The Experts below are selected from a list of 9333 Experts worldwide ranked by ideXlab platform
Astrid M L Kappers - One of the best experts on this subject based on the ideXlab platform.
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Anisotropy in the Haptic Perception of Force Direction and Magnitude
2013Co-Authors: Femke E. Van Beek, W.m. Bergmann Tiest, Astrid M L KappersAbstract:Although force-feedback devices are already being used, the human ability to perceive forces has not been documented thoroughly. The Haptic Perception of force direction and magnitude has mostly been studied in discrimination tasks in the direction of gravity. In our study, the influence of physical force direction on Haptic Perception of force magnitude and direction was studied in the horizontal plane. Subjects estimated the direction and magnitude of a force exerted on their stationary hand. A significant anisotropy in Perception of force magnitude and direction was found. Force direction data showed significant subject-dependent distortions at various physical directions. Normalized force magnitude data showed a consistent elliptical pattern, with its minor axis pointing roughly from the subject's hand to his/her shoulder. This pattern could be related to arm stiffness or manipulability patterns, which are also ellipse-shaped. These ellipses have an orientation consistent with the distortion measured in our study. So, forces in the direction of highest stiffness and lowest manipulability are perceived as being smaller. It therefore seems that humans possess a "sense of effort" rather than a "sense of force," which may be more useful in everyday life. These results could be useful in the design of Haptic devices.
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Haptic Perception of wetness
2012Co-Authors: Wouter M. Bergmann Tiest, N. Dolfine Kosters, Astrid M L Kappers, Hein A.m. DaanenAbstract:In daily life, people interact with textiles of different degrees of wetness, but little is known about the mechanics of wetness Perception. This paper describes an experiment with six conditions regarding Haptic discrimination of the wetness of fabrics. Three materials were used: cotton wool, sponge-structured viscose and thin viscose. Two ways of touching were investigated: static touching, in which only thermal cues were available, and dynamic touching, in which additional mechanical cues were available. For dynamic touching, average Weber fractions for discrimination were around 0.3, whereas for static touching, they ranged from 0.34 to 0.63. The results show that people can make use of the additional mechanical cues to significantly improve their discrimination performance. There was no significant difference between Weber fractions for the three materials, showing that wetness can be judged as a separate perceptual quantity, independent of the material. © 2012 Elsevier B.V.
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discrimination thresholds for Haptic Perception of volume surface area and weight
2011Co-Authors: M Kahrimanovic, Wouter Bergmann M Tiest, Astrid M L KappersAbstract:The present study investigated the human ability to discriminate the size of 3-D objects by touch. Experiment 1 measured the just noticeable differences (JNDs) for three tasks: (1) discrimination of volume without availability of weight information, (2) discrimination of volume with weight information available, and (3) discrimination of surface area. Stimuli consisted of spheres, cubes, and tetrahedrons. For all shapes, two reference sizes were used (3.5 and 12 cm3). No significant effect of task on the discriminability of objects was found, but the effects of shape and size were significant, as well as the interaction between these two factors. Post hoc analysis revealed that for the small reference, the Weber fractions for the tetrahedron were significantly larger than the fractions for the cube and the sphere. In Experiment 2, the JNDs for Haptic Perception of weight were measured for the same objects as those used in Experiment 1. The shape of objects had no significant effect on the Weber fractions for weight, but the Weber fractions for the small stimuli were larger than the fractions for the large stimuli. Surprisingly, a comparison between the two experiments showed that the Weber fractions for weight were significantly larger than the fractions for volume with availability of weight information. Taken together, the results reveal that volume and weight information are not effectively combined in discrimination tasks. This study provides detailed insight into the accuracy of the Haptic system in discriminating objects’ size. This substantial set of data satisfies the need for more fundamental knowledge on Haptic size Perception, necessary for a greater understanding of the Perception of related properties, as well as of more general perceptual processes.
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aging and the Haptic Perception of 3d surface shape
2011Co-Authors: Farley J Norman, Astrid M L Kappers, Amanda M Beers, Kate A Scott, Hideko F Norman, Jan J KoenderinkAbstract:Two experiments evaluated the ability of older and younger adults to perceive the three-dimensional (3D) shape of object surfaces from active touch (Haptics). The ages of the older adults ranged from 64 to 84 years, while those of the younger adults ranged from 18 to 27 years. In Experiment 1, the participants Haptically judged the shape of large (20 cm diameter) surfaces with an entire hand. In contrast, in Experiment 2, the participants explored the shape of small (5 cm diameter) surfaces with a single finger. The Haptic surfaces varied in shape index (Koenderink, Solid shape, 1990; Koenderink, Image and Vision Computing, 10, 557–564, 1992) from −1.0 to +1.0 in steps of 0.25. For both types of surfaces (large and small), the participants were able to judge surface shape reliably. The older participants’ judgments of surface shape were just as accurate and precise as those of the younger participants. The results of the current study demonstrate that while older adults do possess reductions in tactile sensitivity and acuity, they nevertheless can effectively perceive 3D surface shape from Haptic exploration.
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Haptic Perception of gravitational and inertial mass
2010Co-Authors: Wouter Bergmann M Tiest, Astrid M L KappersAbstract:Mass can be perceived in different ways: statically, through gravitational cues; dynamically, through inertial cues; or a combination of both. This article investigates the relationship between these modes of Perception. In three different experiments, subjects matched masses that were held statically in the hand to masses that were either accelerated or decelerated. Accelerated masses were perceived to be smaller than masses of equal physical magnitude held statically by a factor of 2. However, decelerated masses were matched veridically to masses held statically. This difference remained present when contact duration was made very short. This shows that the shift in perceived mass is not the result of differences in the information available, but of differences in the mode of Perception (active acceleration vs. passive deceleration). It is hypothesized that this is due to a suppression of the Perception of applied force in active touch.
Michael Goldfarb - One of the best experts on this subject based on the ideXlab platform.
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the effect of virtual surface stiffness on the Haptic Perception of detail
2004Co-Authors: Marcia K Omalley, Michael GoldfarbAbstract:This brief presents a quantitative study of the effects of virtual surface stiffness in a simulated Haptic environment on the Haptic Perception of detail. Specifically, the Haptic Perception of detail is characterized by identification, detection, and discrimination of round and square cross section ridges. Test results indicate that performance, measured as a percent correct score in the Perception experiments, improves in a nonlinear fashion as the maximum level of virtual surface stiffness in the simulation increases. Further, test subjects appeared to reach a limit in their Perception capabilities at maximum stiffness levels of 300 to 400 N/m, while the hardware was capable of 1000 N/m of maximum virtual surface stiffness. These results indicate that Haptic interface hardware may be able to convey sufficient perceptual information to the user with relatively low levels of virtual surface stiffness.
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the effect of force saturation on the Haptic Perception of detail
2002Co-Authors: Marcia K Omalley, Michael GoldfarbAbstract:This paper presents a quantitative study of the effects of maximum capable force magnitude of a Haptic interface on the Haptic Perception of detail. Specifically, the Haptic Perception of detail is characterized by identification, detection, and discrimination of round and square cross-section ridges, in addition to corner detection tests. Test results indicate that performance, measured as a percent correct score in the Perception experiments, improves in a nonlinear fashion as the maximum allowable level of force in the simulation increases. Further, all test subjects appeared to reach a limit in their Perception capabilities at maximum-force output levels of 3-4 N, while the hardware was capable of 10 N of maximum continuous force output. These results indicate that Haptic interface hardware may be able to convey sufficient perceptual information to the user with relatively low levels of force feedback. The data is compiled to aid those who wish to design a stylus-type Haptic interface to meet certain requirements for the display of physical detail within a Haptic simulation.
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the implications of surface stiffness for size identification and perceived surface hardness in Haptic interfaces
2002Co-Authors: Marcia K Omalley, Michael GoldfarbAbstract:This paper presents a two-part study of the effects of virtual surface stiffness on Haptic Perception. First, size identification experiments were performed to determine the effects of system quality, in terms of surface stiffness, on the ability of a human to identify square cross-section ridges by size in a simulated environment. Then, discrimination experiments were performed to determine relationships between virtual surface stiffness and simulation quality in terms of perceived surface hardness. Results of experiments to test human Haptic Perception for varying virtual surface stiffnesses indicate that Haptic interface hardware may be able to convey sufficient perceptual information to the user at relatively low levels of virtual surface stiffness. Subjects, however, can perceive improvements in perceived simulated surface hardness as stiffness levels are increased in the range of achievable parameters for this hardware. The authors draw several conclusions about the allowable time delays in a Haptic interface system based on the results of the surface stiffness experiments.
Marcia K Omalley - One of the best experts on this subject based on the ideXlab platform.
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effect of interference on multi sensory Haptic Perception of stretch and squeeze
2019Co-Authors: Zane A Zook, Joshua J Fleck, Tiffani W Tjandra, Marcia K OmalleyAbstract:Multi-sensory Haptic systems have the potential to transfer a wide variety of information to a human user by delivering multiple types of Haptic cues simultaneously. However, these systems may cause undesirable perceptual interference, which has already been observed in wearable systems that simultaneously convey skin stretch and squeeze cues. To investigate this observed perceptual interference, we conducted a psychophysical evaluation of the just-noticeable difference (JND) in skin stretch and squeeze cue magnitudes independently as well as in the presence of an interfering cue. A Haptic testbed delivered each cue to a user’s proximal forearm. First, the JNDs of the two Haptic cues were each measured alone. Then, the cues were delivered simultaneously and the JND values for stretch with squeeze interference and squeeze with stretch interference were measured. We found that the JND for the stretch cue increased with the addition of an interference squeeze cue, while the JND for the squeeze cue did not change with interference. Results suggest that there is an interference effect between multi-sensory Haptic cues that, depending on cue type, can negatively impact Haptic Perception. Further development of multi-sensory devices that convey salient cues has the potential to mitigate this observed interference.
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the effect of virtual surface stiffness on the Haptic Perception of detail
2004Co-Authors: Marcia K Omalley, Michael GoldfarbAbstract:This brief presents a quantitative study of the effects of virtual surface stiffness in a simulated Haptic environment on the Haptic Perception of detail. Specifically, the Haptic Perception of detail is characterized by identification, detection, and discrimination of round and square cross section ridges. Test results indicate that performance, measured as a percent correct score in the Perception experiments, improves in a nonlinear fashion as the maximum level of virtual surface stiffness in the simulation increases. Further, test subjects appeared to reach a limit in their Perception capabilities at maximum stiffness levels of 300 to 400 N/m, while the hardware was capable of 1000 N/m of maximum virtual surface stiffness. These results indicate that Haptic interface hardware may be able to convey sufficient perceptual information to the user with relatively low levels of virtual surface stiffness.
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the effect of force saturation on the Haptic Perception of detail
2002Co-Authors: Marcia K Omalley, Michael GoldfarbAbstract:This paper presents a quantitative study of the effects of maximum capable force magnitude of a Haptic interface on the Haptic Perception of detail. Specifically, the Haptic Perception of detail is characterized by identification, detection, and discrimination of round and square cross-section ridges, in addition to corner detection tests. Test results indicate that performance, measured as a percent correct score in the Perception experiments, improves in a nonlinear fashion as the maximum allowable level of force in the simulation increases. Further, all test subjects appeared to reach a limit in their Perception capabilities at maximum-force output levels of 3-4 N, while the hardware was capable of 10 N of maximum continuous force output. These results indicate that Haptic interface hardware may be able to convey sufficient perceptual information to the user with relatively low levels of force feedback. The data is compiled to aid those who wish to design a stylus-type Haptic interface to meet certain requirements for the display of physical detail within a Haptic simulation.
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the implications of surface stiffness for size identification and perceived surface hardness in Haptic interfaces
2002Co-Authors: Marcia K Omalley, Michael GoldfarbAbstract:This paper presents a two-part study of the effects of virtual surface stiffness on Haptic Perception. First, size identification experiments were performed to determine the effects of system quality, in terms of surface stiffness, on the ability of a human to identify square cross-section ridges by size in a simulated environment. Then, discrimination experiments were performed to determine relationships between virtual surface stiffness and simulation quality in terms of perceived surface hardness. Results of experiments to test human Haptic Perception for varying virtual surface stiffnesses indicate that Haptic interface hardware may be able to convey sufficient perceptual information to the user at relatively low levels of virtual surface stiffness. Subjects, however, can perceive improvements in perceived simulated surface hardness as stiffness levels are increased in the range of achievable parameters for this hardware. The authors draw several conclusions about the allowable time delays in a Haptic interface system based on the results of the surface stiffness experiments.
Vincent Hayward - One of the best experts on this subject based on the ideXlab platform.
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Haptic Perception of real and virtual curvature
2008Co-Authors: Maarten W A Wijntjes, Astrid M L Kappers, Akihiro Sato, Vincent HaywardAbstract:In this study we compared human discrimination performance for real and virtual curved shapes. To simulate a curved shape we used a device that could independently orient and elevate a moving surface that was in contact with an exploring finger. Thus, the geometry was preserved up to the first order in the virtual shape. In our experiment we found that this preservation was indeed sufficient: discrimination thresholds were similar for the real and virtual conditions. Our results were also in line with previous curvature studies performed with real stimuli.
Maarten W A Wijntjes - One of the best experts on this subject based on the ideXlab platform.
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Haptic Perception disambiguates visual Perception of 3D shape
2009Co-Authors: Maarten W A Wijntjes, Robert Volcic, Sylvia C Pont, Jan J Koenderink, Astrid M L KappersAbstract:We studied the influence of Haptics on visual Perception of three-dimensional shape. Observers were shown pictures of an oblate spheroid in two different orientations. A gauge-figure task was used to measure their Perception of the global shape. In the first two sessions only vision was used. The results showed that observers made large errors and interpreted the oblate spheroid as a sphere. They also misinterpreted the rotated oblate spheroid for a prolate spheroid. In two subsequent sessions observers were allowed to touch the stimulus while performing the task. The visual input remained unchanged: the observers were looking at the picture and could not see their hands. The results revealed that observers perceived a shape that was different from the vision-only sessions and closer to the veridical shape. Whereas, in general, vision is subject to ambiguities that arise from interpreting the retinal projection, our study shows that Haptic input helps to disambiguate and reinterpret the visual input more veridically.
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Haptic Perception of real and virtual curvature
2008Co-Authors: Maarten W A Wijntjes, Astrid M L Kappers, Akihiro Sato, Vincent HaywardAbstract:In this study we compared human discrimination performance for real and virtual curved shapes. To simulate a curved shape we used a device that could independently orient and elevate a moving surface that was in contact with an exploring finger. Thus, the geometry was preserved up to the first order in the virtual shape. In our experiment we found that this preservation was indeed sufficient: discrimination thresholds were similar for the real and virtual conditions. Our results were also in line with previous curvature studies performed with real stimuli.
