Unidirectional Fabric Drape Testing Method

In most cases, fabrics such as curtains, skirts, suit pants and so on are draped under their own gravity parallel to fabric plane while the gravity is perpendicular to fabric plane in traditional drape testing method. As a result, it does not conform to actual situation and the test data is not convincing enough. To overcome this problem, this paper presents a novel method which simulates the real mechanical conditions and ensures the gravity is parallel to the fabric plane. This method applied a low-cost Kinect Sensor device to capture the 3-dimensional (3D) drape profile, thus we obtained the drape degree parameters and aesthetic parameters by 3D reconstruction and image processing and analysis techniques. The experiment was conducted on our self-devised drape-testing instrument by choosing different kinds of weave structure fabrics as our testing samples and the results were compared with those of traditional method and subjective evaluation. Through regression and correlation analysis we found that this novel testing method was significantly correlated with the traditional and subjective evaluation method. We achieved a new, non-contact 3D measurement method for drape testing, namely unidirectional fabric drape testing method. This method is more suitable for evaluating drape behavior because it is more in line with actual mechanical conditions of draped fabrics and has a well consistency with the requirements of visual and aesthetic style of fabrics.     

Differential Contributions of Vision,Touch and Muscle Proprioception to the Coding of Hand Movements

To further elucidate the mechanisms underlying multisensory integration, this study examines the controversial issue of whether congruent inputs from three different sensory sources can enhance the perception of hand movement. Illusory sensations of clockwise rotations of the right hand were induced by either separately or simultaneously stimulating visual, tactile and muscle proprioceptive channels at various intensity levels. For this purpose, mechanical vibrations were applied to the pollicis longus muscle group in the subjects’ wrists, and a textured disk was rotated under the palmar skin of the subjects’ right hands while a background visual scene was projected onto the rotating disk. The elicited kinaesthetic illusions were copied by the subjects in real time and the EMG activity in the adductor and abductor wrist muscles was recorded. The results show that the velocity of the perceived movements and the amplitude of the corresponding motor responses were modulated by the nature and intensity of the stimulation. Combining two sensory modalities resulted in faster movement illusions, except for the case of visuo-tactile co-stimulation. When a third sensory input was added to the bimodal combinations, the perceptual responses increased only when a muscle proprioceptive stimulation was added to a visuo-tactile combination. Otherwise, trisensory stimulation did not override bimodal conditions that already included a muscle proprioceptive stimulation. We confirmed that vision or touch alone can encode the kinematic parameters of hand movement, as is known for muscle proprioception. When these three sensory modalities are available, they contribute unequally to kinaesthesia. In addition to muscle proprioception, the complementary kinaesthetic content of visual or tactile inputs may optimize the velocity estimation of an on-going movement, whereas the redundant kinaesthetic content of the visual and tactile inputs may rather enhance the latency of the perception.     

SENSORY EVALUATION METHODS FOR TACTILE PROPERTIES OF FABRICS

Sensory evaluation of tactile properties of fabrics is a subject many researchers have studied for years and which still has importance and is also open to improvements. Particularly for suitings, the sensory evaluation of fabric handle or of other tactile properties has a greater importance. This article explains sensory evaluation techniques for stiffness, thickness and smoothness, which are the components of fabric handle of suitings. These sensory techniques are introduced by the authors and studied in 100% worsted wool suitings. The concordances of sensory test results are investigated by Kendall's concordance test, and correlation analyses are carried out to examine the relations between sensory results.     

A common perceptual temporal limit of binding synchronous inputs across different sensory attributes and modalities

The human brain processes different aspects of the surrounding environment through multiple sensory modalities, and each modality can be subdivided into multiple attribute-specific channels. When the brain rebinds sensory content information (‘what’) across different channels, temporal coincidence (‘when’) along with spatial coincidence (‘where’) provides a critical clue. It however remains unknown whether neural mechanisms for binding synchronous attributes are specific to each attribute combination, or universal and central. In human psychophysical experiments, we examined how combinations of visual, auditory and tactile attributes affect the temporal frequency limit of synchrony-based binding. The results indicated that the upper limits of cross-attribute binding were lower than those of within-attribute binding, and surprisingly similar for any combination of visual, auditory and tactile attributes (2–3 Hz). They are unlikely to be the limits for judging synchrony, since the temporal limit of a cross-attribute synchrony judgement was higher and varied with the modality combination (4–9 Hz). These findings suggest that cross-attribute temporal binding is mediated by a slow central process that combines separately processed ‘what’ and ‘when’ properties of a single event. While the synchrony performance reflects temporal bottlenecks existing in ‘when’ processing, the binding performance reflects the central temporal limit of integrating ‘when’ and ‘what’ properties.     

Sensory processing of water currents by fishes

Water currents are extremely important in the aquatic environment and play a very significant role in the lives of fishes. Sensory processing of water currents involves a number of sensory modalities including the inner ear, vision, tactile sense and the mechanosensory lateral line. The inner ear will detect whole-body accelerations generated by changes in flow, or by turbulence, whereas visual and tactile inputs will signal translational movement with respect to an external visual or tactile reference frame. The superficial neuromasts of the mechanosensory lateral line detect flow over the surface of the body and have the appropriate anatomical distribution and physiological properties to signal the strength and the direction of flow and, hence, contribute to the detection of regional differences in flow over different parts of the body.     

Neuropsychology: the touchy, feely side of vision

Some visual attributes, such as colour, are purely visual, but others, such as orientation and movement, can be perceived by touch or audition. A magnetic stimulation study has now shown that the perception of tactile orientation may be influenced by visual Information.     

Tactile Gap Detection Deteriorates during Bimanual Symmetrical Movements under Mirror Visual Feedback

It has been suggested that incongruence between signals for motor intention and sensory input can cause pain and other sensory abnormalities. This claim is supported by reports that moving in an environment of induced sensorimotor conflict leads to elevated pain and sensory symptoms in those with certain painful conditions. Similar procedures can lead to reports of anomalous sensations in healthy volunteers too. In the present study, we used mirror visual feedback to investigate the effects of sensorimotor incongruence on responses to stimuli that arise from sources external to the body, in particular, touch. Incongruence between the sensory and motor signals for the right arm was manipulated by having the participants make symmetrical or asymmetrical movements while watching a reflection of their left arm in a parasagittal mirror, or the left hand surface of a similarly positioned opaque board. In contrast to our prediction, sensitivity to the presence of gaps in tactile stimulation of the right forearm was not reduced when participants made asymmetrical movements during mirror visual feedback, as compared to when they made symmetrical or asymmetrical movements with no visual feedback. Instead, sensitivity was reduced when participants made symmetrical movements during mirror visual feedback relative to the other three conditions. We suggest that small discrepancies between sensory and motor information, as they occur during mirror visual feedback with symmetrical movements, can impair tactile processing. In contrast, asymmetrical movements with mirror visual feedback may not impact tactile processing because the larger discrepancies between sensory and motor information may prevent the integration of these sources of information. These results contrast with previous reports of anomalous sensations during exposure to both low and high sensorimotor conflict, but are nevertheless in agreement with a forward model interpretation of perceptual modulations during goal directed movement.     

Generation of tactile maps for artificial skin

Prior research has shown that representations of retinal surfaces can be learned from the intrinsic structure of visual sensory data in neural simulations, in robots, as well as by animals. Furthermore, representations of cochlear (frequency) surfaces can be learned from auditory data in neural simulations. Advances in hardware technology have allowed the development of artificial skin for robots, realising a new sensory modality which differs in important respects from vision and audition in its sensorimotor characteristics. This provides an opportunity to further investigate ordered sensory map formation using computational tools. We show that it is possible to learn representations of non-trivial tactile surfaces, which require topologically and geometrically involved three-dimensional embeddings. Our method automatically constructs a somatotopic map corresponding to the configuration of tactile sensors on a rigid body, using only intrinsic properties of the tactile data. The additional complexities involved in processing the tactile modality require the development of a novel multi-dimensional scaling algorithm. This algorithm, ANISOMAP, extends previous methods and outperforms them, producing high-quality reconstructions of tactile surfaces in both simulation and hardware tests. In addition, the reconstruction turns out to be robust to unanticipated hardware failure.     

Arthropod touch reception: spider hair sensilla as rapid touch detectors

Wandering spiders like Cupiennius salei are densely covered by tactile hairs. In darkness Cupiennius uses its front legs as tactile feelers. We selected easily identifiable hairs on the tarsus and metatarsus which are stimulated during this behavior to study tactile hair properties. Both the mechanical and electrophysiological hair properties are largely independent of the direction of hair displacement. Restoring torques measure 10(-9) to 10(-8) Nm. The torsional restoring constant S changes non-linearly with deflection angle. It is of the order of 10(-8) Nm/rad, which is about 10,000 times larger than for trichobothria. Angular thresholds for the generation of action potentials are ca.1 degrees. Electrophysiology reveals a slow and a fast sensory cell, differing in adaptation time. Both cells are movement detectors mainly responding to the dynamic phase (velocity) of a stimulus. When applying behaviorally relevant stimulus velocities (up to 11 cm s(-1)) threshold deflection for the elicitation of action potentials and maximum response frequency are reached as early as 1.2 ms after stimulus onset and followed by a rapid decline of impulse frequency. Obviously these hairs inform the spider on the mere presence of a stimulus but not on details of its time-course and spatial orientation.     

Sensilla and Cuticular Appendages on the Female Abdomen of Lasioptera rubi (Schrank) (Diptera,Cecidomyiidae)

Studies by SEM and TEM revealed 6 types of integumental appendages on female uromeres VIII-X in Lasioptera rubi: microtrichia, not innervated; spines, probably without sensory function; nonporous sensory hairs, each containing one dendrite ending with a tubular body indicating a tactile function; uniporous sensory hairs, each innervated partly by 3 dendrites indicating a chemosensory function, partly by an additional dendrite with a tubular body indicating a tactile function; scoop-like sensilla, each containing partly a branched structure of dendrites in the distal half of the sensillum indicating an olfactory function, partly an unbranched dendrite ending at a pore near the base of the sensillum, most probably registrating chemical stimuli by contact or gustation; finally, nonporous bristles, all or some of them innervated, in a manner indicating a tactile function. In addition, two scolopophorous proprioceptors were found inside uromere X. The nonporous sensory hairs, the uniporous sensory hairs and the scolopophores may be used by the midge to determine the mechanical and chemical properties of potential oviposition sites. The spines and nonporous bristles may function as conidia carriers.     

Manual chronostasis: tactile perception precedes physical contact

When saccading to a silent clock, observers sometimes think that the second hand has paused momentarily. This effect has been termed chronostasis and occurs because observers overestimate the time that they have seen the object of an eye movement. They seem to extrapolate its appearance back to just prior to the onset of the saccade rather than the time that it is actually fixated on the retina. Here, we describe a similar effect following an arm movement: subjects overestimate the time that their hand has been in contact with a newly touched object. The illusion's magnitude suggests backward extrapolation of tactile perception to a moment during the preceding reach. The illusion does not occur if the arm movement triggers a change in a continuously visible visual target: the time of onset of the change is estimated correctly. We hypothesize that chronostasis-like effects occur when movement produces uncertainty about the onset of a sensory event. Under these circumstances, the time at which neurons with receptive fields that shift in the temporal vicinity of a movement change their mappings may be used as a time marker for the onset of perceptual properties that are only established later.     

Noninformative vision improves the spatial resolution of touch in humans

Research on sensory perception now often considers more than one sense at a time. This approach reflects real-world situations, such as when a visible object touches us. Indeed, vision and touch show great interdependence: the sight of a body part can reduce tactile target detection times [1], visual and tactile attentional systems are spatially linked [2], and the texture of surfaces that are actively touched with the fingertips is perceived using both vision and touch [3]. However, these previous findings might be mediated by spatial attention [1, 2] or by improved guidance of movement [3] via visually enhanced body position sense [4--6]. Here, we investigate the direct effects of viewing the body on passive touch. We measured tactile two-point discrimination thresholds [7] on the forearm while manipulating the visibility of the arm but holding gaze direction constant. The spatial resolution of touch was better when the arm was visible than when it was not. Tactile performance was further improved when the view of the arm was magnified. In contrast, performance was not improved by viewing a neutral object at the arm's location, ruling out improved spatial orienting as a possible account. Controls confirmed that no information about the tactile stimulation was provided by visibility of the arm. This visual enhancement of touch may point to online reorganization of tactile receptive fields.     

The Efficiency of the Brain-Computer Interfaces Based on Motor Imagery with Tactile and Visual Feedback

In this study we compared tactile and visual feedbacks for the motor imagery-based brain–computer interface (BCI) in five healthy subjects. A vertical green bar from the center of the fixing cross to the edge of the screen was used as visual feedback. Vibration motors that were placed on the forearms of the right and the left hands and on the back of the subject’s neck were used as tactile feedback. A vibration signal was used to confirm the correct classification of the EEG patterns of the motor imagery of right and left hand movements and the rest task. The accuracy of recognition in the classification of the three states (right hand movement, left hand movement, and rest) in the BCI without feedback exceeded the random level (33% for the three states) for all the subjects and was rather high (67.8% ± 13.4% (mean ± standard deviation)). Including the visual and tactile feedback in the BCI did not significantly change the mean accuracy of recognition of mental states for all the subjects (70.5% ± 14.8% for the visual feedback and 65.9% ± 12.4% for the tactile feedback). The analysis of the dynamics of the movement imagery skill in BCI users with the tactile and visual feedback showed no significant differences between these types of feedback. Thus, it has been found that the tactile feedback can be used in the motor imagery-based BCI instead of the commonly used visual feedback, which greatly expands the possibilities of the practical application of the BCI.     

Behavioral impact of unisensory and multisensory audio-tactile events: pros and cons for interlimb coordination in juggling

Recent behavioral neuroscience research revealed that elementary reactive behavior can be improved in the case of cross-modal sensory interactions thanks to underlying multisensory integration mechanisms. Can this benefit be generalized to an ongoing coordination of movements under severe physical constraints? We choose a juggling task to examine this question. A central issue well-known in juggling lies in establishing and maintaining a specific temporal coordination among balls, hands, eyes and posture. Here, we tested whether providing additional timing information about the balls and hands motions by using external sound and tactile periodic stimulations, the later presented at the wrists, improved the behavior of jugglers. One specific combination of auditory and tactile metronome led to a decrease of the spatiotemporal variability of the juggler''s performance: a simple sound associated to left and right tactile cues presented antiphase to each other, which corresponded to the temporal pattern of hands movement in the juggling task. A contrario, no improvements were obtained in the case of other auditory and tactile combinations. We even found a degraded performance when tactile events were presented alone. The nervous system thus appears able to integrate in efficient way environmental information brought by different sensory modalities, but only if the information specified matches specific features of the coordination pattern. We discuss the possible implications of these results for the understanding of the neuronal integration process implied in audio-tactile interaction in the context of complex voluntary movement, and considering the well-known gating effect of movement on vibrotactile perception.     

Probing the settlement signals of Amphibalanus amphitrite

To achieve their reproductive potential, barnacles combine tactile exploration of surface structural properties and integration of cellular signals originating from their antennular sensory setae within a developmentally defined, temporally narrow window of settlement opportunity. Behavioural assays with cyprids coupled with biometric analysis of scanning electron microscopy-acquired images in the presence of specific chemical compounds were used to investigate how settlement on a substratum is altered in response to the presence of these compounds. Impeding tactile exploration was shown which altered cellular signalling and/or induced malformation of anatomical features of the antennular sensory setae, which disrupted the settlement behaviour of the model barnacle species Amphibalanus amphitrite. It is concluded that surface exploration by the cyprids relies on mechanical and nociception-related and calcium-mediated signals while a protein kinase C signalling cascade controls the timely metamorphosis of the cyprids to sessile juveniles.     

Sensory modulation and behavioral choice during feeding in the Australian frog, Cyclorana novaehollandiae

This study investigates how visual and tactile sensory information, as well as biomechanical effects due to differences in physical characteristics of the prey, influence feeding behavior in the frog Cyclorana novaehollandiae. Video motion analysis was used to quantify movement patterns produced when feeding on five prey types (termites, waxworms, crickets, mice and earthworms). Twelve kinematic variables differed significantly among prey types, and twelve variables were correlated with prey characteristics (including mass, length, height and velocity of movement). Results indicate that C.␣novaehollandiae uses a different strategy to capture each prey type. Visual assessment of prey characteristics appeared to be more important in modulating feeding behavior than tactile cues or biomechanical effects. We propose a hierarchical hypothesis of behavioral choice, in which decisions are based primarily on visual analysis of prey characteristics. In this model, the frogs first choose between jaw prehension and tongue prehension based on prey size. If they have chosen jaw prehension, they next choose between upward or downward head rotation based on length and height of the prey. If they have chosen tongue prehension, they next choose between behavior for fast and slow prey. Final decisions may be the result of behavioral fine tuning based on tactile feedback. Accepted: 5 August 1996     

Sensory transduction in an insect mechanoreceptor: extended bandwidth measurements and sensitivity to simulus strenght

The dynamic properties of sensory transduction in an insect mechanoreceptor, the femoral tactile spine of the cockroach, Periplaneta americana, have been studied by measurement of the frequency response function between randomly varying movement of the tactile spine and afferent action potentials from the sensory neuron which innervates it. The frequency response function of the mechanoreceptor has been characterized over a frequency range which is more than ten times larger than has previously been used for this preparation. Also the effects of varying the amplitude of the stimulating signal have been studied by the use of a range of input signal strengths from about 0.5 to 10 m R.M.S. displacement. The measured frequency response functions can all be well fitted by a theoretical relationship which is a fractional exponent of complex frequency, provided that the time delay caused by conduction of the action potentials from the sensory dendrite to the recording electrodes is taken into account. Under small signal conditions the exponent of complex frequency is close to 0.5 but with larger displacements its value decreases to about half this value. The overall sensitivity of the receptor, as measured by the gain of the frequency response function at a natural frequency of 1 radian/s, is not significantly altered by changes in the input movement amplitude, so that the receptor behaves linearly in this respect. However, the mean rate of action potential occurrence is not linearly related to input movement amplitude. These results are discussed in terms of current theories of sensory transduction and the possible role of tubular bodies in the dynamic behaviour of insect cuticular mechanoreceptors.