Improving Web access for visually impaired users

Technology advances and the continuing convergence of computing and telecommunications have made an unprecedented amount of information available to the public. For many people with disabilities, however, accessibility issues limit the impact of such widespread availability. Of the many types of disabilities-mobility, hearing, and learning impairments, for example-vision impairments are most pervasive in the general population, especially among seniors. The world's rapidly aging population is redefining visually impaired, which refers to individuals with low vision (that is, people for whom ordinary eyeglasses, contact lenses, or intraocular lens implants don't provide clear vision), color blindness, and blindness. In 1998, the US Congress amended the Rehabilitation Act, strengthening provisions covering access to government-posted information for people with disabilities. As amended, Section 508 requires federal agencies to ensure that all assets and technologies are accessible and usable by employees and the public, regardless of physical, sensory, or cognitive disabilities. Most current assistive technologies for visually impaired users are expensive, difficult to use, and platform dependent. A new approach by the US National Library of Medicine (NLM), National Institutes of Health (NIH), addresses these weaknesses by locating the assistive capability at the server, thus freeing visually impaired individuals from the software expense, technical complexity, and substantial learning curve of other assistive technologies. NLM's Senior Health Web site (http://nihseniorhealth.gov), a talking Web (a Web application that presents Web content as speech to users), demonstrates the approach's effectiveness.     

A review of assistive spatial orientation and navigation technologies for the visually impaired

Universal Access in the Information Society - The overall objective of this work is to review the assistive technologies that have been proposed by researchers in recent years to address the...     

Sensory navigation guide for visually impaired sea kayakers

At present, a visually impaired kayaker needs the assistance of a kayaker coach in charge of guiding him/her by using loud vocal instructions or a sound device during the sea ride. However, neither the coach nor the visually impaired kayaker feel at ease with such a guiding due to the amount of noise generated by the frequent vocal interactions. This paper describes a novel concept of sensory navigation guide meant to help kayakers with visual disabilities to practice sea kayaking in an autonomous way. The innovation here consists in providing kayakers with wristbands that automatically vibrate left or right, depending on the predefined trajectory to be followed. The main contributions of this work include an original navigation algorithm based on GPS feedback to track a corridor‐shaped path on the sea and the definition of specific metrics to analyze the performance of the kayakers along the ride. Experiments carried out on a population of 10 visually impaired kayakers and 10 sighted kayakers showed convincing results. A satisfaction survey confirmed that all participants acknowledged the added value of the system in terms of increased autonomy. Most of the visually impaired participants also enjoyed a greater sports entertainment experience thanks to this guiding system, which can be extended to other kinds of water sports.     

Context-aware obstacle detection for navigation by visually impaired

This paper presents a context-aware smartphone-based based visual obstacle detection approach to aid visually impaired people in navigating indoor environments. The approach is based on processing two consecutive frames (images), computing optical flow, and tracking certain points to detect obstacles. The frame rate of the video stream is determined using a context-aware data fusion technique for the sensors on smartphones. Through an efficient and novel algorithm, a point dataset on each consecutive frames is designed and evaluated to check whether the points belong to an obstacle. In addition to determining the points based on the texture in each frame, our algorithm also considers the heading of user movement to find critical areas on the image plane. We validated the algorithm through experiments by comparing it against two comparable algorithms. The experiments were conducted in different indoor settings and the results based on precision, recall, accuracy, and f-measure were compared and analyzed. The results show that, in comparison to the other two widely used algorithms for this process, our algorithm is more precise. We also considered time-to-contact parameter for clustering the points and presented the improvement of the performance of clustering by using this parameter.     

An improved Web search engine for visually impaired users

The Google search engine was studied as a Web prototype to be modified and improved for blind users. A Specialized Search Engine for the Blind (SSEB) was developed with an accessible interface and improved functions (searching assistance functions, user-centered functions, and specialized design for the blind). An experiment was conducted with twelve participants, both blind and sighted, to verify the effects of SSEB. The performance was better with the SSEB than with the Google search engine, and the participants also showed higher satisfactions with the SSEB. Interface considerations for designing an accessible Web site for blind users are important. The users of SSEB could in the future be expanded to include most, if not all, visually impaired people, since the World Wide Web and all Internet resources should ideally be accessible to everyone.     

A computer vision-based perception system for visually impaired

In this paper, we introduce a novel computer vision-based perception system, dedicated to the autonomous navigation of visually impaired people. A first feature concerns the real-time detection and recognition of obstacles and moving objects present in potentially cluttered urban scenes. To this purpose, a motion-based, real-time object detection and classification method is proposed. The method requires no a priori information about the obstacle type, size, position or location. In order to enhance the navigation/positioning capabilities offered by traditional GPS-based approaches, which are often unreliably in urban environments, a building/landmark recognition approach is also proposed. Finally, for the specific case of indoor applications, the system has the possibility to learn a set of user-defined objects of interest. Here, multi-object identification and tracking is applied in order to guide the user to localize such objects of interest. The feedback is presented to user by audio warnings/alerts/indications. Bone conduction headphones are employed in order to allow visually impaired to hear the systems warnings without obstructing the sounds from the environment. At the hardware level, the system is totally integrated on an android smartphone which makes it easy to wear, non-invasive and low-cost.

     

Eye symptoms and reading abilities of computer users subjected to visually impaired direct glare

Computer work is a visually demanding task associated with adverse eye symptoms. Frequent use of digital displays is known to cause a deterioration of the so-called binocular control. Direct glare further reduces the capacity for binocular coordination during computer work, leading to reduced reading ability and increased eye symptoms.The purpose of this study was to investigate the effect of different luminance levels of direct glare on binocular eye movement control and reading ability in a computer work environment.Sixteen participants with normal binocular vision performed equal reading tasks in a balanced study. Three controlled lighting conditions of direct glare (2000, 4000 and 6000 cd/m²) were tested, in addition to no glare. After each trial, the participants answered survey questionnaires regarding their understanding of the text, as well as their subjective experience of workload and perceived vision. Horizontal fixation disparity (FD) was measured before and after the reading tasks to evaluate binocular eye movement control.When comparing the responses of visual experience, a significant difference in reported eye symptoms was found between lighting conditions. Based on the variation (SD), a significant difference was found within mean values of repeated measurements of horizontal FD and a significantly higher variation in a comparison of initial FD values measured during lighting conditions of no glare, to final measured values in all three glare conditions. Reading ability was found to be significantly negative affected with the adversity of lighting conditions.This study supports the contention that binocular eye movement control is reduced caused by direct glare. Even lower degree of disability glare caused eye symptoms. The results establish the argument that working with flat screens raises visual demands.     

Alternative modalities for visually impaired users to control smart TVs

Multimedia Tools and Applications - Smart TVs offer a variety of features that increase interactivity and available services when compared to other TVs. Furthermore, remote controls have become...     

Developing a navigation aid for the frail and visually impaired

This paper describes the development of a new navigational aid for the frail, elderly, and visually impaired person. The users were involved both in the user requirements study and in the evaluation of different prototypes. The results show that the users were able to provide information on their current aid, the use situation, and their preference regarding different solutions, but they had difficulties to provide the detailed answers on technical solutions required by the technical development team. Further, prototype evaluations with users enabled the technical team to understand the users and their use situation.     

Sonification and interaction design in computer games for visually impaired individuals

Multimedia Tools and Applications - Video games are changing how we interact and communicate with each other. They can provide an authentic and collaborative platform for building new communities...     

Evaluating interface layout for visually impaired and mobility-impaired users through simulation

The authors have developed a simulator to help with the design and evaluation of assistive interfaces. The simulator can predict possible interaction patterns when undertaking a task using a variety of input devices and estimate the time to complete the task in the presence of different disabilities. This paper presents a study to evaluate the simulator by considering a representative application of searching icons, which was being used by able-bodied, visually impaired and mobility-impaired people. The simulator predicted task completion times for all three groups with statistically significant accuracy. The simulator also predicted the effects of different interface designs on task completion time accurately. The simulator is used to develop inclusive digital TV interfaces. A case study is presented to investigate accessibility requirements of a representative digital TV interface.     

Real-time GPS track simplification algorithm for outdoor navigation of visually impaired

Outdoor navigation of visually impaired people most often is based on data from the GPS maps and Geographic Information Systems (GIS). Such systems cannot be used for navigation in the regions where there are not any GPS maps or the maps are not sufficiently precise and detailed. This article describes an algorithm for real-time GPS track simplification. The test results show that the proposed algorithm (RSTS) has efficiency similar to the Douglas–Peucker algorithm, which is regarded as the best for track simplification. The reduction of the number of points in different transportation modes, while keeping the shape of the route, is over 90%. The size of the file describing the track is reduced more than 30 times. The algorithm finds the critical points of the route. This allows for navigation along the track so conversion of track to route is not needed. The algorithm is part of a low cost and widely accessible Java 2 Mobile Edition (J2ME) application for navigation of visually impaired.     

Comprehensive assessment for motor and visually impaired people using a hierarchical model

Universal Access in the Information Society - The evolution of various modern technologies has inspired researchers to assess the effectiveness of these technologies for people with diversified...     

Visual saliency assistance mechanism based on visually impaired navigation systems

Visually impaired people face significant challenges in their work, studies, and daily lives. Nowadays, numerous visually impaired navigation devices are available to help visually impaired people solve daily life problems. These devices typically include modules for target recognition, distance measurement, and text reading aloud. They are designed to help visually impaired people avoid obstacles and understand the presence of things around them through text reading aloud. Due to the need to avoid all potential obstacles, the target recognition algorithms embedded in these devices must recognize a wide range of targets. However, the text reading aloud module cannot read all of them. Therefore, we designed a visual saliency assistance mechanism that simulates the regions that humans may pay the most attention to in the whole picture. The output of the visual saliency assistance mechanism is overlaid with the target recognition result, which can greatly reduce the target number of text reading aloud. This way, the visually impaired navigation device can not only help to avoid obstacles but also help visually impaired people understand the interest targets of most people in the whole picture. The visual saliency assistance mechanism we designed consists of three components: a spatio-temporal feature extraction (STFE) module, a spatio-temporal feature fusion (STFF) module, and a multi-scale feature fusion (MSFF) module. The STFF module fuses long-term spatio-temporal features and improves the temporal memory between frames. The MSFF module fully integrates information at different scales to improve the accuracy of saliency prediction. Therefore, this proposed visual saliency model can assist in the efficient operation of visually impaired navigation systems. The area under roc curve judd (AUC-J) metric of the proposed model was 93.9%, 93.8%, and 91.5% on three widely used saliency datasets: Holly-wood2, UCF Sports, and DHF1K, respectively. The results show that our proposed model outperforms the current state-of-the-art models.     

User-centered system design for assisted navigation of visually impaired individuals in outdoor cultural environments

Universal Access in the Information Society - The marginalization of people with disabilities, such as visually impaired individuals (VIIs), has driven scientists to take advantage of the fast...     

Blind and visually impaired people studying computer science and mathematics

The author runs an educational experiment at his university where blind and visually impaired people can study computer science or mathematics under conditions adequate to their disabilities. The project is now in its first semester. The paper reveals the problems blind and visually impaired students are presently facing, and it describes the methods used in our educational experiment to overcome these difficulties. It also reports our experience with the project gained so far. An appendix is devoted to a brief survey about the technology used to make computers accessible to blind and visually impaired people.     

Visual search-based design and evaluation of screen magnifiers for older and visually impaired users

The purpose of this study was to achieve the following goals: apply some principles in visual search theory to design and develop a screen magnifier; evaluate if applying such features could increase user performance; and make some recommendations for designing a screen magnifier according to the findings of the study. In order to achieve these goals, a screen magnifier and an experimental tool to present stimulus words were developed. Seventy-two elderly Chinese adults took part in the experiment. The findings indicate that, for a screen magnifier, the overlapping mode is superior to the parallel mode; the yellow-highlighted background is superior to the non-highlighted background; for lower-density text, the dual output mode (visual+auditory) is superior to the mono output mode (visual only), while for the higher-density text, no difference was found between the mono and dual output modes. Based on the findings, several recommendations are made. The overlapping mode should be set as the default working mode. Yellow could be a reasonable choice of background color for a magnifier when the text is black. Auditory output support should be used, and users should be advised to use dual output when the text density is lower and mono output when the text density is higher.     

An empirical investigation into the difficulties experienced by visually impaired Internet users

In this paper, an empirical based study is described which has been conducted to gain a deeper understanding of the challenges faced by the visually impaired community when accessing the Web. The study, involving 30 blind and partially sighted computer users, has identified navigation strategies, perceptions of page layout and graphics using assistive devices such as screen readers. Analysis of the data has revealed that current assistive technologies impose navigational constraints and provide limited information on web page layout. Conveying additional spatial information could enhance the exploration process for visually impaired Internet users. It could also assist the process of collaboration between blind and sighted users when performing web-based tasks. The findings from the survey have informed the development of a non-visual interface, which uses the benefits of multimodal technologies to present spatial and navigational cues to the user.