JP3917944B2 - Fatigue degree evaluation method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for evaluating a worker's fatigue level. The present invention relates to an improvement in a method and an apparatus for evaluating a worker's fatigue level by performing work over a predetermined work time and performing test measurement of the worker's reaction before and after the work time. The present invention is used for objectively and quantitatively evaluating the degree of fatigue caused by human work. The present invention is an apparatus developed to improve the ride quality and other performances of automobiles by quantitatively evaluating the fatigue level of automobile drivers. Can be used to evaluate.
[0002]
[Prior art]
For example, in designing a driver's seat for a new automobile, a structure that is comfortable for the driver and that reduces the fatigue level of the driver even after driving for a long time is required. To design such a seat, an opinion test by a large number of drivers (operators) is effective, but in addition to the opinion test, the fatigue level of the driver as a function of driving time (working time) It is effective to observe quantitatively. For this reason, when an operator performs a specific operation, before or after that operation, or temporarily suspending the operation to be continued, conduct a predetermined fatigue evaluation test, and quantitatively determine the worker's fatigue level. The determination is conventionally performed.
[0003]
As a conventional fatigue evaluation test method for this purpose, a method of observing the reaction time of a subject's vision or hearing is widely known. For example, the subject is watching the screen, and when a specific figure appears on the screen, the subject presses the button, and measures the time from when the figure is displayed until the button is pressed. This measurement result is repeatedly executed several times for each of a plurality of subjects, and statistical processing is performed on the test result. This method utilizes the fact that when the subject is tired, the reaction time from when a specific figure appears on the screen until the button is pressed becomes longer.
[0004]
In addition, there is a method called flicker method. This is an abbreviation for Critical fusion frequency of flicker, which measures the frequency of the boundary of whether it appears as intermittent light or continuous light when you see flashing light. The higher the value, the less fatigue.
[0005]
Furthermore, as a biochemical method, there is a method for measuring a minute amount of a substance that increases or decreases with fatigue by collecting blood or urine of the subject before and after the work or during the work as a biochemical method. Are known. As a method of this type that has been taken up in recent years, there is a method for detecting hydroxydeoxyguanosine (8-OHdG). This is a method for quantifying the degree of generation of active oxygen due to stress, and is considered to be a practical and effective method.
[0006]
As a method for measuring the fatigue level of an operator, a method of observing and evaluating electrocardiograms before and after performing work is also known. It is said that the activity of sympathetic nerves and parasympathetic nerves can be evaluated by heart rate evaluation.
[0007]
Furthermore, as a technique for quantitatively measuring the fatigue level of an operator, for example, Patent Document 1 (Applicant, Kanebo) is known as a technique disclosed in Patent Document. This is an apparatus for examining the time for which a subject reacts after a specific figure is displayed on the screen on which the subject gazes. Specifically, this device is a device for measuring the time from when a graphic is displayed on the screen until the key is pressed. Thus, the fatigue level of the discrimination ability for the screen is observed.
[0008]
A technique disclosed in Patent Document 2 (Applicant, Sharp) is known. This is a device that quantitatively tests eye strain when a computer user is gazing at the screen for a long time. This is also a test of how the discrimination ability with respect to the fine graphic display on the screen where the worker is stationary deteriorates as the work time elapses.
[0009]
[Patent Document 1]
JP 7-111989 A
[Patent Document 2]
Japanese Patent Laid-Open No. 10-192263
[0010]
[Problems to be solved by the invention]
The above-mentioned biochemical method for collecting blood and urine from a subject and performing an examination and the method for measuring an electrocardiogram are highly accurate, but this test method increases the burden on the subject, and the equipment and examinations. In view of the qualifications required by the person in charge, it is not appropriate as a test that is repeatedly and simply performed in the vehicle design room or prototype factory. In this sense, it is an excellent method to have the subject operate the input key while looking at the screen and evaluate the operation result according to a certain logic.
[0011]
All of the fatigue test methods using the screen described in the above-described conventional example are methods for evaluating a subject's reaction time using a still image. The image that appears in the driver's vision is always a moving image and not a still image. It has been found that even if the ability to identify still images is evaluated, the method for testing driver fatigue does not necessarily correspond to the degree of fatigue. That is, the increase in reaction time measured by the conventional method is a secondary phenomenon caused by worker fatigue. The measurement of the degree of driver fatigue is an important factor not only for measuring the delay in reaction time but also for how perceptual or mental fatigue affects the recognition of moving images. In the driver fatigue determination, it is desirable to identify the type of target video in the field of view and determine the ability to recognize the movement form in order to improve the driver fatigue determination accuracy. It came.
[0012]
Focusing on the trend of automobile market demand, commercial vehicles are increasingly used for long-distance or long-time driving. Therefore, there is a demand for a design that reduces the driver's fatigue even when driving for a long time. Further, with regard to general vehicles, elderly people often drive, and there is a demand for a vehicle with a comfortable ride with less fatigue than a professional driver with respect to driving time.
[0013]
Supplementing the above explanation from a different angle, the structure of the driver's seat for automobiles has been considerably improved at the present stage, and a structure that does not get fatigued even when driving for a long time is provided. Therefore, even if a fatigue test of a driver who tests the reaction time as in the conventional case is performed, a result that the driver who is a subject is tired becomes difficult to obtain. In order to cope with this, it is necessary for the subject who performs the driving operation to perform the driving operation for a longer time, but this is not easy. Therefore, there is a need for a fatigue test method and apparatus that improves the test accuracy for testing the driver's fatigue level, that is, makes the test problem difficult and can detect even less fatigue. It ’s easy to understand.
[0014]
The present invention has been made in such a background, and it is an object of the present invention to provide a fatigue test method and apparatus capable of determining the recognition ability of a moving object in the field of view. The recognition ability for a moving object in the field of view corresponds to the recognition ability for a preceding vehicle or a traffic sign that is being driven. An object of the present invention is to provide a fatigue test method and apparatus that can test not only the reaction time of an operator but also the ability of the worker to recognize dynamic images. An object of this invention is to provide the method and apparatus which can determine more directly the deterioration of the driving capability of the motor vehicle due to fatigue. An object of the present invention is to provide a method and an apparatus that can accurately determine the degree of fatigue of an operator without requiring special equipment or special qualifications of a person in charge in a laboratory or factory. And An object of this invention is to provide the fatigue test method and apparatus which can identify even if a test subject's fatigue degree is small. An object of this invention is to provide the determination method and apparatus of the fatigue grade with a small test subject's burden.
[0015]
[Means for Solving the Problems]
The present invention displays the moving image a plurality of times on the screen on which the subject is gazing, and allows the subject to determine whether or not the displayed moving image is the same as the previously displayed moving image. Features. A moving image to be displayed is an image in which a target displayed by a combination of simple figures moves within the screen.
[0016]
Two moving images having the same combination (target) of the figures are repeatedly displayed, for example, twice in a short time. If the subject determines that the two moving images displayed after a short period of time are “same”, the answer is correct, and if it is determined “not”, the answer is incorrect. If the combination of the first displayed image and the graphic that is displayed for the second time is changed, the answer is correct if the subject is determined to be “different”, and the error is determined if the subject is determined to be “same”. Suppose there is. Even if the movement forms are different, it is assumed that the same combination is correct if it is determined to be “same”, and that it is incorrect if it is determined that it is “different”. The time for the image to move in the screen is from a fraction of a second to a few seconds. The interval for performing the display twice, that is, the short time is, for example, 1 second to several seconds.
[0017]
The number of times of repeated display is not limited to two as described above, and can generally be a plurality of n times. That is, a combination of figures is displayed first, a screen in which this combination moves in one direction on the screen is displayed, and (n-1) times, the same combination of figures moves in the same direction. Screen to be displayed, a screen having a different combination figure, or a screen having a different moving direction is displayed. After each (n-1) iterations, the subject is asked to determine whether the screen is “same” or “different” from the first screen. And the correct answer or misunderstanding is processed statistically, and a test subject's fatigue degree is determined.
[0018]
By such a test, it is possible to measure the deterioration of the recognition ability of the subject with respect to the moving image. Thereby, not only the simple reaction time with respect to the display image but also the degree of mental fatigue can be determined based on the recognition level with respect to the dynamic image. The driver of the car recognizes the moving image as long as driving continues, and by determining the moving image as in the present invention, the fatigue level of the subject is more accurately matched to the driver's fatigue level. be able to.
[0019]
The number of repeated display (n) is different from the number of tests (m). In other words, this fatigue test is performed with the subject temporarily interrupted. For example, if the subject is asked to drive from early morning to early evening, one fatigue test is performed before starting driving in the early morning, and then (m-1) times by evening every 3 hours. Suppose the procedure is to perform a fatigue test. At this time, the screen display is performed n times in each of the m tests. That is, in n screen display, (n-1) times of screen display is performed after the first screen display, and whether the (n-1) times of display is the same as the first one. Is the answer.
[0020]
That is, the first aspect of the present invention is a fatigue evaluation method, which allows a subject to perform work (eg, driving operation by a simulator) and executes a fatigue evaluation test on the subject before and after the work (m = 2). In the method for evaluating the fatigue level given to the subject by the work by comparing the result of the fatigue test performed before the work with the result of the fatigue test performed after the work,
In the fatigue evaluation test, (i) an image including a moving image in which a target consisting of a combination of a plurality of simple figures moves within the screen displayed on the subject's gaze is displayed (ii) In the screen, an image including the moving image is displayed at a time interval set a plurality of n times, the same or changed with respect to the combination of the figures and the moving direction thereof, and (iii) out of the n times Let the subject determine whether the image displayed after the second time is the same as the first moving image,
It is characterized by that.
[0021]
Although only the target may be displayed on the screen, an appropriate screen can be displayed on the background. This background screen is, for example, a road surface of a highway or a landscape screen. By making this background screen complicated or making this background screen a moving image plane, the difficulty of determination becomes difficult.
[0022]
The combination of the plurality of simple figures may be two combinations selected from the three types of circle (◯), sankaku (Δ), and cross (x). This "simple figure" includes not only figures but also "characters". Illustratively, it is two characters of A, B, and C. The n is suitably 2 to 10. In addition to the accuracy rate as to whether the second (n = 2) or subsequent images are the same, the length of time required for the determination of the subject can also be used as an evaluation factor.
[0023]
In the above description, it is expressed as “moving direction” of the combination of figures (target), but the moving direction is not necessarily a linear direction, but is configured to change the moving path, and dynamic images with different moving paths. Also, the same or non-identical can be determined. Various variations of such display can be set. However, if the display variations are diversified, this will make the problem difficult, and naturally the accuracy rate will be low. Such variations must be set in harmony with the accuracy rate.
[0024]
A second aspect of the present invention is a fatigue evaluation apparatus, which displays a combination of a plurality of simple figures (including characters) as a target on the screen, and then moves the target within the screen. A pattern generating means and a combination of a plurality of simple figures that are the same as or different from the first pattern generating means are displayed as targets in the screen, and then the target is generated in the screen with the first pattern generation. The second pattern generating means for moving in the same or different direction as the means, and the means for starting the first pattern generating means and then starting the second pattern generating means. This is an expression for n = 2. n is plural and at least 2.
[0025]
The activation means includes a plurality of time intervals set by changing the display content of the target and / or the moving direction of the target for the second pattern generation means after the first pattern generation means is activated ( n-1) It can be configured to include means for starting up a number of times. This represents when n is 3 or more.
[0026]
The screen may include means for displaying a background screen in addition to the target. When this background screen is displayed, the same screen can be displayed n times or different screens. For example, the background screen is a screen in which the road surface in front of the vehicle is viewed from the driver's seat, and the screen can be configured to move so that the vehicle travels. By selecting the configuration of the background screen, the accuracy rate can be increased or decreased. In other words, because the background screen is noisy for the target for the subject, the accuracy rate is lowered by complicating the background screen, such as configuring the background screen misleadingly with the target, or using a moving image screen for the background screen. (To make the problem difficult).
DETAILED DESCRIPTION OF THE INVENTION
The embodiment will be described in more detail with reference to the drawings. FIG. 1, FIG. 2 and FIG. 3 show an example of the screen display of the embodiment apparatus of the present invention. The embodiment of the present invention is a common personal computer. It is desirable to use a personal computer with a large screen. Have the subject sit in front of the screen of this personal computer. A question appears on the screen, and the subject answers this question. The answer is “YES” or “NO”, and the keyboard is input to this personal computer. Enter “Y” for YES and “N” for NO.
[0027]
In a state in which the subject gazes at the screen, a rectangular target appears slightly above the center of the screen as shown in FIG. A set of X and O graphics is displayed in the target. When this target appears on the screen, it immediately moves to the lower left as indicated by the dashed arrow and disappears from the screen. After a few seconds, the target appears on the screen in the same way. This target moves in the same way and disappears from the screen. At this time, the subject is made to judge whether the screen displayed for the second time is the same as the previous screen.
[0028]
If the subject determines that the second display is the same as in FIG. 1, the subject presses “Y” on the keyboard of the personal computer. When determining that they are not the same, the subject presses “N”. This instruction is displayed in characters on the upper left of this screen, but this display is omitted in FIG.
[0029]
As shown in FIG. 2, the target moves in the same direction as shown in FIG. 2, but when the figure in the target is changed, it is correct that it is not the same. If the figure in the target is the same as shown in FIG. 3 and the moving direction moves in the lower right direction and disappears as shown in FIG. 3, the correct answer is to make it the same. In this way, it is determined whether the figures in the target are the same regardless of the moving direction. In this description, it is easy to compare because FIGS. 1 to 3 are on the same sheet, but in the state where this is displayed on the screen and immediately disappears, the subject must make a judgment based on his / her own memory. Become.
[0030]
The target is displayed in this way, and then the display for moving the target to disappear is repeated n times. Whether or not the second and subsequent displays are the same as the first display is answered a total of n-1 times.
[0031]
In the example illustrated in FIGS. 1 to 3, the figures displayed in the target are only ◯ and X. However, as illustrated in FIGS. 4, 5, and 6, the graphic is displayed in the target. Many confusing targets can be prepared by adding Δ as a figure to be displayed. In FIG. 1, the position where the target is initially displayed is substantially above the center of the screen. However, if the display position is changed, for example, the center of the left side of the screen, more misleading displays should be prepared. Can do.
[0032]
In this example apparatus, the initial display of the target was set to a random position slightly above the center of the screen, the movement direction was the lower left direction and the lower right direction, and the test was performed with three types of figures in the target. . In this embodiment apparatus, a background screen is added to this screen, the background screen is a screen on the road looking forward from the driver's seat of the car, and the vehicle is running forward, and the background screen is It was configured to flow from the front to the rear. As a result, it is possible to make the operation of determining which correct answer is quite misleading for the subject.
[0033]
The test as described above is performed once before and after the operation, twice in total (m = 2). If it does so, a test subject will measure a fatigue degree twice about the state before the work, and the state after working. By comparing the measurement results of the two fatigue levels, the degree of fatigue due to the work can be known.
[0034]
This can be performed m times instead of twice before and after the work. For example, ask the subject to work from early morning to early evening, conduct the test once before starting the early morning work, and then interrupt the work for a short time until the evening work is finished (m-1) times We will conduct the test. If it does so, the fatigue degree with respect to the time passage by an operation | work can be measured.
[0035]
As in this embodiment, the fatigue level is measured by measuring the dynamic image content and the ability to recognize the moving direction, such as attention to the vehicle ahead in driving operations, traffic signs displayed during road driving, It can correspond to the attention to the guide plate.
[0036]
The measurement result is recorded in the personal computer and statistically processed. This statistical processing is quantitatively displayed as a correct answer rate with respect to the work content or work time of the subject. Furthermore, the statistical processing method for evaluating the accuracy rate is a problem different from the subject of the present invention, and many methods have been known for these.
[0037]
Next, with reference to FIG. 7, the entire test procedure according to the method of the present invention will be described. This example is an example of performing a performance test of a driver's seat of a car under development and design. In other words, a prototype of the driver's seat was made, and this prototype was evaluated. For this, we ask several subjects to have each seated in their seat, and perform a test to quantitatively grasp how the subject is tired by sitting in the prototype seat and driving. Is.
[0038]
To explain this procedure, a driving simulator is prepared ((1) in FIG. 7). This driving simulator can be roughly understood by imagining a driving simulator for games, for example. This embodiment has a structure in which a cab portion provided with a driver seat of a medium-sized truck is mounted on a vibration test apparatus. The front of the driver's seat is equipped with a screen, which displays a screen that flows according to the driving operation. The driver's seat is equipped with a steering wheel (steering wheel), an accelerator pedal, and a brake pedal, each of which is equipped with a sensor that generates an electrical signal according to the amount of operation input. The sensor output is connected to the operation input of the driving simulator.
[0039]
These can be operated when the subject is seated in the driver's seat. When an operation for starting the vehicle is performed, the screen display flows from a distance to the front, and the screen display changes correspondingly as the steering operation and the acceleration / deceleration operation are performed. The driving simulator used for carrying out the present invention is configured such that vibration accompanying the running of the vehicle is artificially applied to the driver's seat from the vibration test apparatus.
[0040]
A prototype of the driver's seat under development and design is attached to this driving simulator ((2) in FIG. 7). Then, several test subjects are requested to sit down on this prototype and perform a simulated driving operation ((3) in FIG. 7). It should be noted that this driving simulator is a device different from the device described in FIGS.
[0041]
Before having the subject sit on this seat, that is, before performing the driving simulation operation, the subject sits in front of the screen of the fatigue evaluation apparatus described above. The fatigue evaluation device is a device different from the driving simulator, and is provided, for example, in a separate room from the driving simulator. Then, the fatigue evaluation described with reference to FIGS. 1 to 6 is performed on the subject by this fatigue evaluation apparatus. This fatigue level evaluation device is a screen different from the scenery viewed from the driver's seat appearing in this driving simulator. The test subject repeatedly shows the moving image as described above, and asks the subject whether or not the moving image is the same image as the previously shown moving image and continuously answers n−1 times. The result of the evaluation is subjected to a certain statistical process and digitized. The evaluation result is “A1” because it is the first evaluation for the subject A ((4) in FIG. 7).
[0042]
Next, the subject A leaves the front of the screen of the fatigue evaluation apparatus and is seated on the seat of the driving simulator. Then, the vehicle is simulated by a driving simulator. That is, a driving operation is simulated for a time t1 by the driving simulator. At time t2 (t2≤t1) of the driving operation time t1, a pseudo vibration corresponding to vibration generated during road running programmed in advance is applied to the seat from the vibration testing apparatus ( (5) of FIG. The time t1 is, for example, 3 to 5 hours with a short break on the way.
[0043]
When the time for the simulated driving operation is over, the subject A again sits in front of the screen of the fatigue evaluation apparatus. And fatigue degree evaluation by the method of this invention is implemented similarly to said (4) of FIG. The evaluation result is “A2” ((6) in FIG. 7).
[0044]
By comparing the two evaluation results “A1” and “A2” obtained, the fatigue level of the subject A can be quantified ((7) in FIG. 7).
[0045]
Using the same apparatus (fatigue level evaluation apparatus and driving simulator) as described above, the same fatigue level evaluation is performed on the subjects B, C, and D ((7), (8), and (9) in FIG. 7). (10)). And the fatigue degree evaluated about all the test subjects A, B, C, and D is processed statistically ((11) of FIG. 7). This is an evaluation of the seat prototype under development. This can be quantitatively compared by performing a similar evaluation for seats used in existing vehicles. Moreover, it can compare by performing the same evaluation about the seat of another vehicle type.
[0046]
The fatigue evaluation screen for performing the fatigue evaluation may be displayed on the screen, so the driving simulator screen is used with the driver sitting in the driver's seat and being shaken. It is also possible to display a fatigue evaluation screen and measure the response to the fatigue evaluation.
[0047]
【The invention's effect】
The present invention provides a fatigue testing method and apparatus based on the ability to recognize moving objects in the field of view. With the method and apparatus of the present invention, not only the worker's reaction time but also the worker's ability to recognize dynamic objects can be tested. The present invention is suitable for determining deterioration of the driving ability of an automobile due to fatigue. According to the present invention, it is possible to accurately determine the degree of fatigue of an operator without requiring special equipment or qualification of a person in charge in a laboratory or factory. The present invention is also a method and apparatus for determining the degree of fatigue with less burden on the subject. The method and apparatus of the present invention can detect even when the subject's degree of fatigue is small, and can increase the detection accuracy, as compared with the conventional technique that measures the reaction time of the subject with respect to the screen display.
[Brief description of the drawings]
FIG. 1 is a diagram showing a screen display example of an apparatus according to an embodiment of the present invention, and a first display example (n = 1).
FIG. 2 is a diagram showing a screen display example of an apparatus according to an embodiment of the present invention, and a second display example (n = 2).
FIG. 3 is a diagram showing a screen display example of the embodiment device of the present invention, and another display example for the second time (n = 2).
FIG. 4 is a diagram showing a screen display example of the apparatus according to the embodiment of the present invention, and another display example for the first time (n = 1).
FIG. 5 is a diagram showing a screen display example of the apparatus according to the embodiment of the present invention, and another display example for the first time (n = 1).
FIG. 6 is a diagram showing a screen display example of the apparatus according to the embodiment of the present invention, and another display example for the first time (n = 1).
FIG. 7 is a diagram for explaining a main part of a procedure in the case of designing a vehicle seat using the embodiment device of the present invention.

Claims (7)

Have the subject work, and run a fatigue assessment test on the subject before and after the task, and compare the results of the fatigue assessment test performed before and after the task. In the method of evaluating the degree of fatigue given to the subject by the work,
In the fatigue evaluation test, (i) an image including a moving image in which a target consisting of a combination of a plurality of simple figures moves within the screen displayed on the subject's gaze is displayed (ii) In the screen, an image including the moving image is displayed at a time interval set a plurality of n times, the same or changed with respect to the combination of the figures and the moving direction thereof, and (iii) out of the n times Let the subject determine whether the image displayed after the second time is the same as the first moving image,
A fatigue evaluation method characterized by the above. The fatigue evaluation method according to claim 1, wherein the combination of the plurality of simple figures is two combinations selected from the three types of circle (◯), sangaku (Δ), and cross (×). The fatigue evaluation method according to claim 1, wherein n is 2 to 10. The fatigue degree evaluation method according to claim 1, wherein the evaluation factor is an accuracy factor of whether or not the second or subsequent images are the same as well as the length of time required for determination by the subject. A first pattern generating means for displaying a combination of a plurality of simple figures in the screen as a target and then moving the target in the screen;
A combination of a plurality of simple figures that are the same as or different from the first pattern generating means are displayed as targets in the screen, and then the target is the same as or different from the first pattern generating means in the screen. Second pattern generating means for moving in the direction;
A fatigue evaluation apparatus comprising: a first pattern generation unit that activates the second pattern generation unit; and a second pattern generation unit that activates the second pattern generation unit. The activation means includes a plurality of time intervals set by changing the display content of the target and / or the moving direction of the target with respect to the second pattern generation means after the first pattern generation means is activated ( 6. The fatigue evaluation apparatus according to claim 5, comprising means for starting n-1 times. 6. The fatigue evaluation apparatus according to claim 5, further comprising means for displaying a background screen in addition to the target on the screen.

Images