JP2004267339A - Method and device for fatigue degree evaluation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quantitatively measure the degree of the fatigue of an operator (testee) from performing work such as a driving operation for a long period of time and to rationally measure the degree of the fatigue from gazing at a moving object as in the driving operation by not only measuring simply the delay of the reaction time due to the fatigue but also measuring the reaction of the testee to a moving image. <P>SOLUTION: On a screen, a target by the combination of simple graphics is displayed and the moving image in which the target is moved and made to disappear within the screen is repeatedly displayed for (n) times. Then, the testee is made to decide whether or not the moving image of the first time and the moving image of the following (n-1) time are the same for the display contents of the target. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for evaluating a worker's degree of fatigue. The present invention relates to an improvement in a method and an apparatus for evaluating the degree of fatigue of an operator by performing an operation over a predetermined operation time and testing and measuring a reaction of the operator before and after the operation time. INDUSTRIAL APPLICABILITY The present invention is used for objectively and quantitatively evaluating the degree of fatigue caused by performing human work. The present invention is a device developed to improve the ride comfort and other performances of a car by quantitatively evaluating the degree of fatigue of a car driver. Can be used to evaluate.
[0002]
[Prior art]
For example, designing a driver's seat for a new automobile requires a structure that is comfortable for the driver and that reduces the degree of fatigue of the driver even after long driving. To design such a seat, opinion testing by many drivers (operators) is effective, but in addition to opinion testing, the degree of fatigue of the driver as a function of driving time (working time). It is effective to observe quantitatively. For this reason, when a worker performs a specific work, before or after the work, or temporarily suspending the work to be continued, an evaluation test of a predetermined degree of fatigue is performed, and the degree of fatigue of the worker is quantitatively determined. Judgment has been performed conventionally.
[0003]
As a conventional test method for evaluating the degree of fatigue for this purpose, a method of observing the reaction time to the visual and auditory sense of the subject is widely known. For example, when a subject looks at a screen and a specific figure appears on the screen, the subject decides to press a button, and measures the time from when the figure is displayed until the button is pressed. The measurement result is repeatedly executed several times for a plurality of subjects, and the test result is subjected to statistical processing. This method makes use of the fact that when the subject is tired, the reaction time from when a specific figure appears on the screen to when a button is pressed becomes long.
[0004]
In addition to this, there is a method called a flicker method. This is an abbreviation for Critical fusion frequency of a fusion, and measures the frequency of a boundary between whether the light looks like intermittent light or continuous light when seeing blinking light, The higher the value, the less fatigue is considered.
[0005]
Furthermore, as a biochemical method, for a subject performing a specific task, a method of collecting blood or urine of the subject before, during, or after the task, and quantitatively measuring a trace amount of a substance that increases or decreases with fatigue. Are known. As this type of method that has been recently taken up, there is a method for detecting hydroxydeoxyguanosine (8-OHdG). This is a method for quantifying the degree of active oxygen generation due to stress, and is considered to be a practical and effective method.
[0006]
As a method of measuring the degree of fatigue of an operator, a method of observing and evaluating an electrocardiogram before and after performing a work is also known. It is said that the activity of the sympathetic nerve and the parasympathetic nerve can be evaluated by the heart rate evaluation.
[0007]
Further, as a method for quantitatively measuring the degree of fatigue of an operator, for example, Patent Literature 1 (Applicant, Kanebo) is known as a technique disclosed in Patent Literature. This is a device for examining the time during which a subject reacts after a specific figure is displayed on a screen watched by the subject. Specifically, this device is a device for measuring the time from when a graphic is displayed on a screen until a key is pressed. Thereby, the degree of fatigue of the discrimination ability with respect to the screen is observed.
[0008]
Also, a technique disclosed in Patent Document 2 (Applicant, Sharp) is known. This is a device for quantitatively testing eyestrain when a user of a computer watches the screen for a long time. This is also a test for examining how the discrimination ability for a fine graphic display on a screen on which a worker stands still deteriorates over time.
[0009]
[Patent Document 1]
JP-A-7-111989
[Patent Document 2]
JP-A-10-192263
[0010]
[Problems to be solved by the invention]
The above-mentioned biochemical method of collecting blood or urine from a subject for testing and the method of measuring an electrocardiogram are highly accurate, but this test method increases the burden on the subject and increases the equipment and testing. Because of the qualifications required of the person in charge, it is not suitable as a test that is repeatedly and simply performed in a vehicle design room or prototype factory. In this sense, it is an excellent method to have the subject operate the input keys while looking at the screen and evaluate the operation result according to a certain logic.
[0011]
All of the fatigue test methods using screens described in the above-described conventional examples are methods for evaluating the reaction time of a subject using still images. Images appearing in the driver's vision are always moving images, not still images. Even if the ability to identify a still image is evaluated, it has been found that a method of testing driver fatigue does not always correspond to the degree of fatigue. That is, the increase in the reaction time measured by the above-described conventional method is a secondary phenomenon caused by worker fatigue. The measurement of the degree of fatigue of the driver is not only a measure of the delay of the reaction time, but also an important factor in how perceptual or mental fatigue affects recognition of a moving image. In the determination of the driver's fatigue, it is desirable to identify the type of the target image in the visual field and determine the ability to recognize the moving form in order to improve the driver's fatigue determination accuracy. Reached.
[0012]
When attention is paid to the trend of the market demand of the automobile, the work style of the commercial vehicle, which drives a long distance or a long time, is increasing. Therefore, there is a demand for a design that does not fatigue the driver even after a long operation. In addition, with respect to general vehicles, elderly people often drive, and the progress of fatigue is faster than that of professional drivers with respect to driving time, and furthermore, there is a demand for a vehicle with less vibration and a comfortable ride.
[0013]
Supplementing the above description from a different angle, the structure of the driver's seat for automobiles has been considerably improved at this stage, and a structure that is not tired even during long-time driving has been provided. Therefore, even when a conventional fatigue test of a driver for testing a reaction time is performed, it is difficult to obtain a result that the driver as a subject is tired. In order to cope with this, it is necessary to have the subject who performs the driving operation perform the driving operation for a longer time, but this is not easy. Therefore, it is necessary to improve the test accuracy for testing the degree of fatigue of the driver, that is, to make the test problem more difficult, and to provide a fatigue test method and apparatus capable of detecting this even with less fatigue. It's easy to understand.
[0014]
The present invention has been made in such a background, and an object of the present invention is to provide a fatigue test method and apparatus capable of determining a recognition ability for a moving object in a visual field. The ability to recognize a moving object in the field of view corresponds to the ability to recognize a preceding vehicle or a traffic sign during a driving operation. SUMMARY OF THE INVENTION It is an object of the present invention to provide a fatigue test method and apparatus capable of testing not only the reaction time of a worker but also the ability of the worker to recognize dynamic images. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus that can more directly determine the deterioration of the driving performance of an automobile due to fatigue. An object of the present invention is to provide a method and an apparatus capable of accurately determining the degree of fatigue of an operator without requiring special equipment or special qualifications of a person in charge in a laboratory or a factory. And An object of the present invention is to provide a method and an apparatus for testing the degree of fatigue, which can identify the degree of fatigue of a subject even if the degree of fatigue is small. An object of the present invention is to provide a method and an apparatus for determining the degree of fatigue in which the burden on the subject is small.
[0015]
[Means for Solving the Problems]
The present invention displays a moving image a plurality of times on a screen on which the subject is gazing, and makes the subject determine whether or not the displayed moving image is the same as the previously displayed moving image. Features. The displayed moving image is an image in which a target displayed by a combination of simple figures moves on the screen.
[0016]
For example, two moving images in which the combination (target) of the graphics coincides are repeatedly displayed, for example, twice in a short time. Then, if the subject determines that the two moving images displayed after this short time are “same”, it is correct, and if the subject determines “different”, it is erroneous. When the combination of the image displayed first and the image displayed first has been changed, the correct answer is obtained if the subject judges “different” and an error is obtained if the subject is judged “same”. Suppose there is. Also, even if the movement modes are different, it is determined that the same combination is determined to be “same”, and that the correct combination is determined. The time required for the image to move within the screen is a fraction of a second to a few seconds. The interval at which two displays are performed, that is, the short time is, for example, one second to several seconds.
[0017]
The number of times of repetitive display is not limited to two as described above, and may generally be plural times n. That is, a combination of figures is displayed first, and a screen in which this combination moves in one direction of the screen is displayed. Then, the same figure combination moves in the same direction over (n-1) times. Screens with different combinations of figures or screens with different moving directions are displayed. At each (n-1) repetition, the subject is asked to determine whether the screen is the same as or different from the first screen. Then, the correct or wrong answer is statistically processed to determine the degree of fatigue of the subject.
[0018]
Through such a test, it is possible to measure the deterioration of the test subject's ability to recognize moving images. This makes it possible to determine the degree of mental fatigue by taking into account not only the simple reaction time for the display image but also the degree of recognition for the dynamic image. Since the driver of the car recognizes the moving image as long as the driver continues driving, by making a determination on the moving image as in the present invention, the fatigue level of the subject is made to more accurately correspond to the fatigue level of the driver. be able to.
[0019]
The number of times (n) for repeated display is different from the number of tests (m). In other words, this fatigue test is performed by having the subject temporarily suspend work. For example, considering a case where a subject performs a driving operation from early morning to evening, one fatigue test is performed before starting driving operation in the early morning, and then (m-1) times every three hours by evening. It is assumed that the procedure is to execute a fatigue test. At this time, the screen display is performed n times in each of the m tests. That is, in n screen displays, (n-1) screen displays are performed first after one screen display, and whether the (n-1) displays are the same as the first one display or not. Is to be answered.
[0020]
That is, the first aspect of the present invention is a method for evaluating the degree of fatigue, in which a subject is caused to perform a work (eg, driving operation using a simulator), and a fatigue evaluation test is performed on the subject before and after the work (m = 2). In the method of evaluating the degree of fatigue given to the subject by the work by comparing the results of the fatigue evaluation test performed before the work and the results of the fatigue test performed after the work,
The fatigue evaluation test includes: (i) displaying, on a screen watched by the subject, an image including a moving image in which a target composed of a combination of a plurality of simple figures moves within the screen; (ii) An image including the moving image is displayed on the screen at a set time interval a plurality of times n with the same or changed combinations of the figures and the moving direction thereof, and (iii) of the n times Allowing the subject to determine whether the image displayed after the second time is the same as the first moving image,
It is characterized by the following.
[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. If the background screen is complicated or if the background screen is a moving image plane, the difficulty of the determination becomes difficult.
[0022]
The combination of the plurality of simple figures can be two combinations selected from three types of circles (）), sankaku (△), and crosses (×). This "simple figure" includes not only figures but also "characters". For example, it is two characters of A, B, and C. It is appropriate that n is 2 to 10. Along with the accuracy rate of whether or not the second (n = 2) or subsequent images are the same, the length of time required for the subject's determination can be used as an evaluation factor.
[0023]
In the above description, the combination of the figures (target) is expressed as the “moving direction”. However, the moving direction is not necessarily a linear direction, and the moving path is configured to be changed, and a dynamic image having a different moving path is formed. Can also be configured to determine the same or non-identical. Such display variations can be set in various ways. However, if the display variations are diversified, this makes the problem more difficult, and naturally lowers the accuracy rate. The setting of such a variation 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) on a screen as a target, and then moves the target in the screen. A pattern generating means, and displaying a combination of a plurality of simple figures which are the same as or different from the first pattern generating means on the screen as a target, and then displaying the target in the screen on the first pattern generating means. A second pattern generating means for moving in the same or different direction as the means, and means for activating the first pattern generating means and then activating the second pattern generating means. This is expressed as n = 2. n is plural and is at least 2.
[0025]
The activating means changes the display content of the target and / or the moving direction of the target with respect to the second pattern generating means after activating the first pattern generating means, at a plurality of time intervals ( It may be configured to include a means for starting n-1 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 another screen can be displayed. This background screen is, for example, a screen in which the road surface in front of the vehicle is viewed from the driver's seat, and may be configured to be a screen that moves as the vehicle advances. By selecting the configuration of the background screen, the correct answer rate can be increased or decreased. That is, since the background screen becomes noise to the target for the subject, the correct answer rate is lowered by complicating the background screen, such as configuring the background screen as confusing with the target or using a moving image plane as the background screen. (Make the problem harder).
BEST MODE FOR CARRYING OUT THE INVENTION
The embodiment will be described in more detail with reference to the drawings. 1, 2 and 3 show an example of a screen display of the apparatus according to the embodiment of the present invention. The embodiment of the apparatus of the present invention is a common personal computer. It is desirable to use a personal computer with a large screen. The subject sits in front of the screen of this personal computer. A question appears on the screen, and the subject answers the question. The answer is "YES" or "NO", and the input is made to the keyboard of this personal computer. YES may be input as "Y", and NO may be input as "N".
[0027]
When the subject gazes at the screen, a rectangular target appears slightly above the center of the screen as shown in FIG. In the target, a set of X and O figures is displayed. As soon as this target appears on the screen, it moves in the lower left direction, as indicated by the dashed arrow, and disappears from the screen. After a few seconds, the same target appears in the center of the screen. This target also moves and disappears from the screen. At this time, the subject is determined whether or not the screen displayed 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 has to press "Y" on the keyboard of the personal computer. When it is determined that they are not the same, the subject presses “N”. This instruction is displayed in characters at the upper left of this screen, but the description of this display is omitted in FIG.
[0029]
It is correct that the target moves in the same direction as shown in FIG. 2 for the second display, but this is not the same when the graphic in the target is changed. If the figure in the target is the same as shown in FIG. 3 in the second display, and the moving direction moves to the lower right direction and disappears, the correct answer is to make the same. In this way, it is determined whether the figures in the target are the same regardless of the moving direction. Now, in this explanation, it is easy to make a comparison because FIGS. 1 to 3 are on the same paper, but when this is displayed on the screen and disappears immediately, the subject has to judge by his own memory. Become.
[0030]
The display of displaying the target in this way, and then moving the target and extinguishing the target is repeatedly performed n times. Then, the user is asked to answer n-1 times in total whether or not the display after the second time is the same as the display after the first time.
[0031]
Now, in the examples illustrated in FIGS. 1 to 3, the graphics displayed in the target are only O and X, but as illustrated in FIGS. By adding △ as a figure to be displayed, many confusing targets can be prepared. In FIG. 1, the position where the target is initially displayed is almost 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 confusing displays should be prepared. Can be.
[0032]
In this embodiment, the initial display of the target was set at a random position slightly above the center of the screen, the moving direction was set to the lower left direction and the lower right direction, and the test was performed with three types of figures in the target. . In the apparatus of this embodiment, a background screen is added to this screen, and this 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 displayed. It was configured to flow from the front to the back. This can make the operation of determining what the correct answer is for the subject quite confusing.
[0033]
The test as described above is carried out twice before and after the work, respectively, a total of two times (m = 2). Then, the subject is measured for the degree of fatigue in the state before the work and in the state after the work. By comparing the two measurement results of the degree of fatigue, it is possible to know the degree of fatigue due to the work.
[0034]
This can be carried out so as to be performed m times instead of twice before and after the work. For example, the subject was asked to work from early morning to evening, the above test was performed once before starting the early morning work, and then the work was interrupted for a short time until the evening work was completed, and (m-1) times I will do the test. Then, the degree of fatigue with respect to the passage of time due to the work can be measured.
[0035]
Measurement of the degree of fatigue by measuring the contents of the dynamic image and the ability to recognize the moving direction as in this embodiment measures the attention to the vehicle in front of the driving operation, the traffic sign displayed during driving on the road, and the like. It is possible to correspond to the attention to the guide plate.
[0036]
The measurement results are recorded on the personal computer and statistically processed. This statistical processing is quantitatively displayed as a correct answer rate for the work content or work time of the subject. Further, the method of statistical processing on how to evaluate the correct answer rate is a different problem from the subject of the present invention, and a number of methods have been conventionally known.
[0037]
Next, the overall procedure of the test according to the method of the embodiment of the present invention will be described with reference to FIG. In this example, a performance test of a driver's seat of a vehicle under development and design is performed. In other words, a prototype of the driver's seat was made, and this prototype was evaluated. For this purpose, we ask several subjects to sit in their respective seats, and perform tests to quantitatively understand how the subjects get tired by sitting in their prototype seats and performing driving operations. Things.
[0038]
To explain this procedure, a driving simulator is prepared ((1) in FIG. 7). This driving simulator can be generally understood by imagining a driving simulator for a game, for example. This embodiment has a structure in which a cab portion provided with a driver's 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 electric signal according to the operation input amount. The sensor output is connected to the operation input of the driving simulator.
[0039]
These can be operated when the subject sits in the driver's seat. When the operation of starting the vehicle is performed, the screen display flows from a distance to the near side, and the screen display changes correspondingly as the steering operation and the acceleration / deceleration operation are performed. The driving simulator used to carry out the present invention is configured such that vibrations accompanying the traveling of the vehicle are imitated from the vibration testing device to the driver's seat.
[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 asked to perform a simulation operation of driving while sitting on the prototype ((3) in FIG. 7). It should be noted that this driving simulator is a separate device from the device described in FIGS.
[0041]
This test subject is asked to sit before sitting on this seat, that is, before performing the driving simulation operation, 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. The subject is then subjected to the fatigue evaluation described with reference to FIGS. 1 to 6. This fatigue evaluation apparatus is a screen different from the view seen from the driver's seat appearing in the driving simulator. The subject is repeatedly shown the moving image as described above, and is asked to continuously answer n-1 times whether or not the moving image is the same as the previously shown moving image. The result of the evaluation is subjected to a certain statistical process and quantified. The evaluation result is “A1” because it is the first evaluation for the subject A ((4) in FIG. 7).
[0042]
Next, the subject A is separated from 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 simulated driving operation is performed by the driving simulator for the time t1. At time t2 (t2 ≦ t1) of the time t1 of the driving operation, pseudo vibration corresponding to vibration generated during traveling on a road surface programmed in advance is applied to the seat from the vibration test apparatus ( (5) of FIG. 7). The time t1 is, for example, 3 to 5 hours after a short break time on the way.
[0043]
When the time of the simulated driving operation ends, the subject A is again seated in front of the screen of the fatigue evaluation apparatus. Then, the fatigue evaluation is performed by the method of the present invention in the same manner as (4) in FIG. The evaluation result is referred to as “A2” ((6) in FIG. 7).
[0044]
By comparing the two obtained evaluation results “A1” and “A2”, the degree of fatigue of the subject A can be quantified ((7) in FIG. 7).
[0045]
Using the same apparatus (fatigue degree evaluation apparatus and driving simulator) as above, the same degree of fatigue evaluation is performed for subject B, subject C, and subject D ((7), (8), (9) in FIG. 7). (10)). Then, the fatigue levels evaluated for all of the subjects A, B, C, and D are statistically processed ((11) in FIG. 7). This is an evaluation of the seat prototype under development. This makes it possible to make a quantitative comparison by performing a similar evaluation on the seats used in the existing vehicle. In addition, a comparison can be made by performing a similar evaluation on seats of other vehicle types.
[0046]
In addition, since the fatigue evaluation screen for performing the degree of fatigue evaluation may be displayed on the screen, the screen of the driving simulator is used while the driver is sitting in the driver's seat and excited by using the screen of the driving simulator. The fatigue evaluation screen can be displayed by displaying a fatigue evaluation screen and measuring the reaction to the screen.
[0047]
【The invention's effect】
According to the present invention, there is provided a fatigue test method and apparatus based on the recognition ability of a moving object in a visual field. The method and apparatus of the present invention can test not only the reaction time of the worker, but also his or her ability to recognize dynamic objects. INDUSTRIAL APPLICABILITY The present invention is suitable for determining deterioration of the driving performance of a vehicle 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 and qualifications of a person in charge in a laboratory or a factory. The present invention is also a method and an apparatus for judging the degree of fatigue that places less burden on a subject. The method and apparatus of the present invention can detect even when the degree of fatigue of the subject is small, and can increase the detection accuracy, as compared with the conventional technique of measuring the reaction time of the subject to the screen display.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a screen display of an apparatus according to an embodiment of the present invention, and a first (n = 1) display example.
FIG. 2 is a diagram showing a screen display example of the apparatus according to the embodiment of the present invention, a second (n = 2) display example.
FIG. 3 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 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, another display example of 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, another display example of 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, another display example of the first time (n = 1).
FIG. 7 is a view for explaining a main part of a procedure when designing a seat of a vehicle using the apparatus according to the embodiment of the present invention.

Claims (7)

Have the subject work, perform a fatigue evaluation test on the subject before and after the work, and compare the results of the fatigue evaluation test performed before the work with the results of the fatigue test performed after the work In the method for evaluating the degree of fatigue given to the subject by the work by doing,
In the fatigue evaluation test, (i) displaying, on a screen watched by the subject, an image including a moving image in which a target composed of a combination of a plurality of simple figures moves within the screen, (ii) An image including the moving image is displayed on the screen at a set time interval a plurality of n times with the same or changed combination of the graphics and the moving direction thereof, and (iii) out of the n times A fatigue evaluation method characterized by causing the subject to determine whether or not the image displayed after the second time is the same as the first moving image. The fatigue evaluation method according to claim 1, wherein the combination of the plurality of simple figures is two combinations selected from three types of circles (）), sankaku (△), and crosses (×). The fatigue evaluation method according to claim 1, wherein n is 2 to 10. The fatigue evaluation method according to claim 1, wherein the accuracy of the second or subsequent images is the same or not, and the length of time required to determine the subject is also an evaluation factor. First pattern generating means for displaying a combination of a plurality of simple figures as a target in the screen, and then moving the target in the screen;
A plurality of simple graphic combinations 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 displayed in the screen as the same or different from the first pattern generating means. Second pattern generating means for moving in the direction,
Means for activating the first pattern generating means and then activating the second pattern generating means. The activating means may change a display content of the target and / or a moving direction of the target with respect to the second pattern generating means after activating the first pattern generating means, at a plurality of time intervals set. 6. The fatigue evaluation apparatus according to claim 5, further comprising a unit that is activated n-1 times. 6. The fatigue evaluation apparatus according to claim 5, further comprising a unit for displaying a background screen on the screen in addition to the target.

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