The Hybrid Stylus: A Multi-Surface Active Stylus for Interacting with and Handwriting on Paper, Tabletop Display or Both.

The distinct properties and affordances of paper provide benefits that enabled paper to maintain an important role in the digital age. This is so much so, that some pen-paper interaction has been imitated in the digital world with touchscreens and stylus pens. Because digital medium also provides several advantages not available to physical paper, there is a clear benefit to merge the two mediums. Despite the plethora of concepts, prototypes and systems to digitise handwritten information on paper, these systems require specially prepared paper, complex setups and software, which can be used solely in combination with paper, and, most importantly, do not support the concurrent precise interaction with both mediums (paper and touchscreen) using one pen only. In this paper, we present the design, fabrication and evaluation of the Hybrid Stylus. The Hybrid Stylus is assembled with the infinity pencil tip (nib) made of graphite and a specially designed shielded tip holder that is attached to an active stylus. The stylus can be used for writing on a physical paper, while it still maintains all the features needed for tablet interaction. Moreover, the stylus also allows simultaneous digitisation of handwritten information on the paper when the paper is placed on the tablet screen. In order to evaluate the concept, we also add a user-friendly manual alignment of paper position on the underlying tablet computer The evaluation demonstrates that the system achieves almost perfect digitisation of strokes (98.6% of strokes were correctly registered with only 1.2% of ghost strokes) whilst maintaining excellent user experience of writing with a pencil on the paper.

No Interface, No Problem: Gesture Recognition on Physical Objects Using Radar Sensing.

Physical objects are usually not designed with interaction capabilities to control digital content. Nevertheless, they provide an untapped source for interactions since every object could be used to control our digital lives. We call this the missing interface problem: Instead of embedding computational capacity into objects, we can simply detect users' gestures on them. However, gesture detection on such unmodified objects has to date been limited in the spatial resolution and detection fidelity. To address this gap, we conducted research on micro-gesture detection on physical objects based on Google Soli's radar sensor. We introduced two novel deep learning architectures to process range Doppler images, namely a three-dimensional convolutional neural network (Conv3D) and a spectrogram-based ConvNet. The results show that our architectures enable robust on-object gesture detection, achieving an accuracy of approximately 94% for a five-gesture set, surpassing previous state-of-the-art performance results by up to 39%. We also showed that the decibel (dB) Doppler range setting has a significant effect on system performance, as accuracy can vary up to 20% across the dB range. As a result, we provide guidelines on how to best calibrate the radar sensor.

Effects of Eye Vergence and Accommodation on Interactions with Content on an AR Magic-lens Display and its Surroundings.

Augmented reality (AR) magic-lens (ML) displays, such as handheld devices, offer a convenient and accessible way to enrich our environment using virtual imagery. Several display technologies, including conventional monocular, less common stereoscopic, and varifocal displays, are currently being used. Vergence and accommodation effects on depth perception, as well as vergence-accommodation conflict, have been studied, where users interact only with the content on the display. However, little research exists on how vergence and accommodation influence user performance and cognitive-task load when users interact with the content on a display and its surroundings in a short timeframe. Examples of this are validating augmented instructions before making an incision andperforming general hand-eye coordinated tasks such as grasping augmented objects. To improve interactions with future AR displays in such scenarios, we must improve our understanding of this influence. To this end, we conducted two fundamental visual-acuity user studies with 28 and 27 participants, while investigating eye vergence and accommodation distances on four ML displays. Our findings show that minimizing the accommodation difference between the display and its surroundings is crucial when the gaze between the display and its surroundings shifts rapidly. Minimizing the difference in vergence is more important when viewing the display and its surroundings as a single context without shifting the gaze. Interestingly, the vergence-accommodation conflict did not significantly affect the cognitive-task load nor play a pivotal role in the accuracy of interactions with AR ML content and its physical surroundings.

Development and Evaluation of Online Suicide Preventive Tool iAlive to Increase Competences in Engaging With a Suicidal Person.

Background: Online implementation of suicide prevention interventions offers many advantages, facilitating the dissemination of large-scale suicide prevention interventions. An online tool iAlive aimed at raising awareness and increasing suicide prevention competences in lay people was developed and implemented in Slovenia. Aims: To develop, implement, and evaluate the iAlive tool. Method: Following the development and implementation of the tool, a nonrandomized controlled study with 310 participants was conducted. One hundred fifty-six of them fully completed the study [intervention group (used the iAlive tool): N = 85, control group (did not use the tool): N = 71]. Perceived competences in engaging with a suicidal person were assessed in both groups at baseline and at follow-up (3-4 weeks apart), which also represents the time of the intervention. Results: A significant effect of time and condition [F(1,149) = 6.62, p = .011, ηp2 = .043] showed that the intervention group assessed their perceived competences on intervention exposure more positively compared to the control group. Limitations: Additional data on different populations and people's engagement with the tool in relation to perceived competences are needed. Conclusion: The study suggests that the interactive online tool iAlive effectively increases perceived competences in engaging with a suicidal person. These results provide a background for further dissemination of the tool.