Wearable obstacle avoidance electronic travel aids for blind and visually impaired individuals : a systematic review

Background Wearable obstacle avoidance electronic travel aids (ETAs) have been developed to assist the safe displacement of blind and visually impaired individuals (BVIs) in indoor/outdoor spaces. This systematic review aimed to understand the strengths and weaknesses of existing ETAs in terms of hardware functionality, cost, and user experience. These elements may influence the usability of the ETAs and are valuable in guiding the development of superior ETAs in the future. Methods Formally published studies designing and developing the wearable obstacle avoidance ETAs were searched for from six databases from their inception to April 2023. The PRISMA 2020 and APISSER guidelines were followed. Results Eighty-nine studies were included for analysis, 41 of which were judged to be of moderate to high quality. Most wearable obstacle avoidance ETAs mainly depend on camera- and ultrasonic-based techniques to achieve perception of the environment. Acoustic feedback was the most common human-computer feedback form used by the ETAs. According to user experience, the efficacy and safety of the device was usually their primary concern. Conclusions Although many conceptualised ETAs have been designed to facilitate BVIs' independent navigation, most of these devices suffer from shortcomings. This is due to the nature and limitations of the various processors, environment detection techniques and human-computer feedback those ETAs are equipped with. Integrating multiple techniques and hardware into one ETA is a way to improve performance, but there is still a need to address the discomfort of wearing the device and the high-cost. Developing an applicable systematic review guideline along with a credible quality assessment tool for these types of studies is also required. © 2013 IEEE

Aplicación dos produtos de apoio de alta tecnoloxía no desempeño ocupacional das persoas con discapacidade visual: scoping review

[Resumo] Introdución: As persoas con discapacidade visual poden experimentar dificultades na realización de diferentes ocupacións cotiás. A tecnoloxía de apoio (TA) debe actuar coma un facilitador na participación desta poboación en actividades desexadas. Obxectivo: Coñecer se os produtos de apoio de alta tecnoloxía dan resposta ás dificultades no desempeño ocupacional coas que se atopan máis frecuentemente as persoas con discapacidade visual no seu día a día. Metodoloxía: Seguiuse unha metodoloxía de revisión de alcance. A busca bibliográfica foi levada a cabo nas bases de datos CINAHL, PubMed, Scopus e Web of Science. As variables temáticas establecéronse seguindo os compoñentes propostos polo Modelo da Actividade Humana e da Tecnoloxía de Apoio. Para a súa análise empregouse un enfoque mixto. Resultados: Na mostra incluíronse un total de 44 estudos. En moitos casos, non se especificou certa información relativa ás persoas participantes. A TA analizada centrouse principalmente na detección e na evitación de obstáculos, facilitando a mobilidade funcional. Os dispositivos reciben a información mediante sistemas de cámaras para transmitirlla á persoa por son. A TA está deseñada para contextos tanto interiores coma exteriores da vida diaria, e foi testada maiormente en ambientes reais. Conclusión: Os produtos de apoio de alta tecnoloxía están dirixidos principalmente a facilitar a mobilidade funcional, a participación social, e a lectura das persoas con discapacidade visual. En menor medida, abordaron a educación, o deporte e as tarefas do fogar. Así, non se centraron noutras actividades relevantes como a condución ou o emprego.[Resumen] Introducción: Las personas con discapacidad visual pueden experimentan dificultades en la realización de diferentes ocupaciones cotidianas. La tecnología de apoyo (TA) debe actuar como un facilitador en la participación de esta población en actividades deseadas. Objetivo: Conocer si los productos de apoyo de alta tecnología dan respuesta a las dificultades en el desempeño ocupacional con las que se encuentran más frecuentemente las personas con discapacidad visual en su día a día. Metodología: Se siguió una metodología de revisión de alcance. La búsqueda bibliográfica se llevó a cabo en las bases de datos CINAHL, PubMed, Scopus y Web of Science. Las variables temáticas se establecieron siguiendo los componentes propuestos por el Modelo de la Actividad Humana y la Tecnología de Apoyo. Para su análisis se empleó un enfoque mixto. Resultados: En la muestra se incluyeron un total de 44 estudios. En muchos casos, no se especificó cierta información relativa a las personas participantes. La TA analizada se centró principalmente en la detección y evitación de obstáculos, facilitando la movilidad funcional. Los dispositivos reciben la información mediante sistemas de cámaras para transmitírsela a la persona por audio. La TA está diseñada para contextos tanto interiores como exteriores de la vida diaria, y fue testada mayormente en ambientes reales. Conclusión: Los productos de apoyo de alta tecnología están dirigidos principalmente a facilitar la movilidad funcional, la participación social, y la lectura de las personas con discapacidad visual. En menor medida, abordaron la educación, el deporte, o las tareas del hogar. Así, no se centraron en otras actividades relevantes como la conducción o el empleo.[Abstract] Background: People with visual impairment can have difficulties in performing different daily occupations. Assistive technology (AT) should be an enabler in the participation of these population’s desired activities. Aim: To know if high-tech assistive devices respond to difficulties in the occupational performance that people with visual impairment most frequently experiment in their day-to-day lives. Methodology: A methodology of Scoping Review was used. The bibliographic search was carried out in the databases CINAHL, PubMed, Scopus y Web of Science. Thematic variables were established following the components proposed by the Human Activity Assistive Technology Model. For their analyses, a mixed methods approach was used. Results: A total of 44 studies were included in the sample. In many cases, certain information regarding the participants was not specified. The analyzed AT focused mainly on the detection and avoidance of obstacles, facilitating functional mobility. The devices receive the information through camera systems to transmit it to the person by audio. The AT is designed for indoor and outdoor contexts of everyday life, and it was mostly tested in real-world environments. Conclusion: The high-tech assistive devices are primarily aimed at facilitating the functional mobility, social participation, and reading of people with visual impairment. To a lesser extent, they addressed education, sports, or housework. However, they did not focus on other relevant activities such as driving or working.Traballo fin de mestrado (UDC.FCS). Asistencia e investigación sanitaria. Especialidade en Reeducación Funcional, Autonomía Persoal e Calidade de Vida. Curso 2020-202

Tools in and out of sight : an analysis informed by Cultural-Historical Activity Theory of audio-haptic activities involving people with visual impairments supported by technology

The main purpose of this thesis is to present a Cultural-Historical Activity Theory (CHAT) based analysis of the activities conducted by and with visually impaired users supported by audio-haptic technology.This thesis covers several studies conducted in two projects. The studies evaluate the use of audio-haptic technologies to support and/or mediate the activities of people with visual impairment. The focus is on the activities involving access to two-dimensional information, such as pictures or maps. People with visual impairments can use commercially available solutions to explore static information (raised lined maps and pictures, for example). Solu-tions for dynamic access, such as drawing a picture or using a map while moving around, are more scarce. Two distinct projects were initiated to remedy the scarcity of dynamic access solutions, specifically focusing on two separate activities.The first project, HaptiMap, focused on pedestrian outdoors navigation through audio feedback and gestures mediated by a GPS equipped mobile phone. The second project, HIPP, focused on drawing and learning about 2D representations in a school setting with the help of haptic and audio feedback. In both cases, visual feedback was also present in the technology, enabling people with vision to take advantage of that modality too.The research questions addressed are: How can audio and haptic interaction mediate activ-ities for people with visual impairment? Are there features of the programming that help or hinder this mediation? How can CHAT, and specifically the Activity Checklist, be used to shape the design process, when designing audio haptic technology together with persons with visual impairments?Results show the usefulness of the Activity Checklist as a tool in the design process, and provide practical application examples. A general conclusion emphasises the importance of modularity, standards, and libre software in rehabilitation technology to support the development of the activities over time and to let the code evolve with them, as a lifelong iterative development process. The research also provides specific design recommendations for the design of the type of audio haptic systems involved

Digital Navigational Aids for the Visually Impaired A Designer’s Guide for Implementing Effective Feedback Solutions

Mobility and navigation in outdoor environments constitute a formidable daily challenge for the blind and visually impaired community. Difficulty in outdoor mobility limits participation in social activities and employment opportunities which in turn contributes to isolation and a decreased sense of mental well-being. To address these challenges, digital navigational aids (NAVIs) extend the capabilities of traditional mobility aids such as guide dogs and the white cane. However, adoption of these new technologies within the blind and visually impaired community has been low. This low adoption rate suggests that a gap exists between current solutions and user needs and goals. As intermediaries between solutions and the users they serve, designers are ideally situated to bridge this gap. Thus, this research aims to provide designers new to the problem space with an understanding of the considerations that inform NAVI design. To build a rudimentary understanding of these considerations, a literature review of individual NAVI research projects and comparative reviews of NAVIs was con-ducted. The interaction design requirements framework proposed by Sharp et al. (2019) was then used as an organizational tool for further defining these considerations. Requirements categories including user experience goals, usability goals, functional requirements, environmental requirements and data requirements were applied as themes in a thematic analysis of data obtained through interviews with NAVI designers and other designers of feedback systems in an effort to identify challenges, designer approaches and areas where improvements could be made to current NAVI design solutions. Findings from expert interviews suggest that developments emerging from the rap-idly evolving technological environment can be leveraged by designers for creating more user friendly and accessible solutions. For example, user familiarity with smartphone interfaces can reduce the learning curve required when adapting to a new smartphone-based NAVI thus increasing the chances of adoption into daily use. Data obtained in interviews also examines the methods by which designers improve usability, including users not only in their iterative processes but through-out the entire life cycle of a NAVI solution. Finally, expert interviews reveal new prototyping tools for designing feedback systems with wearables which streamline the prototyping process and lower the barrier of entry for designers without prior expertise in coding or electronics

Intelligent computational techniques and virtual environment for understanding cerebral visual impairment patients

Cerebral Visual Impairment (CVI) is a medical area that concerns the study of the effect of brain damages on the visual field (VF). People with CVI are not able to construct a perfect 3-Dimensional view of what they see through their eyes in their brain. Therefore, they have difficulties in their mobility and behaviours that others find hard to understand due to their visual impairment. A branch of Artificial Intelligence (AI) is the simulation of behaviour by building computational models that help to explain how people solve problems or why they behave in a certain way. This project describes a novel intelligent system that simulates the navigation problems faced by people with CVI. This will help relatives, friends, and ophthalmologists of CVI patients understand more about their difficulties in navigating their everyday environment. The navigation simulation system is implemented using the Unity3D game engine. Virtual scenes of different living environments are also created using the Unity modelling software. The vision of the avatar in the virtual environment is implemented using a camera provided by the 3D game engine. Given a visual field chart of a CVI patient with visual impairment, the system automatically creates a filter (mask) that mimics a visual defect and places it in front of the visual field of the avatar. The filters are created by extracting, classifying and converting the symbols of the defected areas in the visual field chart to numerical values and then converted to textures to mask the vision. Each numeric value represents a level of transparency and opacity according to the severity of the visual defect in that region. The filters represent the vision masks. Unity3D supports physical properties to facilitate the representation of the VF defects into a form of structures of rays. The length of each ray depends on the VF defect s numeric value. Such that, the greater values (means a greater percentage of opacity) represented by short rays in length. While the smaller values (means a greater percentage of transparency) represented by longer rays. The lengths of all rays are representing the vision map (how far the patient can see). Algorithms for navigation based on the generated rays have been developed to enable the avatar to move around in given virtual environments. The avatar depends on the generated vision map and will exhibit different behaviours to simulate the navigation problem of real patients. The avatar s behaviour of navigation differs from patient to another according to their different defects. An experiment of navigating virtual environments (scenes) using the HTC Oculus Vive Headset was conducted using different scenarios. The scenarios are designed to use different VF defects within different scenes. The experiment simulates the patient s navigation in virtual environments with static objects (rooms) and in virtual environments with moving objects. The behaviours of the experiment participants actions (avoid/bump) match the avatar s using the same scenario. This project has created a system that enables the CVI patient s parents and relatives to aid the understanding what the CVI patient encounter. Besides, it aids the specialists and educators to take into account all the difficulties that the patients experience. Then, is to design and develop appropriate educational programs that can help each individual patient

Dynamic Haptic Feedback in Comparing Spatial Information

Simple haptic feedback has been used in mobile phones and other hand-held devices. In addition to auditory and visual feedback, haptic feedback would enhance the possibility of multi-modality and cross-modality.In this study, a concept of dynamic haptic feedback is presented and predetermined spatial data was used to conduct an experiment. The goal of the experiment was to find out the most effective haptic feedback method on the palm where the experimented methods were pattern-based and frequency-based haptic feedback. The results showed that pattern-based response accuracy rate was 93% while frequency-based response accuracy rate was 78%. Recognition rates of different frequencies were substantially different while recognition rates of different patterns were closely similar. The result of the study can be further used in development of a new hand-held device which could display more accurate and precise haptic data, and would make haptic feedback through a hand-held mobile device more realistic. Asiasanat: haptic, tactile, spatial data, haptics, pattern, frequenc

Precise positioning in real-time using GPS-RTK signal for visually impaired people navigation system

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 24/9/2010.This thesis presents the research carried out to investigate and achieve highly reliable and accurate navigation system of guidance for visually impaired pedestrians. The main aim with this PhD project has been to identify the limits and insufficiencies in utilising Network Real-Time Kinematic Global Navigation Satellite Systems (NRTK GNSS) and its augmentation techniques within the frame of pedestrian applications in a variety of environments and circumstances. Moreover, the system can be used in many other applications, including unmanned vehicles, military applications, police, etc. NRTK GNSS positioning is considered to be a superior solution in comparison to the conventional standalone Global Positioning System (GPS) technique whose accuracy is highly affected by the distance dependent errors such as satellite orbital and atmospheric biases. Nevertheless, NRTK GNSS positioning is particularly constrained by wireless data link coverage, delays of correction and transmission and completeness, GPS and GLONASS signal availability, etc., which could downgrade the positioning quality of the NRTK results. This research is based on the dual frequency NRTK GNSS (GPS and GLONASS). Additionally, it is incorporated into several positioning and communication methods responsible for data correction while providing the position solutions, in which all identified contextual factors and application requirements are accounted. The positioning model operates through client-server based architecture consisted of a Navigation Service Centre (NSC) and a Mobile Navigation Unit (MNU). Hybrid functional approaches were consisting of several processing procedures allowing the positioning model to operate in position determination modes. NRTK GNSS and augmentation service is used if enough navigation information was available at the MNU using its local positioning device (GPS/GLONASS receiver).The positioning model at MNU was experimentally evaluated and centimetric accuracy was generally attained during both static and kinematic tests in various environments (urban, suburban and rural). This high accuracy was merely affected by some level of unavailability mainly caused by GPS and GLONASS signal blockage. Additionally, the influence of the number of satellites in view, dilution of precision (DOP) and age corrections (AoC) over the accuracy and stability of the NRTK GNSS solution was also investigated during this research and presented in the thesis. This positioning performance has outperformed the existing GPS service. In addition, utilising a simulation evaluation facility the positioning model at MNU performance was quantified with reference to a hybrid positioning service that will be offered by future Galileo Open Service (OS) along with GPS. However, a significant difference in terms of the service availability for the advantage of the hybrid system was experienced in all remaining scenarios and environments more especially the urban areas due to surrounding obstacles and conditions. As an outcome of this research a new and precise positioning model was proposed. The adaptive framework is understood as approaching an integration of the available positioning technology into the context of surrounding wireless communication for a maintainable performance. The positioning model has the capability of delivering indeed accurate, precise and consistent position solutions, and thus is fulfilling the requirements of visually impaired people navigation application, as identified in the adaptive framework

Accessibility of Health Data Representations for Older Adults: Challenges and Opportunities for Design

Health data of consumer off-the-shelf wearable devices is often conveyed to users through visual data representations and analyses. However, this is not always accessible to people with disabilities or older people due to low vision, cognitive impairments or literacy issues. Due to trade-offs between aesthetics predominance or information overload, real-time user feedback may not be conveyed easily from sensor devices through visual cues like graphs and texts. These difficulties may hinder critical data understanding. Additional auditory and tactile feedback can also provide immediate and accessible cues from these wearable devices, but it is necessary to understand existing data representation limitations initially. To avoid higher cognitive and visual overload, auditory and haptic cues can be designed to complement, replace or reinforce visual cues. In this paper, we outline the challenges in existing data representation and the necessary evidence to enhance the accessibility of health information from personal sensing devices used to monitor health parameters such as blood pressure, sleep, activity, heart rate and more. By creating innovative and inclusive user feedback, users will likely want to engage and interact with new devices and their own data

A Formal Approach to Computer Aided 2D Graphical Design for Blind People

The growth of computer aided drawing systems for blind people (CADB) has long been recognised and has increased in interest within the assistive technology research area. The representation of pictorial data by blind and visually impaired (BVI) people has recently gathered momentum with research and development; however, a survey of published literature on CADB reveals that only marginal research has been focused on the use of a formal approach for on screen spatial orientation, creation and reuse of graphics artefacts. To realise the full potential of CADB, such systems should possess attributes of usability, spatial navigation and shape creation features without which blind users drawing activities are less likely to be achieved. As a result of this, usable, effective and self-reliant CADB have arisen from new assistive Technology (AT) research. This thesis contributes a novel, abstract, formal approach that facilitates BVI users to navigate on the screen, create computer graphics/diagrams using 2D shapes and user-defined images. Moreover, the research addresses the specific issues involved with user language by formulating specific rules that make BVI user interaction with the drawing effective and easier. The formal approach proposed here is descriptive and it is specified at a level of abstraction above the concrete level of system technologies. The proposed approach is unique in problem modelling and syntheses of an abstract computer-based graphics/drawings using a formal set of user interaction commands. This technology has been applied to enable blind users to independently construct drawings to satisfy their specific needs without recourse to a specific technology and without the intervention of support workers. The specification aims to be the foundation for a system scope, investigation guidelines and user-initiated command-driven interaction. Such an approach will allow system designers and developers to proceed with greater conceptual clarity than it is possible with current technologies that is built on concrete system-driven prototypes. In addition to the scope of the research the proposed model has been verified by various types of blind users who have independently constructed drawings to satisfy their specific needs without the intervention of support workers. The effectiveness and usability of the proposed approach has been compared against conventional non-command driven drawing systems by different types of blind users. The results confirm that the abstract formal approach proposed here using command-driven means in the context of CADB enables greater comprehension by BVI users. The innovation can be used for both educational and training purposes. The research, thereby sustaining the claim that the abstract formal approach taken allows for the greater comprehension of the command-driven means in the context of CADB, and how the specification aid the design of such a system

MOBILE ASSISTIVE TECHNOLOGIES FOR PEOPLE WITH VISUAL IMPAIRMENT: SENSING AND CONVEYING INFORMATION TO SUPPORT ORIENTATION, MOBILITY AND ACCESS TO IMAGES

Smartphones are accessible to persons with visual impairment or blindness (VIB): screen reader technologies, integrated with mobile operating systems, enable non-visual interaction with the device. Also, features like GPS receivers, inertial sensors and cameras enable the development of Mobile Assistive Technologies (MATs) to support people with VIB. A preliminary analysis, conducted adopting an user-centric approach, highlighted some issues experienced by people with VIB in everyday activities from three main fields: orientation, mobility and access to images. Traditional approaches to address these issues, based on assistive tools and technologies, have some limitations: in the field of mobility, for example, existing navigation support solutions (e.g. the white cane) cannot be used to perceive some environmental features like crosswalks or the current state of traffic lights; in the field of orientation, tactile maps adopted to develop cognitive maps of the environment are limited in the amount of information that can be represented on a single surface and by the lack of interactivity, two issues experienced also in other fields where access to graphical information is of paramount importance like, for example, didactics of STEM subjects. This work presents new MATs that deal with these limitations by introducing novel solutions in different fields of Computer Science. Original computer vision techniques, designed to detect the presence of pedestrian crossings and the state of traffic lights, are used to sense information from the environment and support mobility of people with VIB. Novel sonification techniques are introduced to efficiently convey information with three different goals: first, to convey guidance information in urban crossings; second, to enhance the development of cognitive maps by augmenting tactile surfaces; third, to enable quick access to images. Experience reported in this dissertation shows that the proposed MATs are effective in supporting people with VIB and, in general, that mobile devices are a versatile platform to enable affordable and pervasive access to assistive technologies. Involving target users in the evaluation of MATs emerged as a major challenge in this work. However, it is shown how such challenge can be addressed by adopting large scale evaluation techniques typical of HCI research