69 Table 4.4 Results of stepwise multiple linear regression of each of eleven dependents. variables on screen curvature, task duration, distortion ratio and their interactions. 81 Table 4.5 Bivariate correlation coefficients between eleven dependent variables. below diagonal line, **<0.001, *<0.05) and p-values of simple linear regression lines to verify linear relationship between two variables (above diagonal line).
Introduction
- Background
- Objective and Specific Aims
- Scope
- Dissertation Outline
An overview of experiments on 50-inch multi-monitors, 27-inch curved monitors, and 55-inch curved TVs is shown in Figure 1.4. Improving the experimental limitations of the 50-inch multi-monitor study, Chapter 4 describes a study investigating the effects of screen curvature and task duration on user productivity, safety, and well-being in proofreading tasks on a 27-inch. curved monitor.
Literature review
General Overview of Visual Displays
- Display curvature
- Lateral viewing position
- Field of view
- Viewing angle
- Anisotropy
Using a 7 cm to 13 cm plastic mock-up display, Häkkinen et al. 2008) examined the effects of display curvature (0, ±60 R and ±80 R) and curvature direction (horizontal/vertical) on readability. As screen curvature approaches a given distance, TV viewers' preferences for aesthetics and comfort increase and perceived image distortion decreases (Choi et al., 2015; Na and Suk, 2016).
Human Vision (binocular vision)
- Binocular disparity
- Ocular information
- Horopter
A horopter is defined as "the set of environmental points simulating corresponding points on two retinas". The theoretical horopter is defined "geometrically by projecting pairs of corresponding retinal points outward through the nodal point of the eye" (Palmer, 1999) and describes the location of all object points in space that are imaged on the two corresponding retinal elements at a time assigned. fixation distance (Figure 2.4). Objects that form single-view images on the retina without visual accommodation lie in a straighter line, i.e., the empirical horopter, than a geometrically defined curve, i.e., the theoretical horopter (Ogle, 1950; Shipley and Rawlings , 1970).
Visual Ergonomics
- Productivity Indicators
- Visual task performance
- Safety indicators
- Visual discomfort and visual fatigue
- Well-being indicators
- Presence
- Visual comfort
- Image quality
- Satisfaction
- Mental workload
- Time on VDT Tasks
Non-contextual errors (in one word) are easier to proofread than contextual errors (in words and sentences) (Hacker et al., 1994; Plumb et al., 1994). Presence depends on external (media form and media content) and internal (personal factors) determinants (Lessiter et al., 2001).
Effects of Display Curvature, Display Zone, and Task Duration
Introduction
Readability and visual fatigue in the case of curved screens are often assessed using visual search tasks involving pseudotexts (Lin et al., 2008; Using a 13 cm × 7 cm plastic model screen, Häkkinen, Pölönen, et al. 2008 ) examined the effects of screen curvature (0, ±60 R and ±80 R) and curvature direction (horizontal/vertical) on readability.
Methodology
- Participants
- Experimental setting and procedure
- Data collection and processing
- Dependent measures
- Statistical analysis
Perceived visual fatigue was reported for each viewing zone on a 100 mm VAS and each curvature setting on the ECQ. A VAS was used to analyze the effects of display area and task duration on visual fatigue, while ECQ score and CFF value were used to assess visual fatigue due to display curvature.
Results
- Visual searching task performance
- Letter searching error
- Letter searching speed
- Visual fatigue
- Subjective visual fatigue (VAS)
- Subjective (ECQ) and psychophysiological (CFF) visual fatigue
For the letter search error (%) the interaction effect of the display curvature × display zone was significant (Table 3.2 and Figure 3.5). For the letter search speed (letters/s), the interaction effect of display curvature × display zone was significant (Table 3.2 and Figure 3.6).
Discussion
- Visual searching task performance
- Interaction effects
- Curvature effects
- Display zone effects
- Visual fatigue
- Subjective visual fatigue (VAS)
- Subjective (ECQ) and psychophysiological (CFF) visual fatigue
- Further discussion
- Horizontal viewing distance
- Horopter and comfortable viewing distance
- Horizontal field of view and viewing angle
- Limitations
Among all the settings, the Z1 and Z5 in the flat setting were the worst for visual tasks. This study found that visual fatigue was perceived most strongly in the flat setting, indicating that a curved setting was generally beneficial. In this study, the horizontal field of view and the angle of view of the outer zones increased when the curvature was more flat or more curved than 600 mm.
Such a discrepancy can be partly attributed to simultaneous changes in the viewing angle and viewing distance in this study (vs.
Conclusions
This study used a multi-monitor setup instead of curved monitors to realize varied display curvatures. Since specific display curvatures were realized by arranging five flat display panels, each display zone was flat, resulting in irregular brightness across each screen. In addition, to generalize the results of this study, it is necessary to consider other visual tasks (e.g. word processing and multitasking using multiple display zones) and typical monitor user behavior (e.g. performing primary tasks in the middle zone and secondary tasks at the outer zones, with non-constant viewing distances and monitor trends).
Effects of Display Curvature and Task Duration on Proofreading
Introduction
According to Mustonen et al. 2015), visual processing speed on a convex curvature (r = 50 R) screen at 45 cm viewing distance was impaired. Prolonged visual discomfort and visual fatigue can induce headaches and impair task performance (Sheedy, 1992a, 1992b; Sheedy et al., 2003). VDT tasks induce mental loads and therefore reduce the efficiency of reading tasks (Lee et al., 2011).
Pupil diameter is one of the commonly used physiological measures of visual fatigue and mental workload (Chi et al., 2003).
Methodology
- Participants
- Experimental setting and procedure
- Data collection and processing
- Independent variables
- Dependent variables
- Statistical analysis
Subjective visual fatigue was obtained using a modified version of ECQ of nine items, excluding an item of redness. Also, a segmented linear regression model was developed to investigate the non-linear relationship between visual discomfort and subjective visual fatigue. In turn, first principal component regression analysis was performed to examine the extent to which subjective visual fatigue was influenced by composite factors, extracted from proofreading speed and accuracy, visual discomfort, CFF, blink duration, blink frequency, pupil diameter (left and right). , overall mental workload, and 6 subconcepts of mental workload).
Second principal component regression analysis was performed to investigate the extent to which user satisfaction was influenced by composite factors, extracted from proofing speed and accuracy, visual discomfort, subjective visual fatigue, 9 items for ECQ, CFF, blink duration, blink frequency, pupil diameter (left and right), overall mental workload and six sub-concepts of mental workload.
Results
- Proofreading task performance
- Visual discomfort
- Visual fatigue
- Mental workload
- User satisfaction
- Stepwise regression of dependent variables on display curvature, distortion ratio, and
- Correlation analysis between dependent variables
- Association between visual discomfort and subjective visual fatigue
- Prediction models of visual discomfort, subjective visual fatigue, mental workload,
- Principal component regression of subjective visual fatigue
- Principal component regression of user satisfaction
Proofreading accuracy negatively associated with visual discomfort, subjective visual fatigue, blink duration, blink frequency, and pupil diameter of the left eye. Prediction models of visual discomfort, subjective visual fatigue, mental workload and user satisfaction, workload and user satisfaction. Actual data on visual discomfort, subjective visual fatigue, mental workload and user satisfaction by predictions using four models are shown in Figure 4.17.
The principal component analysis was applied to dependent variables except subjective visual fatigue and user satisfaction.
Discussion
- Effects of display curvature
- Effects of task duration
- Explaining the impact of display curvature, distortion ratio, and task duration on each
- Investigating the association between proofreading speed and accuracy, visual
- Identifying the relationship between visual discomfort and subjective visual fatigue101
- Determining the degree to which composite variables composed of dependent
- Limitations
However, in this study there was no significant effect of display curvature on visual fatigue. Proofreading speed was negatively correlated with proofreading accuracy and CFF, and was positively associated with visual discomfort and subjective visual fatigue. Subjective visual fatigue was negatively associated with user satisfaction and positively correlated with mental workload.
They also reported relatively low levels of visual fatigue during the task duration (60 min) adopted in this study.
Conclusions
Effects of Display Curvature, Viewing Distance, and Lateral
Introduction
However, no widely known research has fully considered various elements of the TV viewing experience or explained screen satisfaction using other experiential elements. Media form factors that influence geometric distortion and brightness (Goldmark and Dyer, 1940), including screen size, viewing distance and image quality (Lee (2009), influence the viewing experience. To date, little is known about how viewing distance and display curvature affects the viewing experience.
Three media form factors (screen curvature, viewing distance, and lateral viewing position) and seven television viewer elements (spatial presence, engagement, ecological validity, negative effects, visual comfort, picture quality, and screen satisfaction) were examined with specific consideration of 1) the main and interactive effects of the media form factors on each item, 2) the extent to which these factors accounted for the variability in each item, and 3) the extent to which the remaining six viewing experience items, other than display satisfaction, accounted for variation in display satisfaction.
Methodology
- Participants
- Experimental setting and procedure
- Independent variables
- Dependent variables
- Statistical analysis
At the same viewing distance, steps 3) - 4) were repeated at each of the remaining four viewing positions. The first four were sub-concepts of presence (Lessiter et al., 2001), which were assessed using 13 items selected from the Independent Television Commission's Sense of Presence Inventory (ITC-SOPI): three related to spatial presence ("I had a feeling , that I am in the scenes shown', 'I felt like I was visiting places in the environment shown', 'I felt as if the characters and/or objects were almost touching me'), three related to engagement ('I felt involved (in the environment shown)', 'I enjoyed it', 'My experience was intense'), three regarding ecological validity ('The content seemed believable', 'The environment shown seemed natural', 'I had a strong feeling that characters and objects were solid") and four related to negative effects ("I felt dizzy", "I felt sick", "I felt a headache", "I felt tired A mixed three-way analysis of variance (ANOVA) was used to examine the main and interaction effects of screen curvature, viewing distance, and lateral viewing position on the seven dependent variables described above.
For each element, a stepwise multiple linear regression analysis was performed to determine the extent to which their variability was explained by display curvature, viewing distance, lateral viewing position, and these interactions.
Results
- Presence
- Spatial presence
- Engagement
- Ecological validity
- Negative effects
- Visual comfort
- Image quality
- User satisfaction
- Stepwise regression of dependent variables on display curvature, viewing distance, and
- Stepwise regression of user satisfaction using other dependent variables
- Principal component regression of user satisfaction
The screen curvature × viewing distance × lateral viewing position interaction effect was significant for engagement (p = 0.022). Although screen curvature (p=0.027) and lateral viewing position (p=0.047) had significant effects on negative effects, all treatments were clustered into the same group (Figure 5.7). Stepwise regression of the dependent variables on screen curvature, viewing distance, and lateral viewing position distance and lateral viewing position.
Stepwise multiple linear regressions were performed for each dependent variable related to screen curvature, viewing distance, lateral gaze position, and their interactions, with adjusted R2 values ranging between 0.01 (for visual comfort) and 0.08 (for spatial presence).
Discussion
- Interaction effects of display curvature × viewing distance × lateral viewing position
- Effects of display curvature
- Effects of viewing distance
- Effects of lateral viewing position
- Effects of field of view and viewing angle
- Explaining the impact of display curvature, viewing distance, and lateral viewing
- Predicting display satisfaction using measures of six watching experience elements129
- Principal component regression (PCR)
- Limitations
Negative effects were reduced as the screen curvature or viewing distance increased and as the lateral viewing position approached P1. Lateral viewing position was 1.5 times more influential on image quality than screen curvature. In the study by Sylaiou et al. 2010), enjoyment and perceived spatial presence were also positively correlated.
In a study by Lombard et al. 2000), the effect of screen size on presence was not significant in the male group, whereas the female group reported higher presence with wider screens.
Conclusions
A separate study by Kwon and Lee (2007) found that those with higher engrossing tendencies reported higher presence during TV viewing, but observed no significant gender effects. Personal characteristics (such as a willingness to suspend disbelief, knowledge or previous experience with the medium and personal types (Heeter, 1992)) are also important factors for presence. Fifth, in addition to media form factors (display curvature, viewing distance, and lateral viewing position), media content factors (overall theme, narrative, and story) can influence viewing experience in terms of engagement (Wirth et al., 2007). involvement, and ecological validity (Lessiter et al., 2001).
In order to focus on the effects of the three media form factors, however, this study controlled for media content factors using similar videos.
General Discussion and Conclusions
General Discussion
- How display curvature affects productivity, safety, and well-being?
- Rest-time interval recommendation
- Association between visual discomfort and subjective visual fatigue
- Predictive models for subjective visual fatigue and user satisfaction
Visual fatigue was lower at the 600 R and 1200 R settings compared to the flat setting on the 50” multi-monitor. In this study, a segmented linear relationship between visual discomfort and subjective visual fatigue showed higher explanatory power compared to a simple linear regression. The developed stepwise models accounted for 70.4% of the subjective variability of visual fatigue and 60.2% of the variability of user satisfaction, respectively.
The first PCR model developed accounted for 49.3% of the variability in subjective visual fatigue and showed that visual discomfort and workload were more determinants of subjective visual fatigue than visual task performance.
Conclusions
- Major outcomes
- Limitations
- Expected contributions and future work
Effects of ambient lighting conditions and background color on visual performance with TFT-LCD displays. Effects of antiglare surface treatment, ambient lighting and curvature on readability and visual fatigue of electronic papers. Effects of screen curvature, display area, and task duration on legibility and visual fatigue during a visual search task.
Illumination, font style, and polarity on visual performance and visual fatigue with electronic paper displays.
