Guidance-based Two-Dimensional Haptic Contour Rendering for Accessible Photography

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Perceived Magnitude Function of Friction Rendered by the Dahl Model

The discrete vectorial Dahl model, proposed by Hayward and Armstrong, is appropriate for haptic friction rendering using a force-feedback interface due to its modeling power of complex frictional behaviors and relatively simple discrete formula favorable for real-time computation. The model has a few parameters that determine the subjective sensations of virtual surface friction, but their perceptual roles have not been clarified. This paper presents the design and results of a perceptual experiment that aimed to quantify the effects of the discrete vectorial Dahl model parameters in the perceived magnitude of friction. It was observed that the maximum magnitude of the sliding friction force has the most critical effect on friction perception. We also fit a nonlinear function between the perceptual magnitude of friction and the maximum sliding friction force in the form of Steven's power law. This function serves as a psychophysical magnitude function that enables haptic application designers to understand the perceptual strength of virtual friction rendering implemented using the Dahl model.1

TouchPhoto: Enabling Independent Picture-taking and Understanding of Photos for Visually-Impaired Users

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Perception of Electrostatic Friction Stimuli in Free Surface Exploration

Assuming the use scenario of free exploration on tactile graphics for people with visual impairments, this study investigated how the users perceive electrostatic friction stimuli on contour-based graphical information. We designed and conducted two experiments with 16 participants (8 visually-impaired and 8 sighted). First, we obtained spatial gap detection thresholds between two lines rendered using the electrostatic display. Second, we investigated spatial numerosity judgement on rendered lines on the display. Results demonstrated that the visually-impaired and sighted participants had similar perceptual performance. We summarize the findings and present suggestions for tactile graphics on an electrostatic friction display.1

Perceived Magnitude Function of Friction Rendered by the Dahl Model

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