294 research outputs found
Rendering volumetric haptic shapes in mid-air using ultrasound
We present a method for creating three-dimensional haptic shapes in mid-air using focused ultrasound. This approach applies the principles of acoustic radiation force, whereby the non-linear effects of sound produce forces on the skin which are strong enough to generate tactile sensations. This mid-air haptic feedback eliminates the need for any attachment of actuators or contact with physical devices. The user perceives a discernible haptic shape when the corresponding acoustic interference pattern is generated above a precisely controlled two-dimensional phased array of ultrasound transducers. In this paper, we outline our algorithm for controlling the volumetric distribution of the acoustic radiation force field in the form of a three-dimensional shape. We demonstrate how we create this acoustic radiation force field and how we interact with it. We then describe our implementation of the system and provide evidence from both visual and technical evaluations of its ability to render different shapes. We conclude with a subjective user evaluation to examine usersâ performance for different shapes
Textured Surfaces for Ultrasound Haptic Displays
We demonstrate a technique for rendering textured haptic surfaces in mid-air, using an ultrasound haptic display. Our technique renders tessellated 3D `haptic' shapes with different waveform properties, creating surfaces with distinct perceptions
Mid-air haptic rendering of 2D geometric shapes with a dynamic tactile pointer
An important challenge that affects ultrasonic midair haptics, in contrast to physical touch, is that we lose certain exploratory procedures such as contour following. This makes the task of perceiving geometric properties and shape identification more difficult. Meanwhile, the growing interest in mid-air haptics and their application to various new areas requires an improved understanding of how we perceive specific haptic stimuli, such as icons and control dials in mid-air. We address this challenge
by investigating static and dynamic methods of displaying 2D geometric shapes in mid-air. We display a circle, a square, and a triangle, in either a static or dynamic condition, using ultrasonic mid-air haptics. In the static condition, the shapes are presented as a full outline in mid-air, while in the dynamic condition, a tactile pointer is moved around the perimeter of the shapes. We measure participantsâ accuracy and confidence of identifying
shapes in two controlled experiments (n1 = 34, n2 = 25). Results reveal that in the dynamic condition people recognise shapes significantly more accurately, and with higher confidence. We also find that representing polygons as a set of individually drawn haptic strokes, with a short pause at the corners, drastically enhances shape recognition accuracy. Our research supports the design of mid-air haptic user interfaces in application scenarios
such as in-car interactions or assistive technology in education
Levitating Particle Displays with Interactive Voxels
Levitating objects can be used as the primitives in a new type of display. We present levitating particle displays and show how research into object levitation is enabling a new way of presenting and interacting with information. We identify novel properties of levitating particle displays and give examples of the interaction techniques and applications they allow. We then discuss design challenges for these displays, potential solutions, and promising areas for future research
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Sampling strategy for ultrasonic mid-air haptics
Mid-air tactile stimulation using ultrasonics has been used in a variety of human computer interfaces in the form of prototypes as well as products. When generating these tactile patterns with mid-air tactile ultrasonic displays, the common approach has been to sample the patterns using the hardware update rate capabilities to their full extent. In the current study we show that the hardware update rate can impact perception, but unexpectedly we find that higher update rates do not improve pattern perception. In a first user study, we highlight the effect of update rate on the perceived strength of a pattern, especially for patterns rendered at slow rate of less than 10 Hz. In a second user study, we identify the evolution of the optimal update rate according to variations in pattern size. Our main results show that update rate should be designated as additional parameter for tactile patterns. We also discuss how the relationships we defined in the current study can be implemented into designer tools so that designers remain oblivious to this additional complexity
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
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