Computer interfaces for the visually impaired

Information access via computer terminals extends to blind and low vision persons employed in many technical and nontechnical disciplines. Two aspects are detailed of providing computer technology for persons with a vision related handicap. First, research into the most effective means of integrating existing adaptive technologies into information systems was made. This was conducted to integrate off the shelf products with adaptive equipment for cohesive integrated information processing systems. Details are included that describe the type of functionality required in software to facilitate its incorporation into a speech and/or braille system. The second aspect is research into providing audible and tactile interfaces to graphics based interfaces. Parameters are included for the design and development of the Mercator Project. The project will develop a prototype system for audible access to graphics based interfaces. The system is being built within the public domain architecture of X windows to show that it is possible to provide access to text based applications within a graphical environment. This information will be valuable to suppliers to ADP equipment since new legislation requires manufacturers to provide electronic access to the visually impaired

Tactile and Touchless Sensors Printed on Flexible Textile Substrates for Gesture Recognition

Tesis por compendio[EN] The main objective of this thesis is the development of new sensors and actuators using Printed Electronics technology. For this, conductive, semiconductor and dielectric polymeric materials are used on flexible and/or elastic substrates. By means of suitable designs and application processes, it is possible to manufacture sensors capable of interacting with the environment. In this way, specific sensing functionalities can be incorporated into the substrates, such as textile fabrics. Additionally, it is necessary to include electronic systems capable of processing the data obtained, as well as its registration. In the development of these sensors and actuators, the physical properties of the different materials are precisely combined. For this, multilayer structures are designed where the properties of some materials interact with those of others. The result is a sensor capable of capturing physical variations of the environment, and convert them into signals that can be processed, and finally transformed into data. On the one hand, a tactile sensor printed on textile substrate for 2D gesture recognition was developed. This sensor consists of a matrix composed of small capacitive sensors based on a capacitor type structure. These sensors were designed in such a way that, if a finger or other object with capacitive properties, gets close enough, its behaviour varies, and it can be measured. The small sensors are arranged in this matrix as in a grid. Each sensor has a position that is determined by a row and a column. The capacity of each small sensor is periodically measured in order to assess whether significant variations have been produced. For this, it is necessary to convert the sensor capacity into a value that is subsequently digitally processed. On the other hand, to improve the effectiveness in the use of the developed 2D touch sensors, the way of incorporating an actuator system was studied. Thereby, the user receives feedback that the order or action was recognized. To achieve this, the capacitive sensor grid was complemented with an electroluminescent screen printed as well. The final prototype offers a solution that combines a 2D tactile sensor with an electroluminescent actuator on a printed textile substrate. Next, the development of a 3D gesture sensor was carried out using a combination of sensors also printed on textile substrate. In this type of 3D sensor, a signal is sent generating an electric field on the sensors. This is done using a transmission electrode located very close to them. The generated field is received by the reception sensors and converted to electrical signals. For this, the sensors are based on electrodes that act as receivers. If a person places their hands within the emission area, a disturbance of the electric field lines is created. This is due to the deviation of the lines to ground using the intrinsic conductivity of the human body. This disturbance affects the signals received by the electrodes. Variations captured by all electrodes are processed together and can determine the position and movement of the hand on the sensor surface. Finally, the development of an improved 3D gesture sensor was carried out. As in the previous development, the sensor allows contactless gesture detection, but increasing the detection range. In addition to printed electronic technology, two other textile manufacturing technologies were evaluated.[ES] La presente tesis doctoral tiene como objetivo fundamental el desarrollo de nuevos sensores y actuadores empleando la tecnología electrónica impresa, también conocida como Printed Electronics. Para ello, se emplean materiales poliméricos conductores, semiconductores y dieléctricos sobre sustratos flexibles y/o elásticos. Por medio de diseños y procesos de aplicación adecuados, es posible fabricar sensores capaces de interactuar con el entorno. De este modo, se pueden incorporar a los sustratos, como puedan ser tejidos textiles, funcionalidades específicas de medición del entorno y de respuesta ante cambios de este. Adicionalmente, es necesario incluir sistemas electrónicos, capaces de realizar el procesado de los datos obtenidos, así como de su registro. En el desarrollo de estos sensores y actuadores se combinan las propiedades físicas de los diferentes materiales de forma precisa. Para ello, se diseñan estructuras multicapa donde las propiedades de unos materiales interaccionan con las de los demás. El resultado es un sensor capaz de captar variaciones físicas del entorno, y convertirlas en señales que pueden ser procesadas y transformadas finalmente en datos. Por una parte, se ha desarrollado un sensor táctil impreso sobre sustrato textil para reconocimiento de gestos en 2D. Este sensor se compone de una matriz formada por pequeños sensores capacitivos basados en estructura de tipo condensador. Estos se han diseñado de forma que, si un dedo u otro objeto con propiedades capacitivas se aproxima suficientemente, su comportamiento varía, pudiendo ser medido. Los pequeños sensores están ordenados en dicha matriz como en una cuadrícula. Cada sensor tiene una posición que viene determinada por una fila y por una columna. Periódicamente se mide la capacidad de cada pequeño sensor con el fin de evaluar si ha sufrido variaciones significativas. Para ello es necesario convertir la capacidad del sensor en un valor que posteriormente es procesado digitalmente. Por otro lado, con el fin de mejorar la efectividad en el uso de los sensores táctiles 2D desarrollados, se ha estudiado el modo de incorporar un sistema actuador. De esta forma, el usuario recibe una retroalimentación indicando que la orden o acción ha sido reconocida. Para ello, se ha complementado la matriz de sensores capacitivos con una pantalla electroluminiscente también impresa. El resultado final ofrece una solución que combina un sensor táctil 2D con un actuador electroluminiscente realizado mediante impresión electrónica sobre sustrato textil. Posteriormente, se ha llevado a cabo el desarrollo de un sensor de gestos 3D empleando una combinación de sensores impresos también sobre sustrato textil. En este tipo de sensor 3D, se envía una señal que genera un campo eléctrico sobre los sensores impresos. Esto se lleva a cabo mediante un electrodo de transmisión situado muy cerca de ellos. El campo generado es recibido por los sensores y convertido a señales eléctricas. Para ello, los sensores se basan en electrodos que actúan de receptores. Si una persona coloca su mano dentro del área de emisión, se crea una perturbación de las líneas de los campos eléctricos. Esto es debido a la desviación de las líneas de campo a tierra utilizando la conductividad intrínseca del cuerpo humano. Esta perturbación cambia/afecta a las señales recibidas por los electrodos. Las variaciones captadas por todos los electrodos son procesadas de forma conjunta pudiendo determinar la posición y el movimiento de la mano sobre la superficie del sensor. Finalmente, se ha llevado a cabo el desarrollo de un sensor de gestos 3D mejorado. Al igual que el desarrollo anterior, permite la detección de gestos sin necesidad de contacto, pero incrementando la distancia de alcance. Además de la tecnología de impresión electrónica, se ha evaluado el empleo de otras dos tecnologías de fabricación textil.[CA] La present tesi doctoral té com a objectiu fonamental el desenvolupament de nous sensors i actuadors fent servir la tecnologia de electrònica impresa, també coneguda com Printed Electronics. Es va fer us de materials polimèrics conductors, semiconductors i dielèctrics sobre substrats flexibles i/o elàstics. Per mitjà de dissenys i processos d'aplicació adequats, és possible fabricar sensors capaços d'interactuar amb l'entorn. D'aquesta manera, es poden incorporar als substrats, com ara teixits tèxtils, funcionalitats específiques de mesurament de l'entorn i de resposta davant canvis d'aquest. Addicionalment, és necessari incloure sistemes electrònics, capaços de realitzar el processament de les dades obtingudes, així com del seu registre. En el desenvolupament d'aquests sensors i actuadors es combinen les propietats físiques dels diferents materials de forma precisa. Cal dissenyar estructures multicapa on les propietats d'uns materials interaccionen amb les de la resta. manera El resultat es un sensor capaç de captar variacions físiques de l'entorn, i convertirles en senyals que poden ser processades i convertides en dades. D'una banda, s'ha desenvolupat un sensor tàctil imprès sobre substrat tèxtil per a reconeixement de gestos en 2D. Aquest sensor es compon d'una matriu formada amb petits sensors capacitius basats en una estructura de tipus condensador. Aquests s'han dissenyat de manera que, si un dit o un altre objecte amb propietats capacitives s'aproxima prou, el seu comportament varia, podent ser mesurat. Els petits sensors estan ordenats en aquesta matriu com en una quadrícula. Cada sensor té una posició que ve determinada per una fila i per una columna. Periòdicament es mesura la capacitat de cada petit sensor per tal d'avaluar si ha sofert variacions significatives. Per a això cal convertir la capacitat del sensor a un valor que posteriorment és processat digitalment. D'altra banda, per tal de millorar l'efectivitat en l'ús dels sensors tàctils 2D desenvolupats, s'ha estudiat la manera d'incorporar un sistema actuador. D'aquesta forma, l'usuari rep una retroalimentació indicant que l'ordre o acció ha estat reconeguda. Per a això, s'ha complementat la matriu de sensors capacitius amb una pantalla electroluminescent també impresa. El resultat final ofereix una solució que combina un sensor tàctil 2D amb un actuador electroluminescent realitzat mitjançant impressió electrònica sobre substrat tèxtil. Posteriorment, s'ha dut a terme el desenvolupament d'un sensor de gestos 3D emprant una combinació d'un mínim de sensors impresos també sobre substrat tèxtil. En aquest tipus de sensor 3D, s'envia un senyal que genera un camp elèctric sobre els sensors impresos. Això es porta a terme mitjançant un elèctrode de transmissió situat molt a proper a ells. El camp generat és rebut pels sensors i convertit a senyals elèctrics. Per això, els sensors es basen en elèctrodes que actuen de receptors. Si una persona col·loca la seva mà dins de l'àrea d'emissió, es crea una pertorbació de les línies dels camps elèctrics. Això és a causa de la desviació de les línies de camp a terra utilitzant la conductivitat intrínseca de el cos humà. Aquesta pertorbació afecta als senyals rebudes pels elèctrodes. Les variacions captades per tots els elèctrodes són processades de manera conjunta per determinar la posició i el moviment de la mà sobre la superfície del sensor. Finalment, s'ha dut a terme el desenvolupament d'un sensor de gestos 3D millorat. A l'igual que el desenvolupament anterior, permet la detecció de gestos sense necessitat de contacte, però incrementant la distància d'abast. A més a més de la tecnologia d'impressió electrònica, s'ha avaluat emprar altres dues tecnologies de fabricació tèxtil.Ferri Pascual, J. (2020). Tactile and Touchless Sensors Printed on Flexible Textile Substrates for Gesture Recognition [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/153075TESISCompendi

User Error Handling Strategies on a Non Visual Multimodal Interface: Preliminary Results from an Exploratory Study

The present study addresses two questions: On a non-visual multimodal interface for textual information browsing, (1) how prevalent is input modality switching as an error handling strategy, and (2) how much does an input modality need to fail before input modality switching occurs. The results indicate that although switching input modalities to correct errors is an expected practice on multimodal GUIs, it is not the prevalent strategy for non-visual multimodal interfaces. We believe that users are more likely to diversify their error handling strategies within a modality, if different strategies are possible, but we have not found conclusive evidence for this belief. However, our analysis suggests that the failure to switch modalities when errors occur may, in part, be due to the prevalence of alternative error handling strategies in a particular input modality, that is, the user prefers to stay in the same modality rather than assume the cognitive load of a switch

AudioFunctions.web: Multimodal Exploration of Mathematical Function Graphs

We present AudioFunctions.web, a web app that uses sonifcation, earcons and speech synthesis to enable blind people to explore mathematical function graphs. The system is designed for personalized access through different interfaces (touchscreen, keyboard, touchpad and mouse) on both mobile and traditional devices, in order to better adapt to different user abilities and preferences. It is also publicly available as a web service and can be directly accessed from the teaching material through a hypertext link. An experimental evaluation with 13 visually impaired participants highlights that, while the usability of all the presented interaction modalities is high, users with different abilities prefer different interfaces to interact with the system. It is also shown that users with higher level of mathematical education are capable of better adapting to interaction modalities considered more diffcult by others

Sparkle: Hover Feedback with Touchable Electric Arcs

Many finger sensing input devices now support proximity input, enabling users to perform in-air gestures. While near-surface interactions increase the input vocabulary, they lack tactile feedback, making it hard for users to perform gestures or to know when the interaction takes place. Sparkle stimulates the fingertip with touchable electric arcs above a hover sensing device to give users in-air tactile or thermal feedback, sharper and more feelable than acoustic mid-air haptic devices. We present the design of a high voltage resonant transformer with a low-loss soft ferrite core and self-tuning driver circuit, with which we create electric arcs 6 mm in length, and combine this technology with infrared proximity sensing in two proof-of-concept devices with form factor and functionality similar to a button and a touchpad. We provide design guidelines for Sparkle devices and examples of stimuli in application scenarios, and report the results of a user study on the perceived sensations. Sparkle is the first step towards providing a new type of hover feedback, and it does not require users to wear tactile stimulators

Electrotactile feedback applications for hand and arm interactions: A systematic review, meta-analysis, and future directions

Haptic feedback is critical in a broad range of human-machine/computer-interaction applications. However, the high cost and low portability/wearability of haptic devices remain unresolved issues, severely limiting the adoption of this otherwise promising technology. Electrotactile interfaces have the advantage of being more portable and wearable due to their reduced actuators' size, as well as their lower power consumption and manufacturing cost. The applications of electrotactile feedback have been explored in human-computer interaction and human-machine-interaction for facilitating hand-based interactions in applications such as prosthetics, virtual reality, robotic teleoperation, surface haptics, portable devices, and rehabilitation. This paper presents a technological overview of electrotactile feedback, as well a systematic review and meta-analysis of its applications for hand-based interactions. We discuss the different electrotactile systems according to the type of application. We also discuss over a quantitative congregation of the findings, to offer a high-level overview into the state-of-art and suggest future directions. Electrotactile feedback systems showed increased portability/wearability, and they were successful in rendering and/or augmenting most tactile sensations, eliciting perceptual processes, and improving performance in many scenarios. However, knowledge gaps (e.g., embodiment), technical (e.g., recurrent calibration, electrodes' durability) and methodological (e.g., sample size) drawbacks were detected, which should be addressed in future studies.Comment: 18 pages, 1 table, 8 figures, under review in Transactions on Haptics. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible.Upon acceptance of the article by IEEE, the preprint article will be replaced with the accepted versio

An acoustic multi-touch sensing method using amplitude disturbed ultrasonic wave diffraction patterns

This paper proposes an acoustic multi-touch tactile sensing method. The proposed method is based on an amplitude disturbed ultrasonic wave diffraction pattern. An A0 Lamb wave transmitted in a thin finite copper plate is processed to provide tactile information, for one or two fingers. A touch event is localized by identifying the diffraction signals among a database of diffracted Lamb wave references. Statistic models are used to improve the localization reliability. An artificial silicone finger is used in the calibration procedure. This touch interface is evaluated as a 2-touch interface