JP6730899B2 - Electronic device, control method, and program - Google Patents

Description

The present disclosure relates to an electronic device, a control method, and a program.

2. Description of the Related Art Conventionally, an apparatus that removes noise from data related to biometric information acquired from a subject (user) is known (see, for example, Patent Document 1 and Patent Document 2).

JP, 2007-054471, A JP, 2013-150772, A

Conventional devices have room for further improvement to increase their usefulness.

An object of the present invention is to provide an electronic device, a control method, and a program that can improve usability.

An electronic device according to one aspect includes a light emitting unit, a light receiving unit, and a control unit. The light emitting unit irradiates a measurement site with measurement light. The light receiving unit receives scattered light of the measurement light from the site to be inspected. The control unit generates biometric information based on the output of the light receiving unit. The control unit determines an amplitude range of the biometric information for each predetermined period defined in the biometric information, and detects noise of the biometric information based on the amplitude range.

A control method according to one aspect is to irradiate a measurement site with measurement light, to receive scattered light of the measurement light from the test site, and to generate biological information based on the received intensity of the scattered light. And a step of performing. The control method further comprises a step of determining a predetermined period in the biological information, a step of determining an amplitude range for the biological information for each of the determined predetermined periods, and based on the determined amplitude range, Detecting noise in the biometric information.

A program according to one aspect of the present invention includes a step of irradiating a computer with measurement light on a test site, a step of receiving scattered light of the measurement light from the test site, and biological information based on the received light intensity of the scattered light. To generate and. The program further comprises a step of determining a predetermined period in the biological information, a step of determining an amplitude range relating to the biological information for each of the predetermined periods determined, and the biological body based on the determined amplitude range. Detecting noise in the information.

According to the electronic device, control method, and program according to the present disclosure, usability can be improved.

FIG. 3 is a functional block diagram showing a schematic configuration of an electronic device according to an embodiment of the present disclosure. It is a figure which shows an example of the graph of the blood flow volume produced|generated by the control part of FIG. 6 is a flowchart showing an example of details of noise detection and correction processing by the electronic device of FIG. 1. It is a figure which shows an example of the histogram produced|generated by the control part of FIG. FIG. 3 is a diagram illustrating an example of noise detection and correction processing by the electronic device of FIG. 1.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

FIG. 1 is a functional block diagram showing a schematic configuration of an electronic device 100 according to an embodiment of the present disclosure. The electronic device 100 includes a biosensor 110, a control unit 120, a storage unit 130, an input unit 140, and a display unit 150.

The electronic device 100 measures biological information of the subject. The electronic device 100 measures the biometric information based on the biometric information data acquired by the biometric sensor 110 (hereinafter, also simply referred to as “data”). The electronic device 100 acquires data, for example, in a state where the biometric sensor 110 is in contact with a test site such as a finger or a forehead. The biological information measured by the electronic device 100 is information about an arbitrary biological body that can be measured using the data acquired by the biological sensor 110. In the present embodiment, the biometric information is described as being information related to blood flow, but the biometric information is not limited to this.

The biometric sensor 110 acquires biometric information data. The biometric sensor 110 acquires biometric information data, for example, in a state of being in contact with a test site. The biological sensor 110 may include a light emitting unit 111 and a light receiving unit 112. The biological sensor 110 irradiates the measurement site with measurement light, and acquires reflected light (scattered light) from the tissue inside the measurement site. The biometric sensor 110 transmits the acquired photoelectric conversion signal of the scattered light to the control unit 120.

The light emitting unit 111 irradiates the measurement site with the measurement light under the control of the control unit 120. The light emitting unit 111 irradiates, for example, a laser beam having a wavelength capable of detecting a predetermined component contained in blood as measurement light onto the test site. The light emitting unit 111 may be configured by, for example, an LD (Laser Diode).

The light receiving unit 112 receives the scattered light of the measurement light from the test site. The light receiving unit 112 may be configured by a PD (Photo Diode), for example. The photoelectric conversion signal of the scattered light received by the light receiving unit 112 is transmitted to the control unit 120.

The control unit 120 includes at least one processor 120a that controls and manages the entire electronic device 100, including each functional block of the electronic device 100. The control unit 120 is configured to include at least one processor 120a such as a CPU (Central Processing Unit) that executes a program that defines a control procedure, and realizes its function. Such a program is stored in, for example, the storage unit 130 or an external storage medium connected to the electronic device 100.

According to various embodiments, at least one processor 120a is implemented as a single integrated circuit (IC) or as a plurality of communicatively coupled integrated circuits ICs and/or discrete circuits. Good. At least one processor 120a may be implemented in accordance with various known techniques.

In one embodiment, the processor 120a includes one or more circuits or units configured to perform one or more data calculation procedures or processes, such as by executing instructions stored in associated memory. In other embodiments, the processor 120a may be firmware (eg, discrete logic component) configured to perform one or more data calculation procedures or processes.

According to various embodiments, the processor 120a may include one or more processors, controllers, microprocessors, microcontrollers, application specific integrated circuits (ASICs), digital signal processors, programmable logic devices, field programmable gate arrays, or the like. Any combination of the above devices or configurations or other known combinations of devices or configurations may be included to perform the function as the control unit 120 described below.

The control unit 120 measures (calculates) the biometric information based on the biometric information data acquired from the biometric sensor 110. The control unit 120 can measure the blood flow rate as the biometric information, but the biometric information is not limited to the blood flow rate. The control unit 120 detects noise in the data when measuring the biological information. Details of noise detection by the control unit 120 will be described later.

When detecting noise in the data, the control unit 120 corrects the data so as to remove the noise. Details of the data correction method by the control unit 120 will be described later. The control unit 120 corrects the noise in the data, so that the measurement accuracy of the biological information by the electronic device 100 is improved.

The storage unit 130 can be configured with a semiconductor memory, a magnetic memory, or the like. The storage unit 130 stores various kinds of information, programs for operating the electronic device 100, and the like. The storage unit 130 may also function as a work memory. The storage unit 130 may store, for example, the data acquired by the biometric sensor 110.

The input unit 140 receives an operation input from the subject, and includes, for example, operation buttons (operation keys). The input unit 140 may be configured by a touch panel, and an operation key for receiving an operation input from the subject may be displayed on a part of the display device to receive the touch operation input by the subject. The subject can cause the electronic device 100 to start measurement of biological information by performing an input operation on the input unit 140, for example.

The display unit 150 is a display device such as a liquid crystal display, an organic EL display, or an inorganic EL display. The display unit 150 displays, for example, a measurement result of biological information by the electronic device 100.

Next, a blood flow measurement technique using the Doppler shift by the control unit 120 will be described.

In living tissues, scattered light scattered from moving blood cells undergoes frequency shift (Doppler shift) due to the Doppler effect proportional to the moving speed of blood cells in blood. The control unit 120 detects a beat signal (also referred to as a beat signal) generated by light interference between the scattered light from the stationary tissue and the scattered light from the moving blood cells. This beat signal is a representation of intensity as a function of time. Then, the control unit 120 converts this beat signal into a power spectrum that represents power as a function of frequency. In the power spectrum of this beat signal, the Doppler shift frequency is proportional to the velocity of blood cells. Also, in the power spectrum of this beat signal, the power corresponds to the amount of blood cells. The control unit 120 obtains the blood flow volume by multiplying the power spectrum of the beat signal by the frequency and integrating the power spectrum.

FIG. 2 is a diagram showing an example of a blood flow rate graph measured by the control unit 120. In FIG. 2, the vertical axis represents blood flow and the horizontal axis represents time. As shown in FIG. 2, the blood flow rate graph has a shape that vertically vibrates in accordance with the pulsation of the subject.

By the way, in the measurement of biometric information, when the positional relationship between the biometric sensor 110 that acquires biometric information data and the site to be examined (skin) changes, the output intensity acquired by the light receiving unit 112 changes. That is, the light receiving unit 112 detects a beat signal from moving blood cells, but a change (deviation) in the positional relationship between the biosensor 110 and the site to be examined can also be detected as a beat signal. The beat signal generated by the displacement between the biometric sensor 110 and the site to be examined becomes noise that reduces the measurement accuracy of biometric information. In the present specification, this noise is also referred to as body movement noise.

Since body movement noise occurs when the positional relationship between the biometric sensor 110 and the site to be examined changes, the graph shown in FIG. 2 includes noise locally. By detecting and correcting (removing) the noise included in the graph, the measurement accuracy of biological information is improved.

On the other hand, biological information such as blood flow may change due to the activity of the human body. For example, the blood flow rate differs between a sitting state and a walking state. Further, for example, the blood flow rate changes before and after ingesting food and drink. Although the graph of the blood flow rate may fluctuate due to the activity of the human body as described above, the fluctuation due to the activity of the human body is not noise, and therefore, if it is detected as noise, it may cause a decrease in measurement accuracy.

The electronic device 100 according to the present embodiment is unlikely to detect fluctuations in blood flow due to activity of the human body as noise, and can improve the accuracy of detecting body movement noise. Hereinafter, the details of the noise detection and correction processing by the electronic device 100 will be described focusing on the processing content of the control unit 120.

FIG. 3 is a flowchart showing an example of details of noise detection and correction processing by the electronic device 100.

First, the control unit 120 acquires biometric information data from the biometric sensor 110 (step S101).

The control unit 120 generates a graph of blood flow as shown in FIG. 2 based on the acquired data (step S102). The blood flow rate graph is generated, for example, in units of a predetermined time length. The length of the predetermined time may be, for example, several seconds to several tens of seconds. The control unit 120 determines the predetermined time length unit as the first period (initial period) used in the process in the flow of FIG. 3, and performs the process.

Next, the control unit 120 determines a predetermined period in the blood flow rate graph. When determining the predetermined period, the control unit 120 generates a histogram for the predetermined period (step S103). Here, the control unit 120 generates a histogram for the initial period.

FIG. 4 is a diagram showing an example of a histogram generated by the control unit 120. As shown in FIG. 4, the histogram shows the value of the blood flow rate in a predetermined period and the appearance frequency of the value of the blood flow rate. The value of blood flow is the value of blood flow in a predetermined minute time. The appearance frequency is a value represented by the number of appearances in a minute time indicating the value of each blood flow. The histogram shows the distribution of the appearance frequency of each blood flow value during a predetermined period.

Next, the control unit 120 determines whether the generated histogram satisfies the division condition (step S104). The division condition is a condition capable of determining whether or not the tendency of the blood flow has changed in a predetermined period. When the predetermined period satisfies the division condition, the control unit 120 determines that the tendency of the blood flow is changed in the predetermined period and divides the predetermined period. When the predetermined period does not satisfy the division condition, the control unit 120 determines that the tendency of the blood flow has not changed in the predetermined period, and determines not to divide the predetermined period.

The division condition may be determined based on the number of peak values (maximum values) in the histogram, for example. For example, in the histogram, when the peak value is equal to or greater than a predetermined number (for example, 15), the control unit 120 can determine that the predetermined period satisfies the division condition. The predetermined number is not limited to the above 15 and may be, for example, 2 or more. The peak value (maximum value) of the histogram refers to the maximum value of the histogram values in the section where the histogram increases and then decreases. Here, since the histogram is a graph of frequency, it does not have a smooth mountain-like distribution, but assuming that the peak value decreases as it approaches the normal distribution, the histogram division conditions are based on the peak value of the histogram. Decided.

The division condition may be determined based on the number of mode values in the histogram, for example. The mode value is the value of the blood flow volume that has the highest appearance frequency. For example, when there are a plurality of mode values, the control unit 120 can determine that the predetermined period satisfies the division condition.

The division condition may be determined based on the shape of the histogram, for example. For example, when it is determined that the histogram has normality, the control unit 120 can determine that the predetermined period satisfies the division condition. For example, when the histogram has a distribution in which the appearance frequency increases as it approaches the peak value of the blood flow as shown in FIG. 4A, the control unit 120 determines that the histogram has normality, and the predetermined period is It can be judged that the division condition is satisfied. For example, the control unit 120 determines that the histogram does not have normality when the histogram does not have a distribution in which the appearance frequency becomes higher as it approaches the peak value of the blood flow as shown in FIG. 4B. It can be determined that the predetermined period does not satisfy the division condition.

The division condition is not limited to the above example. The division condition is an arbitrary condition that allows the control unit 120 to determine whether or not the tendency of the blood flow volume has changed in a predetermined period. In addition, the control unit 120 may combine a plurality of division conditions to make a comprehensive determination.

When determining that the histogram satisfies the division condition (Yes in step S104), the control unit 120 divides the predetermined period (step S105). For example, the control unit 120 can divide the predetermined period into two at the center of the start time and the end time of the predetermined period. In this case, the predetermined period is divided into two periods having the same length of time. The control unit 120 may divide the predetermined period into periods having different lengths of time. The control unit 120 may divide the predetermined period into three or more periods.

After dividing the predetermined period in step S105, the control unit 120 moves to step S103. Then, the control unit 120 sets the divided period as a new predetermined period and executes step S103 and step S104 for each of the predetermined periods generated by the division.

When the control unit 120 determines that the histogram in the predetermined period does not satisfy the division condition (No in step S104), the division of the period ends. Each period divided by the control unit 120 in steps S103 to S105 is hereinafter also referred to as a “divided period”.

FIG. 5 is a diagram illustrating an example of noise detection and correction processing performed by the electronic device 100. In FIG. 5, the processing of the control unit 120 divides the initial period Z _I into four divided periods Z _{1 to} Z ₄ .

When the division of the period is completed, the control unit 120 calculates the central value in each divided period (step S106). The center value is a value indicating the center of vertical vibration in the blood flow rate graph in the divided period. The control unit 120 may determine, for example, the mode value in the histogram of the divided periods as the central value. Note that the method of calculating the center value is not limited to this, and any method that can calculate the center of vertical vibration in the graph of blood flow during the divided period can be used. In the example shown in FIG. 5, the central values of the divided periods Z _{1 to} Z ₄ are shown as C _{1 to} C ₄ , respectively.

Next, in each divided period, the control unit 120 determines whether or not the central values match in the adjacent periods that are temporally adjacent to each other (step S107).

When determining that the central values of the adjacent periods match (Yes in step S107), the control unit 120 combines the adjacent periods (that is, a plurality of divided periods) in which the central values match to one period (step S108).

When the control unit 120 determines that the center values of the adjacent periods do not match (No in step S107), the control unit 120 proceeds to step S109. Through steps S107 and S108, the control unit 120 determines the period for performing the noise detection process. In the example shown in FIG. 5, neither period is combined.

The control unit 120 calculates the average value of the difference between the central value and the actual value in each period (step S109). Here, the actual value is the value of blood flow at each time. Further, the control unit 120 calculates the difference between the central value and the actual value as an absolute value. That is, the difference between the center value and the actual value indicates the difference (distance) from the center value of the actual value.

The control unit 120 determines a range of amplitude determined not to be noise in each period based on the calculated average value (step S110). The control unit 120 may determine, for example, a range in which the difference from the center value is within the average value as the amplitude range. That is, the range of the amplitude is determined as a range from a value lower by the average value to a value higher by the average value with reference to the center value. In FIG. 5, the amplitude ranges determined by the control unit 120 in the respective divided periods Z _{1 to} Z ₄ are shown as M _{1 to} M ₄ , respectively. Note that the control unit 120 determines, for example, a range in which the difference from the central value is within a value calculated by multiplying the average value by a predetermined coefficient as the amplitude range. The range of amplitudes may be determined by different methods.

In the present embodiment, the control unit 120 determines that noise is occurring when it exceeds the amplitude range determined in step S110. That is, when detecting noise, the control unit 120 determines whether or not there is an actual value exceeding the determined amplitude range in each period (step S111).

When determining that there is an actual value that exceeds the determined amplitude range in each period (Yes in step S111), the control unit 120 can determine that noise is occurring in a time zone that exceeds the amplitude range. In this case, the control unit 120 corrects the blood flow rate graph (step S112). The control unit 120 can perform the correction, for example, by replacing the actual value exceeding the amplitude range with the maximum value or the minimum value of the amplitude range. For example, when the actual value exceeds (exceeds) the maximum value of the amplitude range, the control unit 120 may replace the actual value exceeding the amplitude range with the maximum value of the amplitude range. Further, for example, when the actual value exceeds (falls below) the minimum value of the amplitude range, the control unit 120 may replace the actual value exceeding the amplitude range with the minimum value of the amplitude range. The control unit 120 may perform the correction by another method.

When determining that there is no actual value exceeding the determined amplitude range in each period (No in step S111), the control unit 120 determines that body movement noise has not occurred, and ends this flow. ..

The electronic device 100 according to the above-described embodiment determines the range of the amplitude regarding the biometric information for each predetermined period defined in the biometric information, and detects the noise of the biometric information based on the range of the amplitude. This predetermined period is determined based on a division condition that enables determination as to whether or not the tendency of the biological information has changed during the predetermined period. Therefore, according to the electronic device 100, it is possible to determine the range of the amplitude in which the tendency of the change in the biological information is taken into consideration and detect the noise. As a result, for example, fluctuations in biometric information due to activity of the human body are not detected as noise, so that the accuracy of measurement of biometric information by the electronic device 100 is improved. In this way, the electronic device 100 can be more useful than conventional devices.

In addition, when the electronic device 100 detects noise, the electronic device 100 can correct the biometric information by replacing the noise with the maximum value or the minimum value of the amplitude range. In this way, by correcting the noise of the biometric information within the range that can be assumed as the biometric information, it becomes easier to provide the subject with more accurate biometric information. As a result, the electronic device 100 can improve the usefulness as compared with the conventional device.

The invention has been described with reference to an embodiment in order to provide a complete and clear disclosure thereof. However, the appended claims are not to be limited to the above-described embodiments, but all modifications and alternatives that can be made by a person skilled in the art within the scope of the basic matters shown in this specification are possible. It should be configured to embody the different configurations. In addition, the requirements shown in some embodiments can be freely combined.

100 electronic device 110 biometric sensor 111 light emitting unit 112 light receiving unit 120 control unit 120a processor 130 storage unit 140 input unit 150 display unit

Claims (9)

A light emitting unit that irradiates the measurement site with measurement light,
A light receiving unit that receives scattered light of the measurement light from the test site,
A control unit for generating biometric information based on the output of the light receiving unit,
The control unit defines a predetermined period in the biometric information,
The control unit generates a histogram relating to the biological information, and when the histogram satisfies a division condition for determining whether or not a change in the biological information has occurred in the predetermined period, divides the predetermined period. And set a new predetermined period,
Wherein, the predetermined period or for each of the new predetermined time period, to determine the extent of amplitude related to the biological information, based on the range of the amplitude, detecting noise of the biological information,
Electronic device. The electronic device according to claim 1, wherein the control unit detects the noise when the value of the biometric information exceeding the amplitude range is detected in each of the predetermined period or the new predetermined period . The electronic device according to claim 2 , wherein the division condition is a condition based on at least one of the number of modes and the number of peaks in the histogram. Wherein, the predetermined period, or the histogram of the mode in the new predetermined time period determined as the center value, it determines the range of the amplitude of the predetermined range from the center value, claims 1 to 3 The electronic device according to claim 1. The control unit calculates an average value of the difference between the center value and the actual value of the biological information in the predetermined period, and determines the range of the average value from the center value as the range of the amplitude. The electronic device according to item 4 . The electronic device according to claim 1, wherein the control unit corrects the biometric information when the noise is detected. The electronic device according to claim 6 , wherein the control unit performs the correction by replacing the noise in the biological information with a maximum value or a minimum value of the amplitude range. Irradiating the measurement site with measurement light,
Receiving scattered light of the measurement light from the test site,
Generating biometric information based on the received light intensity of the scattered light,
Determining a predetermined period in the biological information,
Generating a histogram relating to the biological information,
If the histogram satisfies a division condition for determining whether or not a change in the tendency of the biological information has occurred in the predetermined period, dividing the predetermined period to define a new predetermined period,
A step of determining a range of amplitude relating to the biological information, for each of the predetermined period defined or the new predetermined period ;
Detecting the noise of the biometric information based on the determined amplitude range;
Control method including. On the computer,
Irradiating the measurement site with measurement light,
Receiving scattered light of the measurement light from the test site,
Generating biometric information based on the received light intensity of the scattered light,
Determining a predetermined period in the biological information,
Generating a histogram relating to the biological information,
If the histogram satisfies a division condition for determining whether or not a change in the tendency of the biological information has occurred in the predetermined period, dividing the predetermined period to define a new predetermined period,
A step of determining a range of amplitude relating to the biological information, for each of the predetermined period defined or the new predetermined period ;
Detecting the noise of the biometric information based on the determined amplitude range;
A program to execute.

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