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Tactile graphics play an essential role in knowledge transfer for blind people. The tactile exploration of these graphics is often challenging because of the cognitive load caused by physiological constraints and their complexity. The coupling of physical tactile graphics with electronic devices offers to support the tactile exploration by auditory feedback. Often, these systems have strict constraints regarding their mobility or the process of coupling both components. Additionally, visually impaired people cannot appropriately benefit from their residual vision. This article presents a concept for 3D printed tactile graphics, which offers to use audio-tactile graphics with usual smartphones or tablet-computers. By using capacitive markers, the coupling of the tactile graphics with the mobile device is simplified. These tactile graphics integrating these markers can be printed in one turn by off-the-shelf 3D printers without any post-processing and allows us to use multiple elevation levels for graphical elements. Based on the developed generic concept on visually augmented audio-tactile graphics, we presented a case study for maps. A prototypical implementation was tested by a user study with visually impaired people. All the participants were able to interact with the 3D printed tactile maps using a standard tablet computer. To study the effect of visual augmentation of graphical elements, we conducted another comprehensive user study. We tested multiple types of graphics and obtained evidence that visual augmentation may offer clear advantages for the exploration of tactile graphics. Even participants with a minor residual vision could solve the tasks with visual augmentation more quickly and accurately.
3D models are an important means for understanding spatial contexts. Today these models can be materialized by 3D printing, which is increasingly used at schools for people with visual impairments. In contrast to sighted people, people with visual impairments have so far, however, neither been able to search nor to print 3D models without assistance. This article describes our work to develop an aid for people with visual impairments that would facilitate autonomous searching for and printing of 3D models. In our initial study, we determined the requirements to accomplish this task by means of a questionnaire and developed a first approach that allowed personal computer-based 3D printing. An extended approach allowed searching and printing using common smartphones. In our architecture, technical details of 3D printers are abstracted by a separate component that can be accessed via Wi-Fi independently of the actual 3D printer used. It comprises a search of the models in an annotated database and 3D model retrieval from the internet. The whole process can be controlled by voice interaction. The feasibility of autonomous 3D printing for people with visual impairments is shown with a first user study. Our second user study examines the usability of the user interface when searching for 3D models on the internet and preparing them for the materialization. The participants were able to define important printing settings, whereas other printing parameters could be determined algorithmically.
Mobility training is an essential part of blind people’s education in order to move in public spaces. In order to safely learn new routes in public space, however, a seeing trainer must assist the blind person. With the increasing availability of VR hardware, it is possible to transfer real spatial environments to virtual representations. The digitized environments can be used as a basis for this training without safety problems by real world hazards. This allows to cope with the limited resources of sighted assistants and enables blind people to become more independent. We propose to capture real public spaces (such as sidewalks, train stations etc.) and make them in this way ascertainable. Orientation and mobility can be trained in this digital model via multimodal sensory feedback while involving intuitive locomotion and white cane exploration. This paper sketches the related work and proposes our novel approach. Furthermore, we suggest additional improvements on our ongoing research.
With Tangible User Interfaces, the computer user is able to interact in a fundamentally different and more intuitive way than with usual 2D displays. By grasping real physical objects, information can also be conveyed haptically, i.e., the user not only sees information on a 2D display, but can also grasp physical representations. To recognize such objects (“tangibles”) it is skillful to use capacitive sensing, as it happens in most touch screens. Thus, real objects can be located and identified by the touch screen display automatically. Recent work already addressed such capacitive markers, but focused on their coding scheme and automated fabrication by 3D printing. This paper goes beyond the fabrication by 3D printers and, for the first time, applies the concept of capacitive codes to laser cutting and another immediate prototyping approach using modeling clay. Beside the evaluation of additional properties, we adapt recent research results regarding the optimized detection of tangible objects on capacitive screens. As a result of our comprehensive study, the detection performance is affected by the type of capacitive signal processing (respectively the device) and the geometry of the marker. 3D printing revealed to be the most reliable technique, though laser cutting and immediate prototyping of markers showed promising results. Based on our findings, we discuss individual strengths of each capacitive marker type.
The interest in virtual and augmented reality increased rapidly in the last years. Recently, haptic interaction and its applications get into focus. In this paper, we suggest the exploration of virtual objects using off-the-shelf VR game controllers. These are held like a pen with both hands and were used to palpate and identify the virtual object. Our study largely coincides with comparable previous work and shows that a ready-to-use VR system can be basically used for haptic exploration. The results indicate that virtual objects are more effectively recognized with closed eyes than with open eyes. In both cases, objects with a bigger morphological difference were identified the most frequently. The limitations due to quality and quantity of tactile feedback should be tackled in future studies that utilize currently developed wearable haptic devices and haptic rendering involving all fingers or even both hands. Thus, objects could be identifiable more intuitively and haptic feedback devices for interacting with virtual objects will be further disseminated.