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.

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.

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.

Today's 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.