Rina Doherty

Stereoscopic Viewing and Reported Perceived Immersion and Symptoms

Purpose. Stereoscopic 3D displays heighten perceived immersion but elevate viewing symptoms for some viewers. The present study measured prevalence and magnitude of perceived immersion and viewing symptoms in stereoscopic viewing, and related them to viewers characteristics and viewing position. Methods. Two hundred three teens and adults viewed a movie in 2D or 3D while sitting at different angles and distances. Their prior viewing symptoms, as well as visual and physical discomfort immediately before and after viewing, were measured with questionnaires. They were also asked to report their perceived immersion after the viewing. Results. Twelve percent and twenty-one percent of 2D and stereoscopic 3D participants reported increases of measured symptoms during and/or after viewing. Stereoscopic 3D viewing incurred greater and more frequent perception of blurred vision, double vision, dizziness, disorientation, and nausea than 2D viewing. Reported ocular and physical symptoms were negatively correlated to perceived immersion in 3D viewing. Older viewers (age 46 years or older) reported greater ocular, visual, and motion sickness symptoms in 2D viewing, and younger viewers (age 24–34 years) reported greater visual and motion sickness symptoms in 3D viewing. Sitting in an oblique position attenuated perceived immersion but also reduced motion symptoms in 3D viewing. Prior viewing symptoms in 2D tasks also predicted ocular and physical symptoms in 2D but less so in 3D viewing. Conclusions. Stereoscopic 3D viewing provides greater immersion, but it can also lead to heightened visual and motion sickness symptoms. Viewers with prior symptoms in viewing TV and computer screen are not more likely to have increased ocular and physical symptoms in 3D viewing. Young viewers incurred higher immersion but also greater visual and motion sickness symptoms in 3D viewing; both will be reduced if a farther distance and a wider viewing angle are adopted.

User Perception of Touch Screen Latency

The goal of this study was to determine the level at which touch screen latency becomes annoying for common tablet tasks. Two types of touch screen latency were manipulated for three applications: Web page browsing, photo viewing, and ebook reading. Initial latency conditions involved an initial delay in the screen’s visual response to touch inputs but with no delay after the beginning of a touch input. Continuous latency involved continuous delay for the duration of a touch input. Both types were tested from 80 to 780 ms. Touch inputs included resizing with multitouch input, panning, scrolling, zooming, and page turning. Results showed a statistically significant main effect for application, but differences were small. Continuous and initial latency showed little difference in ratings except with ebook reading. Trend graphs show levels of user ratings by latency duration.

Diminishing returns?: revisiting perception of computing performance

The computing performance literature offers guidelines and frameworks, but data on the limits of user appreciation for performance are scarce. This paper presents a study of user satisfaction with different levels of computing performance. Thirty-five participants performed common computing tasks such as creating email and Web surfing. They rated computing performance for specific task elements - such as application launching and menu responsiveness - that occurred during those tasks. They repeated the tasks under varying levels of computer performance. Results include user ratings as a function of computing performance for each of the task elements. The results have implications for system designers who create products that must meet user expectations for performance.

Designing Notebook Computers to Ensure a Comfortable User Experience: Effects of Surface Temperature, Material, Locality, and Ambient Temperature

Two studies are described to determine the effect of locality, age, gender, ambient temperature, surface material and surface temperature, on user annoyance during a typing task on notebook computers. The studies were conducted in Oregon and Taiwan, using real computers modified with heaters under the keyboard and palm rests. Computer chassis made from both metal and plastic were studied, and users were exposed to ambient temperatures of both 23 °C and 35 °C. No practically significant effect of locality, age, gender, or ambient temperature was observed, but the ergonomic comfort between metal and plastic surfaces was very different at the same temperature.

Applications of psychoacoustics to information technology products

Emerging usage models for computing devices require low acoustic noise, for example in home entertainment systems. Studies have shown that not only the overall level, but also the psychoacoustic aspects matter. This paper provides an overview of testing techniques that are used in the information technology industry and outlines two specific case studies. First, an extensive subjective psychoacoustic study was designed and conducted in multiple geographies to determine the aspects of sound that best describe the annoyance to sound from information technology products in a home type environment. Over 200 participants in four countries participated in this carefully controlled experiment and rated typical steady state sounds on a 5 point annoyance scale. The relevant sound quality metrics were extracted and geographical variations quantified. Second, in a paired comparison study the influence of modulation on annoyance was investigated by superimposing different frequency and amplitude modulated sounds onto a baseline sound. The results indicate that modulation can have a significant effect on subjective perception.

Applying Flow Theory to Predict User-Perceived Performance of Tablets

A users’ perception of interactive device performance is influenced by their feeling of being in control and that there is a sense of constant progress. A system will be able to keep users in the flow by meeting expectations and keeping up with their inputs and commands. The concept of flow has been discussed since the 1960’s and has been used in the context of computing devices; however, the ability to operationally define and quantitatively measure this construct is limited. This paper describes a study that tested a new framework for measuring flow as it relates to User-Perceived Performance (UPP) of tablets.

Background noise levels in PC home environments

A study was designed and conducted to determine the background noise levels in the home environment. This is an important factor in determining the acoustic performance of the computing devices that go into these environments. A specialized methodology was developed and measurements were carried out in homes in the United States, Sweden, Germany, and China. The sound levels in three rooms in 15–18 homes in each country were collected over 24‐h periods. The results indicated that the background noise levels ranged between 30 and 40 dBA across the four countries. Variations in the background noise levels between the different rooms in the homes were minimal. No significant variations were found between home types (detached, semi‐detached, and apartment) and community types (urban, suburban). However, European homes were quieter than United States and Chinese homes. The variations between countries were statistically significant. In addition to the background noise levels, the acoustical characteristics of t...