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 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.

     

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.     

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.     

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.     

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...     

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.     

An edge detection framework conjoining with IMU data for assisting indoor navigation of visually impaired persons

Smartphone applications based on object detection techniques have recently been proposed to assist visually impaired persons with navigating indoor environments. In the smartphone, digital cameras are installed to detect objects which are important for navigation. Prior to detect the interested objects from images, edges on the objects have to be identified. Object edges are difficult to be detected accurately as the image is contaminated by strong image blur which is caused by camera movement. Although deblurring algorithms can be used to filter blur noise, they are computationally expensive and not suitable for real-time implementation. Also edge detection algorithms are mostly developed for stationary images without serious blur. In this paper, a modified sigmoid function (MSF) framework based on inertial measurement unit (IMU) is proposed to mitigate these problems. The IMU estimates blur levels to adapt the MSF which is computationally simple. When the camera is moving, the topological structure of the MSF is estimated continuously in order to improve effectiveness of edge detections. The performance of the MSF framework is evaluated by detecting object edges on video sequences associated with IMU data. The MSF framework is benchmarked against existing edge detection techniques and results show that it can obtain comparably lower errors. It is further shown that the computation time is significantly decreased compared to using techniques that deploy deblurring algorithms, thus making our proposed technique a strong candidate for reliable real-time navigation.     

Context and selective retreat in hierarchical menu structures

This paper describes an experiment to compare the use of two different forms of menu dialogue to solve a relatively complex problem. The problem involves multiple queries from a videotex database accessed by a potentially deep hierarchical set of menus. The dialogue forms compared are a standard videotex menu system and an enhanced menu system. The latter provides both additional contextual information and a means of selective, rather than incremental, retreat. Although no significant time advantage was measured, the results do demonstrate a significant improvement in navigation for the enhanced menu system and show the value of using realistic problems for this type of evaluation.     

Documentation for computer users

This paper describes the nature, purpose and importance of documentation for users of computers. The key factors in the good design of documentation are considered. Particular emphasis is placed on the matching of the presentation to the background and needs of the users. The problems of production and circulation are also outlined.     

Design and development of an indoor navigation system using denoising autoencoder based convolutional neural network for visually impaired people

A challenging area of research is the development of a navigation system for visually impaired people in an indoor environment such as a railway station, commercial complex, educational institution, and airport. Identifying the current location of the users can be a difficult task for those with visual impairments. The entire selection of the navigation path depends upon the current location of the user. This work presents a detailed analysis of the recent user positioning techniques and methodologies on the indoor navigation system based on the parameters, such as techniques, cost, the feasibility of implementation, and limitations. This paper presents a denoising auto encoder based on the convolutional neural network (DAECNN) to identify the present location of the users. The proposed approach uses the de-noising autoencoder to reconstruct the noisy image and the convolution neural network (CNN) to classify the users' current position. The proposed method is compared with the existing deep learning approaches such as deep autoencoder, sparse autoencoder, CNN, multilayer perceptron, radial basis function neural network, and the performances are analyzed. The experimental findings indicate that the DAECNN methodology works better than the existing classification approaches.

     

Real-time hierarchical POMDPs for autonomous robot navigation

This paper proposes a new hierarchical formulation of POMDPs for autonomous robot navigation that can be solved in real-time, and is memory efficient. It will be referred to in this paper as the Robot Navigation–Hierarchical POMDP (RN-HPOMDP). The RN-HPOMDP is utilized as a unified framework for autonomous robot navigation in dynamic environments. As such, it is used for localization, planning and local obstacle avoidance. Hence, the RN-HPOMDP decides at each time step the actions the robot should execute, without the intervention of any other external module for obstacle avoidance or localization. Our approach employs state space and action space hierarchy, and can effectively model large environments at a fine resolution. Finally, the notion of the reference POMDP is introduced. The latter holds all the information regarding motion and sensor uncertainty, which makes the proposed hierarchical structure memory efficient and enables fast learning. The RN-HPOMDP has been experimentally validated in real dynamic environments.     

Robot-assisted wayfinding for the visually impaired in structured indoor environments

We present a robot-assisted wayfinding system for the visually impaired in structured indoor environments. The system consists of a mobile robotic guide and small passive RFID sensors embedded in the environment. The system is intended for use in indoor environments, such as office buildings, supermarkets and airports. We describe how the system was deployed in two indoor environments and evaluated by visually impaired participants in a series of pilot experiments. We analyze the system’s successes and failures and outline our plans for future research and development.     

Ontology-assisted automatic precise information extractor for visually impaired inhabitants

As the internet grows rapidly, millions of web pages are being added on a daily basis. The extraction of precise information is becoming more and more difficult as the volume of data on the internet increases. Several search engines and information fetching tools are available on the internet, all of which claim to provide the best crawling facilities. For the most part, these search engines are keyword based. This poses a problem for visually impaired people who want to get the full use from online resources available to other users. Visually impaired users require special aid to get?along with any given computer system. Interface and content management are no exception, and special tools are required to facilitate the extraction of relevant information from the internet for visually impaired users. The HOIEV (Heavyweight Ontology Based Information Extraction for Visually impaired User) architecture provides a mechanism for highly precise information extraction using heavyweight ontology and built-in vocal command system for visually impaired internet users. Our prototype intelligent system not only integrates and communicates among different tools, such as voice command parsers, domain ontology extractors and short message engines, but also introduces an autonomous mechanism of information extraction (IE) using heavyweight ontology. In this research we designed domain specific heavyweight ontology using OWL 2 (Web Ontology Language 2) and for axiom writing we used PAL (Protégé Axiom Language). We introduced a novel autonomous mechanism for IE by developing prototype software. A series of experiments were designed for the testing and analysis of the performance of heavyweight ontology in general, and our information extraction prototype specifically.     

On the accessibility of Moodle 2 by visually impaired users,with a focus on mathematical content

In this paper we study the accessibility by visually impaired people of the learning management system (LMS) Moodle 2. The study is conducted by testing four different visually impaired subjects, with different degrees of disability and performing different tasks connected to different roles in the LMS. A peculiar focus is given to the accessibility of content involving mathematics. At the end of the paper, some recommendations to improve the accessibility of Moodle 2 are given.     

A zero-vision music recording paradigm for visually impaired people

At first glance, making electronic music seems to be a domain which is also well suited for people with limited eye-sight. However, a closer analysis reveals that standard software and hardware are both strongly dominated by graphical output. In order to close this gap for visually impaired musicians, we developed a MIDI (Musical Instrument Digital Interface) sequencer with audio-feedback and a new interaction paradigm which eliminates interaction with the PC??s keyboard and screen. The blind musician relies solely on input via the instrument itself. He can both, record and play music via the claviature??s black & white keys but at the same time control all functions of a multi-track MIDI sequencer without ever taking the hands off the instrument. We also use the MIDI-connection for coding different kinds of feedback to the user in an efficient way. The software which runs on a PC that is connected to an electronic instrument has been evaluated and improved extensively.     

User navigation in computer applications

An abstract model of keyboard navigation that is based on real-world requirements is described. The importance of keyboard navigation is discussed, and the current approaches to keyboard navigation are reviewed. Several requirements for a successful model of keyboard navigation, including that keyboard navigation and direct manipulation must coexist in the same application, are described. Examples of successful use of the proposed approach to keyboard navigation in application development are presented     

Real-time pedestrian crossing lights detection algorithm for the visually impaired

In defect of intelligent assistant approaches, the visually impaired feel hard to cross the roads in urban environments. Aiming to tackle the problem, a real-time Pedestrian Crossing Lights (PCL) detection algorithm for the visually impaired is proposed in this paper. Different from previous works which utilize analytic image processing to detect the PCL in ideal scenarios, the proposed algorithm detects PCL using machine learning scheme in the challenging scenarios, where PCL have arbitrary sizes and locations in acquired image and suffer from the shake and movement of camera. In order to achieve the robustness and efficiency in those scenarios, the detection algorithm is designed to include three procedures: candidate extraction, candidate recognition and temporal-spatial analysis. A public dataset of PCL, which includes manually labeled ground truth data, is established for tuning parameters, training samples and evaluating the performance. The algorithm is implemented on a portable PC with color camera. The experiments carried out in various practical scenarios prove that the precision and recall of detection are both close to 100%, meanwhile the frame rate is up to 21 frames per second (FPS).