Fingertip Interaction Metrics Correlate with Visual and Haptic Perception of Real Surfaces (original) (raw)
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Perceptual dimensions of tactile surface texture: A multidimensional scaling analysis
Perception & Psychophysics, 1993
The purpose of this study was to examine the subjective dimensionality of tactile surface texture perception. Seventeen tactile stimuli, such as wood, sandpaper, and velvet, were moved across the index finger of the subject, who sorted them into categories on the basis of perceived similarity. Multidimensional scaling (MDS) techniques were then used to position the stimuli in a perceptual space on the basis of combined data of 20 subjects. A three-dimensional space was judged to give a satisfactory representation of the data. Subjects' ratings of each stimulus on five scales representing putative dimensions of perceived surface texture were then fitted by regression analysis into the MDS space. Roughness-smoothness and hardness-softness were found to be robust and orthogonal dimensions; the third dimension did not correspond closely with any of the rating scales used, but post hoc inspection of the data suggested that it may reflect the compressional elasticity ("springiness") of the surface.
The finishing touches: the role of friction and roughness in haptic perception of surface coatings
Experimental Brain Research, 2020
Humans are extraordinarily skilled in the tactile evaluation of, and differentiation between, surfaces. The chemical and mechanical properties of these surfaces are translated into tactile signals during haptic exploration by mechanoreceptors in our skin, which are specialized to respond to different types of temporal and mechanical stimulation. Describing the effects of measurable physical characteristics on the human response to tactile exploration of surfaces is of great interest to manufacturers of household materials so that the haptic experience can be considered during design, product development and quality control. In this study, methods from psychophysics and materials science are combined to advance current understanding of which physical properties affect tactile perception of a range of furniture surfaces, i.e., foils and coatings, thus creating a tactile map of the furniture product landscape. Participants' responses in a similarity scaling task were analyzed using INDS-CAL from which three haptic dimensions were identified. Results show that specific roughness parameters, tactile friction and vibrational information, as characterized by a stylus profilometer, a Forceboard, and a biomimetic synthetic finger, are important for tactile differentiation and preferences of these surface treatments. The obtained dimensions are described as distinct combinations of the surface properties characterized, rather than as 'roughness' or 'friction' independently. Preferences by touch were related to the roughness, friction and thermal properties of the surfaces. The results both complement and advance current understanding of how roughness and friction relate to tactile perception of surfaces.
Quantifying touch–feel perception: tribological aspects
Measurement Science and Technology, 2008
We report a new investigation into how surface topography and friction affect human touch-feel perception. In contrast with previous work based on micro-scale mapping of surface mechanical and tribological properties, this investigation focuses on the direct measurement of the friction generated when a fingertip is stroked on a test specimen. A special friction apparatus was built for the in-situ testing, based on a linear flexure mechanism with both contact force and frictional force measured simultaneously. Ten specimens, already independently assessed in a 'perception clinic', with materials including natural wood, leather, engineered plastics and metal were tested and the results compared with the perceived rankings. Because surface geometrical features are suspected to play a significant role in perception, a second set of samples, all of one material were prepared and tested in order to minimise the influence of properties such as hardness and thermal conductivity. To minimise subjective effects, all specimens were also tested in a roller-on-block configuration based upon the same friction apparatus, with the roller materials being steel, brass and rubber. This paper reports the detailed design and instrumentation of the friction apparatus, the experimental set up and the friction test results. Attempts have been made to correlate the measured properties and the perceived feelings for both roughness and friction. The results show that the measured roughness and friction coefficient both have a strong correlation with the rough-smooth and grippy-slippery feelings.
Perception & Psychophysics, 2000
Ratio scaling was used to obtain from 5 subjects estimates of the subjective dissimilarity between the members of all possible pairs of 17 tactile surfaces. The stimuli were a diverse array of everyday surfaces, such as corduroy, sandpaper, and synthetic fur. The results were analyzed using the multidimensional scaling (MDS) program ALSCAL. There was substantial, but not complete, agreement across subjects in the spatial arrangement of perceived textures. Scree plots and multivariate analysis suggested that, for some subjects, a two-dimensional space was the optimal MDS solution, whereas for other subjects, a three-dimensional space was indicated. Subsequent to their dissimilarity scaling, subjects rated each stimulus on each of five adjective scales. Consistent with earlier research, two of these (rough/smooth and soft/hard) were robustly related to the space for all subjects. A third scale, sticky/slippery, was more variably related to the dissimilarity data: regressed into three-dimensional MDS space, it was angled steeply into the third dimension only for subjects whose scree plots favored a nonplanar solution. We conclude that the sticky/slippery dimension is perceptually weighted less than the rough/smooth and soft/hard dimensions, materially contributing to the structure of perceptual space only in some individuals.
Humans are proficient at distinguishing different object materials, e.g. metal, glass and plastic, based upon their visual appearance 1 , an important skill for object recognition and for guiding interaction with the environment. Whilst material perception appears effortless, the underlying computations are complex and under-constrained: an object's image is determined not only by how its surface reflects light, but also by the object's shape and the structure of the illumination field. In recent years, one aspect of material perception – visual gloss – has been widely studied 2. Glossy and matte surfaces can be differentiated using specular highlights; bright image patches that occur when light is reflected from a surface regularly, in a mirror-like way, rather than scattered diffusely 3–8. Glossiness is conceptualised as a visual property. In contrast, other material dimensions have been studied within the haptic (touch) domain, such as surface roughness, thermal conductivity, compliance (or softness, i.e. deformation in response to force) and slipperiness (related to the coefficients of friction) 9–11. However, little is known about how visual and haptic information interact when we estimate material properties, with existing research almost entirely constrained to the perception of roughness 12–18 with a few studies on the visual-haptic cues to compliance 19–24. Here we ask whether the feel of an object also affects our perception of its glossiness. A substantial body of work has demonstrated the perceptual benefit of combining vision and haptic information when humans estimate geometric attributes such as surface slant or object size. Visual and haptic information is integrated optimally: judgments are more precise (less variable) for visual-haptic stimuli than when based on either vision or haptics alone 25,26. However, this contrasts with multi-sensory findings in material perception: although some visual-haptic averaging has been found in surface roughness perception, studies have not found improvements in precision when both modalities provide information, relative to a single modality 12,15. Moreover, robust contrast (repulsion) effects – the opposite of integration-have been found within material perception. For example, in the material-weight illusion, when two sized-matched objects appear to be made of different materials (e.g. balsa wood vs. metal), the denser-looking object feels lighter, when both are lifted and have the same mass 27,28. Similarly, in the size-weight illusion, when two objects appear to be constructed of the same material, but differ in size, the larger object feels lighter when both are lifted and have the same mass 29,30. Standard models of sensory integration predict the opposite perceptual effects 31. Here we describe two experiments that investigate whether humans integrate visual gloss information with haptic 'rubberiness' information when judging material properties. In our experiments, 'glossier' objects have higher specular reflectance, and less specular scatter than less glossy objects (see Table 1). We define 'rubbery' objects (e.g. squash balls) as those with high friction and compliance. In contrast, non-rubbery objects (i.e. a snooker ball) have low friction and high stiffness (low compliance), and can be described as feeling slippery and hard (see Table 1). Our experimental setup allows us to present visual-haptic objects that can vary independently along these visual and haptic dimensions (Fig. 1). Visual and haptic stimuli were matched in size, shape and r P
Haptic integration of object properties: Texture, hardness, and planar contour
Journal of Experimental Psychology: Human Perception and Performance, 1989
Planar objects varying in shape, texture, and hardness were classified under haptic exploration. Classes were defined by values on one dimension, or redundantly, by two or three dimensions. Response times and exploratory procedures (Lederman & Klatzky, 1987) were recorded. Experiment l showed that a second dimension speeded responses for all combinations (redundancy gain), but a third dimension produced no further effect. In Experiments 2 and 3, classification trials began with two redundant dimensions, and subsequently one was withdrawn (held constant). When texture and hardness varied redundantly, withdrawal of either increased response time-even when subjects were initially instructed to focus on one dimension. Joint exploration for texture and hardness dominated whenever the two varied redundantly and persisted despite withdrawal. Redundancy gains (Experiment 1), but not substantial withdrawal effects (Experiments 2 and 3), were observed for combinations of texture or hardness with planar contour, indicating less integration than between substance dimensions. Compatibility of exploratory procedures appears to constrain dimensional integration. There has been substantial interest in the integration of information over multiple stimulus dimensions, but largely this work has concentrated on visual displays. Our own recent research (Lederman & Klatzky, 1987) has described a number of stimulus dimensions that can be extracted haptically, by purposive touch. This raises the question of whether information integration occurs in haptics. The present article reports a series of studies investigating three questions: Does integration of distinct stimulus attributes occur under haptic encoding? Does such integration vary with the particular dimensions being encoded? What is the extent of such integration in terms of relative weighting of dimensions and flexibility of processing? Haptics builds on a basic tactual system that incorporates information from cutaneous sensors in the skin and kinesthetic sensors in muscles, tendons, and joints. Its sensory The work reported in this article is part of a continuing collaborative research program directed by Susan Lederman and Roberta L. Klatzky. Their contributions are equal and are not reflected by order of authorship.
The role of multisensory feedback in haptic surface perception
2003
In performing most everyday tasks, we use information from several different sensory modalities, yet our understanding of how these i nputs are integrated is limited. The present study investigated the role of multisensory feedback in the perception of surface roughness, specifically focusing on whether the threshold for distinguishing the roughness of two virtual surfaces was different under visual + haptic conditions, as compared to visual-only or haptic-only conditions. Haptic stimuli were presented via the PHANToM; visual stimuli were presented via computer monitor.
Validating a novel approach to rendering fingertip contact sensations
Proceedings 10th Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems. HAPTICS 2002, 2002
. Exploration of an object using a probe takes advantage of distal attribution -the ability for humans to easily extend their perception to the end of an implement. However, this approach diminishes or eliminates access to basic surface features such as temperature, texture, stick/slip sensations, and surface orientation. These sensations are readily available during direct fingertip exploration.
The tactile dimension: a method for physicalizing touch behaviors
Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems
Figure 1: A physical model is covered with a tracer substance that is invisible under normal lighting conditions (left), but reveals the traces of touch under UV light (middle). Traces are then extracted from the photograph and remapped onto a 3D model (right).