@article{Goetzelmann2018, author = {G{\"o}tzelmann, Timo}, title = {Visually Augmented Audio-Tactile Graphics for Visually Impaired People}, series = {ACM Transactions on Accessible Computing (TACCESS)}, volume = {2018}, journal = {ACM Transactions on Accessible Computing (TACCESS)}, number = {Volume 11, Issue 2, Article No. 8}, publisher = {ACM}, doi = {10.1145/3186894}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:92-opus4-5571}, pages = {31}, year = {2018}, abstract = {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.}, language = {en} } @inproceedings{GoetzelmannSchneider2016, author = {G{\"o}tzelmann, Timo and Schneider, Daniel}, title = {CapCodes: Capacitive 3D Printable Identification and On-screen Tracking for Tangible Interaction}, series = {NordiCHI '16: Proceedings of the 9th Nordic Conference on Human-Computer Interaction}, volume = {2016}, booktitle = {NordiCHI '16: Proceedings of the 9th Nordic Conference on Human-Computer Interaction}, publisher = {ACM}, address = {New York, NY, USA}, isbn = {978-1-4503-4763-1}, doi = {10.1145/2971485.2971518}, pages = {4}, year = {2016}, abstract = {Electronic markers can be used to link physical representations and virtual content for tangible interaction, such as visual markers commonly used for tabletops. Another possibility is to leverage capacitive touch inputs of smartphones, tablets and notebooks. However, existing approaches either do not couple physical and virtual representations or require significant post-processing. This paper presents and evaluates a novel approach using a coding scheme for the automatic identification of tangibles by touch inputs when they are touched and shifted. The codes can be generated automatically and integrated into a great variety of existing 3D models from the internet. The resulting models can then be printed completely in one cycle by off-the-shelf 3D printers; post processing is not needed. Besides the identification, the object's position and orientation can be tracked by touch devices. Our evaluation examined multiple variables and showed that the CapCodes can be integrated into existing 3D models and the approach could also be applied to untouched use for larger tangibles.}, language = {en} } @inproceedings{GoetzelmannPavkovic2014, author = {G{\"o}tzelmann, Timo and Pavkovic, Aleksander}, title = {Towards Automatically Generated Tactile Detail Maps by 3D Printers for Blind Persons}, series = {Computers Helping People with Special Needs}, booktitle = {Computers Helping People with Special Needs}, publisher = {Springer}, isbn = {978-3-319-08599-9}, doi = {10.1007/978-3-319-08599-9_1}, pages = {1-7}, year = {2014}, abstract = {This paper introduces an approach for the (semi)automatic generation of worldwide available, detailed tactile maps including buildings and blind-specific features based on recognized illustrators' guidelines and standards. These guidelines for tactile maps are investigated in order to define a formal rule set and to automatically filter map data accordingly. Using the rule set, our approach automatically abstracts map data in order to generate a 2.1D tactile model providing multiple height levels (layers) which can be printed by usual consumer 3D printers. Based on the popular OpenStreetMap map data, our automated approach allows to generate arbitrary detail maps blind persons individually interested in, without the need for manual adaption of the tactile map. Thus, this approach contributes to the goal to increase the autonomy of blind persons.}, subject = {3D-Drucker}, language = {en} } @inproceedings{SchaeffPuglieseGoetzelmann2014, author = {Sch{\"a}ff, Christian and Pugliese, Gaston and G{\"o}tzelmann, Timo}, title = {Behavior Based Web User Identification}, publisher = {K{\"o}llenDruck+Verlag}, address = {Bonn}, isbn = {978-3-88579-447-9}, issn = {1614-3213}, pages = {201 - 204}, year = {2014}, abstract = {This paper examines different approaches for the identification of users by their personal behavior and discusses techniques which could be used in the context of websites. Such web tracking approaches have the potential to identify users even if they use multiple or shared devices. For web pages mouse and touch input are widely used. Therefore, we propose a survey to evaluate the feasibility to identify users by their interaction behavior.}, subject = {Authentifikation}, language = {en} } @inproceedings{GoetzelmannEichler2015, author = {G{\"o}tzelmann, Timo and Eichler, Laura}, title = {BlindWeb Maps - An Interactive Web Service for the Selection and Generation of Personalized Audio-Tactile Maps}, series = {Proc. 15th International Conference on Computers Helping People with Special Needs}, volume = {2015}, booktitle = {Proc. 15th International Conference on Computers Helping People with Special Needs}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-41266-5}, pages = {139 -- 145}, year = {2015}, abstract = {Tactile maps may contribute to the orientation of blind people or alternatively be used for navigation. In the past, the generation of these maps was a manual task which considerably limited their availability. Nowadays, similar to visual maps, tactile maps can also be generated semi-automatically by tools and web services. The existing approaches enable users to generate maps by entering a specific address or point of interest. This can in principle be done by a blind user. However, these approaches actually show an image of the map on the users display which cannot be read by screen readers. Consequently, the blind user does not know what is on the map before it is printed. Ideally, the map selection process should give the user more information and freedom to select the desired excerpt. This paper introduces a novel web service for blind people to interactively select and automatically generate tactile maps. It adapts the interaction concept for map selection to the requirements of blind users whilst supporting multiple printing technologies. The integrated audio review of the map's contents allows earlier feedback to review if the currently selected map extract corresponds to the desired information need. Changes can be initiated before the map is printed which, especially for 3D printing, saves much time. The user is able to select map features to be included in the tactile map. Furthermore, the map rendering can be adapted to different zoom levels and supports multiple printing technologies. Finally, an evaluation with blind users was used to refine our approach.}, language = {en} } @inproceedings{GoetzelmannAlthaus2016, author = {G{\"o}tzelmann, Timo and Althaus, Christopher}, title = {TouchSurfaceModels: Capacitive Sensing Objects through 3D Printers}, series = {PETRA '16: Proceedings of the 9th ACM International Conference on PErvasive Technologies Related to Assistive Environments}, volume = {2016}, booktitle = {PETRA '16: Proceedings of the 9th ACM International Conference on PErvasive Technologies Related to Assistive Environments}, publisher = {ACM}, address = {New York, NY, USA}, isbn = {978-1-4503-4337-4}, pages = {8}, year = {2016}, abstract = {Nowadays, 3D models can be downloaded from the internet and increasingly be printed by low cost 3D printers. In the future, blind people could benefit from this tendency. Unfortunately, many of these models are rather complex and not appropriate for the purely tactile exploration. To obtain quantitative data about how 3D printable models for blind people should be constructed, the tactile exploration can be recorded by video. However, the analysis of these videos is quite time consuming and expensive. Additionally, inaccuracies and masking effects may impede the use of this technique. In this paper we introduce a novel approach to automatically equip existing 3D models with a mesh of conductive wires which enable a touch sensitive surface for the printed 3D objects. These touch sensing 3D models can be printed in one turn by off-the-shelf 3D printers and used as an alternative to video recording. It allows exact registration of when and where the 3D object has been touched. In our multi-touch solution, particular attention has been paid to limit the number of necessary wires between 3D object and sensing electronics. Finally, our approach is evaluated by a feasibility study.}, language = {en} } @article{Goetzelmann2018, author = {G{\"o}tzelmann, Timo}, title = {Autonomous Selection and Printing of 3D Models for People Who Are Blind}, series = {ACM Transactions on Accessible Computing (TACCESS)}, volume = {11}, journal = {ACM Transactions on Accessible Computing (TACCESS)}, number = {3}, publisher = {ACM}, doi = {10.1145/3241066}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:92-opus4-5587}, pages = {1 -- 25}, year = {2018}, abstract = {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.}, language = {en} } @inproceedings{GoetzelmannVazquez2015, author = {G{\"o}tzelmann, Timo and V{\´a}zquez, Pere-Pau}, title = {InclineType: An Accelerometer-based Typing Approach for Smartwatches}, series = {Proc. 16th International Conference on Human Computer Interaction}, volume = {2015}, booktitle = {Proc. 16th International Conference on Human Computer Interaction}, publisher = {ACM}, address = {New York, NY, USA}, isbn = {978-1-4503-3463-1}, doi = {10.1145/2829875.2829929}, year = {2015}, abstract = {Small mobile devices such as smartwatches are a rapidly growing market. However, they share the issue of limited input and output space which could impede the success of these devices in future. Hence, suitable alternatives to the concepts and metaphors known from smartphones have to be found. In this paper we present InclineType a tilt-based keyboard input that uses a 3-axis accelerometer for smartwatches. The user may directly select letters by moving his/her wrist and enters them by tapping on the touchscreen. Thanks to the distribution of the letters on the edges of the screen, the keyboard dedicates a low amount of space in the smartwatch. In order to optimize the user input our concept proposes multiple techniques to stabilize the user interaction. Finally, a user study shows that users get familiar with this technique with almost no previous training, reaching speeds of about 6 wpm in average.}, language = {en} } @article{WolfGoetzelmann2023, author = {Wolf, Philipp and G{\"o}tzelmann, Timo}, title = {VEPdgets: Towards Richer Interaction Elements Based on Visually Evoked Potentials}, series = {Sensors}, volume = {23}, journal = {Sensors}, number = {22}, publisher = {MDPI AG}, issn = {1424-8220}, doi = {10.3390/s23229127}, year = {2023}, abstract = {For brain-computer interfaces, a variety of technologies and applications already exist. However, current approaches use visual evoked potentials (VEP) only as action triggers or in combination with other input technologies. This paper shows that the losing visually evoked potentials after looking away from a stimulus is a reliable temporal parameter. The associated latency can be used to control time-varying variables using the VEP. In this context, we introduced VEP interaction elements (VEP widgets) for a value input of numbers, which can be applied in various ways and is purely based on VEP technology. We carried out a user study in a desktop as well as in a virtual reality setting. The results for both settings showed that the temporal control approach using latency correction could be applied to the input of values using the proposed VEP widgets. Even though value input is not very accurate under untrained conditions, users could input numerical values. Our concept of applying latency correction to VEP widgets is not limited to the input of numbers.}, language = {en} } @inproceedings{Goetzelmann2017, author = {G{\"o}tzelmann, Timo}, title = {<> 3D Printable Hand Exoskeleton for the Haptic Exploration of Virtual 3D Scenes}, series = {PETRA '17: Proceedings of the 10th International Conference on PErvasive Technologies Related to Assistive Environments}, volume = {2017}, booktitle = {PETRA '17: Proceedings of the 10th International Conference on PErvasive Technologies Related to Assistive Environments}, publisher = {ACM}, address = {New York, NY, USA}, isbn = {978-1-4503-5227-7}, doi = {10.1145/3056540.3064950}, pages = {63 -- 66}, year = {2017}, abstract = {Virtual reality is currently experiencing a comeback. A considerable market has developed for VR computer games and educational applications. Some solutions integrate tracked devices which allow users to freely move within a certain space. Virtual 3D model can be visually explored, implemented collision detected allows users to get a feedback for instance by sound or vibration. For research projects there are several approaches which offer to get the actual feedback for the fingers of a hand, when the users virtually touches the surface of a 3D model. However, in the consumer market currently no product is sold which offers this direct feedback for the whole hand. In this paper we introduce a low-cost hand exoskeleton which is usable in conjunction with commodity hardware. It covers each of the five fingers of the user's hand, its design is open-source, low-cost, can be customized and 3D printed by individuals. It aims at improving the haptic perception of users, bases of a popular physical computing platform and is designed to be assembled even by electronically unexperienced users. We show the integration of our lean interface of the wireless exoskeleton into exemplary VR environment and describe a calibration process which is flexible for customizations.}, language = {en} }