Georgios Korres

Haptogram: Ultrasonic Point-Cloud Tactile Stimulation

Studies of the stimulating effect of ultrasound as a tactile display have recently become more intensive in the haptic domain. In this paper, we present the design, development, and evaluation of Haptogram; a system designed to provide point-cloud tactile display via acoustic radiation pressure. A tiled 2-D array of ultrasound transducers is used to produce a focal point that is animated to produce arbitrary 2-D and 3-D tactile shapes. The switching speed is very high, so that humans feel the distributed points simultaneously. The Haptogram system comprises a software component and a hardware component. The software component enables users to author and/or select a tactile object, create a point-cloud representation, and generate a sequence of focal points to drive the hardware. The hardware component comprises a tiled 2-D array of ultrasound transducers, each driven by an FPGA. A quantitative analysis is conducted to measure the Haptogram ability to display various tactile shapes, including a single point, 2-D shapes (a straight line and a circle) and a 3-D object (a hemisphere). Results show that all displayed tactile objects are perceivable by the human skin (an average of 2.65 kPa for 200 focal points). A usability study is also conducted to evaluate the ability of humans to recognize 2-D shapes. Results show that the recognition rate was well above the chance level (average of 59.44% and standard deviation of 12.75%) while the recognition time averaged 13.87 s (standard deviation of 3.92 s).

Intensifying Emotional Reactions via Tactile Gestures in Immersive Films

The film industry continuously strives to make visitors’ movie experience more immersive and thus, more captivating. This is realized through larger screens, sophisticated speaker systems, and high quality 2D and 3D content. Moreover, a recent trend in the film industry is to incorporate multiple interaction modalities, such as 4D film, to simulate rain, wind, vibration, and heat, in order to intensify viewers’ emotional reactions. In this context, humans’ sense of touch possesses significant potential for intensifying emotional reactions for the film experience beyond audio-visual sensory modalities. This article presents a framework for authoring tactile cues (tactile gestures as used in this article) and enabling automatic rendering of said gestures to intensify emotional reactions in an immersive film experience. To validate the proposed framework, we conducted an experimental study where tactile gestures are designed and evaluated for the ability to intensify four emotional reactions: high valence-high arousal, high valence-low arousal, low valence-high arousal, and low valence-low arousal. Using a haptic jacket, participants felt tactile gestures that are synchronized with the audio-visual contents of a film. Results demonstrated that (1) any tactile feedback generated a positive user experience; (2) the tactile feedback intensifies emotional reactions when the audio-visual stimuli elicit clear emotional responses, except for low arousal emotional response since tactile gestures seem to always generate excitement; (3) purposed tactile gestures do not seem to significantly outperform randomized tactile gesture for intensifying specific emotional reactions; and (4) using a haptic jacket is not distracting for the users.

SOA thresholds for the perception of discrete/continuous tactile stimulation

In this paper we present an experiment to measure the upper and lower thresholds of the Stimulus Onset Asynchrony (SOA) for continuous/discrete apparent haptic motion. We focus on three stimulation parameters: the burst duration, the SOA time, and the inter-actuator distance (between successive actuation points). The experimental setup is based on a set of six (6) vibrotactile actuators to investigate effects of the inter-actuator distance (over the range 4 cm to 20 cm) on the respective SOA thresholds. We found that as the burst duration increases, subjects detected the simultaneous-discrete boundary at lower SOA. Furthermore, the larger the inter-actuator distance, the more linear the relationship between the burst duration and the SOA timing. Finally, the large range between lower and upper thresholds for SOA can be utilized to create continuous movement stimulation on the skin at “varying speeds”. The results are discussed in reference to designing a tactile interface for providing continuous haptic motion with a desired speed of continuous tactile stimulation.

TActile Glasses TAG for Obstacle Avoidance

In this paper, we present a wearable tactile device called TAG TActile Glasses to help visually impaired individuals navigate through complex environments. The TAG device provides vibrotactile feedback whenever an obstacle is detected in front of the user. The prototype is composed of --- in addition to the eyeglasses --- an infrared proximity sensor, an ATMEGA128 microprocessor, a rechargeable battery, and a vibrotactile actuator attached to the right temple tip of the glasses. The TAG system is designed to be highly portable, fashionable yet cost effective, and intuitive to use. Experimental study showed that the TAG system can help visually impaired individuals to navigate unfamiliar lab environment using vibrotactile feedback, and without any previous training. Participants reported that the system is intuitive to use, quick to learn, and helpful.

Characterization of Ultrasound Tactile Display

Traditional haptic interfaces require physical contact between the haptic device and the user. An elegant and novel solution is to provide contactless tactile stimulation via airborne acoustic radiation pressure. However, the characteristics of contactless tactile displays are not well studied in the literature. In this paper, we study the characteristics of the ultrasonic tactile display as a haptic interface. In particular, we examine the effects of increasing the number of ultrasound transducers on four characteristics, namely the maximum producible force, the workspace, the workspace resolution, and the robustness of the simulation. Three rectangular-shaped 2D array configurations are considered: single-tile 10

Touching 2D Images Using Haptogram System

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Combining Full and Partial Haptic Guidance Improves Handwriting Skills Development

10 transducers, two-tiles 10