815 research outputs found
Development of a Multiple Contact Haptic Display with Texture-Enhanced Graphics
This dissertation presents work towards the development of a multiple finger, worn, dynamic display device, which utilizes a method of texture encoded information to haptically render graphical images for individuals who are blind or visually impaired. The device interacts directly with the computer screen, using the colors and patterns displayed by the image as a means to encode complex patterns of vibrotactile output, generating the texture feedback to render the image. In turn, the texture feedback was methodically designed to enable parallel processing of certain coarse information, speeding up the exploration of the diagram and improving user performance. The design choices were validated when individuals who are blind or visually impaired, using the multi-fingered display system, performed three-times better using textured image representations versus outline representations. Furthermore, in an open-ended object identification task, the display device saw on average two-times better performance accuracy than that previously observed for raised-line diagrams, the current standard for tactile diagrams
Transmission of Tactile Roughness through Master-slave Systems
Abstract-In this study, a tactile-roughness transmission system applicable to master-slave systems with a communication time delay is developed. The master-side system constructs a local model of target objects placed in the slave-side environment. Tactile feedbacks presented to an operator at the master side are produced by combining the physical properties of target objects in the local model and the kinetic information of the operator. The time delay between the operator's motion and the tactile feedback is cancelled because the stimuli are synchronized with the exploratory motions. The proposed system is applied to the transmission of tactileroughness. The tactile stimuli presented to the operator are vibratory stimuli whose amplitude and frequency are controlled. These stimuli are locally synthesized by combining the surface wavelength of target objects and the operator's hand velocity. Using the developed tactile-roughness transmission system, an experiment for transmitting the perceived roughness of grating scales was conducted. As a result, the roughness perceived by the operators was found to highly correlate with the roughness of the scales in the slave-side environment with a coefficient of 0.83
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications
Haptics Rendering and Applications
There has been significant progress in haptic technologies but the incorporation of haptics into virtual environments is still in its infancy. A wide range of the new society's human activities including communication, education, art, entertainment, commerce and science would forever change if we learned how to capture, manipulate and reproduce haptic sensory stimuli that are nearly indistinguishable from reality. For the field to move forward, many commercial and technological barriers need to be overcome. By rendering how objects feel through haptic technology, we communicate information that might reflect a desire to speak a physically- based language that has never been explored before. Due to constant improvement in haptics technology and increasing levels of research into and development of haptics-related algorithms, protocols and devices, there is a belief that haptics technology has a promising future
Haptic Stylus and Empirical Studies on Braille, Button, and Texture Display
This paper presents a haptic stylus interface with a
built-in compact tactile display module and an impact module
as well as empirical studies on Braille, button, and texture
display. We describe preliminary evaluations verifying the
tactile display's performance indicating that it can
satisfactorily represent Braille numbers for both the normal
and the blind. In order to prove haptic feedback capability of
the stylus, an experiment providing impact feedback mimicking
the click of a button has been conducted. Since the developed
device is small enough to be attached to a force feedback
device, its applicability to combined force and tactile
feedback display in a pen-held haptic device is also
investigated. The handle of pen-held haptic interface was
replaced by the pen-like interface to add tactile feedback
capability to the device. Since the system provides
combination of force, tactile and impact feedback, three
haptic representation methods for texture display have been
compared on surface with 3 texture groups which differ in
direction, groove width, and shape. In addition, we evaluate
its capacity to support touch screen operations by providing
tactile sensations when a user rubs against an image displayed
on a monitor
The temporal pattern of impulses in primary afferents analogously encodes touch and hearing information
An open question in neuroscience is the contribution of temporal relations between individual impulses in primary afferents in conveying sensory information. We investigated this question in touch and hearing, while looking for any shared coding scheme. In both systems, we artificially induced temporally diverse afferent impulse trains and probed the evoked perceptions in human subjects using psychophysical techniques.
First, we investigated whether the temporal structure of a fixed number of impulses conveys information about the magnitude of tactile intensity. We found that clustering the impulses into periodic bursts elicited graded increases of intensity as a function of burst impulse count, even though fewer afferents were recruited throughout the longer bursts.
The interval between successive bursts of peripheral neural activity (the burst-gap) has been demonstrated in our lab to be the most prominent temporal feature for coding skin vibration frequency, as opposed to either spike rate or periodicity. Given the similarities between tactile and auditory systems, second, we explored the auditory system for an equivalent neural coding strategy. By using brief acoustic pulses, we showed that the burst-gap is a shared temporal code for pitch perception between the modalities.
Following this evidence of parallels in temporal frequency processing, we next assessed the perceptual frequency equivalence between the two modalities using auditory and tactile pulse stimuli of simple and complex temporal features in cross-sensory frequency discrimination experiments. Identical temporal stimulation patterns in tactile and auditory afferents produced equivalent perceived frequencies, suggesting an analogous temporal frequency computation mechanism.
The new insights into encoding tactile intensity through clustering of fixed charge electric pulses into bursts suggest a novel approach to convey varying contact forces to neural interface users, requiring no modulation of either stimulation current or base pulse frequency. Increasing control of the temporal patterning of pulses in cochlear implant users might improve pitch perception and speech comprehension. The perceptual correspondence between touch and hearing not only suggests the possibility of establishing cross-modal comparison standards for robust psychophysical investigations, but also supports the plausibility of cross-sensory substitution devices
Tactile Arrays for Virtual Textures
This thesis describes the development of three new tactile stimulators for active
touch, i.e. devices to deliver virtual touch stimuli to the fingertip in response to
exploratory movements by the user. All three stimulators are designed to provide
spatiotemporal patterns of mechanical input to the skin via an array of contactors,
each under individual computer control. Drive mechanisms are based on
piezoelectric bimorphs in a cantilever geometry.
The first of these is a 25-contactor array (5 × 5 contactors at 2 mm spacing). It
is a rugged design with a compact drive system and is capable of producing strong
stimuli when running from low voltage supplies. Combined with a PC mouse,
it can be used for active exploration tasks. Pilot studies were performed which
demonstrated that subjects could successfully use the device for discrimination of
line orientation, simple shape identification and line following tasks.
A 24-contactor stimulator (6 × 4 contactors at 2 mm spacing) with improved
bandwidth was then developed. This features control electronics designed to transmit
arbitrary waveforms to each channel (generated on-the-fly, in real time) and
software for rapid development of experiments. It is built around a graphics tablet,
giving high precision position capability over a large 2D workspace. Experiments
using two-component stimuli (components at 40 Hz and 320 Hz) indicate that
spectral balance within active stimuli is discriminable independent of overall intensity,
and that the spatial variation (texture) within the target is easier to detect
at 320 Hz that at 40 Hz.
The third system developed (again 6 × 4 contactors at 2 mm spacing) was a lightweight modular stimulator developed for fingertip and thumb grasping tasks;
furthermore it was integrated with force-feedback on each digit and a complex
graphical display, forming a multi-modal Virtual Reality device for the display of
virtual textiles. It is capable of broadband stimulation with real-time generated
outputs derived from a physical model of the fabric surface. In an evaluation study,
virtual textiles generated from physical measurements of real textiles were ranked
in categories reflecting key mechanical and textural properties. The results were
compared with a similar study performed on the real fabrics from which the virtual
textiles had been derived. There was good agreement between the ratings of the
virtual textiles and the real textiles, indicating that the virtual textiles are a good
representation of the real textiles and that the system is delivering appropriate
cues to the user
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