third ratio P into a plurality of classes (classes) at predetermined intervals, and from the time of creating this histogram. The frequency of the third ratio P in each class is obtained by allocating each of the plurality of third ratios P input from the ratio calculation unit 36 up to the predetermined time to one of these classes. Thereby, the histogram calculation unit 35 obtains a histogram of the third ratio P.

The statistical parameter calculation unit 40 calculates a predetermined statistical parameter for the histogram of the third ratio P calculated by the histogram calculation unit 35, and uses the calculated statistical parameter as the pv calculation unit 41, the SpO2 calculation unit 42, and the reliability. This is notified to each part of the calculation unit 44. The predetermined statistical parameter may be, for example, an average value or a standard deviation in a histogram of the third ratio P, and may be an average value or a standard deviation in a moving average histogram of the third ratio P, for example. .

The cross-correlation calculating unit 37 calculates a cross-correlation CC between the first ratio R related to red light and the second ratio IR related to infrared light, and the calculated cross-correlation CC is used as the SpO2 calculating unit 42 and the reliability. This is notified to each part of the calculation unit 44. When the first ratio R at time t is R (t) and the second ratio IR (t) at time t, the cross-correlation CC is expressed by the following equation A1.
CC = Σ (R (t) × IR (t)) (A1)
However, Σ is calculated for each measurement data R (ti), IR (ti); i = 0 to −M from the latest measurement data at the time of histogram calculation to the past measurement data at the time before the predetermined time. Is done. The subscript i represents the i-th measurement data of M + 1 pieces of measurement data.

First correlation calculating unit 38 calculates the first autocorrelation SC _R of the first ratio R according to the red light, each unit of the first autocorrelation SC _R a SpO2 calculation section 42 and the reliability calculation unit 44 that the calculated To notify. The first autocorrelation SC _R, is expressed by the following equation A2.
_{^{SC R = Σ (R (t}} ) 2) ··· (A2)
However, Σ is calculated for each measurement data R (ti), IR (ti); i = 0 to −M from the latest measurement data at the time of histogram calculation to the past measurement data at the time before the predetermined time. Is done.

The second correlation calculation unit 39 calculates a second autocorrelation SC _IR of the second ratio IR related to infrared light, and uses the calculated second autocorrelation SC _IR of the SpO2 calculation unit 42 and the reliability calculation unit 44. It notifies to each part. The second autocorrelation SC _IR is represented by the following equation A3.
SC _IR = Σ (IR (t) ² ) (A3)
However, Σ is calculated for each measurement data R (ti), IR (ti); i = 0 to −M from the latest measurement data at the time of histogram calculation to the past measurement data at the time before the predetermined time. Is done.

The pv calculation unit 41 calculates predetermined second information pv ^ for obtaining the noise component ratio pv based on the statistical parameter in the histogram of the third ratio P calculated by the statistical parameter calculation unit 40, and this The calculated second information pv ^ is notified to the SpO2 calculation unit 42 and the pulse rate calculation unit 43. This second information pv ^ is the position of a dip in the third ratio P histogram. When this predetermined second information pv ^ for obtaining predetermined biological information relating to the measurement target biological body is used as an output variable and the predetermined statistical parameter is set as an input variable x1, x2, x3,. , A model representing the relationship between the output variable pv ^ and the input variables x1, x2, x3, ..., xl; pv ^ = f (x1, x2, x3, ..., xl) is, for example, a multiple regression analysis Etc., and is stored in the pv calculation unit 41. The pv calculation unit 41 uses the statistical parameter obtained by the statistical parameter calculation unit 40 for this model; pv ^ = f (x1, x2, x3,..., xl), thereby obtaining the predetermined second information pv ^. Ask for. Thus, a plurality of statistical parameters x1, x2, x3,..., Xl are used in the model. For this reason, the biological information measuring device SA of the present embodiment can use a model that is more appropriately approximated, and can measure biological information with higher accuracy. From this point of view, the model includes each of a plurality of statistical parameters independently as the input variable, and at least two products of the plurality of statistical parameters and / or a ratio thereof are one or more. It may be included as an input variable.

The SpO2 calculation unit 42 is a statistical parameter in the histogram of the third ratio P calculated by the statistical parameter calculation unit 40, the second information pv ^ calculated by the pv calculation unit 41, and the cross correlation calculated by the cross correlation calculation unit 37. CC, based on the second autocorrelation SC _IR calculated by the first autocorrelation SC _R and the second autocorrelation calculating section 39 calculated by the first autocorrelation calculating unit 38 calculates the oxygen saturation, and the calculated The oxygen saturation is notified to the reliability calculation unit 44 and is output to the display unit 6. More specifically, SpO2 calculation unit 42, the second information pv calculated by pv calculator 41 ^, first autocorrelation SC _R and the second autocorrelation calculating section calculated by the first autocorrelation calculating unit 38 From the second autocorrelation SC _IR calculated by 39, pa ^ = (pv ^ × Σ {R (t) × IR (t)} − Σ {R (t)} ² ) / (pv ^ × Σ {IR (T)} ² −Σ {R (t) × IR (t)}) is used to obtain predetermined first information pa ^ for obtaining predetermined biological information related to the living body to be measured. By using a look-up table (calibration table) representing the relationship between the third ratio P (= R / IR) determined in advance and the oxygen saturation when there is substantially no noise, an estimated value of the oxygen saturation of arterial blood determine the SpO _2. That is, the third ratio R / IR in the lookup table closest to the first information pa ^ in the lookup table representing the relationship between the third ratio R / IR when there is no noise and the oxygen saturation SO _2. And the oxygen saturation SO ₂ corresponding to the third ratio R / IR is set as the estimated value SpO ₂ of the oxygen saturation of arterial blood. Further, SpO2 calculation unit 42, by using a look-up table (calibration table) representing the relationship between the second information pv ^ and oxygen saturation to determine the estimated value SvO ₂ oxygen saturation of venous blood.

The pulse rate calculator 43 calculates the pulse rate within a predetermined time (for example, based on the first ratio R related to red light, the second ratio IR related to infrared light, and pv ^ calculated by the pv calculator 41 (for example, 1 minute pulse rate) is calculated, and this pulse rate is output to the display unit 6.

The reliability calculation unit 44 is a statistical parameter in the histogram of the third ratio P calculated by the statistical parameter calculation unit 40, the oxygen saturation calculated by the SpO2 calculation unit 42, and the cross-correlation CC calculated by the cross-correlation calculation unit 37. , based on the second autocorrelation SC _IR calculated by the first autocorrelation SC _R and the second autocorrelation calculating section 39 calculated by the first autocorrelation calculating unit 38 calculates the predetermined level of reliability, and the calculated The reliability is output to the display unit 6.

The reliability is an index (degree) indicating how reliable the calculated value related to biological information is. Such reliability can be obtained by any one of the following formulas B1 to B6, for example. In the reliability z obtained by such an equation, the reliability of the blood oxygen saturation level decreases as the absolute value of the value z increases. In each of these equations, Σ calculates the sum for i.

z = (ΣR (ti) × IR (ti)) / (Σ {IR (ti)} ² ) − (Σ {R (ti)} ² ) / (ΣR (ti) × IR (ti)) (B1)
z = (Σ {IR (ti)} ² ) / (ΣR (ti) × IR (ti)) − [(Σ {R (ti)} ² ) / (Σ {IR (ti)} ² )] ² · .. (B2)
z = (Σ {R (ti)} ² ) / (Σ {IR (ti)} ² ) − [(ΣR (ti) × IR (ti)) / (Σ {IR (ti)} ² )] ² · .. (B3)
z = [(1 / N) × ΣR (ti) / IR (ti)] ² − (Σ {R (ti)} ² ) / (Σ {IR (ti)} ² ) (B4)
z = (ΣR (ti) × IR (ti)) / (Σ {IR (ti)} ² ) − (1 / N) × ΣR (ti) / IR (ti) (B5)
z = (Σ {R (ti)} ² ) / (ΣR (ti) × IR (ti)) − (1 / N) × ΣR (ti) / IR (ti) (B6)

The display unit 6 is a device for displaying the operating state of the biological information measuring device SA, the biological information obtained by the arithmetic control unit 3A, and the like, for example, a liquid crystal display device (LCD), an organic EL display device, and the like. For example, in the present embodiment, the display unit 6 includes a pulse rate display unit 61 that displays the pulse rate calculated by the pulse rate calculation unit 43 and an SpO2 display unit that displays the oxygen saturation calculated by the SpO2 calculation unit 42. 62, and a reliability display unit 63 that displays the reliability calculated by the reliability calculation unit 44.

Next, the operation of the biological information measuring device SA of the first embodiment will be described. FIG. 2 is a flowchart showing the operation of the biological information measuring apparatus according to the first embodiment when obtaining the oxygen saturation. FIG. 3 is a flowchart showing the operation of the biological information measuring apparatus according to the first embodiment when the pulse rate is obtained. FIG. 4 is a diagram showing a histogram of the third ratio P in the first case. FIG. 5 is a diagram showing a histogram of the third ratio P in the second case. FIG. 6 is a diagram showing a histogram of the third ratio P in the third case. The first case is a case where the living body is quiet and there is almost no noise, and the second and third cases are cases where the noise is superimposed due to, for example, body movement of the living body. FIG. 4 to FIG. 6 show an example of measurement results in each case. Note that the horizontal axis in FIGS. 4 to 6 is a class, and the vertical axis is frequency.

In the biological information measuring apparatus SA, for example, measurement of biological information on a biological object to be measured is started by turning on a power switch (not shown) or turning on a measurement start switch (not shown) after the power switch is turned on.

In the measurement of oxygen saturation, as shown in FIG. 2, first, in step S11, the first sensor unit 11 of the sensor unit 1 generates measurement data Rsignallanddark (including dark current) and its dark current Rdark related to red light. Measurement and conversion from an analog signal to a digital signal, and measurement data IRsignalland (including dark current) and its dark current IRdark relating to infrared light are measured by the second sensor unit 12 of the sensor unit 1 to obtain an analog signal. To digital signal.

Subsequently, in step S12, the first preprocessing unit 31 of the arithmetic control unit 3A performs dark processing (Rsignalland-Rdark) on the measurement data Rsignallandmark related to the red light input from the sensor unit 1, and first processing is performed. The ratio R is calculated, and the second preprocessing unit 32 of the arithmetic control unit 3A performs dark processing (Rsignalland-Rdark) on the measurement data IRsignallandmark related to the infrared light input from the sensor unit 1, A second ratio IR is calculated.

Subsequently, in step S13, the first BPF unit 33 of the calculation control unit 3A filters the first ratio R notified from the first preprocessing unit 31, and the second BPF unit 34 of the calculation control unit 3A executes the first ratio R. 2 The second ratio IR notified from the preprocessing unit 32 is filtered.

Subsequently, in step S14, each correlation value is calculated. That is, the cross-correlation calculating unit 37, the calculated cross-correlation CC between the first ratio R and the second ratio IR is, the first autocorrelation calculating unit 38, the autocorrelation SC _R of the first ratio R is calculated, and The second autocorrelation calculating unit 39 calculates the autocorrelation SC _IR of the second ratio IR. For example, each correlation value is calculated for the measurement data in the time range (tk + ti; i = 0 to −M) from the current time tk + t0 to the past time tk + t−M.

In step S15, the ratio calculation unit 36 of the calculation control unit 3A calculates the third ratio P of the first ratio R to the second ratio IR, and the histogram calculation unit 35 of the calculation control unit 3A calculates the predetermined time range. A histogram of the third ratio P at is calculated. For example, the histogram of the third ratio P is obtained for the measurement data in the time range (tk + ti; i = 0 to −N) from the current time tk + t0 to the past time tk + t−N.

For example, when the living body is resting and noise is hardly superimposed on the measurement data, for example, the histogram shown in FIG. 4 is obtained. When noise is superimposed on the measurement data due to movement, for example, histograms as shown in FIGS. 5 and 6 are obtained. The biological information measuring apparatus SA of the present embodiment, for example, with the profile histogram shown in FIG. 5 or FIG. Biological information such as degree can be measured.

Subsequently, in step S16, a predetermined statistical parameter (x1,...) Such as an average value or standard deviation σ in the histogram of the third ratio P obtained by the histogram calculation unit 35 by the statistical parameter calculation unit 40 of the arithmetic control unit 3A. x2, x3,..., xl) are obtained.

Subsequently, in step S17, the standard deviation σ in the histogram of the third ratio P, which is obtained as one of the statistical parameters in step S16 by the SpO2 calculation unit 42 of the arithmetic control unit 3A, is set to a predetermined threshold Th. It is judged whether it is larger. Since the standard deviation σ is generally an index representing variation in data, it can be used as an index for determining the degree of noise superimposed on the measurement data.

As a result of this determination, when the standard deviation σ is equal to or smaller than the predetermined threshold Th (No), Step S31 is executed, and when the standard deviation σ is larger than the predetermined threshold Th (Yes), Step S31 is performed. S18 is executed.

In step S31, when almost no noise is superimposed on the measurement data measured by the sensor unit 1 (for example, when the noise is 5% or less or 3% or less of the signal, the third ratio P). 4 is the profile shown in FIG. 4), for example, oxygen saturation is obtained by calculating the signal component ratio pa by Σ {(R (t) × IR (t)} / Σ {R (t)} ^2. The SpO2 calculating unit 42 calculates the blood oxygen saturation of the artery and the blood oxygen saturation of the vein by a known existing method such as obtaining the degree of blood, and the calculated blood oxygen saturation is displayed on the display unit. 6 is output to the SpO2 display unit 62, and then step S21 is executed.

Here, when measuring the absorbance of a living tissue, when the signal component corresponding to the change in absorbance is s and the noise component superimposed on this signal component is n, the first ratio R and the second ratio IR are The following expressions C1 and C2 hold.
IR = s + n (C1)
R = s × pa + n × pv (C2)

The signal component ratio pa is a ratio between the signal component s corresponding to the change in absorbance in infrared light and the signal component corresponding to the change in absorbance in red light. This signal component ratio pa is generally the oxygen saturation level in blood. It is known to correspond one-to-one. The noise component ratio pv is a ratio between the noise component n superimposed on the signal component s for infrared light and the noise component superimposed on the signal component for red light.

On the other hand, in step S18, since noise that cannot be ignored is superimposed on the measurement data measured by the sensor unit 1 (when the histogram of the third ratio P is the profile shown in FIGS. 5 and 6). , SpO2 calculation unit 42 calculates pv ^ from pv ^ = f (x1, x2, x3,..., Xl). Subsequently, in step S19, the SpO2 calculation unit 42 causes pa ^ = (pv ^ × Σ {R (t) × IR (t)} − Σ {R (t)} ² ) / (pv ^ × Σ {IR (T)} ² −Σ {R (t) × IR (t)}). However, Σ is calculated for each measurement data from the latest measurement data at the time of calculating the histogram to the past measurement data at the time preceding the predetermined time. That is, Σ is calculated for measurement data in the time range (tk + ti; i = 0 to −M) from the current time tk + t0 to the past time tk + t−M. Then, in step S20, the SpO2 calculation unit 42, these pa ^ and pv blood arterial oxygen saturation from ^ SpO ₂ and venous blood oxygen saturation SvO ₂ blood is calculated, the blood the calculated The intermediate oxygen saturation levels SpO ₂ and SvO ₂ are output to the SpO 2 display section 62 of the display section 6, and then step S 21 is executed.

Subsequently, in step S21, a predetermined reliability is calculated by the reliability calculation unit 44 of the arithmetic control unit 3A, and the calculated reliability is output to the reliability display unit 63 of the display unit 6 to obtain the oxygen saturation level. Is completed, and then the pulse rate calculation process is executed.

On the other hand, in the measurement of the pulse rate, as shown in FIG. 3, first, in step S41, R (t) −pv ^ × IR (t) is binarized by the pulse rate calculation unit 43 of the calculation control unit 3A. The Subsequently, in step S42, the pulse rate calculation unit 43 obtains a period T (j) of the binarized R (t) −pv ^ × IR (t) within a predetermined time, and the period T An average value Tave of (j) is calculated. Subsequently, in step S43, the pulse rate calculation unit 43 calculates the pulse rate based on the average value Tave of 60 / cycle in order to obtain the pulse rate for one minute, and the calculated pulse rate is displayed on the display unit 6. The data is output to the number display unit 61, and the process is terminated.

In the display unit 6, the pulse rate, the arterial and venous oxygen saturation levels and the reliability obtained by the arithmetic control unit 3 A are displayed in the pulse rate display unit 61, the SpO 2 display unit 62 and the reliability display unit 63. Displayed on each.

Since it operates in this way, the biological information measuring apparatus SA of the first embodiment can measure biological information such as pulse rate and oxygen saturation more accurately even when noise occurs due to, for example, body movement of the living body. Can do.

Next, another embodiment will be described.

(Second Embodiment)
FIG. 7 is a diagram illustrating a configuration of the biological information measurement device according to the second embodiment. The biological information measuring device SA according to the first embodiment calculates the second information pv ^ from the statistical parameter in the histogram of the third ratio P and calculates the oxygen saturation, but the biological information measuring device SB according to the second embodiment. Is to obtain the first information pa ^ and the second information pv ^ from the statistical parameters in the histogram of the third ratio P, and calculate the oxygen saturation. For this reason, the biological information measuring device SB of the second embodiment is configured to include an arithmetic control unit 3B described later instead of the arithmetic control unit 3A in the biological information measuring device SA of the first embodiment. That is, the biological information measuring device SB of the second embodiment includes, for example, as shown in FIG. 7, a sensor unit 1 that measures a predetermined physiological phenomenon of the living body and a predetermined physiological state of the living body that is measured by the sensor unit 1. For example, an arithmetic control unit 3B that measures biological information such as a pulse rate and blood oxygen saturation, and a display unit 6 that displays the biological information measured by the arithmetic control unit 3B so as to be recognized from the outside. Configured. Since the sensor unit 1 and the display unit 6 are the same as the sensor unit 1 and the display unit 6 in the biological information measuring apparatus SA of the first embodiment, description thereof is omitted.

And this calculation control part 3B is connected to the display part 6 similarly to the calculation control part 3A of 1st Embodiment, While calculating | requiring biometric information based on the measurement data measured by the sensor part 1, biometric information measurement The device controls the entire device SA, and is configured by, for example, a microcomputer including a microprocessor, a memory, and its peripheral circuits. The microprocessor is functionally executed by executing the program according to the second embodiment, for example, the first preprocessing unit 31, the second preprocessing unit 32, and the first bandpass filter unit (first 1BPF unit) 33, second bandpass filter unit (second BPF unit) 34, histogram calculation unit 35, ratio calculation unit 36, statistical parameter calculation unit 40, pa / pv calculation unit 51, and SpO2 / SvO2 A calculation unit 52, a pulse rate calculation unit 43, and a reliability calculation unit 53 are provided.

In the second embodiment, the first preprocessing unit 31, the second preprocessing unit 32, the first BPF unit 33, the second BPF unit 34, the histogram calculation unit 35, the ratio calculation unit 36, and the statistical parameter calculation unit 40 are the first implementation. Since it is the same as the first preprocessing unit 31, the second preprocessing unit 32, the first BPF unit 33, the second BPF unit 34, the histogram calculation unit 35, the ratio calculation unit 36, and the statistical parameter calculation unit 40 in the embodiment, the description thereof will be given. Omitted.

The pa · pv calculator 51 calculates predetermined first information pa ^ and noise component pv for obtaining the signal component ratio pa based on the statistical parameter in the histogram of the third ratio P calculated by the statistical parameter calculator 40. The predetermined second information pv ^ for obtaining the above is calculated, and the calculated first and second information pa ^ and pv ^ are notified to the SpO2 / SvO2 calculation unit 52 and the pulse rate calculation unit 43. When this predetermined first information pa ^ for obtaining predetermined biological information about the measurement target biological body is used as an output variable, and the predetermined statistical parameter is set as an input variable x1, x2, x3,. , A model representing the relationship between the output variable pa ^ and the input variables x1, x2, x3, ..., xl; pa ^ = g (x1, x2, x3, ..., xl) is, for example, a multiple regression analysis Etc., and is stored in the pa / pv calculation unit 51 in advance. The predetermined second information pv ^ for obtaining predetermined biological information related to the measurement target biological body is used as an output variable, and the predetermined statistical parameters are input variables x1, x2, x3,. Model representing the relationship between the output variable pv ^ and the input variables x1, x2, x3,..., Xl; pv ^ = f (x1, x2, x3,. It is obtained in advance by regression analysis or the like and stored in the pa / pv calculation unit 51. The pa · pv calculation unit 51 uses the statistical parameter obtained by the statistical parameter calculation unit 40 for this model; pa ^ = g (x1, x2, x3,..., xl), thereby obtaining the predetermined first information. By calculating pa ^ and using the statistical parameter obtained by the statistical parameter calculator 40 in this model; pv ^ = f (x1, x2, x3,..., xl), the predetermined second information pv ^ is obtained. Ask.

The SpO2 / SvO2 calculation unit 52 is based on the statistical parameter in the histogram of the third ratio P calculated by the statistical parameter calculation unit 40, and the first and second information pa ^ and pv ^ calculated by the pa / pv calculation unit 51. The oxygen saturation is calculated, and the calculated oxygen saturation is notified to the reliability calculation unit 53 and output to the display unit 6. Further, SpO2 · SvO2 calculator 52, by using a look-up table (calibration table) representing the relationship between the first information pa ^ and oxygen saturation, obtains the estimated value SpO ₂ oxygen saturation of arterial blood, the 2 By using a look-up table (calibration table) representing the relationship between information pv ^ and oxygen saturation, an estimated value SvO ₂ of oxygen saturation of venous blood is obtained.

The pulse rate calculation unit 43 calculates the pulse rate within a predetermined time based on the first ratio R related to red light, the second ratio IR related to infrared light, and pv ^ calculated by the pa · pv calculation unit 51. (For example, the pulse rate for 1 minute) is calculated, and this pulse rate is output to the display unit 6.

The reliability calculation unit 53 is a predetermined calculation set in advance based on the statistical parameter in the histogram of the third ratio P calculated by the statistical parameter calculation unit 40 and the oxygen saturation calculated by the SpO 2 / SvO 2 calculation unit 52. A predetermined reliability is calculated using an equation, and the calculated reliability is output to the display unit 6.

Next, the operation of the biological information measuring device SB of the second embodiment will be described. FIG. 8 is a flowchart showing the operation of the biological information measuring apparatus according to the second embodiment when obtaining the oxygen saturation.

In the biological information measuring device SB, for example, measurement of biological information of a living body to be measured is started by turning on a power switch (not shown) or turning on a measurement start switch (not shown) after the power switch is turned on.

In the biological information measuring device SB of the second embodiment, the operation for obtaining the pulse rate is the same as the above-described operation for obtaining the pulse rate in the biological information measuring device SA of the first embodiment, and thus the description thereof is omitted. Here, the operation for obtaining the oxygen saturation will be described.

That is, in the measurement of oxygen saturation in the biological information measuring device SB of the second embodiment, as shown in FIG. 8, the biological information measuring device SB of the second embodiment is the biological information measuring device SA of the first embodiment. Steps S51 to S57 similar to Steps S11 to S17 described above with reference to FIG. 2 are executed. If the result of determination in step S57 is that the standard deviation σ is equal to or less than the predetermined threshold Th (No), step S71 similar to step S31 in the biological information measuring device SA of the first embodiment is executed. After that, step S60 is executed, and when the standard deviation σ is larger than the predetermined threshold Th (Yes), step S58 is executed.

In this step S58, since noise that cannot be ignored is superimposed on the measurement data measured by the sensor unit 1 (when the histogram of the third ratio P is the profile shown in FIGS. 5 and 6), The SpO2 / SvO2 calculation unit 52 calculates pv ^ from pv ^ = f (x1, x2, x3,..., Xl), and pa ^ = g (x1, x2, x3,..., Xl). pa ^ is calculated. Subsequently, in step S59, the blood oxygen saturation of the artery and the blood oxygen saturation of the vein are calculated from the pa ^ and pv ^ by the SpO2 / SvO2 calculating unit 52, and each of the calculated blood oxygen saturations is calculated. The degree is output to the SpO2 display unit 62 of the display unit 6, and then step S60 is executed.

Subsequently, in step S60, a predetermined reliability is calculated by the reliability calculation unit 53 of the arithmetic control unit 3B, and the calculated reliability is output to the reliability display unit 63 of the display unit 6 to obtain the oxygen saturation level. Is completed, and then the pulse rate calculation process is executed.

As described above, the measurement of the pulse rate is performed in the same manner as the biological information measuring apparatus SA of the first embodiment, whereby the pulse rate is calculated. The calculated pulse rate is the pulse rate of the display unit 6. The data is output to the display unit 61, and the process is terminated.

In the display unit 6, the pulse rate, arterial and venous oxygen saturation levels and reliability obtained by the calculation control unit 3 B are stored in the pulse rate display unit 61, the SpO 2 display unit 62, and the reliability display unit 63. Displayed on each.

Since it operates in this way, the biological information measuring device SB of the second embodiment can measure biological information such as pulse rate and oxygen saturation more accurately even when noise occurs due to, for example, body movement of the living body. Can do.

The biological information measuring devices SA and SB in the first and second embodiments described above are connected to an external storage unit (not shown) or an external storage unit and exchange data with the external storage unit as necessary. For example, an interface unit such as RS-232C standard or USB standard may be further provided. The external storage unit stores data with a storage medium such as a memory card, flexible disk, CD-R (Compact Disc Recordable), DVD-R (Digital Versatile Disc Recordable), and Blu-ray Disc (Blue-ray Disc), for example. An apparatus that performs reading and / or writing, such as a memory card interface, a flexible disk drive, a CD-ROM drive, a CD-R drive, a DVD-R drive, and a Blu-ray disk drive.

In the biological information measuring devices SA and SB having such a configuration, when the program or the like for performing the above-described processing is not stored in the

arithmetic control units

3A and 3B, You may comprise so that it may be installed in

arithmetic control part

3A, 3B via an external memory | storage part. Alternatively, the measurement data measured by the sensor unit 1 or the measurement data after being processed by the first and

second preprocessing units

31 and 32 and the first and

second BPF units

33 and 34 are transmitted to the outside via the interface unit. The measurement data taken out and taken out to the outside may be subjected to arithmetic processing by a computer in which a program or the like for performing the above-described processing is installed, whereby predetermined biological information may be calculated.

Further, in the biological information measuring devices SA and SB in the first and second embodiments described above, the above model is a plurality of models corresponding to the values of statistical parameters, and the pv calculation unit 41 and the pa / pv calculation unit 51 determines the second information pv ^ and the first information pa ^ from the statistical parameters obtained by the statistical parameter calculator 40 by using the plurality of models according to the values of the statistical parameters, and based on these, for example, oxygen Predetermined biological information such as saturation may be obtained. By configuring in this way, the biological information measuring devices SA and SB are used by properly using a plurality of models according to the value of the statistical parameter, so that a model that is more appropriately approximated is provided and the biological information is more accurately obtained. Can be measured.

Further, in the biological information measuring devices SA and SB in the first and second embodiments described above, the above model includes a first model and a second model for correcting a value obtained by the first model, The pv calculation unit 41 and the pa / pv calculation unit 51 use the statistical parameter obtained by the statistical parameter calculation unit 40 as the value obtained by using the statistical parameter obtained by the statistical parameter calculation unit 40 in the first model. Is corrected with a correction value obtained by using the second model, the second information pv ^ and the first information pa ^ may be obtained, and biological information such as oxygen saturation may be obtained based on the second information pv ^. . By configuring in this way, the biological information measuring devices SA and SB can obtain the correction value, so that the biological information can be measured with higher accuracy.

Further, in the biological information measuring devices SA and SB in the first and second embodiments described above, the model described above is the first model, the value obtained by the first model and the first model, and the predetermined statistical parameter as input variables. The pv calculation unit 41 and the pa / pv calculation unit 51 include values obtained by using the statistical parameter obtained by the statistical parameter calculation unit 40 for the first model and the statistical parameter calculation unit 40. By using the obtained statistical parameter in the second model, the second information pv ^ and the first information pa ^ may be obtained, and based on these, biological information such as oxygen saturation may be obtained. By configuring in this way, the biological information measuring devices SA and SB use the second model in which the value of the first model is also an input variable, so that the biological information can be measured with higher accuracy.

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

A biological information measuring apparatus according to an aspect includes a measurement unit that measures a predetermined physiological phenomenon in a living body to be measured and outputs measurement data, and a histogram calculation that obtains a histogram based on the measurement data measured by the measurement unit A statistical parameter calculation unit for obtaining a predetermined statistical parameter in the histogram obtained by the histogram calculation unit, and predetermined information for obtaining predetermined biological information about the biological body to be measured as an output variable and the predetermined parameter A model representing the relationship between the output variable and the input variable (for example, a first-order polynomial, a rational expression, an irrational expression, etc. relating to the input variable) when the statistical parameter of is used as an input variable, and the statistical parameter calculation unit By using the statistical parameters determined by Serial obtains predetermined information, and a biological information calculation unit for determining the predetermined biometric information based on the predetermined information obtained.

According to another aspect of the biological information measurement method, a measurement step of measuring a predetermined physiological phenomenon in a measurement target living body to obtain measurement data, and a histogram based on the measurement data obtained by the measurement step are performed. A histogram calculation step to be obtained, a statistical parameter calculation step to obtain a predetermined statistical parameter in the histogram obtained by the histogram calculation step, and predetermined information for obtaining predetermined biological information about the living body to be measured are output variables. In addition, a model (for example, a linear polynomial, a rational expression, an irrational expression, etc. relating to the input variable) representing the relationship between the output variable and the input variable when the predetermined statistical parameter is an input variable is stored in advance. The statistical parameter obtained by the parameter calculation unit is used for the model. It obtains the predetermined information by Rukoto, and a biological information calculation step of calculating said predetermined biometric information based on the predetermined information obtained.

In the biological information measuring apparatus and the biological information measuring method configured as described above, predetermined biological information in the living body is obtained based on statistical parameters in a histogram based on measurement data obtained from the living body to be measured. For this reason, the living body information measuring apparatus and the living body information measuring method having such a configuration can measure living body information with higher accuracy even when noise occurs due to, for example, body movement of the living body.

Moreover, the biological information measuring device according to another aspect irradiates a biological tissue of a living body to be measured with a first light having a predetermined first wavelength, and receives the first light transmitted or reflected by the living tissue of the living body. The first sensor unit for outputting the first measurement data, and the second biological light with a predetermined second wavelength different from the first wavelength is irradiated to the biological tissue of the living body, and transmitted or reflected through the living tissue of the living body. A second sensor unit that receives the second light and outputs second measurement data; a first ratio of an AC component to a DC component in the first measurement data; and a DC component in the second measurement data A histogram calculation unit for obtaining a histogram of a third ratio calculated based on the second ratio of the AC component, and a statistical parameter for obtaining a predetermined statistical parameter in the histogram obtained by the histogram calculation unit Data calculation unit, and when the predetermined information for obtaining the oxygen saturation of the living body to be measured is an output variable and the predetermined statistical parameter is an input variable, the output variable and the input variable A model representing a relationship (for example, a first order polynomial, a rational expression, an irrational expression, etc. relating to an input variable) is stored in advance, and the predetermined information is obtained by using the statistical parameter obtained by the statistical parameter calculation unit for the model. And a biological information calculation unit for determining the oxygen saturation based on the determined predetermined information.

According to another aspect of the biological information measurement method, a measurement step of measuring a predetermined physiological phenomenon in a measurement target living body to obtain measurement data, and a histogram based on the measurement data obtained by the measurement step are performed. A histogram calculation step to be obtained, a statistical parameter calculation step to obtain a predetermined statistical parameter in the histogram obtained by the histogram calculation step, and predetermined information for obtaining the oxygen saturation of the living body to be measured as output variables A model representing a relationship between the output variable and the input variable when the predetermined statistical parameter is an input variable (for example, a first order polynomial, a rational expression, an irrational expression, etc. regarding the input variable) is stored in advance, and the statistical parameter Using the statistical parameter obtained by the calculation unit for the model It obtains the predetermined information I, and a biological information calculation step of calculating the oxygen saturation based on the predetermined information obtained.

The living body information measuring apparatus and living body information measuring method having such a configuration can measure the oxygen saturation of a living body with higher accuracy even when noise occurs due to, for example, body movement of the living body. And according to this structure, what is called a pulse oximeter which can measure oxygen saturation is provided.

In another aspect, in the above-described biological information measuring device, preferably, the statistical parameter is plural. In another aspect, in the above-described biological information measurement method, preferably, the statistical parameter is plural.

According to this configuration, since a plurality of statistical parameters are used, a more appropriately approximate model is provided, and biological information can be measured with higher accuracy.

In another aspect, in the above-described biological information measurement device, preferably, the model includes each of the plurality of statistical parameters independently as the input variable and at least two of the plurality of statistical parameters. And / or ratios as one or more of the input variables.

According to this configuration, a plurality of statistical parameters are used not only as input variables of the model, but also their products and / or their ratios are used as input variables of the model, so that a more appropriately approximate model is provided. The biological information can be measured with higher accuracy.

In another aspect, in the above-described biological information measurement device, preferably, the model is a plurality of models according to a value of a statistical parameter, and the biological information calculation unit is configured according to a value of the statistical parameter. The predetermined information is obtained from the statistical parameter obtained by the statistical parameter calculation unit using the plurality of models, and the predetermined biological information is obtained based on the obtained predetermined information.

According to this configuration, since a plurality of models are selectively used according to the value of the statistical parameter, a more appropriately approximate model is provided, and biological information can be measured with higher accuracy.

In another aspect, in the above-described biological information measuring device, preferably, the model includes a first model and a second model for correcting a value obtained by the first model. The information calculation unit uses a value obtained by using the statistical parameter obtained by the statistical parameter calculation unit for the first model, and uses the statistical parameter obtained by the statistical parameter calculation unit for the second model. The predetermined information is obtained by correcting with the correction value obtained in this way, and the predetermined biological information is obtained based on the obtained predetermined information. Here, for the first and second models, for example, linear polynomials relating to input variables, rational expressions, and irrational expressions are used.

According to this configuration, since a correction value is obtained, biological information can be measured with higher accuracy.

In another aspect, in the above-described biological information measuring device, preferably, the model is a second model using a first model, a value obtained by the first model, and the predetermined statistical parameter as input variables. The biological information calculation unit includes the value obtained by using the statistical parameter obtained by the statistical parameter calculation unit for the first model and the statistical parameter obtained by the statistical parameter calculation unit. The predetermined information is obtained by using the second model, and the predetermined biological information is obtained based on the obtained predetermined information.

According to this configuration, since the second model using the value of the first model as an input variable is used, biological information can be measured with higher accuracy.

This application is based on Japanese Patent Application No. 2010-008012 filed on January 18, 2010, the contents of which are included in the present application.

In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

According to the present invention, it is possible to provide a living body information measuring apparatus and a living body information measuring method for measuring living body information related to a living body by measuring a physiological phenomenon of the living body.

Claims

A measurement unit that measures a predetermined physiological phenomenon in the living body to be measured and outputs measurement data; and
A histogram calculation unit for obtaining a histogram based on the measurement data measured by the measurement unit;
A statistical parameter calculator for obtaining a predetermined statistical parameter in the histogram obtained by the histogram calculator;
A model representing a relationship between the output variable and the input variable when the predetermined information for obtaining the predetermined biological information related to the measurement target biological body is an output variable and the predetermined statistical parameter is an input variable. Biological information calculation that obtains the predetermined information by using the statistical parameter stored in advance and obtained by the statistical parameter calculation unit in the model, and obtains the predetermined biological information based on the obtained predetermined information A biological information measuring device.
A first sensor unit that irradiates a living tissue of a living body to be measured with a first light having a predetermined first wavelength, receives the first light transmitted or reflected by the living tissue of the living body, and outputs first measurement data; Irradiating the living tissue of the living body with second light having a predetermined second wavelength different from the first wavelength, receiving the second light transmitted or reflected through the living tissue of the living body, and outputting second measurement data A measurement unit comprising a second sensor unit;
A histogram calculation unit for obtaining a histogram of a third ratio calculated based on a first ratio of the AC component to the DC component in the first measurement data and a second ratio of the AC component to the DC component in the second measurement data;
A statistical parameter calculator for obtaining a predetermined statistical parameter in the histogram obtained by the histogram calculator;
A model representing a relationship between the output variable and the input variable in a case where the predetermined information for obtaining the oxygen saturation of the living body to be measured is an output variable and the predetermined statistical parameter is an input variable. A biological information calculation unit for storing and obtaining the predetermined information by using the statistical parameter obtained by the statistical parameter calculation unit in the model, and obtaining the oxygen saturation based on the obtained predetermined information; A biological information measuring device comprising:
The biological information measuring apparatus according to claim 1, wherein the statistical parameter is plural.
The model includes each of the plurality of statistical parameters independently as the input variable, and includes at least two products and / or ratios of the plurality of statistical parameters as one or more of the input variables. The biological information measuring device according to claim 3.
The model is a plurality of models according to the value of a statistical parameter,
The biological information calculation unit determines the predetermined information from the statistical parameter obtained by the statistical parameter calculation unit by properly using the plurality of models according to the value of the statistical parameter, and adds the obtained predetermined information to the obtained predetermined information. The biological information measuring device according to claim 1, wherein the predetermined biological information is obtained based on the biological information.
The model comprises a first model and a second model for correcting a value obtained by the first model,
The biological information calculation unit is configured to use a value obtained by using the statistical parameter obtained by the statistical parameter calculation unit for the first model, and the statistical parameter obtained by the statistical parameter calculation unit to the second model. The biological information according to claim 1, wherein the predetermined information is obtained by correcting with a correction value obtained by using the information, and the predetermined biological information is obtained based on the obtained predetermined information. measuring device.
The model consists of a first model and a second model with values obtained by the first model and the predetermined statistical parameters as input variables,
The biological information calculation unit uses the statistical parameter obtained by the statistical parameter calculation unit for the first model and the statistical parameter obtained by the statistical parameter calculation unit in the second model. The biological information measuring device according to claim 1, wherein the predetermined information is obtained by use, and the predetermined biological information is obtained based on the obtained predetermined information.
A measurement process for obtaining measurement data by measuring a predetermined physiological phenomenon in a living body to be measured;
A histogram calculation step for obtaining a histogram based on the measurement data obtained by the measurement step;
A statistical parameter calculating step for obtaining a predetermined statistical parameter in the histogram obtained by the histogram calculating step;
A model representing a relationship between the output variable and the input variable when the predetermined information for obtaining the predetermined biological information related to the measurement target biological body is an output variable and the predetermined statistical parameter is an input variable. Biological information calculation that obtains the predetermined information by using the statistical parameter stored in advance and obtained by the statistical parameter calculation unit for the model, and obtains the predetermined biological information based on the obtained predetermined information A biological information measuring method comprising the steps of:
The biological information measuring method according to claim 8, wherein the statistical parameter is plural.