KR20140057867A - System for mearsuring stress using thermal image - Google Patents

Abstract

Disclosed is a system for measuring a stress index using a thermal image. The system for measuring a stress index using a thermal image according to an embodiment of the present invention includes an image detection unit including a charge coupled device (CCD) camera for photographing an image of an object of which a stress index is to be measured (hereinafter, an object-to-be-measured) and an infrared thermal image camera for photographing a thermal image of the object-to-be-measured; and a computer including an operation control unit for detecting a face of the object-to-be-measured from an image transmitted from the CCD camera and controlling an operation of the CCD camera, a thermal image processing unit for measuring a body temperature of the object-to-be-measured from the thermal image transmitted from the infrared thermal image camera and measuring an amount of aspiration through a nose temperature change of the object-to-be-measured, and a stress index measurement unit for measuring a stress index form the body temperature of the object-to-be-measured and the amount of aspiration transmitted from the thermal image processing unit. The stress index measurement unit measures a stress index by adding the temperature change and the aspiration change of the object-to-be-measured while giving weighted values to the temperature change and the aspiration change.

Description

[0001] SYSTEM FOR MEASURING STRESS USING THERMAL IMAGE [0002]

The present invention relates to a system for measuring a stress index using a thermal image, and more particularly, to a system for measuring a body temperature and respiration using an infrared thermography camera and measuring a stress index through the measurement.

Stress is a nonspecific biological response that occurs in the body in response to a number of injuries and irritations to the living body, resulting in physical or mental tension or such tension that may cause discomfort in staying with other people.

Recently, as society has changed rapidly and the economy has become more difficult, modern people are increasingly stressed due to increasing knowledge and information, excessive workload and fatigue.

Stress can cause psychological symptoms such as nervous breakdown or loss of motivation, and can lead to diseases such as diabetes, hypertension, heart disease, gastric ulcer, cancer, and behavioral symptoms that develop from interpersonal to aggressive behavior . Thus, personal or social loss due to stress is very large, and it is necessary to prepare measures to alleviate such stress. However, most people do not know their stress level, and most of them do not have measures to deal with stress.

Therefore, it is required to measure the stress index quickly and quickly and solve it quickly. Conventionally, in order to measure the state of stress, a method such as a questionnaire, an electrocardiogram or a drug-based hormone test was used in a hospital. However, in such a case, the subject himself / herself can not quickly recognize the current state of health, and there is a problem that he can not cope with the deterioration of health promptly.

It is an object of the present invention to easily measure a stress index using an infrared radiographic camera without a separate examination or medicine inspection.

According to an embodiment of the present invention, there is provided a system for measuring a stress index using a thermal image, comprising: a CCD (Charge Coupled Device) camera for capturing an image of a subject to be measured of a stress index (hereinafter, An image sensing unit including an infrared radiographic camera for capturing a thermal image of the measurement subject; And an operation control unit for controlling the operation of the CCD camera by detecting the face of the person to be measured from the image transmitted from the CCD camera, a temperature measuring unit for measuring the temperature of the measurement subject from the thermal image transmitted from the infrared radiographic camera, And a stress index measuring unit for measuring a stress index from the body temperature and respiration amount of the subject to be measured transmitted from the thermal image processing unit, wherein the stress index measuring unit measures the stress index The stress index is measured by summing up the changes in body temperature and respiratory volume of the subject to be measured by adding weights.

According to the embodiments of the present invention, the stress index can be easily measured using an infrared camera without any separate examination or drug inspection.

In addition, since the stress index person can measure the stress index only by standing in front of the infrared camera, it is possible to reduce the hassle of the person to be measured.

In addition, since the stress index is measured according to the predetermined formula, it is possible to confirm whether the stress index is measured and whether the stress index is stable or stable after a predetermined time.

FIG. 1 is a diagram showing a configuration of a stress index measuring system 100 using a thermal image according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a method of detecting a face of a person to be measured through an image taken by the CCD camera of FIG. 1;
FIG. 3 is a flowchart illustrating a method of tracking a face of a person to be measured through an image photographed by the CCD camera of FIG. 1;
4 is a diagram showing a method of measuring a body temperature of a face portion of a subject to be measured by an infrared radiographic camera.
5 is a diagram showing a method of measuring respiratory rate using a temperature change measured by an infrared radiographic camera.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, this is merely an example and the present invention is not limited thereto.

In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intention or custom of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

The technical idea of the present invention is determined by the claims, and the following embodiments are merely a means for effectively explaining the technical idea of the present invention to a person having ordinary skill in the art to which the present invention belongs.

FIG. 1 is a diagram showing a configuration of a stress index measuring system 100 using a thermal image according to an embodiment of the present invention.

The thermal image stress index measuring system 100 according to the embodiment of the present invention includes an image sensing unit 102 and a computer 108 as shown in FIG.

First, the image sensing unit 102 includes a CCD (Charge Coupled Device) camera 104 and an infrared thermal imaging camera 106.

The image sensing unit 102 captures a thermal image for acquiring biometric information from a person to be measured of a stress index (hereinafter referred to as a " subject to be measured "). Since the image sensing unit 102 does not directly acquire information by contacting the measurement subject, but rather captures the measurement subject at a certain distance, the measurement subject must be photographed in real time.

The CCD camera 104 is a device for photographing a person to be measured. The CCD camera 104 captures an image of a measurement subject and detects the face of the measurement subject. When the measurement subject moves, the face of the measurement subject is tracked by rotating in the up, down, left, and right directions under the control of the computer 108 in real time.

A method of detecting a face of a person to be measured by using the image photographed by the CCD camera 102 and tracking the face of the person to be measured when they are moved will be described later in detail with reference to FIG. 2 and FIG.

Next, the infrared radiographic camera 106 photographs a thermal image representing the thermal distribution of the measurement subject's body in order to detect the biometric information of the measurement subject.

The infrared ray camera 106 may be composed of the CCD camera 104 and one body. Since the infrared radiographic camera 106 has a small rotational range in relation to the CCD camera 104, it may be somewhat difficult to track the subject when the subject moves during shooting. Therefore, when the CCD camera 104 tracks and rotates the measurement subject in real time, the infrared thermal camera 106 captures the thermal image of the measurement subject and transmits it to the computer 108.

A pan device and a tilt device may be coupled to the infrared radiographic camera 106 to rotate the infrared radiographic camera 106 right and left or to tilt the infrared radiographic camera 106 at a predetermined angle.

The computer 108 includes an operation control unit 110, a thermal image processing unit 112 and a stress index measuring unit 114. The computer 108 controls operations of the image sensing unit 102 and analyzes To measure the stress index of the subject to be measured.

First, the thermal image processing unit 112 of the computer 108 receives a thermal image taken by the infrared thermal imaging camera 106, detects a face using a Haar-like algorithm, and, when the measurement subject moves during shooting, The tracking algorithm is used to track the subject's face from thermal images and measure body temperature and respiration.

The computer 108 communicates with the image sensing unit 102 via a wired network or a wireless network. If a wireless network is used, the computer 108 may communicate with the image sensing unit 102 directly.

The thermal image processing unit 112 detects the face of the person to be measured from the thermal image captured by the infrared thermal camera 106, and then measures the body temperature and respiration amount of the person to be measured through the face of the person to be measured.

A method of measuring the body temperature and the respiration amount of the measurement subject will be described later in detail with reference to FIG. 4 and FIG.

Meanwhile, the operation control unit 110 of the computer 108 obtains a difference image of input images transmitted in real time from the CCD camera 104 when a measurement subject moves during shooting, The face of the person to be measured is traced from the image. Then, the operation of the CCD camera 104 is controlled so that the CCD camera 104 rotates up, down, left, and right along the movement of the measurement subject. Here, the one-dimensional projection method can reduce the amount of computation in image processing, which is advantageous for real-time motion tracking of objects.

Lastly, the stress index measuring unit 114 calculates the stress index through the amount of change in body temperature measured by the thermal image processor 112.

In the stress state, the subject's heartbeat accelerates, the volume increases, and the body temperature changes. That is, as the stress increases, the subject's breathing volume increases and the body temperature decreases.

At this time, the body temperature change is larger than the change in the respiration amount of the measurement subject, and the stress index (SI) measurement according to the first embodiment can be calculated by the following equation (1).

[Equation 1]

Stress Index ( Stress Index : SI ) = a × (B-12) + b × (36.5 ° C.-T)

B is the number of breaths per minute at the time of the measurement of the stress index of the subject, T is the body temperature at the time of measuring the stress index of the subject, 12 is the reference breath rate, 36.5 ° C is the reference body temperature, a and b are the weight coefficients, 1.5, and b = 25.

. The reference breathing rate is based on the average respiratory rate of the adult male and female, and the reference body temperature refers to the temperature of the human body in a normal state. That is, the stress index is measured by adding the weight change and the change in the respiratory volume to each other when the respiration rate is higher than the reference breath rate and the body temperature is lower than the reference body temperature due to an increase in the stress of the measurement subject. The weighting factors a = 1.5 and b = 25 are values that take into account changes in body temperature and respiratory volume, and are values for equally reflecting body temperature and respiration in the calculation of the stress index. The weighting coefficients are most preferable when a = 1.5 and b = 25, but there is no great difficulty in measuring the stress index within an even range.

For example, if the subject is stressed and breathes 17 times more per minute than the reference breath rate of 12 and the body temperature is 36 ° C lower than the reference body temperature of 36.5 ° C, the stress index SI = 1.5 × (17-12) + 25 占 (36.5 占 폚 -36 占 폚) = 20, and when there is no stress, SI = 0 because the measurement subject has the reference breath rate and the reference body temperature.

When the stress index (SI) shows a negative value, it means that the number of breaths per minute at the time of measuring the stress index of the subject is lower than the reference breath rate, or the body temperature at the time of measuring the stress index of the subject is higher than the reference body temperature. It is determined that an abnormality has occurred in the body of the measurement subject.

In addition, when the average respiration rate per minute is lower or higher than the average respiratory rate per 12 breaths, the stress index can be measured using the average respiration rate per minute of the subject other than the reference respiration rate of 12.

The stress index (SI) measurement according to the second embodiment can be calculated by the following equation (2).

&Quot; (2) "

Stress Index ( Stress Index : SI ) = a × (B-B0) + b × (36.5 ° C.-T)

B is the number of breaths per minute at the time of the measurement of the stress index of the subject, T is the body temperature at the time of measuring the stress index of the subject, ° B0 is the average respiratory rate per minute of the subject, 36.5 ° C is the reference body temperature, A = 1.5 and b = 25, respectively.

As can be seen from the above equation, the stress index is calculated using the average respiration rate (B0) of the measurement subject instead of the reference breath rate (12). The average respiratory rate (B0) of the subject to be measured can be applied when the average respiratory rate of the subject to be measured is different from the average respiratory rate of the average adult male and female in general, in order to reflect individual characteristics.

For example, assuming that the average respiratory rate (B0) per minute of the measurement subject is 15 instead of 12, the subject is stressed and breathes 18 times per minute, and the body temperature is 36 ° C. lower than the reference body temperature 36.5 ° C. , The stress index SI = 1.5 x (18-15) + 25 x (36.5 캜 -36 캜) = 17.

That is, the stress index can be efficiently calculated reflecting the average respiration rate per minute according to the characteristics of the individual.

In Equation (2), the remainder after excluding the average respiratory rate (B0) per minute of the measurement subject is as described above in Equation (1), and a detailed description thereof will be omitted.

According to the first and second embodiments described above, the stress index of the measurement subject can be indirectly measured, and it is useful to confirm whether or not the measurement subject is stressed by digitizing it to a specific value. In addition, it is possible to easily measure the stress index by using infrared camera without any separate examination or medicine inspection, and it is possible to measure the stress index only by standing the subject in front of the infrared thermal camera, thereby reducing the hassle of the subject have.

FIG. 2 is a diagram illustrating a method of detecting a face of a person to be measured through an image taken by the CCD camera of FIG. 1;

The method of detecting the face can be largely divided into a preprocessing step and a face detection step.

First, the preprocessing step is a step for appropriately processing the thermal image so that the face can be detected well in the face detection step. For example, the brightness of the input image may be adjusted, the color may be changed to gray scale, or the image may be converted into a histogram.

Next, the facial detection step uses a Haar-like algorithm. The Haar-like algorithm expresses facial feature values using a simple sum image. When a template is applied to the input thermal image, if there is a shape included in the template in the thermal image, the Haar- And the edge of the set face region is inspected to determine the position of the eyes, nose, and mouth, and finally the face region is determined. For example, various types of edge patterns can be used for face detection, and the eye pattern, the nose, and the like are detected by applying the edge pattern to the original image captured by the CCD camera 104. That is, in the face region, the eyes and mouth can be detected as a transverse edge, and the nose can be detected as a vertical edge.

FIG. 3 is a flowchart illustrating a method of tracking a face of a person to be measured through an image photographed by the CCD camera of FIG. 1;

In the process of detecting the face of the person to be measured by the method shown in FIG. 2, when the person to be measured moves during shooting, the CCD camera 104 tracks the face according to the movement of the person to be measured and continues without stopping the shooting .

Referring to FIG. 3, since the CCD camera 104 transmits an image to the computer 108 in real time, there is a predetermined time difference between the images received by the computer 108. The computer 108 simplifies the image by using a morphological filter for two images having a predetermined time difference (S302). Then, a difference image between the two images is obtained (S304), and an absolute value image of the difference image is acquired (S306). Next, an object is extracted from the absolute value image (S308), a motion vector is extracted from the extracted object (S310), and motion of the object is determined. Here, the morphological filter is a filter used to change the shape while maintaining the basic characteristics of the image.

In this manner, the operation control unit 110 of the computer 108 obtains the difference image between the input images captured by the CCD camera 104 and transmitted in real time, And controls the operation of the CCD camera 104 so that the CCD camera 102 tracks and moves the movement of the measurement subject.

4 is a diagram showing a method of measuring a body temperature of a face portion of a subject to be measured by an infrared radiographic camera.

The thermal image processing unit 112 detects the face region of the measurement subject in the input thermal image. If a region having a large temperature difference exists simultaneously in the face region, the thermal image processing unit 112 sets the regions as the region of interest, adds all the degradation points of the regions of interest, calculates an average value, do. Here, the thermal image processing unit 112 may set predetermined comparison values and set the regions as interest regions when there are regions having a temperature difference of more than a comparison value among the face regions.

A high dynamic range imaging (HDRI) technique can be used to measure the temperature of the subject. The HDRI method is a technique for obtaining more precise data by selectively increasing the thermal resolution for a range of temperature changes. For example, when the computer 108 analyzes the thermal image at a thermal resolution of 10 ° C, if the thermal resolution is further subdivided in the range of 30 ° C to 40 ° C, where human body temperature changes are intensively distributed, It can be analyzed precisely.

5 is a diagram showing a method of measuring respiratory rate using a temperature change measured by an infrared radiographic camera.

As shown in FIG. 5, the thermal image processing unit 112 sets the nose of the subject in the face region of the thermal image as the region of interest, and detects the amount of respiration through the change of the subcutaneous temperature.

That is, when the subject to be measured breathe, the temperature of the submucosa is changed by the snorting.

Change in submerged temperature = current Temperature value  - past Temperature value

Next, the number of times of the portion where the temperature change amount is 0 for a predetermined time (for example, 5 seconds or 10 seconds) is counted, and this value is divided by time to calculate the number of respirations per second. The calculated value is multiplied by 60, Converts to a number.

As shown in FIG. 5, for example, if the number of portions where the temperature change amount is 0 is twice for 5 seconds, dividing the two times by the measurement time of 5 seconds, the respiration rate per second is 0.4 / sec. In order to convert the breath rate per second to 0.4 breaths per minute to 60 breaths per minute, the respiratory rate per minute is 24 breaths per minute.

That is, as described above with reference to FIGS. 4 and 5, the body temperature and respiratory rate of the subject to be measured can be obtained and the heart rate can be measured.

As described above, the system for measuring stress index using thermal images according to the embodiment of the present invention collects biometric information of a subject to be measured from a thermal image of a face of a subject to be measured, Of the stress index.

In addition, the information collection for the measurement target person is not an electronic device directly attached to the measurement target person, but is made in a non-contact manner through the image sensing unit 102 located at a certain distance from the measurement target person, so that the hassle of the measurement target person can be reduced.

In addition, the stress index can be easily measured using an infrared thermal camera without a separate examination or drug inspection.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand.

Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by equivalents to the appended claims, as well as the appended claims.

100: a stress index measuring system 100 using a thermal image according to an embodiment of the present invention;
102: Image sensing unit
104: CCD camera
106: Infrared thermal camera
108: Computer
110:
112: Thermal image processor
114: stress index measuring unit

Claims (5)

An image sensing unit including a CCD (Charge Coupled Device) camera for capturing an image of a person to be measured of a stress index (hereinafter, referred to as a "subject to be measured") and an infrared radiographic camera for capturing thermal images of the subject; And
An operation control unit for detecting the face of the person to be measured from the image transmitted from the CCD camera and controlling the operation of the CCD camera; a temperature measuring unit for measuring the body temperature of the measurement subject from the thermal image transmitted from the infrared thermal camera, And a stress index measuring unit for measuring a stress index from the body temperature and respiration amount of the measurement subject transmitted from the thermal image processor,
The stress index measuring unit includes:
Measuring the stress index by summing the changes in body temperature and respiratory volume of the subject to be measured,
System for measuring stress index using thermal image.
The method according to claim 1,
The stress index measuring unit includes:
Wherein the stress index is measured using the following equation (1).
[ Equation 1]
Stress index (Stress Index : SI ) = a 占 (B-12) + b 占 (36.5 占 폚 -T)
B is the number of breaths per minute at the time of the measurement of the stress index of the subject, T is the body temperature at the time of measuring the stress index of the subject, 12 is the reference breath rate, 36.5 ° C is the reference body temperature, a and b are the weight coefficients, 1.5, and b = 25.
The method according to claim 1,
The stress index measuring unit includes:
Wherein the stress index is measured using the following equation (2).
& Quot; ( 2) & quot ;
Stress index (Stress Index : SI ) = a 占 B-B0 + b 占 36.5 占 폚 -T)
B is the number of breaths per minute at the time of the measurement of the stress index of the subject, T is the body temperature at the time of measuring the stress index of the subject, ° B0 is the average respiratory rate per minute of the subject, 36.5 ° C is the reference body temperature, A = 1.5 and b = 25, respectively.
The method according to claim 1,
The operation control unit,
Wherein the face is detected using Haar-like algorithm for the image of the measurement subject transmitted from the image sensing unit.
The method according to claim 1,
The thermal image processing unit,
The method comprising the steps of: summing up thermal image points of the regions in a region of the face region of the measurement subject where a temperature difference greater than a predetermined comparison value exists, and calculating an average value to measure a body temperature of the measurement subject;
System for measuring stress index using thermal image.

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