Denise Prescher

A tactile windowing system for blind users

Todays window systems present the information in a graphical and thereby a spatial manner making the text-only access of a standard Braille device insufficient to enable blind users an equivalent exploration of the data. In this paper we present the planar Braille Window System (BWS) designed for a tactile display consisting of a pin-matrix of 120 columns and 60 rows. The system is composed of six separate regions enabling the user to receive different types of information simultaneously. The content of the main region containing Braille windows can be shown in various manners (text-or graphics-based) through four different views. The interaction within our Braille Window System is implemented not only by keyboard shortcuts but also by the use of multitouch gestures. Therefore the user is able to interact directly on the touch-sensitive display. A study conducted with eight blind users has confirmed the concept of Braille windows, regions and views. Especially the gestural input for exploring details of the content offers new possibilities in interacting within a GUI.

Collaborative Creation of Digital Tactile Graphics

The Tangram Workstation is a collaborative system for creating tactile graphics. A transcriber composing a tactile graphic from a visual source is supported by a non-visual reviewer on a two-dimensional tactile pin-matrix device on which he can observe and adapt the work of his sighted team member. We present the results of an evaluation with eight teams, each consisting of a transcriber and a blind reviewer. Overall, quality of tactile graphics can be improved by a collaborative approach. In most cases blind users recommended changes on tactile graphics even when they have been prepared by professional sighted editors. The study also showed that the blind reviewer is able to do simple editing tasks independently with our workstation.

Exploration and avoidance of surrounding obstacles for the visually impaired

Proximity-based interaction through a long cane is essential for the blind and the visually impaired. We designed and implemented an obstacle detector consisting of a 3D Time-of-Flight (TOF) camera and a planar tactile display to extend the interaction range and provide rich non-visual information about the environment. Users choose a better path after acquiring the spatial layout of obstacles than with a white cane alone. A user study with 6 blind people was analyzed and showed extra time is needed to ensure safe walking while reading the layout. Both hanging and ground-based obstacles were circumvented. Tactile mapping information has been designed for representation of precise spatial information around a blind user.

Production of Accessible Tactile Graphics

To allow blind and visually impaired users participation in learning visualized concepts and ideas it is important to provide them not only with text but also with graphics. As the effort and expertise needed for manually transcribing graphics is time-consuming we need a better understanding of the decision-making process leading to the support of alternative descriptions and materials for tactile exploration. We performed two surveys, the first one on current practices used for the production of accessible graphics in Germany, the second one on user experiences in exploring and constructing tactile graphics. As result we have defined some requirements for enhancing the production of accessible tactile graphics by a software tool that not only supports the creation of image masters and descriptions, but also includes blind users in the editing process.

Translating floor plans into directions

Project Mobility supports blind and low-vision people in exploring and wayfinding indoors. Facility operators are enabled to annotate floor plans to provide accessible content. An accessible smartphone app is developed for presenting spatial information and directions on the go, regarding the users position. This paper describes some of the main goals and features of the system and the results of first user tests we conducted at a large airport.

Inclusive Production of Tactile Graphics

In this article a collaborative workstation for creating audio-tactile graphics is presented. The system is based on a common open source office suite and supports a transcriber for tactile graphics with several tools. In addition the system allows a blind reviewer to get involved at every stage of the creation process. This is achieved through a refreshable two-dimensional tactile display. The blind participant can independently manipulate graphical objects and make annotations in parallel. As a result, a tandem team of a sighted graphic creator and a blind partner may create a tactile graphic with better quality.

SVGPlott – Generating Adaptive and Accessible Audio-Tactile Function Graphs

Curve sketching is a hard task for blind and visually impaired pupils and students, but it is an essential part in education. To help those students as well as their colleges, teachers and other people to prepare good tactile function plots the platform independent console program SVGPlott was developed. It enables users without any special knowledge about creating graphics for blind or visually impaired people to prepare highly adaptable mathematical function plots in the SVG format, which can also be used for audio-tactile exploration. SVGPlott was developed in a user-centered design process, including teachers and users. We show that blind and sighted users can prepare function plots including key as well as an automatically generated textual description not only for tactile, audio-tactile and print output, but also for usage on a dynamic tactile pin device and as a high contrast visualization for low vision people.

Improving screen magnification using the HyperBraille multiview windowing technique

Screen magnification is an important means to support visually impaired people when working with computers. Many improvements have been made on appropriate software. But unfortunately, in the last years, those improvements where mainly in realization detail. A number of problems remain, that, to our minds, need conceptual rethinking. In this paper, we present a new concept for magnification software. It uses different views to support the user efficiently in different situations. Thereby, it reveals the possibility to build upon current magnification methods and so retain features of current magnification software. The described views are derived from a concept that was originally developed for a tactile graphics display. We found that both topics, rendering for a tactile graphics display and screen magnification, have very much in common. Initial user feedback confirms the usefulness of the concept.

Touching graphical applications: bimanual tactile interaction on the HyperBraille pin-matrix display

Novel two-dimensional tactile displays enable blind users to not only get access to the textual but also to the graphical content of a graphical user interface. Due to the higher amount of information that can be presented in parallel, orientation and exploration can be more complex. In this paper we present the HyperBraille system, which consists of a pin-matrix device as well as a graphical screen reader providing the user with appropriate presentation and interaction possibilities. To allow for a detailed analysis of bimanual interaction strategies on a pin-matrix device, we conducted two user studies with a total of 12 blind people. The task was to fill in .pdf forms on the pin-matrix device by using different input methods, namely gestures, built-in hardware buttons as well as a conventional PC keyboard. The forms were presented in a semigraphic view type that not only contains Braille but also tactile widgets in a spatial arrangement. While completion time and error rate partly depended on the chosen input method, the usage of special reading strategies seemed to be independent of it. A direct comparison of the system and a conventional assistive technology (screen reader with single-line Braille device) showed that interaction on the pin-matrix device can be very efficient if the user is trained. The two-dimensional output can improve access to .pdf forms with insufficient accessibility as the mapping of input controls and the corresponding labels can be supported by a spatial presentation.

Locating Widgets in Different Tactile Information Visualizations

Large tactile displays demand for novel presentation and interaction strategies. In this paper, different tactile view types and orientation tools are evaluated with 13 blind users. The study has shown that the different view types are usable for different tasks. Orientation can be kept best in view types with Braille output but these are often not sufficient for graphical tasks. The usage of planar orientation tools, such as structure region or minimap, need to be trained to allow for an efficient support of two-dimensional tactual exploration.