KR100995972B1 - A system and method measuring 3D display-induced subjective fatigue quantitatively - Google Patents

Abstract

The present invention relates to a qualitative visual fatigue measurement method and apparatus that can quantitatively measure the subjective fatigue generated when viewing contents (or stereoscopic images) presented through a three-dimensional display. (A) Regarding visual fatigue of a three-dimensional display Receiving the questionnaire candidates asking questions, and analyzing the selected questionnaire candidates to derive the number of factors and the questionnaire for each factor; (b) performing a feasibility assessment and a reliability assessment on the questionnaire for each factor; (c) receiving fatigue ratings for each group by receiving the ratings of the survey items given by N or more groups of subjects with different external factors; (d) creating a population fatigue distribution from the N fatigue score data; (e) obtaining fatigue scores of the 3D display by receiving the ratings of the survey items given by the group of subjects viewing the 3D display to be measured; and (f) determining a relative position in the population fatigue distribution in which the fatigue of the three-dimensional display to be measured is located.

By using the method and apparatus for measuring the visual fatigue of the three-dimensional display as described above, the factors explaining the questionnaire (or parameter) for measuring the subjective fatigue are appropriately extracted, so that the objective parameters such as viewing conditions affect the subjective fatigue. Differentiated effects can be identified, and the reliability and validity of the survey items that measure subjective fatigue can be verified, so that a reliable and valid subjective fatigue can be measured.

3d display fatigue feeling measurement questionnaire

Description

A subjective visual fatigue measurement method and apparatus for quantitatively measuring three-dimensional display induced fatigue {A system and method measuring 3D display-induced subjective fatigue quantitatively}

The present invention belongs to the technical field of qualitative visual fatigue measurement apparatus and method that can quantitatively measure the subjective fatigue known to occur to the user when viewing the content (or stereoscopic image) presented through the three-dimensional display.

In addition, the present invention, in order to determine the questionnaire used to properly measure the three-dimensional display-induced fatigue, to select the questionnaire candidates surveyed for the subjects, to extract the factors from the questionnaire candidates, to derive the questionnaire by factor It belongs to the technical field to evaluate the reliability and validity of the survey questions.

In addition, the present invention belongs to the technical field for determining the total population distribution by measuring the three-dimensional display-induced fatigue for various viewing conditions to determine where the measured fatigue is located in the overall population distribution.

Unlike 2D plane information, a 3D stereoscopic image is a more realistic image that simultaneously provides depth and spatial shape information. The stereoscopic image display is a technology based on the principle of binocular disparity effect, which allows both eyes to show images observed at different angles, thereby recognizing a sense of space due to the action of the brain. The three-dimensional image display can be classified according to the three-dimensional display method, view point (view point), viewing conditions, whether the viewer wears a separate glasses, and various methods have been proposed.

However, since the 3D stereoscopic image does not provide the exact same image as the 3D real thing, the viewer causes more viewing fatigue than the 2D image. That is, since the fatigue caused to the user when viewing the 3D display was not solved, the commercialization of the 3D display as described above was not made even though it was proposed and developed.

In other words, it may be easier to develop a three-dimensional display if the viewing conditions that minimize the fatigue level are identified. The viewing condition is an objective viewing condition of a three-dimensional display that causes fatigue, and refers to binocular disparity, viewing time, focal length, sharpness, size of an object, motion amount and speed of the three-dimensional display. The fatigue felt by the viewer may vary depending on the viewing conditions. Therefore, if it is possible to grasp the relationship between viewer fatigue and viewing conditions, it will be possible to easily grasp the viewing conditions that can minimize fatigue. Then, by improving these viewing conditions, development for commercialization of a 3D display may be easier.

Therefore, before exploring the solution to such a fatigue, the first thing to be solved is that the fatigue caused by viewing the 3D display must be properly measured.

 The fatigue is a fatigue that a viewer feels while watching a 3D image, and may be expressed as a subjective emotion expressed by the viewer as a vocabulary or a change that appears in the viewer's body. In the latter case, that is, a technique for measuring fatigue by detecting an objective biosignal, the difference in skin temperature between the forehead and the nose and the degree of blinking of the eyes (Japanese Patent Laid-Open No. 1997-023451), and visually induced potential (VEP: Visual Evoked Potential) (Japanese Laid-Open Patent Publication No. 1998-052402), eye movement (Japanese Laid-Open Patent Publication No. 1996-019520), and changes in pupil (Korean Laid-Open Patent Publication No. 1999-016853) have been proposed to measure fatigue. Since a biosignal having a high correlation with the subjective fatigue is selected, the reliability is ultimately determined by the high correlation between the subjective fatigue and the objective biosignal, and a presumed subjective fatigue is assumed.

In other words, the development of a tool for measuring objective fatigue is to develop a tool for measuring biological signals that are systematically changed according to the manipulation of these parameters while manipulating parameters such as binocular disparity that are expected to affect subjective fatigue. Considering the logical procedure of such an objective fatigue measurement tool, a tool for measuring subjectively fatigue with reliability and validity should be developed first, and subjective fatigue should be measured reliably and reasonably with this subjective fatigue measurement tool. It is possible to develop an objective fatigue measurement tool for measuring bio signals.

In general, fatigue is measured as a subjective fatigue by measuring the emotions of the viewers through a questionnaire survey for viewers watching the 3D display. Fatigue is a subjective conscious subject, and the only way to measure this subject is to receive a report directly from the subject. The fatigue measured through the direct report from the human subject who experiences a particular subject is subjective fatigue.

However, subjective fatigue measurement, like the measurement of human subjectivity in general, may be severe and unreliable and may not measure what it was intended to measure in the first place, so that (1) the reliability of the questionnaire reliably measures the internal state. And check the validity of measuring what is intended to be measured, and (2) standardize to determine the meaning of the measured value in the overall distribution, and (3) additionally, what factors contribute to fatigue? Should be presented using factor analysis (factor analysis).

However, the conventional subjective fatigue measurement directly reports subjective fatigue on a five-point scale for a single item or multiple items, and the reliability and validity of the measurement tool have not been verified. In addition, there is a possibility that the subjective fatigue is composed of a number of factors, the existing measuring tools do not reveal the components of the various subjective fatigue. Therefore, the objective fatigue measure, which does not presuppose an appropriate subjective fatigue measurement method, is suspected of reliability and validity.

For example, there are research papers to identify objective variables (or objective parameters) that affect fatigue. In other words, conventional qualitative measuring tools used to measure 3D display-induced fatigue can be found in the literature for identifying variables that affect fatigue. In many cases, a single question (eg, "visual fatigue How much do you feel? ") It is configured to respond with a 5-point scale (1 point: hardly feels, 5 points: very feel) [document 1-4].

In other words, [Document 1] is a study verifying the effects of convergent eye movement, lens adjustment, and disagreement on visual fatigue, and the effects of visual fatigue caused by HDTV and 3D-HDTV. The single item fatigue measurement tool was compared with the vergence-accommodation measurement, and [Ref. 2] is a verification that the gaze point variables and the motion variables are important variables in inducing visual fatigue when a 3D display is presented on an HDTV. It is a study measured by a single item, [3] is verified by measuring a single item fatigue feeling that the left and right image mismatch is a variable causing visual discomfort, [4] is a 3D fused display (depth-fused) developed by NTT It was verified by measuring single item fatigue that 3-D: DFD) caused no visual fatigue compared to the typical 2D display.

As described above, the qualitative measuring tool composed of a single item has a disadvantage in that it is not properly measured when the three-dimensional display-induced fatigue is composed of various factors.

In some cases, a three-dimensional display-induced fatigue measurement consisting of one or more questions has been attempted. For example, Document 5 verified that 3D displays cause more visual fatigue than typical 2D displays, and that fusional amplitude is an appropriate index of visual fatigue, and visual fatigue was measured using multiple items. However, even in this case, it is unclear how the items used in the measurement were selected, and since the factor analysis of the items used in the measurement was not carried out, as in the case of single item measurement, if fatigue was composed of various factors, It has the same disadvantages that it cannot measure.

Yano, S., Ide, S., Mitsuhashi, T. & Thwaites, H., "A study of visual fatigue and visual comfort for 3D HDTV / HDTV images," Displays, 23, 191-201 (2002). ).

Yano, S., Emoto, M. & Mitsuhashi, T., "Two factors in visual fatigue caused by stereoscopic HDTV images," Displays, 25, 141-150 (2004).

3 Kooi, F. L. & Toet, A., "Visual comfort of binocular and 3D displays," Displays, 25, 99-108 (2004).

Suyama, H. Ishigure, I., Takada, H., Nakazawa, K., Hosohata, J., Takao, Y. & Fujikado, T., "Evaluation of visual fatigue in viewing a depth-fused 3 -D display in comparison with a 2-D display, "NTT Technical review, 3, 82-89 (2005).

[5] Emoto, M., Nojiri, Y. & Okano, F., "Changes in fusional vergence limit and its hysteresis after viewing stereoscopic TV," Displays, 25, 67-76 (2004).

The parameters that affect subjective fatigue (various parameters that characterize viewing conditions and 3D viewing stimuli) are very diverse, and their effects on subjective fatigue are likely to vary. If the subjective fatigue is composed of a number of independent factors, not one, as described in the present invention, it becomes possible to identify which of the factors that make up the subjective fatigue differentially affect each of the objective parameters. . However, if the tool for measuring subjective fatigue is composed of a single question, it is impossible to measure various factors that make up subjective fatigue, and at the same time, it is impossible to identify the differential effects of each objective parameter on subjective fatigue. Efficiently overcoming or eliminating subjective fatigue will also be difficult. Therefore, by constructing the sub-items of the factors constituting subjective fatigue into multiple items, the objective parameters affecting the fatigue can be examined separately from the effects on the overall fatigue and the effects on each factor, and the degree of fatigue can be subdivided. For this reason, a multi-item measurement tool has a practical advantage.

On the other hand, by grasping the relationship between the subjective fatigue information (or subjective parameters) expressed by the viewer and the objective viewing conditions (or objective parameters) affecting the fatigue feeling, a technology that can directly predict fatigue according to the objective viewing conditions is disclosed. Patent 10-2007-0071927 (hereinafter, referred to as Prior Art 1). As shown in FIG. 1, the prior art 1 selects a vocabulary representing fatigue degree for a 3D stereoscopic image among a plurality of vocabularies (S10) and performs a factor analysis on the selected vocabulary to group the selected vocabularies. Categorizing the data into groups (S20), setting the vocabulary included in the top N groups having the highest factor weight among the groups as subjective parameters (S30), and objectively representing numerically the characteristics of the 3D stereoscopic image. While receiving a test score of the subjective parameter while changing the test value of the parameter candidate (S40), and using the input scores to obtain the relationship between the indicator and the objective parameter candidate for each of the N groups (S50) And applying the factor weight to each indicator to indicate the final fatigue degree by the objective parameter candidate (S60). It is done.

The prior art proposes a measurement tool that can immediately calculate (predict) fatigue levels given only viewing conditions (objective parameters). However, since the prediction of fatigue level for a given viewing condition is based on the results of multiple regression analysis of the viewing conditions obtained through a kind of experimental group and subjective fatigue under these conditions, the reliability of this measuring instrument depends on the reliability of the subjective fatigue measurement. do. And subjective fatigue measurement, after all, depends on the reliability of whether the subjective parameters for the measurement are properly selected.

In detail on the selection of the subjective parameters in the prior art, in order to perform factor analysis on the selected vocabulary, a rating value was used as the data for subjects to evaluate the relevance of the 3D display for each vocabulary. Through factor analysis, data are grouped and simple factors with the highest factor weights (unique values) are selected for N factors, and as a specific example, only two of the top two factors are selected for selection. It is described as physiological fatigue and emotional fatigue.

Therefore, it is not just to evaluate the fatigue after viewing the 3D image for each vocabulary, but simply to evaluate the relevance to the 3D display, so it is not guaranteed to be a proper vocabulary for measuring the 3D display induced fatigue. In addition, several factors of subjective parameters for 3D induced fatigue are not selected and their meanings are not presented. As such, the prior art lacks the reliability of subjective fatigue.

Moreover, in comparison with the requirements necessary for a method of measuring a subjective kind of human, the prior art does not evaluate reliability or validity of subjective parameters for subjective fatigue measurement, nor is it standardized.

In conclusion, since all the techniques for objectively measuring fatigue depend on the fatigue measurement of the subjective fatigue measurement tool, it is essential to first develop a qualitative measurement tool that can measure subjectively fatigue feeling reasonably and reliably. However, at present, since there is no subjective fatigue measurement method that has been verified for reliability and validity, the reliability and validity of the above-described objective fatigue measurement method are not high. The development of a qualitative fatigue measurement tool is meaningful in itself, but it is also necessary for the development of an objective fatigue measurement tool. In addition, in order to create a subjective fatigue measurement tool that can identify the differential effects of objective parameters such as viewing conditions on subjective fatigue, the factors describing the questionnaire (parameter) for measuring subjective fatigue should be appropriately extracted.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems described above, and can provide a qualitative visual measurement that can quantitatively measure the subjective fatigue known to the user when viewing contents (or stereoscopic images) presented through a three-dimensional display. It is to provide a method and apparatus for measuring fatigue.

Another object of the present invention is to select the questionnaire candidates surveyed for the subjects, and to extract the factors from the questionnaire candidates in order to determine the questionnaire used to properly measure the three-dimensional display-induced fatigue In addition, to provide a method and apparatus for measuring visual fatigue of a three-dimensional display for evaluating reliability and validity of the survey items.

Another object of the present invention is to obtain a total population distribution by measuring the three-dimensional display-induced fatigue for a variety of viewing conditions, and to determine where the measured fatigue is located in the total population distribution visual fatigue measurement method and apparatus To provide.

The present invention for achieving the above object is to measure the visual fatigue of the three-dimensional display by using a visual fatigue measurement device having an input device and a database for inputting a rating value of a survey item of a group of subjects watching the three-dimensional display A method comprising: (a) the measuring device is configured to receive, via the input device, a rating of two or more survey questions and a question of a first group of subjects asking about visual fatigue of a three-dimensional display; Determining the questionnaire as a variable and determining the rating as data (variable values) for factor analysis, and deriving a number of factors and a questionnaire for each factor corresponding to each factor as a result of factor analysis; (b) The measuring device receives a rating value of the survey items of two second groups of subjects viewed by the viewing condition combined with two variables through the input device, and uses the rating value by each viewing condition. Determining whether to adopt a survey item according to a significance level obtained as a result of performing two-way Anova and t-test on the two variables; (c) The measuring device receives the rating value of the survey items of the N third groups of subjects viewed by the viewing conditions combined by two or more factors (hereinafter, viewing factors) through the input device, and the third subject Obtaining fatigue scores for each group using the ratings of each group of groups; (d) the measuring device making a population fatigue distribution for viewing factors from the N fatigue score data; (e) measuring the fatigue score of the measurement target display by receiving the evaluation values of the survey items of the fourth group of test subjects watching the three-dimensional display (hereinafter, the measurement target display) as the measurement target through the input device; ; (f) The measurement apparatus determines a relative position in the population fatigue distribution in which the fatigue score of the measurement target display is located, wherein the relative position is a distribution of fatigue in the population when the viewing factor is the same as the viewing factor of the measurement target display. Characterized in that it comprises the step of being in position for the fatigue score.

In addition, in the visual fatigue measurement method of the three-dimensional display according to the present invention, the step (a), (a1) the measuring device inputs a question to ask about the visual fatigue of the three-dimensional display through the input device Receiving step; (a2) the measuring device receiving the ratings of the survey items of two equal groups of first subjects through the input device; (a3) The measuring device sets the survey item as a variable, sets the first group of first subjects as variable values, performs factor analysis, and as a result of factor analysis, the number of factors (for variables) and each factor Deriving a questionnaire for each factor corresponding to the above; (a4) The measuring device sets the survey question as a variable, sets the second set of first test subjects as variable values, performs factor analysis, and as a result of factor analysis, the number of factors (for variables) and each factor Deriving a questionnaire for each factor corresponding to the above; (a5) If the result of the second first group of subjects is the same as the result of the first group of first subjects, the measuring device includes the step of determining the factor and the question for each factor.

In addition, in the method for measuring visual fatigue of a three-dimensional display according to the present invention, in the step (a3) or the step (a4), the eigenvalue is equal to or greater than M when the number of factors is M and the number of factors increases than M. If the change is less than the standard, the number of factors is set to M, and the survey questions grouped by the factors are characterized as a survey question for each factor.

In addition, in the visual fatigue measurement method of the three-dimensional display according to the present invention, the number of factors derived in the step (a3) is five, the factors are eye fatigue, desire to stop watching the three-dimensional display, image blur discomfort, Pain in limbs, characterized in that determined by roaring.

In addition, in the visual fatigue measurement method of the three-dimensional display according to the present invention, the step (b), (b2) the measuring device is a group of two equal second subjects viewed by viewing conditions combined with two variables Receiving a rating value of the survey question through the input device; (b3) the measuring device performing a two-way Anova on the two variables using the ratings of the first group of the second group of subjects; (b4) the measuring device performing a t-test on the two variables using the ratings of the two second groups of subjects; (b5) The measuring device has a significance level (p) derived as a result of the two-factor variable analysis being less than or equal to a first significance level criterion, and a significance level (p) derived as a result by the t-test is a second significance. If the level is above the standard characterized in that it comprises the step of adopting the survey question.

In addition, in the visual fatigue measurement method of the three-dimensional display according to the present invention, the step (b1), the binocular parallax consisting of three levels of extreme cases when the variables are 0, medium, The viewing time is composed of two levels of 5 minutes and 25 minutes, and the viewing condition is characterized by being composed of six by crossing (combining) three levels of binocular disparity and two levels of viewing time.

In the method for measuring visual fatigue of a three-dimensional display according to the present invention, the first significance level criterion is 0.05, and the first significance level criterion is 0.75.

In addition, in the method for measuring visual fatigue of a three-dimensional display according to the present invention, the external factors (viewing factors) are classified into display factors, content factors, and user characteristic factors, and the display factors are glasses, glasses, and display. An implementation manner; The content factor includes an amount of binocular disparity, a display relative position of a gaze point, a temporal frequency, a spatial frequency, and a viewing time; The user characteristic factor is characterized by including eyesight, age, and near point.

In addition, in the visual fatigue measurement method of the three-dimensional display according to the present invention, the step (e) or (f), characterized in that the fatigue score is calculated as the average of the ratings.

In addition, in the visual fatigue measurement method of the three-dimensional display according to the present invention, the survey question candidates in the step (a), the items used in the paper known to measure the fatigue and engaged in the field of three-dimensional display development The questionnaire is selected from the open questionnaire for fatigue, and the questionnaire selected from the open questionnaire for fatigue for the subjects who watched the 3D display for a long time.

In addition, the present invention relates to a visual fatigue device of a three-dimensional display receiving a rating value of a questionnaire of a group of subjects who watched the three-dimensional display through an input device, and having a database, the visual fatigue of the three-dimensional display An item input unit which receives the question items to be asked through the input device; A rating value of a survey question of a first subject group is input through the input device, factor analysis is performed by setting the survey question as a variable and the rating as a data (variable value), and the number of factors as a result of factor analysis. And a factor extraction unit for deriving a questionnaire for each factor corresponding to each factor; The ratings of the survey items of the two second groups of subjects watched by the viewing conditions combined with the two variables are inputted through the input device, and the ratings for the two variables using the ratings by each viewing condition. A questionnaire evaluation unit that determines whether to adopt a questionnaire according to the two-way Anova and the t-test, and the significance level obtained as a result; The ratings of the survey items of the N third subject groups viewed by the viewing condition combined with more than two factors (hereinafter, viewing factors) are inputted through the input device, and the ratings of each group of the third subject groups are received. A normalization unit for calculating fatigue fatigue scores of each group using the N fatigue fatigue score data and creating a population fatigue distribution for viewing factors from N fatigue score data; Through the input device, the evaluation values of the survey items of the fourth group of subjects watching the three-dimensional display (hereinafter, referred to as measurement object display) to be measured are obtained through the input device, and the fatigue reduction score of the display to be measured is obtained. Determine a relative position in the population fatigue distribution, wherein the relative position includes a distribution discriminating unit in contrast to the fatigue score of the population fatigue distribution when the viewing factor is the same as the viewing factor of the measurement target display. Characterized in that.

In addition, in the apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, the factor extracting unit receives the evaluation values of the survey items of two equal groups of first subjects through the input device and converts the survey questions into variables. And factor analysis using the first set of first subjects as variable values, and as a result of factor analysis, derive the number of factors (for variables) and the questionnaire for each factor corresponding to each factor. Factor analysis was performed by setting the items as variables and the second group of first test subjects as variable values, and deriving the number of factors (for variables) and the questionnaire for each factor as a result of the factor analysis. And if the result of the second first group of subjects is the same as the result of the first first group of subjects, the factor and the survey question for each factor are determined.

Further, in the apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, the factor extracting unit has a factor of 1 if the eigenvalue is 1 or more when the number of factors is M and the number of factors increases more than M, but the variation of the eigenvalue is less than the reference value. The number of M is set, and the survey questions grouped by the factor are characterized in that the survey questions for each factor are set.

In addition, in the apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, the factor extracting unit has a number of derived factors, and the factors include eye fatigue, a desire to stop watching 3D display, image blur discomfort, and a body. Pain in the extremities, characterized by nausea.

In addition, in the apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, the survey item evaluating unit may evaluate the ratings of the survey items of two equal groups of second subjects viewed by viewing conditions combined by two variables. Input through an input device, perform a two-way Anova on the two variables, using the ratings of the first group of the second group of subjects, and perform the two second subjects By performing the t-test on the two variables using group estimates, the significance level (p) as a result of the two-factor variance analysis is less than or equal to the first significance level criterion. If the significance level (p) derived as a result is greater than or equal to the second significance level criterion, the survey question is adopted.

In addition, in the apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, the questionnaire item evaluator includes: binocular disparity configured to three levels of extremes when the variables are 0, medium, and 5 The viewing time is composed of two levels of minutes and 25 minutes, and the viewing conditions are characterized by being composed of six by crossing (combining) three levels of binocular disparity and two levels of viewing time.

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In the apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, the first significance level criterion is 0.05, and the first significance level criterion is 0.75.

In addition, in the apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, the viewing factors (external factors) are divided into display factors, content factors, and user characteristic factors, and the display factors are glasses, glasses, and display. An implementation manner; The content factor includes an amount of binocular disparity, a display relative position of a gaze point, a temporal frequency, a spatial frequency, and a viewing time; The user characteristic factor is characterized by including eyesight, age, and near point.

In the apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, the normalizing unit or the distribution discriminating unit may calculate the fatigue feeling score as an average of the evaluation values.

In addition, in the apparatus for measuring the visual fatigue of a three-dimensional display according to the present invention, the item input unit is used for the researchers used in the field of the three-dimensional display and the items used in the paper known to measure the fatigue. The selected items from the open questionnaire for fatigue, and the selected subjects from the open questionnaire for fatigue for the subjects who watched the 3D display for a long time.

The present invention also relates to a computer-readable recording medium recording the above-described method for measuring visual fatigue of a three-dimensional display.

As described above, according to the method and apparatus for measuring visual fatigue of a three-dimensional display according to the present invention, it is possible to quantitatively measure the three-dimensional display-induced fatigue, so that an objective fatigue measuring method is used to secure reliability and validity. It has the effect of making it possible.

In addition, according to the method and apparatus for measuring the visual fatigue of the three-dimensional display according to the present invention, by verifying the reliability and validity of the questionnaire for measuring the subjective fatigue, there is an effect that can measure a reliable and reasonable subjective fatigue.

In addition, according to the method and apparatus for measuring the visual fatigue of the three-dimensional display according to the present invention, by properly extracting the factors explaining the questionnaire (parameter) for measuring the subjective fatigue, the objective parameters such as viewing conditions affect the subjective fatigue There is an effect that can identify discriminatory effects.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. In addition, in describing this invention, the same code | symbol is attached | subjected and the repeated description is abbreviate | omitted.

First, the configuration of the entire system for implementing the subjective visual fatigue measurement method and apparatus according to the present invention according to FIG. 2 is a diagram illustrating a configuration of the entire system.

As shown in FIG. 2, the subjective visual fatigue measurement apparatus 30 according to the present invention includes a database 40 and an input device 50.

The input device 50 is a device for subjects 11 viewing the 3D display 20 to receive a rating value for the survey items, such as an LCD monitor, a touch screen, an OMR card input device, a scanner, and a character recognition device. This can be done with conventional input devices. Since the devices are well known in the art, specific description thereof will be omitted.

The subjects 11 input a rating value according to a survey question by watching the content (or stereoscopic image) provided on the 3D display. In general, the survey questions are composed of equal scales, and the survey questions are graded and input through the input device 11. The subjects 11 scan and write on a paper and automatically recognize the text, directly input the input device with a keyboard or a mouse, or when a question is displayed on the touch screen, input the corresponding value by touching the corresponding value. Have it read.

The test subjects 11 are formed into a single test subject group 10 so that all the evaluation values of the question items of the test subjects 11 in the group are subject to analysis. That is, the subjects 11 in the group all evaluate the survey question after watching the content provided on the 3D display.

The 3D display 20 is a device for displaying 3D content such as stereoscopic images, and the viewing conditions may be changed by the visual fatigue measurement apparatus 30.

Next, the visual fatigue measurement method of the three-dimensional display according to an embodiment of the present invention will be described with reference to FIGS.

3 is a flowchart illustrating a visual fatigue measurement method of a 3D display according to an embodiment of the present invention.

As shown in Figure 3, the method for measuring the visual fatigue of the three-dimensional display according to an embodiment of the present invention, (a) receiving the questionnaire candidates asking about the visual fatigue of the three-dimensional display, the selected question Deciding a number of factors and a question item for each factor by performing factor analysis on the candidates (S110); (b) performing a feasibility evaluation and a reliability evaluation on the question items for each factor (S120); (c) receiving external factors, the ratings of the survey items given by the group of N or more subjects, and obtaining fatigue scores for each group (S130); (d) creating a population fatigue distribution from the N fatigue score data (S140); (e) receiving fatigue ratings of the survey items determined by the group of subjects viewing the three-dimensional display to be measured, and obtaining a fatigue score of the three-dimensional display (S150); (F) step (S160) of determining the relative position in the population fatigue distribution in which the fatigue of the three-dimensional display to be measured is located.

First, step (a) will be described in more detail with reference to FIG. 4. 4 is a flowchart illustrating a step of deriving a survey question according to an exemplary embodiment of the present invention.

As shown in Figure 4, the step (a), the step (a), (a1) step of receiving survey question candidates to ask about the visual fatigue of the three-dimensional display (S111); (a2) receiving the ratings of the question candidates given from two groups of equal numbers (S112); (a3) deriving a number of factors and a questionnaire for each factor by factor analysis of the first group's ratings (S113); (a4) performing factor analysis on the ratings of the second group in the same manner and criteria as defined in the first group (S114); (a5) If the result of the second group is the same as the result of the first group, it is divided into the step (S115) of determining the factors and the questionnaire for each factor.

In the step (a1), the items used in the paper known to measure the fatigue feeling and the questions selected from the open questionnaire about the fatigue for the researchers working in the field of 3D display development, the 3D display The subjects selected from the open questionnaire about fatigue for the long-term subjects are inputted as the questionnaire candidates.

In order to develop a measurement tool by constructing a questionnaire for measuring 3D display-induced fatigue, the questionnaire used for qualitative fatigue measurement must be guaranteed to measure the fatigue caused by viewing 3D display, not other characteristics. This is called validity in the field of professional research on tools for measuring human subjectivity.

For this purpose, the questionnaire candidate (the questionnaire and the questionnaire candidate are the same as the actual contents and there is only a difference between whether the questionnaire is selected or not). Three methods were used in combination. (1) Existing papers known to measure 3D display-induced fatigue were examined and the items used in these papers were selected. (2) An open questionnaire was conducted for 27 researchers currently working in the field of 3D display and contents development to freely describe the 3D display-induced fatigue experienced during R & D. Screened. (3) The questionnaire was selected from the survey results obtained through an open questionnaire for 10 subjects to watch the 3D display for 50 minutes and to freely describe the fatigue experienced during the viewing time.

Of the items obtained in the above three methods, duplicate items were removed and the first 37 items were composed. Unlike the previous two methods, this item selection procedure was selected from the results of a study of 3D display-induced fatigue, a group of experts who experienced real fatigue, and a questionnaire obtained from a group of subjects who watched 3D display for a long time. It is judged as a valid item to measure the three-dimensional display-induced fatigue due to the questions.

More specifically described as follows. First, the initial item selection method in the paper known to measure the existing three-dimensional display induced fatigue is as follows. 1) Set the range of articles to be searched using the terms "visual fatigue", "3D Display", "stereopsis", and "disparity". 2) If the searched article measures subjective fatigue, Collect questions (all but one article were used as a single question). Second, an open questionnaire was conducted for 27 researchers working in the field of 3D display and contents development to freely describe the 3D display-induced fatigue they had experienced during R & D. Here's how. 1) The e-mail addresses of members belonging to the 3D display research group under the Korea Society of Broadcast Engineers were collected. 2) A separate questionnaire file was recorded that requires experience in 3D display-related fields, 3D research fields, and gender, and if you have experienced visual fatigue, to specifically describe the experience. 3) Responses to the open questionnaires of all 27 respondents were selected without overlapping terms. Third, an initial question was constructed by conducting an open questionnaire related to 3D display-induced visual fatigue for 10 subjects who did not know the research hypothesis (pure subjects not engaged in 3D related industries). 1) We recruit 10 naive subjects who do not know the research hypothesis. 2) Present a 3D video with binocular parallax for 50 minutes, which is larger than 30 minutes of viewing time, which is known to cause visual fatigue. 3) An open questionnaire is required to ask each subject to freely describe any discomfort he may have experienced while viewing 3D video. 4) Construct initial questions based on non-overlapping terms among 10 participants' survey responses. Finally, the duplicated terms were removed from the initial items composed in the above three methods, and a total of 37 items were determined as the initial items.

Steps (a2) to (a5) receive data (measurement values) for evaluating the selected survey items at equal scale for the subjects who watched the 3D display for a long time, and the data are divided into two groups of equal numbers. The exploratory factor analysis is performed on the first data group, the number of factors and the final survey items are determined, and the final survey questions are classified by the group for the factors. In the second data group, a confirmatory factor analysis of the questionnaire 41 for each factor is performed to determine that the questionnaire 41 for each factor is reliable when it is below the significance level.

The questionnaire candidate received in step (a1) is first selected as a questionnaire for measuring 3D display-induced fatigue. After watching the 3D display for 50 minutes, which is expected to cause the actual 3D display-induced fatigue, each of the 208 subjects evaluated the fatigue they experienced during the experiment on a 5-point scale for the first selected item. . It is expected that 208 subjects experienced visual fatigue because they actually watched the 3D display for 50 minutes. Subjects who experienced visual fatigue assessed their fatigue using the first-chosen item, and the data presented by the evaluation results of 208 subjects directly measured three-dimensional display-induced fatigue. Therefore, the present invention is to present the actual three-dimensional display and to report their experiences using the first selected item expected to measure the three-dimensional display induced visual fatigue feeling selected by the item input unit 31, the actual subjects would experience Three-dimensional display-induced fatigue was measured, and factor analysis using this data reveals what factors actually constitute the three-dimensional display-induced fatigue.

Factor analysis (or factor analysis) itself is a statistical analysis technique widely used throughout the social sciences. In the present invention, 208 subjects experienced direct visual fatigue as described above and evaluated the first selected item. In the present invention, the principal analysis was used among the factor analysis techniques and the axial rotation technique was applied. Factor analysis itself does not automatically suggest how many factors the measured variable consists of, ultimately for the researcher. The present invention divides the data of 208 subjects into two groups of 104 persons in two groups in order to reliably confirm how three-dimensional display-induced fatigue consists of, and the first group is an exploratory factor analysis group. The second group was used as a confirmatory factor analysis group to confirm whether the factors obtained in the first exploratory factor group were reliably rediscovered in other groups. Factor analysis using exploratory factor analysis group data follows general factor analysis techniques. However, in the exploratory factor analysis, ambiguous items appearing to be related across various variables were removed. Finally, the number of final factors was selected based on the theoretical analysis of the cree test, eigenvalues, and three-dimensional display-induced fatigue.

The factor analysis only suggests the possibility of how many factors can be grouped into the whole question, but it is generally up to the researcher to decide how many factors to finalize the question. However, there are some criteria to consider when determining the number of factors. First, the Eigen Value is presented along with the possible number of factors, which means the average number of items that each factor can have, assuming that the entire item consists of a certain number of factors. If the eigenvalue of a particular number of factors is 2, it suggests that the number of items these factors have on average is two. An eigenvalue of 1.0 or less means that each factor has less than one item on average. In general, one factor has many items, so the number of factors below the eigenvalue of 1.0 is not appropriate. Second, the graph showing how the eigenvalues change with increasing number of factors is the Scree Test, when the eigenvalues in the graph drop sharply and at the same time the eigenvalues do not change as the number of factors increases (generally the amount of change is 1.0 ~ 0.5). ), It is determined that the increase in the number of factors no longer acquires explanatory power, and the number of factors at this point is determined as the number of factors that distinguish the entire question. Third, the above method only has a quantitative meaning, but how many factors the entire question is composed of is referred to the previous two methods and a theoretical analysis of the concept to be measured at the same time is necessary for determining the number of factors. This is a theoretical analysis of three-dimensional display-induced fatigue, for example, theoretical analysis and discussion of whether it is appropriate to consider that three-dimensional display-induced fatigue is composed of four factors or five factors. will be. In particular, in theoretical analysis, the homogeneity of items grouped into four factors and when classified into five factors becomes an important criterion. If there are four, the homogeneity between the sub-items of a specific factor is lowered. If five factors are used, the homogeneity of the sub-items by each factor becomes clearer and clearer. However, if the increase in the number of factors does not increase the homogeneity of the items in the factor, the four factor becomes a more efficient model than the five factor.

In the present invention, a method of determining the number of factors and a method of selecting a final survey question will be described in more detail as follows. Factor analysis generally uses correlation analysis between multiple items known to measure specific variables to distinguish which items are related to each other and group items with high similarity into one factor, ultimately to determine which factors It is a statistical technique that suggests whether it can be bound together. As mentioned earlier, factor analysis as a statistical technique does not, by itself, determine how many factors are grouped together. However, it suggests possible factors that can be grouped by multiple items and provides researchers with statistics on how many factors are appropriate to group multiple items.

First, the present invention divided 208 subjects into two groups, the first group conducted exploratory factor analysis and the second group data was used for confirmatory factor analysis. Second, in the exploratory factor analysis of the data of the first group 104, 37 items were analyzed by how many factors. 37 items were based on the theoretical analysis of the cree test, eigenvalue, and visual fatigue. It was found that these were classified into five factors. How to determine the number of factors based on the theoretical analysis of scree test, eigenvalue, and visual fatigue is described above. Third, if the number of factors is determined as 5 and factor analysis is performed, the correlation coefficient between 37 items and 5 factors is calculated. In general, most items show high correlation with specific factors and low correlation with other factors. Seems. In general, if the correlation with a specific factor is less than the correlation coefficient of 0.3 or less, it is considered not to be related to the specific factor. If a particular item does not have a correlation of 0.3 or more with any factor, it is removed because it is not appropriate as a survey question. Also, if an item has a correlation of 0.3 or more with multiple factors, this item is also removed because it is an ambiguous item that spans multiple factors without inherently measuring a factor. In the present invention, five items in exploratory factor analysis did not satisfy these criteria and were eliminated. Fourth, through exploratory factor analysis, a large number of questions were grouped into five factors. Even though the factor analysis was performed using the same method and criteria using data from other subject groups, the same as in exploratory factor analysis Factor analysis is performed using data from a second group of 104 people to determine whether factor analysis results are present (ie, they are grouped into five factors as in exploratory factor analysis and sub-items of each factor are classified equally). This is called confirmatory factor analysis. When confirmatory factor analysis is carried out, it is not uncommon for the results to be completely identical to those of exploratory factor analysis. This is probably due to errors or individual differences in the measurements. In the confirmatory factor analysis of the present invention, three items correlated with different factors from those in the exploratory factor analysis, which is a negligible ratio in consideration of the whole item. In the confirmatory factor analysis, if the survey items included in the exploratory factor analysis and other factors are less than 10%, it is judged to be reliable. In the present invention, 37 items were included in the exploratory factor analysis and 32 items were included in the confirmatory factor analysis. However, only three items (less than 10% of the total 32 items) were included in the exploratory factor analysis and other factors. Therefore, it is judged that the confirmatory factor analysis in the present invention reliably shows the same result of the factor analysis as in the exploratory factor analysis. Fifth, in the exploratory factor analysis and confirmatory factor analysis, the items that did not satisfy the criteria were removed from the initial items, and the remaining items were assigned to each factor based on the correlation with each factor, and then the contents of the items constituting each factor. The factors are named in consideration of the present invention. In the present invention, five factors are named as eye pain factor, discontinuation desire factor, nausea murmur factor, somatic pain factor, and upper blurriness factor (see FIG. 5). At this time, the five factors are three-dimensional display-induced fatigue factor (hereinafter referred to as "fatigue factor"). Confirming that the confirmatory factor analysis result is the same as the result of the exploratory factor analysis means that the number of factors in the exploratory factor analysis and the sub-items with each factor appear in the confirmatory factor analysis as shown in FIG. 5. In the example of the present invention, the same results as those of the exploratory factor analysis were obtained in the confirmatory factor analysis.

5 is a diagram illustrating question-by-factor questions according to an embodiment of the present invention. The qualitative visual fatigue component factors described in the present invention using the apparatus are five factors, as shown in FIG. In addition, the survey questions constituting each factor are illustrated in FIG. 5.

Next, evaluating the validity and reliability of the questionnaire according to an embodiment of the present invention will be described with reference to FIG. 6 is a flowchart illustrating the evaluation of the validity and reliability of the question.

As shown in FIG. 6, the step (b) may include: (b1) combining viewing variables of visual fatigue of the three-dimensional display to configure viewing conditions; (b2) for each viewing condition, receiving ratings of the question items from a group of two equal numbers of subjects; (b3) performing a two-way Anova on the variables, using the ratings of the first group of each viewing condition; (b4) performing a t-test on the ratings of the survey questions between the two groups; (b5) If the significance level (p) derived by the factor analysis is less than the criterion and the significance level (p) derived by the t-test is more than the criterion, the survey item is divided into steps.

The viewing conditions are configured by manipulating a plurality of objective variables that directly affect the fatigue feeling, and the fatigue feeling data for each viewing condition, which is measured by the survey question, is input to the same number of different subjects for each viewing condition. Two-way Anova is performed on these variables to evaluate validity if there is a significant difference. The fatigue feeling data for each viewing condition obtained by dividing the fatigue feelings for the viewing conditions are divided into two groups, and the t-test for the significant difference between the measured values between the two groups is received. Evaluate

More specifically, the objective variable is defined as binocular disparity and viewing time, and the binocular disparity is composed of three levels of extreme cases when 0, medium, and viewing time are 5 minutes and 2/25 minutes. And the viewing conditions are composed of six viewing conditions by crossing the binocular disparity and the viewing time. In addition, the significance level (p) criterion of the validity evaluation is set to 0.05 or less, and the significance level (p) criterion of the reliability evaluation is set to 0.75 or more.

The final three-dimensional display-induced fatigue measurement tool, established through the exploratory and confirmatory factor analysis procedures mentioned above, is a reliable tool in itself, and the items included in this tool reasonably measure the three-dimensional display-induced fatigue. can see. However, since the method uses the three-dimensional display used in the measurement item development process, it is necessary to measure whether the tool developed in the present invention consistently and reasonably measures the three-dimensional display-induced fatigue in other stimulus situations. Generally, reliability and validity are measured using different data at different stages, but the present invention proposes a method of simultaneously measuring two in one experiment.

Although there are various variables affecting the 3D display induced fatigue, two variables are manipulated in an experiment for measuring the reliability and validity of the 3D display induced fatigue measurement tool proposed in the present invention. First, the variable directly affecting 3D display-induced fatigue is the amount of binocular disparity. For example, even though a display having a binocular disparity of 0 is presented through a 3D display, the perception of the present invention is not different from that of a perception when presented through a 2D display. In the present invention, the content having binocular disparity of zero, the content having moderate binocular disparity, and the content having an extreme amount of binocular disparity are constructed using a three-dimensional graphic tool. Second, even the same 3D display content may cause different 3D display-induced fatigue depending on the viewing time. In the present invention, a total of six experimental conditions are constructed by intersecting three levels of binocular disparity and two levels of viewing time of three-dimensional display (5 minutes, 25 minutes) which directly affect the three-dimensional display induced fatigue. Three different subjects were placed to watch a three-dimensional display at a given condition and then their three-dimensional display-induced fatigue was measured using the final qualitative fatigue measurement tool described in 3) above.

The six test conditions described above differ in the level of variables expected to affect three-dimensional display-induced fatigue. If the qualitative visual fatigue measurement tool described in the present invention measures the 3D display-induced fatigue reasonably, there should be a difference in the fatigue measurement value measured using the final survey question (or the survey question for each factor). In addition, the 20 subjects included in each of the six test conditions were all placed under the same conditions. If the qualitative fatigue measurement tool described in the present invention is a reliable tool, there is a statistically significant difference between the fatigue measurement values of the subjects in each condition. There should be no difference. Therefore, the reliability and validity of the measuring instrument are measured in the following way.

Reliability is obtained by t-testing half the 20 subjects in each of the six conditions to see if there is a significant difference between the measurements between the two groups. If the p-value shown by the t-test is 0.75 or more, the three-dimensional display-induced fatigue measurement tool described in the present invention can be defined as a reliable measurement tool. In general, a p value of less than 0.05 means that there is a difference between groups, and a p value of greater than 0.05 means that no sufficient evidence has been found. The reliability test in the present invention is to verify that there is no difference between 20 measurements in each of the six conditions belonging to the same group, so that the p value is 0.75 or more (there is sufficient evidence that there is a difference between groups). P values that are higher than 0.05, which means that they do not (the theoretical maximum of p values is 1.0), are appropriate. The validity can be measured by statistically verifying whether there is a difference in the measurement of fatigue between the six test conditions. Two-way Anova analysis of two factors, the amount of binocular disparity, and the viewing time. Confirm by doing. According to the level of each variable, it is possible to check whether the fatigue measurement value is different or whether there is an interaction between two variables. When the p-value indicated by the variance analysis is 0.05 or less, the three-dimensional display-induced fatigue measurement tool described in the present invention. Is a highly valid measurement tool.

In order to evaluate the reliability and validity of the tool for measuring visual fatigue, the conditions in the above experiment were a total of six conditions combining both three conditions of binocular disparity and two conditions of viewing time. The variables affecting visual fatigue may be other variables besides binocular disparity and viewing time, but it is not necessary to include all the variables in the experimental setup to evaluate the reliability and validity. The purpose of this experiment is to verify that the measurement tool reliably and properly calculates different fatigue feeling measurements when manipulating variables known to cause visual fatigue to different degrees. Therefore, in experiments evaluating the reliability and validity of measurement tools, it is sufficient to manipulate only binocular disparity and viewing time variables known to directly affect visual fatigue. To determine whether a manipulated variable (eg binocular parallax) affects a measured variable (eg fatigue), this means that the variable must be manipulated to at least two levels. . There is no rule for how many levels of variables to manipulate. However, it is desirable to set a minimum level within a range sufficient to reveal the effect of each variable. Therefore, the amount of binocular disparity should be controlled to three levels of minimum (0), medium, and extreme, and viewing time is controlled to two levels of 5 minutes, which is insufficient time to cause fatigue, and 25 minutes, which is sufficient time to cause fatigue. It is preferable.

Steps (c) and (d) manipulate the objective external factors in various ways to generate the entire population fatigue distribution (42) by receiving the population fatigue data of the subjects for measuring the fatigue (S130, S140). In the step (e), the fatigue feeling data 161 measured for a specific external factor is input to calculate the feeling of fatigue (S150), and the step (f) is located at a relatively relatively anywhere in the overall population fatigue distribution 42. It is determined whether or not (S160).

The fatigue measurement obtained when the three-dimensional display-induced fatigue is measured using the qualitative fatigue measurement tool described above is meaningful in itself, but the relative position in the overall population visual fatigue distribution (from the visual fatigue distribution of all users). Relative position or relative position in the distribution of visual fatigue caused by a full three-dimensional display.

The fatigue measurement using the qualitative fatigue measurement tool has its own meaning because the measurement itself has a meaning because for each measurement item (item measuring three-dimensional display-induced fatigue), the user has a five-point scale (one point at all). No, 5 very much), so the overall average score of the questionnaire is distributed between 1 and 5 points and has a relative meaning between them. For example, a score near one point indicates very low three-dimensional display-induced fatigue and a score near five points indicates very high three-dimensional display-induced fatigue.

However, as described above, the standardization of the measurement tool is necessary to determine where the value measured using the qualitative fatigue measurement tool proposed in the present invention is located relatively in the overall population visual fatigue distribution. It includes the same standardization procedure.

Three-dimensional display-induced fatigue is known to be affected by the display itself (hardware), content and user characteristics. Therefore, in order to know where the fatigue measured using the 3D display-induced fatigue measurement tool is located relatively in the visual distribution of the overall population, the 3D display is presented by variously manipulating the display factors and content factors that cause fatigue. The total population fatigue distribution is obtained by measuring three-dimensional display induced fatigue using a qualitative fatigue measurement tool described in the present invention for a large number of subjects who satisfy a variety of user factors. The overall population fatigue distribution can thus be used to know where the measured three-dimensional display-induced fatigue is located in the overall population distribution.

Display factors, content factors, and user characteristics factors affecting 3D display-induced fatigue are as follows.

(1) display factors

   (1-1) glasses type (red-blue, red-green, polarized light) / glasses-free type (short-term, multi-view)

   (1-2) Display Implementation Method

(2) Content Factors:

   (2-1) amount of binocular disparity

   (2-2) Display relative position of watch point (before / behind display)

   (2-3) temporal frequency

   (2-4) spatial frequency

   (2-5) Watching time

(3) user characteristics factors

   (3-1) eyesight

   (3-2) age

   (3-3) Nearest point

The following section describes the fatigue score in more detail. The average score of all the ratings for the survey question 41 for each factor described above is calculated as the overall fatigue score, and the average score of the rating for the survey questions constituting the factor for each factor is calculated as the fatigue score for each factor. .

In other words, regardless of the number of questions that make up each factor, the fatigue score for each factor is the average score of the ratings for the questions that make up each factor. For example, if the number of questionnaires that make up the ocular pain factor is nine and the sum of the ratings for the nine questionnaires of the user is 30, then the ocular pain factor score in the qualitative fatigue is 3.33, which is an average value (30/9). . The overall three-dimensional display-induced fatigue score is taken as the average of the five factor scores. For example, if the sum of the five factor scores is 20, the overall three-dimensional display induced fatigue score is an average five factor fatigue score, 20/5, or 4.0.

The fatigue quantification technique proposed in the prior art 1 calculates the 3D display induced fatigue feeling as one score, while the technology proposed by the present invention calculates the 3D display induced fatigue score as one score, Calculate fatigue scores by factor. One reason for measuring the three-dimensional display-induced fatigue is to eliminate visual fatigue, which is an obstacle to commercialization, and to achieve this, fatigue scores by constituting factors of visual fatigue are calculated rather than calculating visual fatigue as a single score. It is necessary to refine the. There are various factors influencing the three-dimensional display-induced fatigue, and the fatigue calculation method for each component proposed by the present invention has an effect of identifying which fatigue-inducing factor affects which fatigue component. Ultimately, it is possible to segment and target by fatigue inducing factor to remove visual fatigue.

The fatigue measurement calculated using the measurement tool is an arbitrary value, and in order to give meaning to this value, it is determined which position in the fatigue measurement distribution (population distribution) of all viewers (population) watching the 3D display. It is necessary to do Theoretically, it is impossible to define the characteristics of the population distribution by measuring the fatigue caused by the 3D display for the entire 3D display viewer group. However, after viewing a three-dimensional display for a sufficiently large sample (for example, 500 representatives of the entire population) and then measuring their three-dimensional display-induced fatigue, the characteristics of the population distribution (population) from the distribution of these fatigue measurements The shape of the distribution, the mean of fatigue in the population distribution, and the standard deviation of the population distribution. The shape of the population distribution (normal or skewness) is the shape of the sample distribution, the mean of the population distribution is the mean of the sample distribution, and the standard deviation of the population distribution is estimated from the standard deviation of the sample distribution. Knowing the characteristics of the population distribution, it is possible to relatively assess how far a particular viewer's fatigue measurement is from the population mean fatigue in the overall population fatigue distribution and where it is in the upper or lower percentage of the overall fatigue distribution.

It should be noted that the characteristics of this population fatigue distribution are affected by objective variables (display variables, content variables, and user variables) that affect the three-dimensional display-induced fatigue as described above. Therefore, in order to standardize the fatigue measurement tool proposed by the present invention, after determining the level of the objective variables (for example, binocular parallax variables or viewer ages) to have a specific value, the characteristics of the population fatigue distribution are estimated. The characteristics of the distribution will change depending on the level of the variable (in the end, viewing conditions).

The characteristics of the population fatigue distribution vary according to the viewing conditions (the above-described display variables, content variables, and user characteristic variables), which is not a characteristic of the measuring tool but a common characteristic of all tools for measuring 3D display induced fatigue. What is important is that if you know the nature of the distribution by viewing condition (i.e., when the standardization test is complete), when you are watching a particular 3D display or content and measured fatigue, where is the fatigue in the overall population distribution (e.g. When viewing conditions are fixed, it becomes possible to evaluate relatively whether the relevant display or content causes more fatigue or less fatigue than the population average fatigue. This is the advantage of standardization.

Next, an apparatus for measuring visual fatigue of a 3D display according to an exemplary embodiment of the present invention will be described with reference to FIG. 7. 7 is a block diagram of the configuration of the visual fatigue measurement apparatus of the three-dimensional display.

As shown in FIG. 7, the apparatus for measuring visual fatigue of a three-dimensional display according to an exemplary embodiment of the present invention includes an item input unit 31, a factor extractor 32, a question item evaluator 33, and a standardizer 35. And a distribution discrimination unit 36.

The question input unit 31 receives survey questions asking about the fatigue. The item input unit 31 includes items used in a paper known to measure the fatigue feeling, and items selected from an open questionnaire for the fatigue feeling for researchers working in a 3D display development field, and a 3D display. Were selected from questions selected from the open questionnaire for fatigue

The factor extracting unit 32 performs factor analysis on the selected question candidates to derive a number of factors and a question item for each factor.

The factor extracting unit 32 receives the ratings of the candidate candidates determined by two groups of equal numbers of subjects, and analyzes the ratings of the first group to derive the number of factors and the survey questions for each factor. Factor analysis of the group estimates is conducted in the same manner and criteria as the first group, and if the result of the second group is different from the result of the first group, the factor and the questionnaire for each factor are determined.

When the number of factors is M, the factor extracting unit 32 has one or more eigenvalues, and if the number of factors increases more than M, if the eigenvalue change becomes less than the reference and the homogeneity of the survey items in the factor does not increase, The number of questions is set as M, and the survey questions grouped by the above factors are determined as the survey questions for each factor.

The factor extracting unit 32 determines that the number of factors derived is five, and the factors are eye fatigue, desire to stop watching 3D display, image blur discomfort, body limb pain, and whine.

The questionnaire item evaluator 33 evaluates the validity and the reliability of the questionnaire item by factor.

The survey item evaluator 33 configures viewing conditions by combining variables of visual fatigue of a 3D display, and receives rating values of the survey items from two groups of equal numbers for each viewing condition. Two-way Anova is performed on the variables using the first group ratings of each viewing condition, and t-testing on the ratings of the survey items between the two groups is performed. If the significance level (p) derived by the factor analysis is less than the reference and the significance level (p) derived by the t-test is more than the reference, the survey question is adopted.

The survey item evaluator 33 includes binocular disparity consisting of three levels of fatigue, extreme, and extreme levels of zero, medium, and two levels of 5 minutes and 25 minutes. Set as time, the viewing condition consists of six crossing three levels of binocular disparity and two levels of viewing time.

The questionnaire item evaluator 33 sets a significance criterion (p) for two-way Anova as 0.05 and a criterion for the significance level (p) for t-test as 0.75.

The standardization unit 35 receives the ratings of the survey items given by N or more groups of subjects with different external factors, obtains fatigue scores for each group, and calculates population fatigue distribution from the N fatigue score data. Make.

The standardization unit 35 divides the external factors into display factors, content factors, and user characteristic factors, and the display factors include glasses, glasses-free, and display implementation; The content factor includes an amount of binocular disparity, a display relative position of a gaze point, a temporal frequency, a spatial frequency, and a viewing time; The user characteristic factors include visual acuity, age, and near point.

The distribution discriminating unit 36 receives the ratings of the survey items given by the group of subjects viewing the three-dimensional display as a measurement object, obtains the fatigue score of the three-dimensional display, and calculates the fatigue of the three-dimensional display as the measurement object. The relative position in the population fatigue distribution in which this is located is determined.

The normalizing unit 35 or the distribution discriminating unit 36 calculates the fatigue score as an average of the ratings.

For the incomplete description of the visual fatigue measurement apparatus, refer to the description of the visual fatigue measurement method described above.

As mentioned above, although the invention made by this inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example, Of course, a various change is possible in the range which does not deviate from the summary.

The present invention is applicable to the field of measuring fatigue for the 3D display, in particular, it is applicable to the field of grasping the obstacles in developing for the commercialization of the 3D display.

1 is a flow chart illustrating a method for quantifying fatigue degree for a three-dimensional stereoscopic image according to the prior art.

2 is a diagram showing the configuration of an entire system for implementing a subjective visual fatigue measurement method and apparatus according to the present invention.

3 is a flowchart illustrating a subjective visual fatigue measurement method according to an embodiment of the present invention.

4 is a flowchart illustrating a step of deriving a survey question according to an exemplary embodiment of the present invention.

5 is a diagram illustrating question-by-factor questions according to an embodiment of the present invention.

6 is a flowchart illustrating a step of evaluating validity and reliability of a survey question according to an exemplary embodiment of the present invention.

7 is a block diagram of the configuration of the subjective visual fatigue measurement apparatus according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: subject group 11: subject

20: 3D display 30: Visual fatigue measuring device

40: database 50: input device

Claims (21)

In the method of measuring the visual fatigue of the three-dimensional display by using a visual fatigue measurement device having an input device and a database for inputting the rating of the survey questions of the group of subjects who watched the three-dimensional display, (a) the measuring device receives, via the input device, a rating of two or more survey questions and a questionnaire of a first group of subjects asking about visual fatigue of a three-dimensional display; Determining the questionnaire as a variable and determining the rating as data (variable values) for factor analysis, and deriving a number of factors and a questionnaire for each factor corresponding to each factor as a result of factor analysis; (b) The measuring device receives a rating value of the survey items of two second groups of subjects viewed by the viewing condition combined with two variables through the input device, and uses the rating value by each viewing condition. Determining whether to adopt a survey item according to a significance level obtained as a result of performing two-way Anova and t-test on the two variables; (c) The measuring device receives the rating value of the survey items of the N third groups of subjects viewed by the viewing conditions combined by two or more factors (hereinafter, viewing factors) through the input device, and the third subject Obtaining fatigue scores for each group using the ratings of each group of groups; (d) the measuring device making a population fatigue distribution for viewing factors from the N fatigue score data; (e) measuring the fatigue score of the measurement target display by receiving the evaluation values of the survey items of the fourth group of test subjects watching the three-dimensional display (hereinafter, the measurement target display) as the measurement target through the input device; ; (f) The measurement apparatus determines a relative position in the population fatigue distribution in which the fatigue score of the measurement target display is located, wherein the relative position is a distribution of fatigue in the population when the viewing factor is the same as the viewing factor of the measurement target display. Visual fatigue measurement method of the three-dimensional display, characterized in that it comprises the step of being in position for the fatigue score. The method of claim 1, wherein step (a) comprises: (a1) the measuring device receiving research questions asking about visual fatigue of a 3D display through the input device; (a2) the measuring device receiving the ratings of the survey items of two equal groups of first subjects through the input device; (a3) The measuring device sets the survey item as a variable, sets the first group of first subjects as variable values, performs factor analysis, and as a result of factor analysis, the number of factors (for variables) and each factor Deriving a questionnaire for each factor corresponding to the above; (a4) The measuring device sets the survey question as a variable, sets the second set of first test subjects as variable values, performs factor analysis, and as a result of factor analysis, the number of factors (for variables) and each factor Deriving a questionnaire for each factor corresponding to the above; (a5) if the result of the second first group of subjects is the same as the result of the first group of first subjects, the measuring device includes determining the factors and the question items for each of the factors. How to measure visual fatigue The method of claim 2, wherein step (a3) or step (a4), When the number of factors is M, if the eigenvalue is 1 or more and the number of factors increases more than M, if the eigenvalue change is less than the standard, the number of factors is set to M, and the survey items grouped by the factors are determined as the question items for each factor. Visual fatigue measurement method of the three-dimensional display. The method of claim 3, wherein The number of factors derived in step (a3) is five, The factor is eye fatigue, the desire to stop viewing the three-dimensional display, image blur discomfort, body limb pain, whistle determined how the visual fatigue measurement method of the three-dimensional display. According to claim 1, wherein step (b), (b2) the measuring device is configured to receive, through the input device, an evaluation value of the survey items of two equal groups of second subjects viewed by viewing conditions combined into two variables; (b3) the measuring device performing a two-way Anova on the two variables using the ratings of the first group of the second group of subjects; (b4) the measuring device performing a t-test on the two variables using the ratings of the two second groups of subjects; (b5) The measuring device has a significance level (p) derived as a result of the two-factor variable analysis being less than or equal to a first significance level criterion, and a significance level (p) derived as a result by the t-test is a second significance. The visual fatigue measurement method of the three-dimensional display, characterized in that it comprises the step of adopting the questionnaire if the level is above. The method of claim 5, wherein step (b2), The variables are set to 0, medium, binocular disparity consisting of three levels of extreme cases, and viewing time consisting of two levels of 5 minutes and 25 minutes, And said viewing condition comprises six of three levels of binocular disparity and two levels of viewing time. The method of claim 5, The first significance level criterion is 0.05, and the first significance level criterion is 0.75. The method of claim 1, The viewing factors are divided into display factors, content factors, and user characteristic factors. The display factors include spectacles, glasses-free, display implementation; The content factor includes an amount of binocular disparity, a display relative position of a gaze point, a temporal frequency, a spatial frequency, and a viewing time; The user characteristic factors include visual acuity, age, and near point; Visual fatigue measurement method of the three-dimensional display, characterized in that. The method of claim 1, wherein step (e) or (f) comprises: And said fatigue score is calculated as an average of said ratings. delete In the visual fatigue device of the three-dimensional display having a rating of the survey questions of the group of the subjects who watched the three-dimensional display through the input device, having a database, An item input unit configured to receive survey questions asking about visual fatigue of a 3D display through the input device; A rating value of a survey question of a first subject group is input through the input device, factor analysis is performed by setting the survey question as a variable and the rating as a data (variable value), and the number of factors as a result of factor analysis. And a factor extraction unit for deriving a questionnaire for each factor corresponding to each factor; The ratings of the survey items of the two second groups of subjects watched by the viewing conditions combined with the two variables are inputted through the input device, and the ratings for the two variables using the ratings by each viewing condition. A questionnaire evaluation unit that determines whether to adopt a questionnaire according to the two-way Anova and the t-test, and the significance level obtained as a result; The ratings of the survey items of the N third subject groups viewed by the viewing conditions combined by two or more factors (hereinafter, viewing factors) are inputted through the input device, and the rating values of each group of the third subject groups are received. A standardization unit for obtaining a fatigue score of each group by using and generating a population fatigue distribution for viewing factors from N fatigue score data; Through the input device, the evaluation values of the survey items of the fourth group of subjects watching the three-dimensional display (hereinafter, referred to as measurement object display) to be measured are obtained through the input device, and the fatigue reduction score of the display to be measured is obtained. Determine a relative position in the population fatigue distribution, wherein the relative position includes a distribution discriminating unit in contrast to the fatigue score of the population fatigue distribution when the viewing factor is the same as the viewing factor of the measurement target display. Visual fatigue measurement apparatus of a three-dimensional display, characterized in that. The method of claim 11, wherein the factor extracting unit, Receive the ratings of the survey items of two equal groups of first subjects through the input device, perform the factor analysis by setting the survey items as variables and the ratings of the first first group of subjects as variable values, and factor analysis As a result, the number of factors (for variables) and the questionnaire for each factor corresponding to each factor are derived, and the factor is analyzed by setting the questionnaire as a variable and the ratings of the second first subject group as the variable value. As a result of factor analysis, the number of factors (for variables) and the questionnaire for each factor corresponding to each factor are derived, and if the result of the second first subject group is the same as that of the first first subject group, , Visual fatigue measurement apparatus of the three-dimensional display, characterized in that for determining the factors and the question for each factor. The method of claim 12, wherein the factor extracting unit, When the number of factors is M, if the eigenvalue is 1 or more and the number of factors increases more than M, if the eigenvalue change is less than the standard, the number of factors is set to M, and the survey items grouped by the factors are determined as the question items for each factor. Visual fatigue measurement device of a three-dimensional display. The method of claim 13, wherein the factor extracting unit, The number of factors derived is five, The factor is a visual fatigue measurement device of the three-dimensional display, characterized in that the eye fatigue, the three-dimensional display viewing discontinuation desire, image blur discomfort, body limb pain, whirling. The method of claim 11, wherein the survey item evaluation unit, A rating value of the survey items of the two equal groups of second subjects viewed by the viewing conditions combined with the two variables is inputted through the input device, Two-way Anova is performed on the two variables using the first group of the second group of subjects, and the second two groups of subjects are used. By performing a t-test on the two variables, If the significance level (p) derived as a result of the factor analysis is less than or equal to the first significance level standard, and the significance level (p) derived as a result from the t-test is greater than or equal to the second significance level criterion Apparatus for visual fatigue measurement of a three-dimensional display, characterized in that the adoption. The method of claim 15, wherein the survey item evaluation unit, The variables are set to 0, medium, binocular disparity consisting of three levels of extreme cases, and viewing time consisting of two levels of 5 minutes and 25 minutes, And said viewing condition comprises six of three levels of binocular disparity and two levels of said viewing time. The method of claim 15, The first significance level criterion is 0.05 and the first significance level criterion is 0.75. The method of claim 11, The viewing factors are divided into display factors, content factors, and user characteristic factors. The display factors include spectacles, glasses-free, display implementation; The content factor includes an amount of binocular disparity, a display relative position of a gaze point, a temporal frequency, a spatial frequency, and a viewing time; The user characteristic factors include visual acuity, age, and near point; Visual fatigue measurement apparatus of a three-dimensional display, characterized in that. The method of claim 11, wherein the standardization unit or the distribution discrimination unit, Visual fatigue measurement apparatus of the three-dimensional display, characterized in that for calculating the fatigue score as the average of the ratings. delete A computer-readable recording medium having recorded thereon a program for performing the method for measuring visual fatigue of a three-dimensional display according to any one of claims 1 to 9.

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