Effect of display polarity and luminance contrast on visual lobe shape characteristics

The effect of display polarity and luminance contrast on visual lobe (effective visual field) shape characteristics was studied using three levels of luminance contrast with combinations of positive and negative polarities. The binocular effective visual field for a detection task, with a peripherally presented target (V) embedded in a homogeneous competing background (Xs), was mapped on 24 imaginary axes passing through the fixation point. The results showed that visual lobes mapped using positive polarity were statistically larger in area, rounder and more regular in shape than those for negative polarity. The medium contrast condition lobes were more symmetric and regular than low contrast condition lobes, and lobe area and perimeter increased with increasing luminance contrast ratio. Under the interaction of positive polarity and high luminance contrast, visual lobes were found to be larger, smoother and rounder. The high level of luminance and contrast however resulted in a higher degree of visual discomfort. The results indicated that positive polarity and contrast of medium (26:1) to high (41:1) levels are possible display settings for better visual lobe characteristics and better anticipated search performance. Practitioner Summary: The effect of display polarity and luminance contrast on visual lobe shape characteristics was examined with uniform stimulus materials in this study. The results help to identify the optimum display settings for luminance contrast and display polarity to enhance lobe shape characteristics and hence search performance in industrial inspection tasks.     

Eyestrain and visual display units: a review

A review is presented of current knowledge about the nature, incidence and causes of eyestrain or visual fatigue among VDU operators. It is suggested that fatigue and discomfort may result from visual, postural, environmental, work design and personal factors. However, it is concluded that all these problems can be overcome by sufficient attention to ergonomics in the design, implementation and use of VDUs.     

Evaluating and improving color washout of vertical aligned liquid crystal display

We demonstrated an optimized 8-domain vertical aligned (VA) liquid crystal display (LCD) by minimizing its color washout. The index G is adopted to analyze the degree of color washout through simulation. By using linearly and circularly polarized incident light, the optimized regime of the area and applied voltage ratios of sub-pixels is obtained. In the experiments with the circularly polarized light, the images are sensuously improved in a coupled capacity type LCD by applying the simulated applied voltage ratio of two sub-pixels.     

Co-located collaborative visual analytics around a tabletop display

Co-located collaboration can be extremely valuable during complex visual analytics tasks. We present an exploratory study of a system designed to support collaborative visual analysis tasks on a digital tabletop display. Fifteen participant pairs employed Cambiera, a visual analytics system, to solve a problem involving 240 digital documents. Our analysis, supported by observations, system logs, questionnaires, and interview data, explores how pairs approached the problem around the table. We contribute a unique, rich understanding of how users worked together around the table and identify eight types of collaboration styles that can be used to identify how closely people work together while problem solving. We show how the closeness of teams’ collaboration and communication influenced how they performed on the task overall. We further discuss the role of the tabletop for visual analytics tasks and derive design implications for future co-located collaborative tabletop problem solving systems.     

Operating characteristics and TV image display of a grid-controlled matrix fluorescent display panel

The basic structure and the driving methods for a grid-controlled matrix fluorescent display panel are discussed Two experimental TV image display sets were made using a four-electrode display panel and a five-electrode display panel with 268 × 392 = 105 056 and 573 × 782 = 448 086 pixels respectively. The vertical scanning and driving circuits are considerably simplified by means of the anode grid decoding. One TV set has only 24 sets of anode drivers, and for the other the number of anode drivers is further reduced from 24 to one. A technique for diminishing cross-talk between the neighbouring picture elements is also discussed, and a cathode pulse driving method adopted to provide a uniform display.     

Relationships among display features, eye movement characteristics, and reaction time in visual search

The relative contribution of number of fixations and fixation duration to reaction time in visual search was investigated. Ten participants (age 20-24 years) took part in each of two experiments. In Experiment 1, the experimental factors were display type (icon and file name), organization (arrangements with and without grouping), and number of stimuli presented (4, 8, and 16). In Experiment 2, a search task for a target stimulus (three prespecified random letters) was conducted, and the experimental factor was the display's layout complexity. Multiple regression analysis was used to examine whether reaction time was explained by a mediational model in which reaction time is mediated by eye movements and display features are not directly related to reaction time. The mediational model was not supported, and the effects of display features on reaction time were not attributable solely to eye movements. The interaction between number of fixations and fixation duration was also explored as a function of display features. As the display feature changed and the task became more difficult, the contribution of the number of fixations to explain the variation in reaction time became dominant for both experiments. Potential applications include measurements of cognitive ability, eye muscle balance disorders, and binocular fusion ability.     

Accommodation and visual fatigue in display work

Being in the midst of the evolution of the species Homo termino-videns, demands for (eye) rest-time allowances are commonplace among vdu operators the world over. Today some 13 per cent of Swedish salaried employees daily sit at a vdu and Sweden is the first country to have issued national safety and health directives on vdu work. Experiments using a laser optometer have shown that visual tasks in vdu work may induce temporary effects in the visual accommodation system; increased refractive power in darkness (‘night myopia’) and levelling-out of accommodation responses in good lighting (‘distance myopia’ and ‘near hyperopia’). It is believed that laser optometry will eventually make possible the formulation of objective criteria of visual fatigue and its prevention.     

How to select a technology lawyer

Investigating your technology law needs may save you money and headaches down the lines. IT professionals are dealing more with outside vendors and consultants. In these transactions, it is vital to protect your intellectual property (IP). One of the best ways to do this is to use the appropriate “legalese”. Poorly written nondisclosure agreements (NDAs), contracts, memorandums of understanding, and other legal documents can sink a business. Large corporations usually have sizable legal staffs to protect their interests. It's the smaller firms that need the most help. If you are making technology decisions at smaller companies, be aware that: (i) any dealings you enter into without legal representation automatically put you at a disadvantage, and will appear to the opposing parties as a sign of weakness; (ii) protecting technology today can substantially increase its future value-for example, the value of America Online is greatly enhanced by its recognizable trademark; (iii) some law firms will work at reduced rates if they believe in your technology and you agree to retain their services in the future (after you hit the big time). The article gives advice on how to select an appropriate lawyer     

Electromagnetic radiation emissions from visual display units: a review

The suggestion that workers using visual display units may be exposed to potentially hazardous electromagnetic radiations emitted by such equipment has raised the question of operational safety. In order to assess and quantify any risk a number of radiation surveys have been conducted in several countries. These surveys have followed different protocols and used a variety of field survey instruments. All have arrived at similar conclusions indicating that there are no significant levels of radiation to be found in any part of the electromagnetic spectrum emitted by such equipment.     

The association between visual discomfort and the use of visual display units

This paper reports the results of a two-year survey of the visual problems associated with the use of visual display units (VDUs). The survey examined both discomfort levels and visual function, and asked whether there were differences in these measures between subjects who used a VDU in the completion of their tasks and controls who did not. In total, 202 subjects were examined. The main study examined four groups of which two, Data Preparation and Word Processing (WP) used a VDU in the completion of their tasks, while the other two, General Clerical and Typing (TY), did not. Subjective measures of visual discomfort and objective measures of visual function were taken at both the beginning and end of the day.

Two analyses were performed on the data; the first considered all four groups together, and the second directly compared the WP and TY groups—these two groups being considered well matched. The first analysis showed that statistically significant differences existed between the groups at the end of the day. However, differences were also shown between the groups at the beginning of the day, and when the measure 'change over the day' was used, no significant differences attributable to the VDU were found. The second analysis found no significant differences between the TY and WP groups, nor were any trends apparent.

A further study was done on ten subjects who alternated on a daily basis between using a word processor and a typewriter. No significant differences were found between the days using one and those using the other, confirming the above finding.

Whilst both optometric measures of visual function and reported visual discomfort did change over the day, we conclude we have no evidence lo support the idea that the VDU is in itself a causal factor of these changes to any greater extent than is the paper in a typewriter.     

Using a capability evaluation to select a contractor

The experiences of a government team in determining the winner of a three-year, $95-million software avionics contract using the Software Engineering Institute's Software Capability Evaluation program are discussed. The proposal evaluations, on-site evaluations, and post-on-site evaluation activities are all described. It is concluded that the evaluation method integrated well into the contractor-selection process     

Space, colour and typography on visual display terminals

Some guidelines are given to meet the observed need for rules about layout, the use of colour and typography on display screens so as to create texts with optimal legibility. Examples of videotex pages are used to illustrate right and wrong layouts, applications of colour and of letter type. The guidelines can be generalized to other types of display such as those used in personal computers and, to a more limited extent, to the use of graphics instead of text. Finally, figures are given on the general public's subjective appreciation of some alternative display layouts.     

基于视觉反馈和预测仿真的Internet机器人遥操作

随着网络技术的发展,基于Internet的机器人遥操作因其广泛的应用前景而成为研究的热点,如何消除Internet引入的复杂时延对控制系统的影响是解决问题的关键.该文在分析Internet两点间时延规律的基础上,设计并实现了一个基于视觉反馈和预测仿真的机器人遥操作系统(Telemanipulator,Tman),三维仿真服务器模拟出操作现场,远程用户根据视觉反馈和本机的三维仿真及时做出控制决策;同时,为了消除时延可能导致的超调所带来的安全隐患,采取远程控制结合本地自主控制的模式,由本地服务器完成最后的小区域内的精细操作.实验结果表明仿真预测和控制模式切换有效地补偿了时延,保证了控制系统的鲁棒性和安全性.     

Effects of display position of a visual in-vehicle task on simulated driving

To determine the relative safety of onboard display positions while driving, participants performed a lane-keeping task in a driving simulator. Concurrently, they reacted to a light by pushing the brake pedal. A secondary task was projected onto a display at one of the seven different locations in the cockpit. Behavioral data, eye movements, and subjective rating scales showed that the manipulation of display information during driving disturbed drivers' performance exponentially as a function of distance between the line of sight to the outside primary task and the onboard display position. Vertical eccentricity had a greater detrimental effect than horizontal distance. Under a certain condition with a high secondary task load, reaction time of pushing the brake to the outside stimulus nearly doubled with a diagonal eccentricity of 35 degrees as compared to lower eccentricities. Subjective workload measures complement the behavioral data of clear detrimental effects with eccentricities of at least 35 degrees .     

Spatial stimulus response compatibility for a horizontal visual display with hand and foot controls

In this study, two experiments were conducted to examine spatial stimulus–response compatibility (SRC) effects for a horizontal visual display with hand and foot controls. In experiment 1, the hand and foot controls were in a hands above and feet below vertical plane, such that the display and controls were orthogonal to each other. In experiment 2, the foot pedals were moved forward and placed directly underneath the front row of signals, resulting in an additional horizontal display and control relationship. The results of experiment 1 revealed a strong orthogonal SRC effect, such that the best performance was for the front signals with hand controls and rear signals with foot pedals, which was not altered with the presence of horizontal location mappings in experiment 2. These findings indicate that the front-hand/rear-foot mapping relationship was quite robust with regard to changes in the relative locations of the hand and foot response devices.

Statement of Relevance: The results of this study provide useful ergonomics recommendations for designing control consoles with visual signals presented in a horizontal plane and control devices operated by hands and feet. They are helpful for improving efficiency and overall system performance in person–machine systems.     

Spatial stimulus response compatibility for a horizontal visual display with hand and foot controls

In this study, two experiments were conducted to examine spatial stimulus-response compatibility (SRC) effects for a horizontal visual display with hand and foot controls. In experiment 1, the hand and foot controls were in a hands above and feet below vertical plane, such that the display and controls were orthogonal to each other. In experiment 2, the foot pedals were moved forward and placed directly underneath the front row of signals, resulting in an additional horizontal display and control relationship. The results of experiment 1 revealed a strong orthogonal SRC effect, such that the best performance was for the front signals with hand controls and rear signals with foot pedals, which was not altered with the presence of horizontal location mappings in experiment 2. These findings indicate that the front-hand/rear-foot mapping relationship was quite robust with regard to changes in the relative locations of the hand and foot response devices. STATEMENT OF RELEVANCE: The results of this study provide useful ergonomics recommendations for designing control consoles with visual signals presented in a horizontal plane and control devices operated by hands and feet. They are helpful for improving efficiency and overall system performance in person-machine systems.     

An overview of standards and guidelines for visual display terminals

This paper provides a discussion of several standards and guidelines for design of visual display terminal (VDT) workplaces. The material represents products of government agencies, commercial standards organisations and of labour unions. Seven documents are reviewed: US MIL STD 1472-C, German DIN 66234, British HSE, Swedish ISO Proposal, British APEX, US NYCOSH, and Australian ACTU-VTHC. There is considerable disagreement in the specification of design parameters in these standards. The issues are discussed in terms of their importance and the availability of supporting ergonomics research. There are several types of VDT tasks and the number and variety of applications are growing rapidly. Due to these factors and the development of new display technologies, different recommendations may be appropriate depending upon the task and the technology. Research and careful deliberation will be required to deal with this development.     

Effects of display vibration and whole-body vibration on visual performance

Fifteen subjects performed a numeral reading task during (a) vibration of the display, (b) vibration of the subject, (c) simultaneous vibration of both subject and display. Sinusoidal motion at eleven frequencies (0·5 to 5·0 Hz) was presented at five acceleration magnitudes (1·0 to 2·5ms^?2 r.m.s.). Measures of reading time and reading error showed that for all except the highest frequencies, vibration of the display resulted in the poorest performance. Simultaneous whole-body-and-display vibration produced least performance decrement. The effects of both the viewing conditions and the vibration frequency are discussed in relation to known characteristics of the visual system.     

Interactions between memory scanning and visual scanning in display monitoring

Many real-world tasks require the simultaneous performance of memory scanning of several memorized items and visual scanning of several physically separated sources of information in the visual field. This paper reports a study that was conducted to quantify the possible interactions between memory scanning and visual scanning. A quantitative model was derived to integrate Sternberg's linear model of memory scanning and Neisser's linear model of visual scanning. The derived model was tested through two experiments. The experiments simulated a process controller's task of monitoring an array of instrument meters to detect if any of them indicated a system error. The subjects were required to keep a number of items in their working memory (the definition of errors) and search through an organized array of instrument meters to decide whether any of the meters carried an item that matched any of the memorized items in their working memory. Two experimental factors were investigated in both experiments: the number of memorized items and the number of circles needed to be searched These defined memory scanning demand and visual scanning demand respectively. Experiment 1 employed a different set of memorized items for each experimental trial, whereas experiment 2 employed the same set for all the trials that had the same experimental condition. The experiments identified both the strengths and the limitations of the derived model. Implications for human-machine interface design and human performance modelling are discussed.     

Fixation disparity: binocular vergence accuracy for a visual display at different positions relative to the eyes

Some observers do not fixate accurately at the point of regard: Their vergence angle (between the visual axes of the two eyes) may correspond to points slightly nearer or farther away. This vergence error, or fixation disparity, was measured with nonius (vernier) lines at six positions of a visual display relative to the eyes. At viewing distances of 40, 60, and 100 cm, the display was located either at eye level or at a downward inclination of gaze direction of -25 degrees relative to horizontal. Viewing conditions resembled typical office work. Lowering the screen induced a near shift in mean vergence response of 0.6 min arc, irrespective of viewing distance; the closer the screen, the more distant was the vergence response relative to the target (by 2.5 min arc on average). The slope of this proximity-fixation-disparity curve is an individual parameter of the vergence system. Actual or potential applications of this research include recommendations for the comfortable viewing distance of visual displays.