Where's My Cellphone: Non-contact based Hand-Gestures and Ultrasound haptic feedback for Secondary Task Interaction while Driving

Drivers regularly use their smartphones to perform secondary tasks while driving, which can negatively impact traffic safety. In such complex interaction, multimodal feedback has been associated with lowering driver distraction. We investigated four methods for completing a phone-based secondary task while driving: smartphone in hand, smartphone in a rack, buttons on the steering wheel with Head-up-display (HUD), and mid-air gestures with an ultrasound haptic feedback and a HUD. Participants (N=16) drove the Lane Change Test (LCT) simulator with each method to complete predefined secondary tasks. To measure performance in primary task, we recorded lane deviations and for secondary task we measured response times and errors. Additionally, the participants filled in the NASA-TLX questionnaire and ranked each method according to their preferences. The results showed that the performance and preference for the hand and rack conditions were similar, while performance with buttons and gestures was worse, even with ultrasound haptic feedback, than in hand and rack conditions. The results highlight the importance of rigorous user testing when introducing new modalities for in-vehicle interaction to enhance primary and secondary task performance.acceptedVersionPeer reviewe

HaptiRead: Reading Braille as Mid-Air Haptic Information

Mid-air haptic interfaces have several advantages - the haptic information is delivered directly to the user, in a manner that is unobtrusive to the immediate environment. They operate at a distance, thus easier to discover; they are more hygienic and allow interaction in 3D. We validate, for the first time, in a preliminary study with sighted and a user study with blind participants, the use of mid-air haptics for conveying Braille. We tested three haptic stimulation methods, where the haptic feedback was either: a) aligned temporally, with haptic stimulation points presented simultaneously (Constant); b) not aligned temporally, presenting each point independently (Point-By-Point); or c) a combination of the previous methodologies, where feedback was presented Row-by-Row. The results show that mid-air haptics is a viable technology for presenting Braille characters, and the highest average accuracy (94% in the preliminary and 88% in the user study) was achieved with the Point-by-Point method.Comment: 8 pages, 8 figures, 2 tables, DIS'2

Ultrasound Feedback for Mid-air Gesture Interaction in Vibrating Environment

Mid-air ultrasound skin stimulation is a known technology used to provide haptic feedback for touchless communication. Even though some in-car interaction already takes place with mid-air gestures, the utilization of this type of feedback is still uncommon. In this study we evaluated how environmental vibration affects the recognition of ultrasound haptic feedback exposed to the driver’s hand.publishedVersionPeer reviewe

Feel the Noise: Mid-Air Ultrasound Haptics as a Novel Human-Vehicle Interaction Paradigm

Focussed ultrasound can be used to create the sensation of touch in mid-air. Combined with gestures, this can provide haptic feedback to guide users, thereby overcoming the lack of agency associated with pure gestural interfaces, and reducing the need for vision – it is therefore particularly apropos of the driving domain. In a counter-balanced 2×2 driving simulator study, a traditional in-vehicle touchscreen was compared with a virtual mid-air gestural interface, both with and without ultrasound haptics. Forty-eight experienced drivers (28 male, 20 female) undertook representative in-vehicle tasks – discrete target selections and continuous slider-bar manipulations – whilst driving. Results show that haptifying gestures with ultrasound was particularly effective in reducing visual demand (number of long glances and mean off-road glance time), and increasing performance (shortest interaction times, highest number of correct responses and least ‘overshoots’) associated with continuous tasks. In contrast, for discrete, target-selections, the touchscreen enabled the highest accuracy and quickest responses, particularly when combined with haptic feedback to guide interactions, although this also increased visual demand. Subjectively, the gesture interfaces invited higher ratings of arousal compared to the more familiar touch-surface technology, and participants indicated the lowest levels of workload (highest performance, lowest frustration) associated with the gesture-haptics interface. In addition, gestures were preferred by participants for continuous tasks. The study shows practical utility and clear potential for the use of haptified gestures in the automotive domain

Measuring tactile sensitivity and mixed-reality-assisted exercise for carpal tunnel syndrome by ultrasound mid-air haptics

IntroductionCarpal tunnel syndrome (CTS) is the most common nerve entrapment neuropathy, which causes numbness and pain in the thumb, the index and middle fingers and the radial side of the ring finger. Regular hand exercises may improve the symptoms and prevent carpal tunnel surgery. This study applied a novel ultrasonic stimulation method to test tactile sensitivity in CTS and also a mixed-reality-assisted (MR-assisted) exercise program which measured hand movements and provided haptic feedback for rehabilitation.MethodsTwenty patients with mild unilateral CTS took part in the experiments. A mid-air haptics device (Ultrahaptics STRATOS Explore) was used to apply amplitude-modulated ultrasound waves (carrier frequency: 40 kHz) onto the skin to create tactile stimulation mechanically. Participants performed a two-alternative forced-choice task for measuring tactile thresholds at 250-Hz modulation frequency. They were tested at the index fingers and the thenar eminences of both hands. Additionally, 15 CTS patients used an MR-assisted program to do hand exercises with haptic feedback. Exercise performance was assessed by calculating errors between target and actual hand configurations. System Usability Scale (SUS) was adopted to verify the practical usability of the program.ResultsThresholds at the thenar eminences of the affected and healthy hands were not significantly different. While the thresholds at the healthy index fingers could be measured, those of the affected fingers were all higher than the stimulation level produced by the maximum output from the ultrasound device. In the exercise program, a significant positive correlation (ρ = 0.89, p < 0.001) was found between the performance scores and the SUS scores, which were above the criterion value established in the literature.DiscussionThe results show that thenar tactile sensitivity is not affected in mild CTS as expected from the palmar cutaneous branch of the median nerve (PCBm), but index finger threshold is likely to be higher. Overall, this study suggests that mid-air haptics, with certain improvements, may be used as a preliminary test in the clinical setting. Moreover, the device is promising to develop gamified rehabilitation programs and for the treatment follow-up of CTS