No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Situational visual impairments on mobile devices - modeling the effects of bright outdoor environments
ResearchGate has not been able to resolve any citations for this publication.
Eight neutral patches displayed on a mobile display were visually assessed under a dark and an outdoor ambient viewing condition. Those data were used to establish the contrast sensitivity function (CSF) under the outdoor condition. It was verified by the results measured using the contrast threshold detection method. 4
In this work we investigate the effect of ambient light on performance during mobile interaction. We evaluate three conditions of ambient light – normal light, dimmed light, normal light while wearing sunglasses. Our results show that wearing sunglasses and dimmed light negatively affect reaction time, while dimmed light negatively affects accuracy performance in target acquisition tasks. We also show that wearing sunglasses increases memorising time in visual search tasks. Our study contributes to the growing body of research on the effects of different situational impairments on mobile interaction.
Billions of mobile devices are used worldwide for a significant number of important tasks in our personal and professional lives. Unfortunately, mobile devices are prone to interaction challenges as a result of the changing contexts of use, resulting in the user experiencing a situational impairment. For example, when typing in a vehicle being driven over an uneven road, it is difficult to avoid incorrect key presses.
Situational visual impairments (SVIs) are one type of usability and accessibility challenge mobile device user's face (e.g., not being able to read and reply to an important email when outside under bright sunlight), which suggests that current mobile industry practices are insufficient for supporting designers when addressing SVIs.
However, there is little HCI research that provides a comprehensive understanding of SVIs through qualitative research. Considering that we primarily interact with mobile devices through the screen, it is arguably important to further research this area. Understanding the true context of SVIs will help to identify adequate solutions.
To address this, I recruited 174 participants for an online survey and 24 participants across Australia and Scotland for a two-week ecological momentary assessment to establish what factors contribute to SVIs experienced when using a mobile device. My findings revealed that SVIs are a complex phenomenon with several interacting factors. I introduce a mobile device SVI Context Model to conceptualise the problem. I identified that mobile content design was the most practical first step towards addressing SVIs.
Following this, I surveyed 43 mobile content designers and ran four follow-on interviews to identify how often SVIs were considered and how I could provide effective support. I found key similarities and differences between accessibility and designing to reduce SVIs. The participants requested guidelines, education, and digital design tools for improved SVI design support. I focused on identifying the necessary features and implementation for an SVI design tool that would support designers because this would have an immediate and positive influence on addressing SVIs.
Next, I surveyed 50 mobile app designers using an online survey to understand how mobile app interfaces are designed. I identified a wide variety of tools and practices used, and the participants also raised challenges for designing mobile app interfaces that had implications for users experiencing SVIs.
Using my new understanding of SVIs and the challenges mobile designers face, I ran two design workshops. The purpose of the first workshop was to generate ideas for SVI design tools that would fit within a typical designer's workflow. I then created high-fidelity prototypes to elicit more informed feedback in the second workshop.
To address the problem of insufficient support for designers, I present a set of recommendations for developing SVI design tools to support designers in creating mobile content that reduces SVIs in different contexts. The recommendations provide guidance on how to incorporate SVI design support into existing design software (e.g., Sketch) and future design software. Design software companies following my recommendations will lead to an improved set of tools for designers to expand mobile content designs to different contexts. The development and inclusion of these designs within mobile apps (e.g., allowing alternative modes such as for day or night) will provide users with more control in addressing SVIs through enhanced content design.
Situationally-induced impairments and disabilities (SIIDs) make it difficult for users of interactive computing systems to perform tasks due to context (e.g., listening to a phone call when in a noisy crowd) rather than a result of a congenital or acquired impairment (e.g., hearing damage). SIIDs are a great concern when considering the ubiquitousness of technology in a wide range of contexts. Considering our daily reliance on technology, and mobile technology in particular, it is increasingly important that we fully understand and model how SIIDs occur. Similarly, we must identify appropriate methods for sensing and adapting technology to reduce the effects of SIIDs. In this workshop, we will bring together researchers working on understanding, sensing, modelling, and adapting technologies to ameliorate the effects of SIIDs. This workshop will provide a venue to identify existing research gaps, new directions for future research, and opportunities for future collaboration.
With the growing popularity of mobile devices, Situational Visual Impairments (SVIs) can cause accessibility challenges. When addressing SVIs, interface and content designers are lacking guidelines based on empirically-determined SVI con trast sensitivities. To address this, we developed BrightLights-a game that collects screen-content-contrast data in-the-wild that will enable new SVI-pertinent contrast ratio recommen dations. In our evaluation with 15 participants, we found significantly worse performance with low screen brightness versus medium or high screen brightness, showing that Bright-Lights is sensitive to at least one factor that contributes to SVI (screen brightness). Once validated for in-the-wild deploy ment, BrightLights data will finally help designers address SVIs through their designs.
Mobile technologies are used in increasingly diverse and challenging environments. With the predominantly visual nature of mobile devices, Situational Visual Impairments (SVIs) are a growing concern. However, fundamental knowledge is lacking about the causes of SVIs, how people deal with SVIs, and whether their solutions are effective. To address this, we first conducted a convenience-sampled online questionnaire with 174 participants, and identified many causes and (ineffective) solutions. To firmly ground our initial results, we then conducted a two-week ecological momentary assessment with 24 participants, balanced by age and gender across Australia and Scotland. We confirmed that SVIs are experienced often and during typical mobile tasks, and can be very frustrating. We identify a range of factors causing SVIs, discuss mobile design implications, and introduce an SVI Context Model rooted in empirical evidence. The contributions in this paper will support the development of new effective SVI solutions.
Mobile devices are a substantial part of our lives, supporting communication, work, and play. However, situational visual impairments (SVIs) can make completing tasks a challenge (e.g., browsing online in bright sunlight) and poorly designed content can cause or exacerbate SVIs. We surveyed 43 mobile content designers and ran four follow-on interviews to understand what designers currently do regarding SVIs, what resources they know of, and what is required to best support them in designing to reduce SVIs. Our findings highlight key similarities and differences between accessibility and designing to reduce SVIs. Our participants requested improved guidelines, education, and digital design tools for SVIs. To accommodate the growing number of people affected by SVIs and improve the inclusion of accessibility in design, we introduce recommendations that leverage the overlap between accessibility and SVIs to minimise the effort required in extending current design processes.
A subset of "Situationally Induced Impairments and Disabilities" (SIID), termed "Severely Constraining Situational Impairments" (SCSI), was explored at the user task and motivational level, to better understand the challenges faced by users attempting to perform tasks using a mobile device. Through structured interviews, participants were found to deploy workarounds in attempting to complete mobile I/O transactions, even if that workaround might place them in considerable danger. The motivations underlying user decisions were also explored resulting in a set of rich scenarios which will be used in the final participatory design stage of the study to discover ways that technology can be designed to overcome SCSIs.
Handheld devices such as smartphones and tablets are becoming useful in the medical field, as they allow physicians, radiologists, and researchers to analyze images with the benefit of mobile accessibility. However, for handheld devices to be effective, the display must be able to perform well in a wide range of ambient illumination conditions. We conducted visual experiments to quantify user performance for testing the image quality of two current-generation devices in different ambient illumination conditions while measuring ambient light levels with a real-time illuminance meter. We found and quantified that due to the high reflectivity of handheld devices, performance deteriorates as the user moves from dark areas into environments of greater ambient illumination. The quantitative analysis suggests that differences in display reflection coefficients do not affect the low illumination performance of the device but rather the performance at higher levels of illumination.
Color vision deficiencies (CVDs) cause problems in situations where people need to differentiate the colors used in digital displays. Recoloring tools exist to reduce the problem, but these tools need a model of the user's color-differentiation ability in order to work. Situation-specific models are a recent approach that accounts for all of the factors affecting a person's CVD (including genetic, acquired, and environmental causes) by using calibration data to form the model. This approach works well, but requires repeated calibration - and the best available calibration procedure takes more than 30 minutes. To address this limitation, we have developed a new situation-specific model of human color differentiation (called ICD-2) that needs far fewer calibration trials. The new model uses a color space that better matches human color vision compared to the RGB space of the old model, and can therefore extract more meaning from each calibration test. In an empirical comparison, we found that ICD-2 is 24 times faster than the old approach, and had small but significant gains in accuracy. The efficiency of ICD-2 makes it feasible for situation-specific models of individual color differentiation to be used in the real world.
Color is commonly used to convey information in digital environments, but colors can be difficult to distinguish for many users -- either because of a congenital color vision deficiency (CVD), or because of situation-induced CVDs such as wearing colored glasses or working in sunlight. Tools intended to improve color differentiability (recoloring tools) exist, but these all use abstract models of only a few types of congenital CVD; if the user's color problems have a different cause, existing recolorers can perform poorly. We have developed a recoloring tool (SSMRecolor) based on the idea of situation-specific modeling -- in which we build a performance-based model of a particular user in their specific environment, and use that model to drive the recoloring process. SSMRecolor covers a much wider range of CVDs, including acquired and situational deficiencies. We evaluated SSMRecolor and two existing tools in a controlled study of people's color-matching performance in several environmental conditions. The study included participants with and without congenital CVD. Our results show both accuracy and response time in color-matching tasks were significantly better with SSMRecolor. This work demonstrates the value of a situation-specific approach to recoloring, and shows that this technique can substantially improve the usability of color displays for users of all types.
Small displays are widely used for mobile phones, PDA and Portable DVD players. They are small to be carried around and viewed under various surround conditions. An experiment was carried out to accumulate colour appearance data on a 2 inch mobile phone display, a 4 inch PDA display and a 7 inch LCD display using the magnitude estimation method. It was divided into 12 experimental phases according to four surround conditions (dark, dim, average, and bright). The visual results in terms of lightness, colourfulness, brightness and hue from different phases were used to test and refine the CIE colour appearance model, CIECAM02 (1). The refined model is based on continuous functions to calculate different surround parameters for mobile displays. There was a large improvement of the model performance, especially for bright surround condition. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 u' v'
Color vision deficiency (CVD) affects approximately 200 million people worldwide, compromising the ability of these individuals to effectively perform color and visualization-related tasks. This has a significant impact on their private and professional lives. We present a physiologically-based model for simulating color vision. Our model is based on the stage theory of human color vision and is derived from data reported in electrophysiological studies. It is the first model to consistently handle normal color vision, anomalous trichromacy, and dichromacy in a unified way. We have validated the proposed model through an experimental evaluation involving groups of color vision deficient individuals and normal color vision ones. Our model can provide insights and feedback on how to improve visualization experiences for individuals with CVD. It also provides a framework for testing hypotheses about some aspects of the retinal photoreceptors in color vision deficient individuals.
Display manufacturers require new data and computational models that consider the effect of ambient illumination in order to develop higher-quality displays. In this study, typical variations of small-sized mobile LCDs that exist in the real world were first simulated using a device characterization technique. In addition, psychophysical attributes (e.g., naturalness, clearness, sharpness, contrast, colorfulness, and preference) affecting the image quality evaluation process were analyzed. Consequently, naturalness and clearness were found to be the most statistically significant psychophysical attributes for modeling image quality. As the ambient-illumination level was increased, the image quality was exponentially impaired and the contribution of clearness increased.
We propose an algorithm that transforms a digitized color image so as to simulate for normal observers the appearance of the image for people who have dichromatic forms of color blindness. The dichromat's color confusions are deduced from colorimetry, and the residual hues in the transformed image are derived from the reports of unilateral dichromats described in the literature. We represent color stimuli as vectors in a three-dimensional LMS space, and the simulation algorithm is expressed in terms of transformations of this space. The algorithm replaces each stimulus by its projection onto a reduced stimulus surface. This surface is defined by a neutral axis and by the LMS locations of those monochromatic stimuli that are perceived as the same hue by normal trichromats and a given type of dichromat. These monochromatic stimuli were a yellow of 575 nm and a blue of 475 nm for the protan and deutan simulations, and a red of 660 nm and a blue–green of 485 nm for the tritan simulation. The operation of the algorithm is demonstrated with a mosaic of square color patches. A protanope and a deuteranope accepted the match between the original and the appropriate image, confirming that the reduction is colorimetrically accurate. Although we can never be certain of another's sensations, the simulation provides a means of quantifying and illustrating the residual color information available to dichromats in any digitized image.
When creating digital artefacts, it is important to ensure that the product being made is accessible to as much of the population as is possible. Many guidelines and supporting tools exist to assist reaching this goal. However, little is known about developers' understanding of accessible practice and the methods that are used to implement this. We present findings from an accessibility design workshop that was carried out with a mixture of 197 developers and digital technology students. We discuss perceptions of accessibility, techniques that are used when designing accessible products, and what areas of accessibility development participants believed were important. We show that there are gaps in the knowledge needed to develop accessible products despite the effort to promote accessible design. Our participants are themselves aware of where these gaps are and have suggested a number of areas where tools, techniques and guidance would improve their practice.
This article identifies, catalogues, and discusses factors that are responsible for causing visual impairment of either a pathological or situational nature for touch and gesture input on smart mobile devices. Because the vast majority of interactions with touchscreen devices are highly visual in nature, any factor that prevents a clear, direct view of the mobile device’s screen can have potential negative implications on the effectiveness and efficiency of the interaction. This work presents the first overview of such factors, which are grouped in a catalogue of users, devices, and environments. The elements of the catalogue (e.g., psychological factors that relate to the user, or the social acceptability of mobile device use in public that relates to the social environment) are discussed in the context of current eye pathology classification from medicine and the recent literature in human–computer interaction on mobile touch and gesture input for people with visual impairments, for which a state-of-the-art survey is conducted. The goal of this work is to help systematize research on visual impairments and mobile touchscreen interaction by providing a catalogue-based view of the main causes of visual impairments affecting touch and gesture input on smart mobile devices.
Colour forms an essential element of day-to-day life for most people, but at least 5% of the world have Impaired Colour Vision (ICV) - seeing fewer colours than everyone else. Those with typical colour vision find it difficult to understand how people with ICV perceive colour, leading to misunderstanding and challenges for people with ICV. To help improve understanding, personalized simulations of ICV have been developed, but are computationally demanding (so limited to static images), which limits the value of these simulations. To address this, we extended personalized ICV simulations to work in real time on a mobile device to allow people with typical colour vision greater freedom in exploring ICV. To validate our approach, we compared our real-time simulation technique to an existing adjustable simulation technique and found general agreement between the two. We then deployed three real-time personalized ICV simulations to nine people with typical colour vision, encouraging them to take photos of interesting colour situations. In just over one week, participants recorded over 450 real-world images of situations where their simulation presented a distinct challenge for their respective ICV participant. Through a questionnaire and discussion of photos with participants, we found that our solution provides a valuable mechanism for building understanding of ICV for people with typical colour vision.
Users frequently experience situations in which their ability to differentiate screen colors is affected by a diversity of situations, such as when bright sunlight causes glare, or when monitors are dimly lit. However, designers currently have no way of choosing colors that will be differentiable by users of various demographic backgrounds and abilities and in the wide range of situations where their designs may be viewed. Our goal is to provide designers with insight into the effect of real-world situational lighting conditions on people's ability to differentiate colors in applications and imagery. We therefore developed an online color differentiation test that includes a survey of situational lighting conditions, verified our test in a lab study, and deployed it in an online environment where we collected data from around 30,000 participants. We then created ColorCheck, an image-processing tool that shows designers the proportion of the population they include (or exclude) by their color choices.
The focus of this paper is to evaluate the ability to reproduce preferred colors for mobile displays under ambient illumination condition. Mobile liquid crystal display (LCD) and active matrix organic light emitting diode (AMOLED) are used and 3D gamut volume in CIECAM02 QMh space is utilized to take absolute perceptual attributes into account. The ‘degree of inclusion (DOI)’ is calculated from the quantity of colors included within display gamut volume among the preferred colors of 1260 from six categories of image database. As a result of this evaluation, the ability of LCD to reproduce preferred colors is similar with a level of AMOLED due to its high brightness under general office environment.
Colour vision deficiencies (CVD) affect the everyday lives of a large number of people, but it is difficult for others - even friends and family members - to understand the experience of having CVD. Simulation tools can help provide this experience; however, current simulations are based on general models that have several limitations, and therefore cannot accurately reflect the perceptual capabilities of most individuals with reduced colour vision. To address this problem, we have developed a new simulation approach that is based on a specific empirical model of the actual colour perception abilities of a person with CVD. The resulting simulation is therefore a more exact representation of what a particular person with CVD actually sees. We tested the new approach in two ways. First, we compared its accuracy with that of the existing models, and found that the personalized simulations were significantly more accurate than the old method. Second, we asked pairs of participants (one with CVD, and one close friend or family member without CVD) to discuss images of everyday scenes that had been simulated with the CVD person's particular model. We found that the personalized simulations provided new insights into the details of the CVD person's experience. The personalized-simulation approach shows great promise for improving understanding of CVD (and potentially other conditions) for people with ordinary perceptual abilities.
The image quality of two active matrix organic light emitting diode
(AMOLED) smart-phone displays and two in-plane switching (IPS) ones was
visually assessed at two levels of ambient lighting conditions
corresponding to indoor and outdoor applications, respectively.
Naturalness, colorfulness, brightness, contrast, sharpness, and overall
image quality were evaluated via psychophysical experiment by
categorical judgment method using test images selected from different
application categories. The experimental results show that the AMOLED
displays perform better on colorfulness because of their wide color
gamut, while the high pixel resolution and high peak luminance of the
IPS panels help the perception of brightness, contrast, and sharpness.
Further statistical analysis of ANOVA indicates that ambient lighting
levels have significant influences on the attributes of brightness and
contrast.
Since Weiser introduced his vision of ubiquitous computing, computing devices have become lighter, smaller, cheaper, and more powerful. At the same time, pervasive computing and the concept of context have attracted significant attention, with the goal of supporting the use of computing devices anywhere, anytime, as computers fade into the environment. While there has been some success inferring the users' intensions, reliably understanding users' general goal remains a significant challenge. Using limited context information, such as location, can be useful, but the benefits are limited. Context is more than location. As computers are embedded into everyday things, the situations users encounter become more variable. As a result, situationally- induced impairment and disabilities (SIID) will become more common and user interfaces will play an even more important role. Recent understandings on context suggested the importance of applications themselves as parts of the whole context space. This article will explain and discuss the characteristics of SIID under a three-dimension (human, environment, and applications) context model. We suggest integrating information from all dimensions to have a whole picture of context. More studies are needed to understand the relationship among different dimensions, and to help design effective context-aware applications overcoming SIID.
This study examined the effects of surround luminance on the shape of the spatial luminance contrast sensitivity function (CSF). The reduction in brightness of uniform neutral patches shown on a computer controlled display screen is also assessed to explain the change of CSF shape. Consequently, a large amount of reduction in contrast sensitivity at middle spatial frequencies can be observed; however, the reduction is relatively small for low spatial frequencies. In general, the effect of surround luminance on the CSF appears similar to that of mean luminance. Reduced CSF responses result in less power of the filtered image; therefore, the stimulus should appear dimmer with a higher surround luminance.
When plotted in three-dimensional color-space, thresholds of colored lights fall on or near the surface of an ellipsoid. Using data reported in the literature, we estimate the deviation between sets of spectral threshold measurements and the ellipsoid that passes closest to the data. Seventy-three percent of the reported spectral thresholds fall within 0.1 log units of the best-fitting ellipsoid. Our ability to distinguish one ellipsoidal fit as significantly better than another is limited by the choice of sampling directions in color-space. Spectral lights do not provide a good set of sampling directions for reducing the uncertainty about the estimated best-fitting ellipsoid. Complete characterization of visual sensitivity requires measuring thresholds to mixtures of spectral lights.
Electronic device design for energy harvesting of indoor and outdoor light sources for multiple low power usage
- Stelios Kouridakis
- Panagiotis Giakoumakis
- Kouridakis Stelios
Vision and Brain: How We Perceive the World
- V James
- Stone
- Stone V.