Jens Bornschein

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.

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.

Markdown – A Simple Syntax for Transcription of Accessible Study Materials

Transcription of study materials into accessible formats is a challenging but necessary task. The sources of study materials vary from images to multimedia files, which often have to be transcribed manually. A fully accessible target format such as HTML is the goal of every transcription process, supported by guidelines and helpful tools. Therefore the transcribers have to deal not only with the content but also with the right usage of the used tools. We show that the usage of the easy to use Markdown language can improve the technical quality and accessibility of the resulting documents. For further improvements of the transcription process several helping tools are presented to simplify and speed up the process as well.

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.

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.

Comparing Computer-Based Drawing Methods for Blind People with Real-Time Tactile Feedback

In this paper, we present a drawing workstation for blind people using a two-dimensional tactile pin-matrix display for in- and output. Four different input modalities, namely menu-based, gesture-based, freehand-stylus and a Time-of-Flight (ToF) depth segmentation of real-world object silhouettes, are utilized to create graphical shapes. Users can freely manipulate shapes after creation. Twelve blind users evaluated and compared the four image creation modalities. During evaluation, participants had to copy four different images. The results show that all modalities are highly appropriate for non-visual drawing tasks. There is no generally preferred drawing modality, but most participants rated the robust and well-known menu-based interaction as very good. Furthermore, menu was second in performance and the most accurate drawing modality. Our evaluation demonstrated direct manipulation works well for blind users at the position of the reading hand. In general, our drawing tool allows blind users to create appealing images.

TOF Tactile Stamps: Drawing Object Silhouettes through Depth Segmentation by Blind People

We present a workstation utilizing a simple depth segmentation approach to let visually impaired users transform real-world objects into their two-dimensional silhouette shape. Therefore, we use a Kinect TOF system for detection and a novel two-dimensional dynamic tactile pin-matrix display for presenting the captured result. The calibration, segmentation as well as some experimental findings about the used TOF system are explained. Based on the limitations of the TOF system, the segmentation is limited to objects being at least 29mm high. Furthermore, the segmented shapes are less detailed, ragged and sometimes optical deformed. A brief evaluation with three blind users showed that they would accept little such deformations. However, they would like to use such a system for drawing complex objects or share an objects impression with other users in a very fast and enjoyable way.

Digital Drawing Tools for Blind Users: A State-of-the-Art and Requirement Analysis

Blind people normally fulfill drawing tasks with low-tech analog tools in school and everyday life. Such tools are lacking in drawing support and error correction. To overcome these problems, systems for digital graphic access and creation exist. In this paper, an analysis of several software projects for non-visual drawing support is performed. The analysis is used to extract requirements for a digital non-visual drawing system from developers and users. The literature-based findings are extended to a more complete checklist of thirty-five requirements in four categories that cover the principles of the ISO 9241-110 standard. Subsequently, the analyzed projects are tested against the proposed checklist. Finally, six blind people rated the individual importance of each requirement to give a hint which features are most important for user acceptance.

Consistency of a Tactile Pattern Set

Consistency over multiple images is a central requirement in most guidelines for creating tactile graphics. By contrast, tactile consistency over multiple production media for tactile graphics is not very common. In this article, we describe a user-centered approach of developing a tactile fill pattern set to be used for tactile graphics on microcapsule paper, tactile matrix embossers, and dynamic tactile pin-matrix devices. We show the results of our iterative user evaluations with visually impaired and blind-folded sighted participants. Finally, we present a Scalable Vector Graphics pattern set that comprises nine intuitively recognizable and distinctive patterns keeping their meaning and recognizability over the different production media.