JPH08252226A - Stress measuring instrument - Google Patents

Abstract

PURPOSE: To provide a stress measuring instrument with which quantitative evaluation values having high accuracy are obtainable by addition of individual differences to an evaluation method and which does not require a long time for measurement. CONSTITUTION: A thermocamera 2 for measuring the skin temp. of the nose and the skin temp. of the forehead is connected to a stress measuring circuit 3. A difference ΔT of the skin temp. of the nose and the skin temp. of the forehead is first calculated in a temp. difference calculating section 6 in this stress measuring circuit 3. Next, the stress degree S corresponding to the temp. difference ΔT is derived in accordance with stress degree-temp. difference characteristic stored in an S-ΔT characteristic memory 8 in an S-ΔT characteristic processing section 7. The derived stress degree is outputted to a printer 9 and a display 10, by which the value thereof is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applicable to tension, excitement,
Alternatively, the present invention relates to a stress measuring device that quantitatively measures the stress level in a stress state such as an awake state.

[0002]

2. Description of the Related Art Conventionally, a stress level has been evaluated in order to manage one's own health condition. For example, it can be obtained by subjecting a pulse wave measurement data of a fingertip to chaos analysis. A device for estimating the stress level based on a chaotic attractor has been proposed. In the apparatus, the pattern of chaotic attractor drawn on the display is visually identified to qualitatively evaluate the degree of stress.

Further, it has been conventionally known that the skin temperature of a peripheral part such as a human fingertip is decreased during stress. The amount of decrease in skin temperature is measured, and the evaluated value of the degree of stress is determined by the amount of decrease in temperature. It is possible to

[0004]

However, in the evaluation of the stress level based on the chaotic attractor, it is difficult to quantitatively grasp the stress level. on the other hand,
According to the stress level evaluation method based on the amount of decrease in peripheral skin temperature, a quantitative evaluation value can be obtained, but there are individual differences in the amount of decrease in peripheral skin temperature due to stress load. Since it is not taken into account in the evaluation, there is a problem in the accuracy of the evaluation value. In addition, in order to accurately measure the amount of skin temperature decrease from a resting state, it is necessary to keep the resting state until the skin temperature becomes constant, so not only does the measurement take time, but also the environment with the passage of time. As the temperature and humidity change, errors will occur due to differences in the environment.

The object of the present invention is to obtain highly accurate quantitative evaluation values by adding individual differences to the evaluation method.
An object of the present invention is to provide a stress measuring device that does not require a long time for measurement.

[0006]

A first stress measuring device according to the present invention comprises a skin temperature measuring means for measuring the skin temperature of the erasure part of the human body and the trunk part exposed to the outside, and the measured erasure part. A temperature difference calculating means for calculating the temperature difference ΔT of the skin temperature of the trunk, and a memory that stores the stress degree-temperature difference characteristics that are established between the stress degree S when the stress is applied to the person at rest and the temperature difference ΔT. Means, a stress degree deriving means for deriving a stress degree corresponding to the calculated temperature difference ΔT based on the stress degree-temperature difference characteristic stored in the memory means, and an output for outputting the derived stress degree. And means.

Here, the erasing part of the human body is, for example, the nose, and the trunk is, for example, the forehead. The stress level S is the electrocardiogram R
-R interval, a value defined as a function of the amount of sweat in the palm (spiritual sweating amount), or the power value of β-wave included in the brain wave, for example, an electrocardiogram RR interval from rest to stress The change rate of is adopted.

A second stress measuring apparatus according to the present invention is a physiological test means for actually measuring a physiological state quantity whose value changes according to the magnitude of stress, and an erasing part and a body of the human body exposed to the outside world. A skin temperature measuring means for measuring the skin temperature of the trunk, and a stress degree calculating means for calculating a stress degree S under a stress load with respect to a rest by a predetermined definitional expression based on the measured physiological state quantity, Based on the temperature difference calculating means for calculating the temperature difference ΔT between the skin temperature of the peripheral portion and the trunk and the calculation result of the stress level S and the temperature difference ΔT, the stress level-temperature established between the stress level S and the temperature difference ΔT. A characteristic determining means for determining the difference characteristic, a memory means for storing the determined stress degree-temperature difference characteristic, and a temperature difference calculated by the temperature difference calculating means based on the stored stress degree-temperature difference characteristic. A stress level deriving means for deriving a stress level corresponding to T, and comprises an output means for outputting the derived stress level.

Here, the physiological state quantity is, for example, an electrocardiogram R-R interval, a palm sweating rate (mental sweating rate), or a β-wave power value included in an electroencephalogram.

[0010]

In the present invention, the difference ΔT between the peripheral skin temperature and the trunk skin temperature is used to evaluate the degree of stress. Peripheral skin temperature changes depending on the level of stress,
As the stress level increases, the skin temperature in the peripheral area decreases.
In addition, if the environmental conditions such as environmental temperature and humidity change, the skin temperature of the peripheral area also changes. On the other hand, the skin temperature of the trunk does not change depending on the magnitude of stress, but changes only according to changes in environmental conditions. Therefore, if the difference between the skin temperature at the peripheral portion and the skin temperature at the trunk is taken, the temperature change component due to the change in environmental conditions is canceled out, and the temperature difference becomes an index representing only the magnitude of the stress level. Further, according to the difference between the skin temperature of the peripheral portion and the skin temperature of the trunk, the resting state is not used as a standard as in the conventional case, so that the temperature measurement value may be an instantaneous value, and the measurement does not take time.

In the first stress measuring apparatus, the stress level S and the temperature difference ΔT are previously set for a specific one or a plurality of test subjects whose stress levels are to be measured.
Preliminary measurement for defining the stress level-temperature difference characteristic that is established during the period is performed, and the stress level-temperature difference characteristic for each subject is made into a function or tabulated and stored in the memory means. Here, since the stress level-temperature difference characteristic is defined for each subject, individual differences are added to the stress level-temperature difference characteristic, and the relationship between the stress level and the temperature difference is uniquely determined for each subject. It will be. In the actual measurement of the stress level, the skin temperature of the peripheral part of the human body and the skin temperature of the trunk part are simultaneously measured, and the temperature difference ΔT between them is calculated. Then, the stress level corresponding to the temperature difference ΔT is derived based on the stress level-temperature difference characteristic.

The second stress measuring device has a structure for the preliminary measurement in addition to the structure of the first stress measuring device. That is, in the preliminary measurement, the physiological state quantity is actually measured by the physiological test means, and at the same time, the skin temperatures of the peripheral part and the trunk of the human body are measured, and the physiological state quantity is calculated based on these measurement data. One defined stress level S and temperature difference ΔT at the same time point
Group data is calculated. Then, the set data of the stress degree S and the temperature difference ΔT is accumulated until a predetermined plurality of sets are formed, and based on these set data, the stress degree-temperature difference characteristic established between the stress degree S and the temperature difference ΔT. Is prescribed. The characteristic is made into a function or tabulated and stored in the memory means. After that, the measurement mode is switched from the preliminary measurement to the stress measurement, and the same degree of stress measurement as in the first stress measurement device is performed.

[0013]

According to the stress measuring device of the present invention, individual differences are added to the stress level to realize highly accurate quantitative evaluation of the stress level. However, in measuring the skin temperature, since it is sufficient to capture the instantaneous value without waiting for a steady state, it does not require a long time for the measurement.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows the configuration of a stress measuring device, which is an electrocardiograph (1) for measuring an electrocardiogram RR interval, which is a physiological state quantity, and a forehead which is a nose and a trunk, which are peripheral parts. It is equipped with a thermo camera (2) for measuring the skin temperature of the area.

The electrocardiograph (1) and the thermo camera (2) are connected to a stress measuring circuit (3) composed of a microcomputer or the like, and the stress level S derived by the circuit is measured.
Is output to the printer (9) and / or the display (10).

The stress measuring circuit (3) is based on the RR interval measuring section (4) for measuring the RR interval from the output signal of the electrocardiograph (1) and the measured RR interval. The stress level calculation unit (5) for calculating the stress level S and the temperature data of the nose part and the forehead part are extracted from the infrared face image taken by the thermo camera (2), and the temperature difference ΔT between the two is extracted. And a temperature difference calculation unit (6) for calculating the stress degree-temperature difference characteristic based on the calculated stress degree S and temperature difference ΔT, or an S-ΔT characteristic for deriving the stress degree S from the temperature difference ΔT. It comprises a processing unit (7) and an S-ΔT characteristic memory (8) for storing the determined stress level-temperature difference characteristic.

The stress level S is defined by the following equation 1.

## EQU1 ## S = (RR interval at rest / RR interval at stress measurement-1) .times.100 Here, when S> 100, S = 100. Thereby, the stress level S is expressed in the range of 0-100. Generally, the RR interval during stress is about half that at rest.

According to the definition formula, since the stress level S is defined as the reduction rate of the RR interval from the resting state to the stressed state, an objective stress level without individual difference is obtained. To be Therefore, in the measurement of stress, if the electrocardiogram RR interval is actually measured and the stress level S is calculated from Equation 1, the most accurate evaluation value of the stress level can be obtained. Therefore, in the present invention, the stress level is estimated from the measured value of the skin temperature as described later.

The definition of the stress level is not limited to the definition formula based on the electrocardiogram RR interval of the above formula 1, but also the definition formula based on the palm sweat rate (psychotic sweat rate) as shown in the following formula 2. Β wave (14-30
Various well-known physiological state variables that change depending on the magnitude of stress, such as a definition formula based on the power value of (Hz) (see "Autonomic nerve function test" edited by the Japanese Society of Autonomic Neurology, Bunkodo Publishing).
The definition formula based on can be adopted.

[0020]

## EQU00002 ## S = (perspiration amount during stress measurement / perspiration amount at rest) × 10 Here, when S> 100, S = 100. Generally, the amount of sweat perspiration during stress is about 10 times that at rest. When the ventilation capsule method is used to measure the amount of sweat, the unit of the amount of sweat is humidity.

[0021]

## EQU3 ## S = (β-wave power value during stress measurement / β-wave power value at rest) × 20 Here, when S> 100, S = 100. Generally, the power value of β wave during stress is about 5 times that at rest. The unit of the β wave power value is dB.

Next, various measurement data which is the basis of the stress measuring method according to the present invention will be described. FIG.
Resting state and various stressed states (tracking work of tracking one point moving on the screen by mouse operation, addition by one digit arithmetic calculation, targeting 117 subjects)
The forehead skin temperature and the nose skin temperature in horror video viewing, etc.) were measured and the relationship between the two skin temperatures was graphed. As shown in the figure, in a stress-free state, that is, at rest, the skin temperature varies depending on the subject, but in any subject, the skin temperature shows almost the same value in the forehead and the nose. On the other hand, in a stressed state, the nose skin temperature is lower than the forehead skin temperature and varies, but the forehead skin temperature is stable in the range of 34 ° C to 36 ° C.

As shown in FIG. 4, at rest, the skin temperature of the nose and the skin temperature of the forehead were substantially the same in all subjects,
However, since the forehead is the trunk, and its skin temperature does not change depending on the stress load, the nose skin temperature at rest is used as a reference value for the decrease in the nose skin temperature. The skin temperature can be adopted.

Further, FIGS. 5, 6 and 7 respectively show tracking work for specific test subjects A, B and C,
Three kinds of stress, 1-digit arithmetic calculation and horror video watching, were applied to measure the stress level based on the ECG RR interval, and at the same time, the difference between the forehead skin temperature and the nose skin temperature was measured to determine the stress level. Is a graph of the relationship between the temperature difference and the temperature difference.

The subject A shown in FIG. 5 has the largest temperature difference due to the stress load, that is, the stress reaction, and the maximum temperature difference is 2.2 ° C. Subject B shown in FIG. 6 has a moderate stress response and a maximum temperature difference of 1.8 ° C. Subject C represented in FIG.
The stress reaction is the smallest, and the maximum temperature difference is 1.4 ° C.

As is clear from the three graphs, even if the stress level S is the same, the temperature difference ΔT differs depending on the subject, but in any test subject, the stress level S is irrespective of the type of stress and the measurement time. A certain functional relationship is established between the temperature difference ΔT and the temperature difference ΔT. When these relational expressions are obtained by the least squares method, the following equation 4 is obtained for FIG. 5, the following equation 5 is obtained for FIG. 6, and the following equation 6 is obtained for FIG.

[0027]

(4) ΔT = −0.10805 + 0.021875 × S

[Expression 5] ΔT = −0.111184 + 0.020703 × S

(6) ΔT = −0.128847 + 0.014636 × S

As described above, the constant functional relationship is established between the stress level S and the temperature difference ΔT because the skin temperature of the forehead is subtracted from the skin temperature of the nose to determine the environmental conditions such as environmental temperature and humidity. It is considered that this is because the temperature change component due to the change is offset, and further, the nose skin temperature largely changes due to the load of stress, while the forehead skin temperature is not affected by the stress.

Therefore, the above equations 4 to 6 are the stress level-temperature difference characteristics peculiar to the subjects A, B and C, respectively.
It can be said that it represents (S-ΔT characteristic).

Therefore, in the stress measuring device of FIG. 1, first, in the S-ΔT characteristic memory (8) of the stress measuring circuit (3), the preliminary measurement by the electrocardiograph (1) and the thermo camera (2) is performed. , The stress level-temperature difference characteristic for each subject is stored, and the S-ΔT characteristic memory is stored at the time of stress measurement.
Based on the stress level-temperature difference characteristics stored in (8),
The degree of stress is derived from the measurement results of the forehead skin temperature and the nose skin temperature using only the thermo camera (2).

FIG. 2 shows the processing in the preliminary measurement mode. In the preliminary measurement mode, the output device such as the printer (9) and the display (10) in FIG. 1 is not always necessary and may be separated from the stress measurement circuit (3). First, in step S1, the resting eye closed state is maintained for about 10 minutes, and the RR interval at rest is measured using the electrocardiograph (1). At this time, the output signal of the electrocardiograph (1) is sent to the RR interval measuring section (4) of the stress measuring circuit (3) of FIG.
The R-interval is automatically measured.

Next, in the state where some work (for example, tracking work) is given to the subject, the process proceeds to step S2, and the measurement signals from the electrocardiograph (1) and the thermo camera (2) are sent to the stress measurement circuit ( 3) Simultaneously take in, measure RR interval, and detect infrared face image. Subsequently, in step S3, the stress level calculation unit (5) of the stress measurement circuit (3) calculates the stress level S by the above formula 1 based on the measurement data of the RR interval at rest and under stress. To do. In step S4, the temperature difference calculation unit (6)
However, by extracting the temperature data of the forehead and nose from the infrared face image,
Further, in step S5, the temperature difference ΔT between the forehead and the nose is calculated.

Then, in step S6, one set data of the stress degree S and the temperature difference ΔT thus obtained is stored in the S-ΔT characteristic memory (8). Then, in step S7, it is determined whether or not the number of sets of data exceeds a predetermined number N (for example, N = 12). If NO, step S2
Return to and the measurement is repeated.

When the number of sets of data exceeds the predetermined number N, the process proceeds to step S8 and the S-ΔT characteristic processing section (7) causes S-ΔT to be processed.
All the set data are read from the characteristic memory (8) and the stress degree-temperature difference characteristic is determined by applying the least squares method. The time required to determine one stress level-temperature difference characteristic by performing steps S2 to S8 is about 1 minute. The determined stress level-temperature difference characteristic is output to the printer (9) and / or the display (10) as needed.

Then, the stress measurement mode is entered automatically or by giving a mode switching command. In the stress measurement mode, the electrocardiograph (1) shown in FIG. 1 is unnecessary and can be separated from the stress measurement circuit (3).

In the stress measurement mode, as shown in FIG. 3, first, in step S11, the infrared face image of the subject is detected by the thermo camera (2). In step S12, the temperature difference calculation unit (6) of the stress measurement circuit (3) extracts the temperature data of the forehead and nose, and then the temperature difference ΔT is calculated in step S13.

Next, in step S14, the S-ΔT characteristic processing unit (7) of the stress measuring circuit (3) displays the stress level-temperature difference characteristic of the subject stored in the S-ΔT characteristic memory (8). It is read and the stress level S corresponding to the calculated temperature difference ΔT is derived. When deriving the stress level S, a method of back-calculating the stress level S from the temperature difference ΔT using the characteristic formulas shown in the above equations 4 to 6 or a table of the stress level-temperature difference characteristics to obtain the temperature difference ΔT is used. A method of directly reading the stress level S can be adopted. At this time, when the stress level S has a negative value, S = 0. When the stress level S exceeds 100, S = 1
00.

The stress level S thus derived is
In step S15 of FIG. 3, the value is output to the printer (9) and / or the display (10) and the value is displayed. Then, in step S16, the measurement process is terminated after determining whether or not the measurement is terminated.

In the above stress measuring device, by determining the stress level-temperature difference characteristic for each subject,
Since individual differences are added to the stress level, it is possible to obtain a highly accurate stress level S. Further, in the measurement of the skin temperature, it is sufficient to capture the instantaneous value without waiting for a steady state, so that the measurement can be performed quickly.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims. For example, not only the device configuration of FIG. 1 but also a device that executes only the preliminary measurement mode and a device that executes only the stress measurement mode can be separately configured and used separately.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a stress measuring device according to the present invention.

FIG. 2 is a flowchart showing a process in a preliminary measurement mode.

FIG. 3 is a flowchart showing a process in a stress measurement mode.

FIG. 4 is a graph showing the relationship between forehead skin temperature and nose skin temperature.

5 is a graph showing the stress level-temperature difference characteristics of subject A. FIG.

FIG. 6 is a graph showing the stress level-temperature difference characteristics of subject B.

FIG. 7 is a graph showing the stress level-temperature difference characteristics of subject C.

[Explanation of symbols]

 (1) Electrocardiograph (2) Thermo camera (3) Stress measurement circuit (4) RR interval measurement unit (5) Stress degree calculation unit (6) Temperature difference calculation unit (7) S-ΔT characteristic processing unit ( 8) S-ΔT characteristic memory (9) Printer (10) Display

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiko Ishikawa 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (2)

[Claims] 1. A stress measuring device for measuring the degree of stress on a human body, comprising: skin temperature measuring means for measuring the skin temperature of the peripheral part and trunk of the human body; and the measured skin temperature of the peripheral part and trunk. Temperature difference calculating means for calculating the temperature difference ΔT, a memory means for storing a stress degree-temperature difference characteristic that is established between the stress degree S when a stress is applied to a rest and the temperature difference ΔT, and a memory means. And a stress degree deriving means for deriving a stress degree corresponding to the calculated temperature difference ΔT, and an output means for outputting the derived stress degree. A stress measuring device characterized in that 2. A stress measuring device for measuring the degree of stress on a human body, which comprises a physiological test means for actually measuring a physiological state quantity whose value changes according to the magnitude of stress, and a erasing part and a trunk part of the human body. Skin temperature measuring means for measuring the skin temperature of the, and a stress degree calculating means for calculating the stress degree S under a stress load with respect to a rest by a predetermined definition formula based on the measured physiological state quantity, and From the temperature difference calculation means for calculating the temperature difference ΔT between the skin temperature of the peripheral part and the trunk, and the stress degree-temperature difference established between the stress degree S and the temperature difference ΔT from the calculation results of the stress degree S and the temperature difference ΔT. A characteristic determining means for determining the characteristic, a memory means for storing the determined stress degree-temperature difference characteristic, and a temperature difference calculating means based on the stress degree-temperature difference characteristic stored in the memory means. It was equipped with stress level deriving means for deriving a stress level corresponding to the calculated temperature difference [Delta] T, and output means for outputting the derived stress level Te stress measuring device according to claim.