Roberta Klatzky - Academia.edu (original) (raw)

Papers by Roberta Klatzky

The purpose of this study is to investigate multimodal visual-haptic texture perception for which... more The purpose of this study is to investigate multimodal visual-haptic texture perception for which we used virtual reality techniques. Participants judged a broad range of textures according to their roughness and their spatial density under visual, haptic and visual-haptic exploration conditions. Participants were well able to differentiate between the different textures both by using the roughness and the spatial density judgment. When provided with visualhaptic textures, subjects performance increased (for both judgments) indicating sensory combination of visual and haptic texture information. Most interestingly, performance for density and roughness judgments did not differ significantly, indicating that these estimates are highly correlated. This may be due to the fact that our textures were generated in virtual reality using a haptic pointforce display (PHANToM). In conclusion, it seems that the roughness and spatial density estimate were based on the same physical parameters given the display technology used.

2021 IEEE World Haptics Conference (WHC)

This paper presents an initial study of a soft wearable tactile device that stimulates the finger... more This paper presents an initial study of a soft wearable tactile device that stimulates the finger pad via lateral forces. The device is wrapped around the finger and consists of a 4 × 4 array of pucks with a 2.6 mm pitch. Users interact with a magnet that achieves displacements of ± 56 µm. Two psychophysical experiments were conducted to explore the utility of the device. They showed that the lateral forces obtained were sufficient for the perception of angled lines, and the array-based system provided repeatable edge detection.

2017 IEEE World Haptics Conference (WHC), 2017

Two experiments tested young adults' ability to discriminate the direction of friction-defined te... more Two experiments tested young adults' ability to discriminate the direction of friction-defined textural gradients rendered by the Senseg FeelScreen TM. Gradients were particularly effective when they spanned the low end of the intensity range. This trend likely reflects saturation of the device's rendering capabilities at high intensities, as confirmed by measurements with a manual linear tribometer. The results show promise for use of gradients rendered with variable friction displays to aid non-visual navigation on tablets.

2013 World Haptics Conference (WHC), 2013

This work investigates how haptic percepts are combined across two fingertips. Two single-degree-... more This work investigates how haptic percepts are combined across two fingertips. Two single-degree-of-freedom haptic interfaces were used to present virtual bumps to the thumb and index finger of subjects' right hand. As subjects slid the two interfaces from left to right while maintaining a fixed finger separation, they would encounter one bump with the index finger and one with the thumb. The objective bump locations were varied randomly, from spatially coincident to separated by slightly more than the fingertips. Subjects were asked to report the number of bumps in the objective world and the number of times they encountered each bump, and also to point to the locations of the bumps. We found that subjects exhibited a strong bias toward reporting a single objective bump in the virtual world. However, the percept varied from one bump encountered twice, when the two virtual bumps were nearly spatially coincident, to one bump encountered once, which occurred when the two virtual bumps were close to finger separation and therefore encountered nearly simultaneously. The latter result is evidence for a kinesthetic grouping phenomenon: temporally synchronized sensations at multiple fingers can be perceptually collapsed into a single percept in both time and space.

IEEE Transactions on Haptics, 2019

This paper describes a prototype guidance system, "FingerSight," to help people without vision lo... more This paper describes a prototype guidance system, "FingerSight," to help people without vision locate and reach to objects in peripersonal space. It consists of four evenly spaced tactors embedded into a ring worn on the index finger, with a small camera mounted on top. Computer-vision analysis of the camera image controls vibrotactile feedback, leading users to move their hand to near targets. Two experiments tested the functionality of the prototype system. The first found that participants could discriminate between five different vibrotactile sites (four individual tactors and all simultaneously) with a mean accuracy of 88.8% after initial training. In the second experiment, participants were blindfolded and instructed to move their hand wearing the device to one of four locations within arm's reach, while hand trajectories were tracked. The tactors were controlled using two different strategies: (1) repeatedly signal axis with largest error, and (2) signal both axes in alternation. Participants demonstrated essentially straight-line trajectories toward the target under both instructions, but the temporal parameters (rate of approach, duration) showed an advantage for correction on both axes in sequence.

IEEE Transactions on Haptics, 2019

An electrostatic friction modulation device based on a tablet computer was used to present patter... more An electrostatic friction modulation device based on a tablet computer was used to present pattern stimuli to the fingertip for two tasks: detecting patches of friction and matching a frictional pattern to the visual image that produced it. In the detection task, friction patterns were displayed on zero, one two or three cells in a matrix. Errors, whether misses or false alarms, were few. Duration of target-present trials was a linear function of the number of patterns in the display. The intercept indicated an average of under 1 sec to test a location for the presence of a friction patch. The slope was 1.0 sec per item, representing the time to confirm friction change, verify the location, and report. In contrast to fast and accurate detection of friction modulation, identification of patterns by matching to a visual display was at chance, although the patterns were differentiated by form and scale. Given that the patterns fall within the normal acuity of the fingertip, along with previous evidence that fingertip motion per se does not preclude pattern recognition, it appears that the failure to match tactual patterns to visual images resides in processes inherent in information pickup from friction-modulation displays.

IEEE transactions on haptics, Jan 7, 2017

Despite the fact that conventional haptic interfaces and rendering algorithms commonly approximat... more Despite the fact that conventional haptic interfaces and rendering algorithms commonly approximate interactions with force only, the dynamic effects of even simple tasks, e.g. writing on a paper, involve both forces and torques. To extend previous algorithms as well as to investigate the effects of torque feedback on human roughness perception, we deployed a novel haptic platform with two probes, fingertip and penhandle. Three torque conditions were examined: 1) Slope Torque, which orients the probe perpendicular to the surface, 2) No Torque, where no active torque is provided by the device, and 3) Stiff Torque, where torque feedback is provided to keep the probe upright. A conventional magnitude estimation experiment was performed. The results indicated that both the torque signals and grasp type mediate human perception of virtual textures. Slope Torque led to greater perceived roughness when the fingertip was used, and the fingertip led to higher roughness ratings than the penhan...

IEEE transactions on haptics, Jan 3, 2016

The Gestalt theory of perception offered principles by which distributed visual sensations are co... more The Gestalt theory of perception offered principles by which distributed visual sensations are combined into a structured experience ("Gestalt"). We demonstrate conditions whereby haptic sensations at two fingertips are integrated in the perception of a single object. When virtual bumps were presented simultaneously to the right hand's thumb and index finger during lateral arm movements, participants reported perceiving a single bump. A discrimination task measured the bump's perceived location and perceptual reliability (assessed by differential thresholds) for four finger configurations, which varied in their adherence to the Gestalt principles of proximity (small vs. large finger separation) and synchrony (virtual spring to link movements of the two fingers vs. no spring). According to models of integration, reliability should increase with the degree to which multi-finger cues integrate into a unified percept. Differential thresholds were smaller in the virtual...

2015 IEEE World Haptics Conference (WHC), 2015

Figure 1. (left) A user holding a handheld device (tablet) embedded with two vibrators pressing t... more Figure 1. (left) A user holding a handheld device (tablet) embedded with two vibrators pressing the hands. (right) A pictorial illustration of apparent tactile motion and its parametric space.

Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (WHC'07), 2007

2008 Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2008

IEEE Transactions on Haptics, 2011

IEEE transactions on haptics

Haptic interfaces controlled by a single fingertip or hand-held probe tend to display surface fea... more Haptic interfaces controlled by a single fingertip or hand-held probe tend to display surface features individually, requiring serial search for multiple features. Novel surface haptic devices, however, have the potential to provide displays to multiple fingertips simultaneously, affording the possibility of parallel search. Using variable-friction surface haptic devices, we investigated the ability of participants to detect a target feature among a set of distractors in parallel across the fingers. We found that searches for a material property (slipperiness) and an illusory shape (virtual hole) were significantly impaired by distractors, while search for an abrupt discontinuity (virtual edge) was not. The efficiency of search for edges rendered by surface haptics suggests that they engage primitive detectors in the haptic perceptual system.

IEEE transactions on haptics, Jan 10, 2011

Three experiments investigated whether force and torque cues interact in haptic discrimination of... more Three experiments investigated whether force and torque cues interact in haptic discrimination of force, torque and stiffness, and if so, how. The statistical relation between force and torque was manipulated across four experimental conditions: Either one type of cue varied while the other was constant, or both varied so as to be positively correlated, negatively correlated, or uncorrelated. Experiment 1 showed that the subjects' ability to discriminate force was improved by positively correlated torque but impaired with uncorrelated torque, as compared to the constant torque condition. Corresponding effects were found in Experiment 2 for the influence of force on torque discrimination. These findings indicate that force and torque are integrated in perception, rather than being processed as separate dimensions. A further experiment demonstrated facilitation of stiffness discrimination by correlated force and torque, whether the correlation was positive or negative. The finding...

Cognitive Brain Research, 2005

Two experiments are reported that used fMRI to compare the brain activation during the imagery of... more Two experiments are reported that used fMRI to compare the brain activation during the imagery of material and geometric object features. In the first experiment, participants were to mentally evaluate objects along either a material dimension (roughness, hardness and temperature; e.g., Which is harder, a potato or a mushroom?) or a geometric dimension (size and shape; e.g., Which is larger, a pumpkin or a cucumber?). In the second experiment, when given the name of an object and either a material (roughness and hardness) or geometric (size and shape) property participants rated the object on a scale from 1 to 4. Both experiments were designed to examine the underlying neural substrate that supports the processing of material object properties with respect to geometric properties. Considering the relative amount of activation across the two types of object properties, we found that (1) the interrogation of geometric features differentially evokes visual imagery which involves the region in and around the intraparietal sulcus, (2) the interrogation of material features differentially evokes the processing of semantic object representations which involves the inferior extrastriate region, and (3) the lateral occipital cortex (LOC) responds to shape processing regardless of whether the feature being queried is a material or geometric feature.

Multisensory Research, 2014

Many developers wish to capitalize on touch-screen technology for developing aids for the blind, ... more Many developers wish to capitalize on touch-screen technology for developing aids for the blind, particularly by incorporating vibrotactile stimulation to convey patterns on their surfaces, which otherwise are featureless. Our belief is that they will need to take into account basic research on haptic perception in designing these graphics interfaces. We point out constraints and limitations in haptic processing that affect the use of these devices. We also suggest ways to use sound to augment basic information from touch, and we include evaluation data from users of a touch-screen device with vibrotactile and auditory feedback that we have been developing, called a vibro-audio interface.

Perception, 2010

Sighted blindfolded individuals can successfully classify basic facial expressions of emotion (FE... more Sighted blindfolded individuals can successfully classify basic facial expressions of emotion (FEEs) by manually exploring simple 2-D raised-line drawings (Lederman et al 2008, IEEE Transactions on Haptics1 27–38). The effect of training on classification accuracy was assessed by sixty sighted blindfolded participants (experiment 1) and by three adventitiously blind participants (experiment 2). We further investigated whether the underlying learning process(es) constituted token-specific learning and/or generalization. A hybrid learning paradigm comprising pre/post and old/new test comparisons was used. For both participant groups, classification accuracy for old (ie trained) drawings markedly increased over study trials (mean improvement = 76%, and 88%, respectively). Additionally, RT decreased by a mean of 30% for the sighted, and 31% for the adventitiously blind. Learning was mostly token-specific, but some generalization was also observed for both groups. The sighted classified ...

Perception, 2007

The magnitude of perceived roughness was haptically estimated as subjects freely explored linear ... more The magnitude of perceived roughness was haptically estimated as subjects freely explored linear gratings with either the bare finger or a rigid stylus-shaped probe. A considerably expanded range of ridge and groove width was investigated, relative to the extant literature. The four experiments collectively indicate that, for both finger and probe-end effectors, the variance in the estimates of perceived roughness was predominantly predicted by a single parameter: groove width. The functions relating perceived roughness to groove width increased over a narrow band relative to the full range of values, then flattened. These data have archival values for models of roughness perception involving both direct and indirect touch.

The purpose of this study is to investigate multimodal visual-haptic texture perception for which... more The purpose of this study is to investigate multimodal visual-haptic texture perception for which we used virtual reality techniques. Participants judged a broad range of textures according to their roughness and their spatial density under visual, haptic and visual-haptic exploration conditions. Participants were well able to differentiate between the different textures both by using the roughness and the spatial density judgment. When provided with visualhaptic textures, subjects performance increased (for both judgments) indicating sensory combination of visual and haptic texture information. Most interestingly, performance for density and roughness judgments did not differ significantly, indicating that these estimates are highly correlated. This may be due to the fact that our textures were generated in virtual reality using a haptic pointforce display (PHANToM). In conclusion, it seems that the roughness and spatial density estimate were based on the same physical parameters given the display technology used.

2021 IEEE World Haptics Conference (WHC)

This paper presents an initial study of a soft wearable tactile device that stimulates the finger... more This paper presents an initial study of a soft wearable tactile device that stimulates the finger pad via lateral forces. The device is wrapped around the finger and consists of a 4 × 4 array of pucks with a 2.6 mm pitch. Users interact with a magnet that achieves displacements of ± 56 µm. Two psychophysical experiments were conducted to explore the utility of the device. They showed that the lateral forces obtained were sufficient for the perception of angled lines, and the array-based system provided repeatable edge detection.

2017 IEEE World Haptics Conference (WHC), 2017

Two experiments tested young adults' ability to discriminate the direction of friction-defined te... more Two experiments tested young adults' ability to discriminate the direction of friction-defined textural gradients rendered by the Senseg FeelScreen TM. Gradients were particularly effective when they spanned the low end of the intensity range. This trend likely reflects saturation of the device's rendering capabilities at high intensities, as confirmed by measurements with a manual linear tribometer. The results show promise for use of gradients rendered with variable friction displays to aid non-visual navigation on tablets.

2013 World Haptics Conference (WHC), 2013

This work investigates how haptic percepts are combined across two fingertips. Two single-degree-... more This work investigates how haptic percepts are combined across two fingertips. Two single-degree-of-freedom haptic interfaces were used to present virtual bumps to the thumb and index finger of subjects' right hand. As subjects slid the two interfaces from left to right while maintaining a fixed finger separation, they would encounter one bump with the index finger and one with the thumb. The objective bump locations were varied randomly, from spatially coincident to separated by slightly more than the fingertips. Subjects were asked to report the number of bumps in the objective world and the number of times they encountered each bump, and also to point to the locations of the bumps. We found that subjects exhibited a strong bias toward reporting a single objective bump in the virtual world. However, the percept varied from one bump encountered twice, when the two virtual bumps were nearly spatially coincident, to one bump encountered once, which occurred when the two virtual bumps were close to finger separation and therefore encountered nearly simultaneously. The latter result is evidence for a kinesthetic grouping phenomenon: temporally synchronized sensations at multiple fingers can be perceptually collapsed into a single percept in both time and space.

IEEE Transactions on Haptics, 2019

This paper describes a prototype guidance system, "FingerSight," to help people without vision lo... more This paper describes a prototype guidance system, "FingerSight," to help people without vision locate and reach to objects in peripersonal space. It consists of four evenly spaced tactors embedded into a ring worn on the index finger, with a small camera mounted on top. Computer-vision analysis of the camera image controls vibrotactile feedback, leading users to move their hand to near targets. Two experiments tested the functionality of the prototype system. The first found that participants could discriminate between five different vibrotactile sites (four individual tactors and all simultaneously) with a mean accuracy of 88.8% after initial training. In the second experiment, participants were blindfolded and instructed to move their hand wearing the device to one of four locations within arm's reach, while hand trajectories were tracked. The tactors were controlled using two different strategies: (1) repeatedly signal axis with largest error, and (2) signal both axes in alternation. Participants demonstrated essentially straight-line trajectories toward the target under both instructions, but the temporal parameters (rate of approach, duration) showed an advantage for correction on both axes in sequence.

IEEE Transactions on Haptics, 2019

An electrostatic friction modulation device based on a tablet computer was used to present patter... more An electrostatic friction modulation device based on a tablet computer was used to present pattern stimuli to the fingertip for two tasks: detecting patches of friction and matching a frictional pattern to the visual image that produced it. In the detection task, friction patterns were displayed on zero, one two or three cells in a matrix. Errors, whether misses or false alarms, were few. Duration of target-present trials was a linear function of the number of patterns in the display. The intercept indicated an average of under 1 sec to test a location for the presence of a friction patch. The slope was 1.0 sec per item, representing the time to confirm friction change, verify the location, and report. In contrast to fast and accurate detection of friction modulation, identification of patterns by matching to a visual display was at chance, although the patterns were differentiated by form and scale. Given that the patterns fall within the normal acuity of the fingertip, along with previous evidence that fingertip motion per se does not preclude pattern recognition, it appears that the failure to match tactual patterns to visual images resides in processes inherent in information pickup from friction-modulation displays.

IEEE transactions on haptics, Jan 7, 2017

Despite the fact that conventional haptic interfaces and rendering algorithms commonly approximat... more Despite the fact that conventional haptic interfaces and rendering algorithms commonly approximate interactions with force only, the dynamic effects of even simple tasks, e.g. writing on a paper, involve both forces and torques. To extend previous algorithms as well as to investigate the effects of torque feedback on human roughness perception, we deployed a novel haptic platform with two probes, fingertip and penhandle. Three torque conditions were examined: 1) Slope Torque, which orients the probe perpendicular to the surface, 2) No Torque, where no active torque is provided by the device, and 3) Stiff Torque, where torque feedback is provided to keep the probe upright. A conventional magnitude estimation experiment was performed. The results indicated that both the torque signals and grasp type mediate human perception of virtual textures. Slope Torque led to greater perceived roughness when the fingertip was used, and the fingertip led to higher roughness ratings than the penhan...

IEEE transactions on haptics, Jan 3, 2016

The Gestalt theory of perception offered principles by which distributed visual sensations are co... more The Gestalt theory of perception offered principles by which distributed visual sensations are combined into a structured experience ("Gestalt"). We demonstrate conditions whereby haptic sensations at two fingertips are integrated in the perception of a single object. When virtual bumps were presented simultaneously to the right hand's thumb and index finger during lateral arm movements, participants reported perceiving a single bump. A discrimination task measured the bump's perceived location and perceptual reliability (assessed by differential thresholds) for four finger configurations, which varied in their adherence to the Gestalt principles of proximity (small vs. large finger separation) and synchrony (virtual spring to link movements of the two fingers vs. no spring). According to models of integration, reliability should increase with the degree to which multi-finger cues integrate into a unified percept. Differential thresholds were smaller in the virtual...

2015 IEEE World Haptics Conference (WHC), 2015

Figure 1. (left) A user holding a handheld device (tablet) embedded with two vibrators pressing t... more Figure 1. (left) A user holding a handheld device (tablet) embedded with two vibrators pressing the hands. (right) A pictorial illustration of apparent tactile motion and its parametric space.

Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (WHC'07), 2007

2008 Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2008

IEEE Transactions on Haptics, 2011

IEEE transactions on haptics

Haptic interfaces controlled by a single fingertip or hand-held probe tend to display surface fea... more Haptic interfaces controlled by a single fingertip or hand-held probe tend to display surface features individually, requiring serial search for multiple features. Novel surface haptic devices, however, have the potential to provide displays to multiple fingertips simultaneously, affording the possibility of parallel search. Using variable-friction surface haptic devices, we investigated the ability of participants to detect a target feature among a set of distractors in parallel across the fingers. We found that searches for a material property (slipperiness) and an illusory shape (virtual hole) were significantly impaired by distractors, while search for an abrupt discontinuity (virtual edge) was not. The efficiency of search for edges rendered by surface haptics suggests that they engage primitive detectors in the haptic perceptual system.

IEEE transactions on haptics, Jan 10, 2011

Three experiments investigated whether force and torque cues interact in haptic discrimination of... more Three experiments investigated whether force and torque cues interact in haptic discrimination of force, torque and stiffness, and if so, how. The statistical relation between force and torque was manipulated across four experimental conditions: Either one type of cue varied while the other was constant, or both varied so as to be positively correlated, negatively correlated, or uncorrelated. Experiment 1 showed that the subjects' ability to discriminate force was improved by positively correlated torque but impaired with uncorrelated torque, as compared to the constant torque condition. Corresponding effects were found in Experiment 2 for the influence of force on torque discrimination. These findings indicate that force and torque are integrated in perception, rather than being processed as separate dimensions. A further experiment demonstrated facilitation of stiffness discrimination by correlated force and torque, whether the correlation was positive or negative. The finding...

Cognitive Brain Research, 2005

Two experiments are reported that used fMRI to compare the brain activation during the imagery of... more Two experiments are reported that used fMRI to compare the brain activation during the imagery of material and geometric object features. In the first experiment, participants were to mentally evaluate objects along either a material dimension (roughness, hardness and temperature; e.g., Which is harder, a potato or a mushroom?) or a geometric dimension (size and shape; e.g., Which is larger, a pumpkin or a cucumber?). In the second experiment, when given the name of an object and either a material (roughness and hardness) or geometric (size and shape) property participants rated the object on a scale from 1 to 4. Both experiments were designed to examine the underlying neural substrate that supports the processing of material object properties with respect to geometric properties. Considering the relative amount of activation across the two types of object properties, we found that (1) the interrogation of geometric features differentially evokes visual imagery which involves the region in and around the intraparietal sulcus, (2) the interrogation of material features differentially evokes the processing of semantic object representations which involves the inferior extrastriate region, and (3) the lateral occipital cortex (LOC) responds to shape processing regardless of whether the feature being queried is a material or geometric feature.

Multisensory Research, 2014

Many developers wish to capitalize on touch-screen technology for developing aids for the blind, ... more Many developers wish to capitalize on touch-screen technology for developing aids for the blind, particularly by incorporating vibrotactile stimulation to convey patterns on their surfaces, which otherwise are featureless. Our belief is that they will need to take into account basic research on haptic perception in designing these graphics interfaces. We point out constraints and limitations in haptic processing that affect the use of these devices. We also suggest ways to use sound to augment basic information from touch, and we include evaluation data from users of a touch-screen device with vibrotactile and auditory feedback that we have been developing, called a vibro-audio interface.

Perception, 2010

Sighted blindfolded individuals can successfully classify basic facial expressions of emotion (FE... more Sighted blindfolded individuals can successfully classify basic facial expressions of emotion (FEEs) by manually exploring simple 2-D raised-line drawings (Lederman et al 2008, IEEE Transactions on Haptics1 27–38). The effect of training on classification accuracy was assessed by sixty sighted blindfolded participants (experiment 1) and by three adventitiously blind participants (experiment 2). We further investigated whether the underlying learning process(es) constituted token-specific learning and/or generalization. A hybrid learning paradigm comprising pre/post and old/new test comparisons was used. For both participant groups, classification accuracy for old (ie trained) drawings markedly increased over study trials (mean improvement = 76%, and 88%, respectively). Additionally, RT decreased by a mean of 30% for the sighted, and 31% for the adventitiously blind. Learning was mostly token-specific, but some generalization was also observed for both groups. The sighted classified ...

Perception, 2007

The magnitude of perceived roughness was haptically estimated as subjects freely explored linear ... more The magnitude of perceived roughness was haptically estimated as subjects freely explored linear gratings with either the bare finger or a rigid stylus-shaped probe. A considerably expanded range of ridge and groove width was investigated, relative to the extant literature. The four experiments collectively indicate that, for both finger and probe-end effectors, the variance in the estimates of perceived roughness was predominantly predicted by a single parameter: groove width. The functions relating perceived roughness to groove width increased over a narrow band relative to the full range of values, then flattened. These data have archival values for models of roughness perception involving both direct and indirect touch.