JPH1080405A - Vitial information measuring instrument, vital information measuring method and vital information measuring program memory medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to decide the degree of awakening right after the start of the measurement of vital information, to exactly decide the degree of awakening even when the degree of awakening of a person to be measured at the time of starting the measurement is low and to exactly decide the exact degree of awakening with each of the respective plural persons to be measured. SOLUTION: The CPU 2 of the vital information measuring instrument 1 forms correction data by using the measured values of the skin impedance at the time of resting and closing the eyes measured by a sensor 8 from a driver in the state of resting and closing the eyes and the average of the measured values at the time of ordinary activity in the state that the steering signal from a steering sensor 9 is kept inputted. The measured value of the skin impedance is corrected by the formed correction data and the corrected value is compared with the preset threshold. The CPU 2 emits an alarm to urge the awakening to the driver by driving a speaker 12 when the corrected value is higher than the threshold in this comparison.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biological information measuring device for outputting biological information such as skin impedance measured from a subject as control data to an external device, a biological information measuring method and a biological information measuring program storage medium. .

[0002]

2. Description of the Related Art In a device in which a human performs a control operation, the mental and physical state of the human influences the appropriateness of the control. For example, the driving state of a vehicle is greatly affected by the mental and physical state of the driver who controls the vehicle. Is more likely to occur. Therefore,
In order to properly control such a device, the operator's mind and body must be maintained in a normal state.

Therefore, conventionally, there has been proposed a biological information measuring device which measures biological information from an operator and outputs the measured value as control data for an operating device or an attached device. For example, the skin of the human palm sweats not only by a thermal sweating action based on a homeostatic function for maintaining body temperature but also by a mental sweating action in response to an external stimulus. That is, sweating in the human palm serves as an index indicating the functional state of the sympathetic nerve, that is, the degree of arousal. Since the skin impedance decreases or increases depending on the amount of sweating, the degree of arousal can be detected by measuring the change in the skin impedance of the palm. By measuring the skin impedance as biological information and outputting a measurement result of the skin impedance or a determination result of the arousal level based on the measurement result to an awakening device that notifies a driver of a warning, a driver with a low arousal level It is conceivable to give a warning to prevent accidents from occurring.

However, biological information such as skin impedance has a large individual difference between subjects. For example, a threshold value for determining whether the arousal level is high or low from the measured value of skin impedance is set for all subjects. It cannot be set uniquely. For this reason, in the conventional biological information measuring device, the average value of the measured values in a certain period at the time of starting the measurement of the biological information is obtained, and the average is used to normalize the measured values. That is, the average of a plurality of measured values measured within a certain period of time after the start of the measurement of biological information, and the subsequent measured value is compared with the average value to determine the degree of arousal, or the average value and a standard standard The arousal level is determined by comparing a value obtained by multiplying the measured value by the ratio with the value with a standard reference value.

[0005]

However, the conventional biological information measuring device corrects the subsequent measured values based on the average value of a plurality of measured values within a fixed time after the start of the measurement of the biological information. However, since the individual differences in the measured values are eliminated, the arousal level cannot be determined within a certain time immediately after the start of the measurement of the biological information. In addition, the state of the subject at the start of the measurement has a large effect on the output value after normalization.For example, when the arousal level of the subject at the start of the measurement is low, it is necessary to accurately determine the arousal level Can not. Furthermore, the range in which the measured value of biological information can be taken varies greatly between individuals, and the same measured value for a plurality of subjects does not necessarily represent the same arousal level, and the measured value within a certain time after the start of measurement In the normalization based on the average value of, there has been a problem that it is not possible to accurately determine the arousal level for each of a plurality of subjects.

SUMMARY OF THE INVENTION An object of the present invention is to pay attention to the fact that the measured value of the biological information at the time of resting eyes is substantially equal to the measured value of the biological information at the time of sleep. By performing the measurement, it is not necessary to obtain a plurality of measurement values within a certain time after the start of the measurement, and the arousal level can be determined immediately after the start of the measurement. Without affecting the output value after the conversion, the arousal level can be accurately determined even when the arousal level of the subject at the start of the measurement is low,
It is an object of the present invention to provide a biological information measuring device, a biological information measuring method, and a biological information measuring program storage medium that can determine an accurate arousal level for each of a plurality of subjects.

[0007]

According to the first, fourth and seventh aspects of the present invention, when outputting the biological information measured from the subject as a control signal of an external device, the subject is placed at the time of resting eyes closed. Measuring biological information, creating correction data representing the relationship between the measured value and the output value based on the measured value when the eyes are at rest, correcting the measured value to an output value with this corrected data, and outputting the output value to an external device It is characterized by.

Therefore, according to the first, fourth and seventh aspects of the present invention, the measured value is converted into the output value by the correction data created based on the measured value at the time of resting eyes substantially equal to the measured value of the biological information in the sleep state. To correct, it is not necessary to determine conversion data for normalization based on a plurality of measurement values within a certain time after the start of measurement, and it is possible to determine the arousal level immediately after the start of measurement of biological information, and at the start of measurement The arousal state of the subject does not affect the determination of the arousal level. Further, since the measured value is corrected based on the correction data representing the relationship between the measured value and the output value for each subject, the arousal level is accurately determined for each of the plurality of subjects.

According to the second and fifth aspects of the present invention, in creating the correction data, the average value of a plurality of biological information measurement results during the normal activity of the subject and the biological A correction curve representing the relationship between the measured value and the output value is created from the measured value of the information.

Therefore, according to the second and fifth aspects of the present invention, the correction curve representing the relationship between the measured value and the output value by connecting the measured value during normal activity of the subject and the measured value when the subject is at rest with the eyes closed. The measured value is corrected to the output value based on

According to the third and sixth aspects of the present invention, in preparing the correction data, the correction data on the skin impedance measured from the subject is measured on a logarithmic scale and the output value is corrected on a normal scale. It is characterized by being created as a curve.

Therefore, in the inventions according to the third and sixth aspects, the measured value of the skin impedance, which generally changes exponentially as the arousal level decreases, can be expressed as a linear function with respect to the output value. As a result, the arousal level can be easily recognized, and the number of bits of output data can be reduced.

[0013]

FIG. 1 is a block diagram showing a configuration of a biological information measuring device according to an embodiment of the present invention. The biological information measuring device 1 measures the degree of awakening of the driver of the automatic operator, and outputs drive data to the speaker 12 when the degree of awakening of the driver is low. For this reason, the biological information measuring device 1 has a CP including the ROM 3, the RAM 4, and the PROM 5.
A keyboard 7, a sensor 8, and a steering sensor 9 are connected to U2 via an I / O interface 6. Further, the CPU 2 includes the correction data creating means of the present invention. The speaker 2 which is an external device and a storage medium 21 which will be described later are connected to the CPU 2 via the I / O interface 6.

The keyboard 7 accepts an input of driver authentication data and an input of a resting eye closed state. The sensor 8 is
The skin impedance of the driver's palm holding the handle 11 is measured. The steering sensor 9 includes a steering wheel 11
The steering state of the vehicle is detected. The CPU 2 controls the input / output devices of the keyboard 7, the sensor 8, the steering sensor 9, and the speaker 12 according to a program written in the ROM 3 in advance. At this time, the input / output data is temporarily stored in the RAM 4. The PROM 5 stores the measurement data of the sensor 8 with identification data attached to each driver.

The sensor 8 is constituted by exposing a plurality of electrodes exhibiting a loop shape over the entire circumference of the handle 11 on the peripheral surface, and measures the skin impedance of the palm by a three-electrode method using a constant current. Can be. Further, other configurations such as a configuration in which the electrode is exposed on the inner peripheral surface in a ring shape can be used. Further, other biological information such as a pulse wave and an electroencephalogram can be measured instead of or together with the skin impedance. Also,
The steering sensor 9 detects a steering state of the steering wheel 11 for determining that the driver is in a normal activity. Instead of the steering sensor 9 or together with the steering sensor 9, a speed sensor for detecting a traveling speed and a pedal sensor for detecting an operation state of a pedal can be provided.

The CPU 2 measures the driver's skin impedance during normal activity and at rest with the eyes closed, and creates correction data based on both measured values. As described above, sweating in the human palm serves as an index indicating the functional state of the sympathetic nerve, that is, the degree of arousal, and the skin impedance decreases or increases according to the amount of sweating. That is, as shown in FIG. 2, in a state where the arousal level where the sympathetic nerve is dominant is high, the amount of sweating of the palm is large, and the level of the signal SIL corresponding to the equivalent series resistance component of the skin impedance is low. Conversely,
In the state of low arousal level where the parasympathetic nerve is dominant, the amount of palm sweating is small and the level of SIL is high. However, S
IL levels, especially SIL in low alertness
It is difficult to determine a general threshold value for judging that the level of has a large individual difference and low arousal level.

Then, the CPU 2, as shown in FIG.
Points indicating the relationship between the measured value da and the correction value Da during normal activity and points indicating the relationship between the measured value ds and the correction value Ds when the eyes are at rest in the coordinate system having the measured value and the correction value as axes. Is calculated as correction data for each driver, and the measured value is corrected based on the correction data. By the correction using the correction data, the measurement value of the sensor 8 is normalized to a uniquely determined value, and it is possible to determine whether or not the arousal level is low for all drivers using a predetermined constant value as a threshold. .

As will be described later, the measured value da during normal activity is used to improve the reliability of the calculated correction data.
Use the average of multiple measurements. In addition, for a new driver who has not yet measured the biological information at the time of resting closed eyes and has not calculated correction data, a provisional value prepared in advance as a measurement value ds at resting eye closing and a measurement value at normal activity is provided. From the value dt of the temporary correction straight line RLt, and the slope of the straight line RLt is used as temporary correction data.

FIG. 4 is a flowchart showing a processing procedure of the biological information measuring device. C of the biological information measuring device 1
After starting, the PU 2 waits for the driver to input the authentication data by operating the keyboard 7 (s1). Note that a message for instructing the driver to input the authentication data may be generated after the activation. This authentication data is, for example, a four-digit number. The CPU 2 searches the PROM 5 for the authentication data input by the driver (s
2) If the input authentication data does not exist in the PROM 5, the processing of the measurement mode of the biometric information when the eyes are at rest is executed (s3 → s4).

That is, when the driver inputs that the eye is in the quiet closed state by operating the resting eye closed button arranged on the keyboard 7 (s4), the CPU 2 reads the skin impedance measured by the sensor 8 (s5), and Correction data is created using the measured value when the eyes are closed (s6). At this time, temporary correction data is created using the temporary value dt as described above. In addition, when starting the processing of the measurement mode of the biometric information at the time of resting eyes closed, the driver measures the biometric information at the time of resting eyes closed, the state that the eyes should be kept at rest, and when the eyes are at rest. A message indicating that the resting eye closing button should be operated may be generated at a predetermined timing. On the other hand, when the authentication data input by the driver exists in the PROM 5, the CPU 2 reads out the corresponding correction data (s7).

The CPU 2 permits the start of the engine in a state where the correction data of the measured value is ready in this way (s
8) Start periodic measurement of skin impedance (s9). The CPU 2 determines whether a steering signal has been input from the steering sensor 9 when measuring the skin impedance (s10). When the steering signal is input, the CPU 2 determines that the measured value is the value during the normal activity, calculates the average of the measured values during the normal activity (s11), and converts the correction data using the average value. Update (s12). If the steering signal is not input when the skin impedance is measured by the sensor 8, it is not clear whether the measured value is a measured value during normal activity, and the CPU 2 performs an average value calculation process and a correction data update process. Absent.

Next, the CPU 2 corrects the measured value of the skin impedance using the correction data (s13), and compares the corrected value with a preset threshold value (s14). CPU2
In this comparison, when the correction value is higher than the threshold value, a drive signal is output to the speaker 12 to generate an alarm to urge the driver to wake up (s15), and when the correction value is lower than the threshold value, the alarm is generated. Is stopped (s16).

With the above processing, according to the biological information measuring apparatus of this embodiment, correction data of the measured value is obtained from the measured value when the driver is at rest and eyes closed and the measured value during normal activity. Since the value corrected by the above is compared with a uniquely set threshold value, it is possible to accurately detect that the arousal degree has decreased for a plurality of drivers. In addition, once the correction data is calculated, the degree of arousal of the driver can be determined immediately after the start of the measurement of the biological information, so that even when the degree of awakening is low at the start of the measurement, the state can be accurately detected. it can. Furthermore, even for a driver who has not yet measured the biometric information during normal activity, temporary correction data is calculated using the measured value at rest and closed eyes and the value at normal activity prepared in advance, so immediately after the start of biometric information Thus, the degree of awakening of the driver can be determined in a pseudo manner.

The input of the authentication data of the operator can use a storage medium such as a card. In particular, with regard to automobiles, it is possible to provide storage means for storing authentication data in an ignition key individually owned by each driver, and to provide means for reading authentication data from the storage means in an ignition switch in which the ignition key is inserted. it can. However, in an automobile in which it is determined that only a specific single person drives, the configuration and processing related to the input and search of the authentication data are unnecessary. In a vehicle operated by a plurality of drivers, correction data of the driver is stored in a storage medium individually owned by each driver, and correction data is input instead of authentication data at the start of driving. Can also. Further, the present invention can be similarly applied to devices other than automobiles.

FIG. 5 is a diagram showing a relationship between a measured value of biological information and a correction value in a biological information measuring device according to another embodiment of the present invention. The figure shows the measured values of the biological information on a logarithmic scale and the correction values on a normal scale. FIG.
As shown in the figure, the measured value of palm skin impedance is
It changes exponentially as the arousal level decreases. Therefore, when both the measured value and the correction value are taken on a normal scale, the relationship between the measured value and the correction value becomes non-linear, and the measured value of biological information, which is an analog signal, is output as a correction value, which is digital data. In addition to the increase in the number of bits of the output circuit, the cost increases, and it is difficult for the device that displays the arousal level to intuitively grasp the displayed arousal level.

Therefore, as shown in FIG. 5, by taking the measured value of the biological information on a logarithmic scale, the relationship between the measured value and the correction value can be linearized, and the number of bits of the output circuit can be reduced. The increase in cost can be prevented, and the displayed arousal level can be easily grasped sensuously. Specifically, the measured value of the biological information is converted into a logarithm by a logarithmic conversion circuit constituted by an analog circuit.

Note that the processing procedure executed by the CPU
It is stored in a storage medium 21 such as an OM or an HDD, and this C
The present invention can be implemented using a general-purpose CPU by supplying the CPU from a storage medium 21 such as a DROM or HDD.

[0028]

According to the first, fourth and seventh aspects of the present invention, the measured value is output by the correction data created based on the measured value at the time of resting eyes which is substantially equal to the measured value of the biological information in the sleep state. It is not necessary to obtain conversion data for normalization based on a plurality of measured values within a certain period of time after the start of measurement, and it is possible to determine the arousal level immediately after the start of measurement of biological information, Does not affect the determination of the arousal level.
Further, since the measurement value is corrected based on the correction data representing the relationship between the measurement value and the output value for each subject, the arousal level can be accurately determined for each of the plurality of subjects.

According to the second and fifth aspects of the present invention,
In order to correct the measured value to the output value based on the correction line representing the relationship between the measured value and the output value between the measured value during the normal activity of the subject and the measured value with the eyes closed, The arousal level can be output on the same scale for each person.

According to the third and sixth aspects of the present invention,
In general, a measured value of skin impedance that changes exponentially with a decrease in arousal level can be expressed as a linear function with respect to an output value, and the arousal level can be easily grasped, and the number of bits of output data can be reduced. It is possible to simplify the circuit configuration and prevent cost increase.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a biological information measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a general relationship between a measured value of palm skin impedance and a degree of arousal.

FIG. 3 is a diagram showing a relationship between a measured value of biological information and a correction value in the biological information measuring device.

FIG. 4 is a flowchart showing a processing procedure of the biological information measuring device.

FIG. 5 is a diagram showing a relationship between a measured value of biological information and a correction value in a biological information measuring device according to another embodiment of the present invention.

[Explanation of symbols]

 1-Biometric information measuring device 2-CPU 3-ROM 4-RAM 5-PROM 8-Sensor 11-Handle 12-Speaker 21-Storage medium

Claims (7)

[Claims] 1. A biological information measuring device for outputting biological information measured from a subject as a control signal of an external device, wherein the measured value and the output value are determined based on the measured value of the biological information when the subject is in a resting eye closed state. A biological data measuring device provided with a correction data generating means for generating correction data representing the relationship. 2. The method according to claim 1, wherein the correction data creating means is configured to measure the average value of the measurement results of the plurality of pieces of biological information during the normal activity of the subject, and the measured value of the biological information when the subject is in a quiet closed eye. The biological information measuring device according to claim 1, wherein a correction curve representing a relationship between the value and the output value is created. 3. The correction data creation means according to claim 1, wherein the correction data about the skin impedance measured from the subject is
3. The biological information measuring apparatus according to claim 2, wherein the measurement value is created as a correction curve with a logarithmic scale and an output value with a normal scale. 4. When outputting the biological information measured from the subject as a control signal of an external device, the biological information when the subject is at rest and closed eyes is measured, and the measured value is based on the measured value at rest and closed eyes. A biological information measuring method, comprising: creating correction data representing a relationship between the data and an output value; correcting the measured value into an output value using the corrected data; and outputting the output value to an external device. 5. The method according to claim 1, wherein the step of preparing the correction data comprises measuring an average value of a plurality of measurement results of the biological information during a normal activity of the subject and a measurement value of the biological information when the subject is at rest with the eyes closed. The biological information measuring method according to claim 4, wherein a correction curve representing a relationship between the value and the output value is created. 6. The correction data according to claim 5, wherein the correction data for the skin impedance measured from the subject is prepared as a correction curve in which the measured value is set on a logarithmic scale and the output value is set on a normal scale. Biological information measurement method. 7. When outputting the biological information measured from the subject as a control signal of an external device, the biological information of the subject at the time of resting eyes closed is measured, and the measured value is obtained based on the measurement value at the time of resting eyes closed. 1. A biological information measurement program storage medium, wherein a program for generating correction data representing a relationship between the data and an output value, storing a program for correcting a measured value to an output value with the correction data and outputting the corrected output value to an external device is stored.