Abstract
The purpose of this study was to assess the visual fatigue after watching 3D TV in wave-front aberration (WFA) test methods. The evaluation method is different from the previous visual fatigue test method (such as accommodation response, subjective assessment and electroencephalography). The self-developed wave-front aberrometer used to collect the data. 60 participants were recruited, who watched 3D TV by wearing two glasses respectively. SPSS18.0 was used for analysis and significance is defined as p < 0.05. The results show that MTF (Modulation Transfer Function) and means of WFA (3rd to 5th) of before and after watching 3D TV had significant differences (p < 0.05) and consistent trends. The RMS (root mean square) of WFA had no significance. Meanwhile, we found that the result of MTF of wearing different glasses had significant differences (p < 0.01). In conclusion, MTF and mean of WFA (3rd to 5th) can be used as the evaluation index of visual fatigue. In follow-up studies, more relationship between changes of higher-order aberrations (6th–35th order) and visual fatigue will be studied.
Keywords
1 Introduction
With the development of 3D picture production technology, a large number of excellent films such as Avatar and Titanic have showed successively, which leads to the rapid increase in the number of audience. And 3D display technology (3D film, 3D TV, etc.) has been the main trend of Screen Display Technology. At the same time, the long-time watching 3D films will lead to the problem of visual quality descending, which has been paid more and more attention by people. So developing a set of reliable and accurate index to evaluate visual fatigue has a very important and urgent effect on people optical health.
In recent years, a lot of scholars have made pre-explorations in this respect. Yano et al. explored the comfort of watching 3D HDTV/HDTV picture by testing the accommodation response of eyes [1]. Kuze et al. evaluated visual fatigue led by watching 3D video in five aspects (visual fatigue, general discomfort, nausea, difficulty of focusing, headache) by means of subjective evaluation [2]. Ntuen et al. discovered that the growth rate of visual fatigue led by watching 3D video is higher than 2D by expression of human vision [3]. Mun et al. carried out the research of electroencephalography (EEG), and discovered that steady-state visually evoked potential (EEVEP) and event-related potential (ERP) were related to the cognitive fatigue after watching 3D video [4]. Previous research indicated that long-time watching 3D TV will lead people to visual fatigue, headache, nausea and other fatigue symptoms [5–7]. However, these evaluation methods don’t consider of the physiological essence of eyes. Furthermore, methods such as subjective evaluation and EEG, are unable to quantize assessment index effectively.
Measuring wave-front aberration is to analyse the visual quality of human eyes. It mainly uses Zernike polynomial, which is an orthonormalized function, to describe the optical aberration of pupillary zone in ocular [8, 9]. With the development of exploration to optical aberration of Ocular, people pay more and more attention to high order aberration, and the change of high order aberration is very important to the improvement of the quality of visual in ocular. And the modulation transfer function (MTF) decided by wave-front aberration is the total response of eyes to spatial video. Research of Yang showed that there was hope to realize evaluating the visual quality of corneal refractive surgery by the MTF of wave-front aberration [10]. From the physiological optics characteristics of human eyes, this study summarizes and evaluates the effect of watching 3D TV to visual health, by means of testing the wave-front aberration of participants while they were in the course of watching 3D TV.
2 Methods
2.1 Participants
Total 60 subjects (age: 31.4 ± 7.1; sexuality ratio: 1/1) were recruited, who were told about the detailed experimental process before the test and signed a volunteer agreement. Avoiding the disturbing of fatigue, all the subjects had enough sleep and were arranged half an hour’s rest with eyes closed before the test, ensuring all the subjects had a good mental and physiological state during the test.
2.2 Methods
2.2.1 Human Eyes Screening
Before the test, subjects were tested by optometer (NIDEK AR-310), dominant eye and wavefront aberration analyzer, in order to eliminate the high degree of myopia, big visual acuity difference between left and right eye and poor stereopsis feeling.
2.2.2 Testing Process
TV type in this study was 42 in. polarizing LED-3D (LG 42LW5500CA). Screen resolution is 1080 p. There were two types of 3D glasses (The degree of polarization of type A is 98.8 %, attaching angle is 125°–127°; The degree of polarization of type B is 99 %, attaching angle is 109°–112°, optical index of type A is better than type B’s), their photos are shown in Fig. 1. Schematic testing diagram is shown in Fig. 2: the entire test is in the darkroom environment, distance between subjects and TV is 3500 mm, video is the 3D standard sample.
At first, after having a rest of half an hour with eyes closed in a darkroom, subjects were tested by wavefront analyzer, and the value of wave-front aberrations of subjects are collected. Then they began on the 3D standard samples’ watching. The whole watching time was 90 min, and there was an aberration test every 45 min. In two days subjects had done the all test, and assured that everyone has worn the two kinds of glasses, A and B.
2.2.3 Test Equipments
Using the self-developed wave-front aberrometer (calibrated by The measurement test research institute of Beijing, Calibration certificate No.: H413Z-G0125) to test, and parameters are include overall wave-front aberrations and the 7th order and 35th term value of aberration calculated by Zernike function.
2.3 Statistical Methods
Statistics were performed using SPSS (Version 18.0 for Windows). Means and standard deviations were calculated for the total 60 subjects for wave-front aberrations. Paired t-test was used to describe the differences of the data before watching, 45 min after watching and 90 min after watching. And the two kinds of 3D glasses are also conducted by paired sample t test. Significance is defined as p < 0.05.
3 Results
3.1 Modulation Transfer Function (MTF)
MTF is one of the most important and visual evaluation index of video quality in applied optics. In this study, we synthesize 35 terms aberration indices, and calculate the MTF value of human eyes at various time spans. Results of the three MTF tests can be seen in Fig. 3, among them, “before watching” is the test result after subjects having a rest with the eyes closed on test site for 30 min, “45 min after watching” is the test result of the subjects who had viewed 3D film for 45 min, and “90 min after watching” is the test result after watching 3D film for 90 min. As Fig. 3 shows, “before watching” and “45 min after watching”, “before watching” and “90 min after watching”, are conducted by using the paired sample t test respectively, p < 0.05, and the difference in statistics is obvious. Meanwhile, we can find that the MTF value is gradually lowered (as the red arrow shows).
3.2 The Root Mean Square (RMS) of Higher-Order Aberration
The RMS value of higher-order aberration is always used to evaluate the visual quality [11]. This study is analysing the variation trend of the 3rd, 4th and 5th order aberrations. All samples from 3rd–5th orders aberrations of ‘before watching’, ‘45 min after watching’, and ‘before watching’ and ‘90 min after watching’, are conducted by using the paired sample t-test. No obvious difference in statistics exists (p > 0.05). And variations of each order aberration are not consistent (As shown in Fig. 4).
3.3 The Mean of Higher-Order Aberration
This study begins statistical analysis from the variation trend of 3rd, 4th and 5th order aberration mean (as show in Fig. 5). The 3rd–5th orders aberration means of ‘before watching’, ‘45 min after watching’, and ‘before watching’, ‘90 min after watching’, are conducted by using the paired sample t test. Among them, ‘before watching’ and ‘45 min after watching in 3rd order (p < 0.01) and 5th order (p < 0.05) show ‘Before watching’ and ‘45 min after watching’ in 3rd, 4th order (p < 0.05) and 5th order (p < 0.01) also have statistically significant. With the increase of watching time, we can find that 4th and 5th order aberration means are in the upward trend, as the red arrow shows in Fig. 5.
3.4 Comparing of A and B 3D Glasses
The range of MTF changes of the two types glasses was compared by the analysis of the difference of MTF value between the time of 45 and 90 min after watching and the time before watching. The two changes were conducted by using Paired Sample T test. The results are shown in Fig. 6. The parameters of the glasses A is superior to B in this study, and test results show that the MTF decline of wearing B glasses is significantly (p < 0.01) greater than A. The longer it was worn, the shaper it changed.
4 Discussion and Conclusion
4.1. In this study, MTF (Modulation Transfer Function) can be used as an analysis index for evaluation of visual comfort after watching 3D TV. With the increase of viewing time, MTF is gradually increasing.
4.2. From the result of study, we can conclude that RMS of higher order aberration has no significant difference before and after watching, and the change trend has no consistency. The index cannot be used to assess the visual health quality.
4.3. In this study, the changing trend of average value of 4th and 5th order aberration gradually grows with the increase of viewing time, and there is a significant difference between times before and after watching. So the parameter can be used to evaluate the visual health quality after watching the 3D TV.
4.4. Wearing different types of 3D glasses for watching 3D TV, the quality of glasses greatly affected the viewing quality of eye imaging after the view. Glasses with poor parameters caused higher eye fatigue level than glasses with better parameters.
4.5. This research just analyzed and compared aberrations of 3rd to 5th order, In follow-up studies, more relationship between index changes of higher-order aberrations (6th–35th order) and visual health will be studied. We will supply data and technical support for the formulation of visual health evaluation standards in the future.
References
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)
Kuze, J., Ukai, K.: Subjective evaluation of visual fatigue caused by motion images. Displays 29, 159–166 (2008)
Ntuen, C.A., Goings, M., Reddin, M., Holmes, K.: Comparison between 2-D & 3-D using an autostereoscopic display: the effects of viewing field and illumination on performance and visual fatigue. Int. J. Ind. Ergon. 39, 388–395 (2009)
Muna, S., Park, M.-C., Park, S., Whang, M.: SSVEP and ERP measurement of cognitive fatigue caused by stereoscopic 3D. Neurosci. Lett. 525, 89–94 (2012)
Ukai, K., Howarth, P.A.: Visual fatigue caused by viewing stereoscopic motion images: background, theories, and observations. Displays 19(2), 106–116 (2008)
Lambooij, M., Fortuin, M.F., IJsselsteijn, W.A., Heynderickx, I.: Visual discomfort associated with 3D displays. In: Fifth International Workshop on Video Processing and Quality Metrics (VPQM) (2010)
Lambooij, M., IJsselsteijn, W.A., Heynderickx, I.: Visual discomfort of 3DTV: assessment methods and modeling. Displays 32(4), 209–218 (2011)
Maeda, N.: Wavefront technology in ophthalmology. Cur. Opin. Ophthalmol. 12, 294–299 (2001)
Thibos, L.N., Applegate, R.A., Schwiegerling, J.T., et al.: Standards for reporting the optical aberrations of eyes. J. Refract. Surg. 18, S652–S660 (2002)
Yan, W.: Research on visual and optical quality evaluation based on wavefront aberration and Modulation Transfer Function (MTF) before and after corneal refractive surgery. Doctor thesis, Tianjin Medical University, Tianjin, China (2006). (in Chinese)
Liu, F., Yong, J.H., Xu, M., Xu, H.W., Wei, F., Jing, C.L.: High-order aberration and visual quality. Int. J. Ophthalmol. 7(4), 1113–1115 (2007)
Acknowledgments
This work is supported by the National Major Scientific Instrument Development Special Project of Ministry of Science and Technology of the People’s Republic of China (2012YQ12008001).
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Yang, F., Cai, J., Guo, Y., Zhou, Q., Liu, Z. (2016). Based on High Order Aberration Analysis of Influence Index of Vision Fatigue by Watching 3D TV. In: Marcus, A. (eds) Design, User Experience, and Usability: Novel User Experiences . DUXU 2016. Lecture Notes in Computer Science(), vol 9747. Springer, Cham. https://doi.org/10.1007/978-3-319-40355-7_64
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