Tactile Images Research Articles

Influence of Errors in Tactile Sensors on Some High Level Parameters Used for Manipulation with Robotic Hands.

Tactile sensors suffer from many types of interference and errors like crosstalk, non-linearity, drift or hysteresis, therefore calibration should be carried out to compensate for these deviations. However, this procedure is difficult in sensors mounted on artificial hands for robots or prosthetics for instance, where the sensor usually bends to cover a curved surface. Moreover, the calibration procedure should be repeated often because the correction parameters are easily altered by time and surrounding conditions. Furthermore, this intensive and complex calibration could be less determinant, or at least simpler. This is because manipulation algorithms do not commonly use the whole data set from the tactile image, but only a few parameters such as the moments of the tactile image. These parameters could be changed less by common errors and interferences, or at least their variations could be in the order of those caused by accepted limitations, like reduced spatial resolution. This paper shows results from experiments to support this idea. The experiments are carried out with a high performance commercial sensor as well as with a low-cost error-prone sensor built with a common procedure in robotics.

Accessible educational digital book on tablets for people with visual impairment

Tablet adoption is massive and increasing. Many applications are leveraging this marked widespread, including digital interactive books. A proposal for an educational and accessible digital book reader in mobile devices is presented, focusing on people with visual impairment. An implementation was developed, aiming to complement digital accessible books for education. The work presents a digital book with support for knowledge assessing, text reading, worksheets, drawing and tactile images and maps.

MO‐F‐CAMPUS‐I‐05: The Total Internal Reflection Based Elastography Method for Tissue Elasticity Quantification and Characterization

Purpose:Diagnosing early formation of tumors or lumps, particularly those caused by cancer, has been a problem. Our goal is to develop a simple and easy to use system that can document the properties of palpable lumps in soft tissue using noninvasive technique.Methods:The tactile sensor we propose comprises of an elastic optical waveguide unit, a high resolution CCD camera unit, a LED light source unit, and a laptop computer. The sensing element is formed on poly dimethylsiloxane (PDMS) and is illuminated along its four edges by LED light sources. The tactile sensor operates on the principle of total internal reflection (TIR) within an optical waveguide. The light directed into the waveguide remains within it due to the TIR generated, since the waveguide is surrounded by air having a lower refractive index than the waveguide. When an object adheres to the waveguide and compresses, the contact area of the waveguide deforms and causes the light to scatter.Results:To validate the proposed method, three patients presented with a lesion that was initially detected by another modality (mammography, ultrasound, or manual palpation). When performing the sensor scans, the doctor already knew where the lesions were located. For each lesion, 10 tactile images were obtained and the estimated parameters were averaged. Regarding the hardness estimation of the lesions, malignant breast lesion of the patient 1 had increased Young's modulus (146 kPa), compared to benign lesions (97 kPa and 103 kPa, patient 2 and 3). The elasticity information was correlated with the malignancy data from the pathology reports. The minimum and maximum relative errors are 1.1% and 11.72%. The mean error is 5.07% with 3.39% standard deviation.Conclusion:In this paper, a tactile elasticity imaging sensor using the total internal reflection principle is designed and experimentally evaluated.

Multisensory image as a component of destination image

Destination image involves the use of all five senses: vision, sound, smell, taste and touch. This research note applies the literature on sensory inputs to the concept of ancient towns, in a case study of Phoenix, Hunan Province, China. The results from 16 depth-interviews with tourists illustrate the five senses' importance in tourism. Tourists noted all five senses, with visual image receiving the most attention and tactile image the least. The results support the existence and significance of a ‘multisensory image’. The results contribute to the nascent ‘sensory’ literature and research into the appeals of an ‘ancient town’, while adding implications for destination management.

The Difference of Imagery Perception between Visual and Tactile Sensation

Images aroused by sensory faculties, especially that of touch and vision, play a very important role in human-product interaction. Most studies tackled sensory modalities in isolation, which is somewhat insufficient, as cross-talks among sensory channels would be unduly overlooked. In this study we compared visual and tactile images at the same time, trying to reveal the correlations and distinctiveness of these two primary modalities. In the first stage of the study, we obtained 35 pieces of modern design works as the visual stimuli according to the opinion of interviewed experts. The material compositions of these works were then analyzed and 37 materials were abstracted for tactile evaluation. The vocabularies used by the experts to describe their feelings on evaluating the design works and the materials were grouped into 21 adjective pairs with KJ method. Thirty five subjects were then recruited to give semantic differential evaluation with the scale of the 21 adjective pairs on the 35 visual and 37 tactile stimuli. Through factor analysis, we found four principle factors of image for both of the two modalities. However, the components of adjective pairs in each factor of the two modalities are slightly different. This variation may imply that although tactile and visual sensation often function cooperatively to enhance the perception of each other, they sometime work competitively; the dominant modality will suppress the other one especially for some imagery perception. Finally, this study found that the tactile oriented feeling of roughness may influence visual images. The result of the investigation can help researchers to further understand the influence between multisensory images and to treat it as a useful reference for relative studies, while it can help designers to design products with demanded tactile and visual feeling.

Research and Teaching: Methods for Creating and Evaluating 3D Tactile Images to Teach STEM Courses to the Visually Impaired

Research and Teaching: Methods for Creating and Evaluating 3D Tactile Images to Teach STEM Courses to the Visually Impaired

Real-Time Computing of Touch Topology via Poincare–Hopf Index

While visual or tactile image data have been conventionally processed via filters or perceptron-like learning machines, the recent advances of computational topology may make it possible to successfully extract the global features from the local pixelwise data. In fact, some inventive algorithms have succeeded in computing the topological invariants, such as the number of objects or holes and irrespective of the shapes and positions of the touches. However, they are mostly offline algorithms aiming at big data. A real-time algorithm for computing topology is also needed for interactive applications such as touch sensors. Here, we propose a fast algorithm to compute the Euler characteristics of touch shapes by using the Poincare-Hopf index for each pixel. We demonstrate that our simple algorithm, implemented solely as logical operations in Arduino, correctly returns and updates the topological invariants of touches in real time.

3D Printing Technology: A Unique Way of Making Hubble Space Telescope Images Accessible to Non-Visual Learners

Astronomy traditionally is a visual science by which sighted people have contemplated the night sky. Astronomy has also spurred the development of sophisticated telescopes and instruments, featuring capabilities that extend to wavelengths beyond the visible, to record images of celestial objects. While the scientific data from telescopes is somewhat specialized and technical, astronomers routinely process their data to produce visually appealing formats for the public at large and also widely contribute to education and outreach efforts. Astronomical data is treated through image processing techniques including color and intensity choices that result in imagery that best represents the science being investigated in its greatest aesthetic appeal. Making such astronomical imagery accessible to those who are visually impaired has been a long-standing challenge. Yet, it is recognized that such individuals should have an opportunity to explore, discover, learn about, and contribute to astronomy and science in general. Considerable work has been done by educators, scientists, and artists to make science in general and astronomy in particular more accessible through the use of various technologies, including low resolution tactile images on thermoform and swell-touch pages based on the visual materials. Recently, 3D printers have emerged as a new tool for making reproductions of objects so that they can be useable and understood by a broader community of learners, including the visually impaired. This article outlines an innovative study that is aimed at taking images of astronomical objects and translating them into a 3D tactile representation of the object’s structure and composition for engagement and discovery by a range of users and learning styles. Using the star cluster NGC 602 as observed by the Hubble Space Telescope as the initial test case, we investigated processes for creating appropriate digital file structures, tested tactile approaches, and utilized focus groups to determine usability of the products.

Book Review: Psychology of Touch and Blindness, Morton A. Heller and Edouard Gentaz

Psychology of Touch and Blindness, Morton A. Heller and Edouard Gentaz. New York: Psychology Press, Taylor & Francis Group, 2014,284 pp.; paperback, $59.95; hardcover, $150. Psychology of Touch and Blindness, by Morton A. Heller and Edouard Gentaz, offers a comprehensive look at the nature of touch for researchers and other professionals who seek a deep understanding of the theoretical and neurological aspects of the subject. Practitioners, however, may find the book too theoretical and lacking discussion about how the information included in the text can be applied when working with adults or children who are visually impaired (that is those who are or have low vision). Although the book does not provide strategies for the explicit application of its theories, the text includes a large amount of information on the basic science of touch and the haptic abilities of people with visual impairments. Those readers who are willing to investigate the information fully enough to make their own connections between the research being presented and practice could apply such knowledge to the education of people with visual impairments. CONFUSING TERMINOLOGY Although the book covers an incredible amount of information, the tone of the book is quite understandable. Technical terms and jargon are explained and often include examples or analogies that further illustrate the concepts or points. The authors frequently relay personal experiences and encounters with individuals who are to support points being made. Although I appreciated this approach and the attention the authors gave to explaining concepts and unfamiliar terms that might lead to confusion, I was surprised that person-first language was not used. The language used by the authors also caused confusion at times--they always used the terms people or subjects, which left me wondering if all the individuals who participated in the highlighted studies were totally blind. Another example of confusing language occurred in the chapter Picture Perception and Blind People, in which one study that was discussed reported that blind individuals did very poorly when asked to draw Surely the study was not conducted with participants who are totally blind; otherwise, the finding could not have been surprising! THOUGHT-PROVOKING RESEARCH Despite some of the confusion surrounding the subjects described in the chapter on picture perception, the information provided on the ability of individuals who are to accurately interpret pictures was quite interesting. The analysis of the research provided simple, practical strategies (such as making the tactile images larger) for improving the abilities of individuals who are visually impaired to better interpret tactile pictures. The book also provided a thorough and engaging discussion of the haptic abilities and inabilities of individuals who are blind, some of which were quite surprising. For instance, studies found participants could not only identify unknown people with great accuracy by touching the individuals' faces, but they could also tactually identify a range of facial expressions indicating a wide variety of emotions without any training. The functional implications of these skills are not obvious, but it is interesting to learn about the refined haptic abilities of those studied. Another study discussed in the book found that haptic perception of texture could be even more accurate than visual perception. Another highlight of the book was the in-depth discussion of the implications for weighing one sense against another in bimodal sensory situations, which could have interesting application for individuals with low vision. …

Interfacing robotic tactile sensation with human vibrotactile perception for digit recognition

To achieve human like functionality, artificial arms are required to be incorporated with the sense of touch that can be achieved by affixing tactile sensors to them. The user operating these artificial arms, for any Human–Computer Interactive task, should be able to perceive the same tactile sensation as is acquired by the tactile sensor fitted artificial arms. This work is an initial step to interface artificial tactile sensations of robots with human perception. Pressure distribution images are acquired while a robot arm fitted with a tactile sensor palpates embossed digits (0–9) and are classified. The image classification results are transmitted via control signals as vibrotactile stimuli to humans using vibration motors attached on their backs. Vibrotactile stimulus is chosen as a feedback sensation in an attempt to not engage visual/auditory channels such that the work can be extended in a multitasking environment in future. Vibrotactile stimuli are also essential for a person using prosthetic arm, suffering from sensory-motor disabilities that inhibit the use of the audio and/or visual sensory channels as well as for applications such as tele-operation. Electroencephalogram (EEG) signal analysis during vibrotactile stimulus presentation as well as subjects’ response evaluation show that vibrotactile stimuli for particular digits as recognized from tactile data is capable of imparting information from artificial somato-sensation to humans. Fuzzy k-Nearest Neighbor classifier classifies both tactile images and vibrotactually stimulated EEG signals online with average accuracies of 85.25% and 72.60%, and runtimes of the order of 0.11 and 35 s respectively.

Relação texto-imagem: a resposta de crianças com deficiência visual ao livro ilustrado contemporâneo

Exploratory, the paper presents and discusses the response of children with visual impairment on the illustrated children’s book, analyzing how to establish relationships and dialogue between text and image support in the book from the perspective of non- visual , mainly in concerns the cognitive feature and the specific conditions of visual impairment . This study is justified by the importance that access to different languages ( image and text ) , added to the literary function of fictional narrative can provide the Bantam player, as well as access to imaging and its meaning to the reader , there is still the possibility include children with visual impairment in the literary universe in a field whose intricate set of languages provides the reader with a multiplicity of meanings that can take children’s reader to find new ways to relate to the world . The method used here , interview - conversation ( SARAMAGO , 2001) , questions blind and low vision between 10 and 14 years Londrinense Institute of Education and Work for the Blind of Londrina / PR on the relationship between image and text children during reading two illustrated works adapted : forgotten Adelia Adelia and dreamy, both selected by the diversity of graphical features ( smooth textures , flocked , granular , etc.) used in the translation of images for relief . The aim is to compare two aspects equivalences and differences between reading narratives that rely on graphics to convey its essential message and that can easily be understood only by the text in order to verify that an integration or fragmentation of languages that exist on integrating image text - in the context of visual impairment . Results indicate that the experience of reading is complexed in each book , unique to each turn of the page and predominantly verbal. However, typologies act as effective parameter for understanding the various relationships between image and text observed during the interview and awaken to the vast field of possibilities that are there to be explored in the adapted children’s literature . We conclude that tactile image and text has not yet reached the status of parity adapted works, it is necessary to increase dialogue and information sharing between the mediators of the books and the public with visual impairments , so that not only promotes increased quality and quantity of suitable products, but also a greater critical exercise for the front of interdependent narratives with image and text reader.

Sensory Imagery in Individuals who Are Blind and Sighted: Examining Unimodal and Multimodal Forms

Introduction Previous research has suggested that visual images are more easily generated, more vivid, and more memorable than other sensory modalities. This research examined whether or not imagery is experienced in similar ways by people with and without sight. Specifically, the imageability of visual, auditory, and tactile cue words was compared. The degree to which images were multimodal or unimodal was also examined. Methods Twelve participants who were totally blind from early infancy and 12 sighted participants generated images in response to 53 sensory and nonsensory words, rating imageability and the sensory modality, and describing images. From these 53 items, 4 subgroups of words that stimulated images that were predominantly visual, tactile, auditory, and low-imagery were created. Results T-tests comparing imageability ratings from blind and sighted participants found no differences for auditory and tactile words (both p > .1). Nevertheless, although participants without sight found auditory and tactile images equally imageable, sighted participants found images in response to tactile cue words harder to generate than visual cue words (mean difference: −0.51, p = .025). Participants with sight were also more likely to develop multisensory images than were participants without sight (both U ≥ 15.0, N1 = 12, N2 = 12, p ≤.008). Discussion For both the blind and sighted groups, auditory and tactile images were rich and varied, and similar language was used. Sighted participants were more likely to generate multimodal images, and this was particularly the case for tactile words. Nevertheless, cue words that resulted in multisensory images were not necessarily rated as more imageable. The discussion considers whether or not multimodal imagery represents a method of compensating for impoverished unimodal imagery. Implications for practitioners Imagery is important not only as a mnemonic in memory rehabilitation, but also in everyday uses for modes such as autobiographical memory. This research emphasizes the importance of not only auditory and tactile sensory imagery, but also spatial imagery for people without sight.

OBJECT-SHAPE RECOGNITION BY TACTILE IMAGE ANALYSIS USING SUPPORT VECTOR MACHINE

The sense of touch is important to human to understand shape, texture, and hardness of the objects. An object under grip, i.e. object exploration by enclosure, provides a unique pressure distribution on the different regions of palm depending on its shape. This paper utilizes the above experience for recognition of object shapes by tactile image analysis. The high pressure regions (HPRs) are segmented and analyzed for object shape recognition rather than analyzing the entire image. Tactile images are acquired by capacitive tactile sensor while grasping a particular object. Geometrical features are extracted from the chain codes obtained by polygon approximation of the contours of the segmented HPRs. Two-level classification scheme using linear support vector machine (LSVM) is employed to classify the input feature vector in respective object shape classes with an average classification accuracy of 93.46% and computational time of 1.19 s for 12 different object shape classes. Our proposed two-level LSVM reduces the misclassification rates, thus efficiently recognizes various object shapes from the tactile images.

Generación de contenidos digitales para la reactivación del patrimonio arquitectonico. Estudio de caso: plaza de mercado de techo cubierto de Guayaquil, Medellín

Thanks to own technological resources and the convergence of media such as interactive texts, data that allow tactile navigation, maps, planes, images, and virtual models, among others, the material patrimony can be celebrated, contemplated, and admired just by pushing a key. Graphic recreation of a historical building, such as “Plaza de Mercado de Techo Cubierto de Guayaquil,” study case of this research and city site colloquially known as “Plaza Cisneros de Medellin,” was a social milestone of the nineteenth century, since places around this building were the scenarios of marketing and transportations movements in Medellin. For this reason, and thanks to the technology known as Augmented Reality (AR) and the creation of digital contents provided in the research, personalization of information related to cultural patrimony ca be achieved, as well as its handling through mobile devices as mass communication tools by means of which several audiences access contents, navigation routines, and digital information consumption, entertainment experiences, online networking through communication services

On the Quest for Better Communication through Tactile Images

Abstract Art in Western civilization has become a commodity that is fixed to walls and viewed through the eyes. In fact, most museums and galleries post "Do not touch" signs dissuading audiences from partaking in anything but the visual aspects of art. Yet art production is something that is inherently tactile; it involves engaging with art media such as paint and brush or clay that is molded by the human hand. Compounded by the "Do not touch" attitude is the taboo in society that draws people away from sensuality, especially touch. Yet touch is a natural way of exploring the world and, according to many researchers, a natural and important way of exploring art as well. There are many historical examples of art that have tactile components, for example, relief on Egyptian stone tablets and brush-stroked textures on a Mondrian painting. Even so, these are typically intended for visual-centric audiences and are not necessarily designed or intended to be touched. Yet, another story exists, which is the development of tactile representations of maps, artwork, and other materials for people who are visually impaired.3

Seeing by touch: evaluation of a soft biologically-inspired artificial fingertip in real-time active touch.

Effective tactile sensing for artificial platforms remains an open issue in robotics. This study investigates the performance of a soft biologically-inspired artificial fingertip in active exploration tasks. The fingertip sensor replicates the mechanisms within human skin and offers a robust solution that can be used both for tactile sensing and gripping/manipulating objects. The softness of the optical sensor's contact surface also allows safer interactions with objects. High-level tactile features such as edges are extrapolated from the sensor's output and the information is used to generate a tactile image. The work presented in this paper aims to investigate and evaluate this artificial fingertip for 2D shape reconstruction. The sensor was mounted on a robot arm to allow autonomous exploration of different objects. The sensor and a number of human participants were then tested for their abilities to track the raised perimeters of different planar objects and compared. By observing the technique and accuracy of the human subjects, simple but effective parameters were determined in order to evaluate the artificial system's performance. The results prove the capability of the sensor in such active exploration tasks, with a comparable performance to the human subjects despite it using tactile data alone whereas the human participants were also able to use proprioceptive cues.

Object-shape recognition and 3D reconstruction from tactile sensor images

This article presents a novel approach of edged and edgeless object-shape recognition and 3D reconstruction from gradient-based analysis of tactile images. We recognize an object's shape by visualizing a surface topology in our mind while grasping the object in our palm and also taking help from our past experience of exploring similar kind of objects. The proposed hybrid recognition strategy works in similar way in two stages. In the first stage, conventional object-shape recognition using linear support vector machine classifier is performed where regional descriptors features have been extracted from the tactile image. A 3D shape reconstruction is also performed depending upon the edged or edgeless objects classified from the tactile images. In the second stage, the hybrid recognition scheme utilizes the feature set comprising both the previously obtained regional descriptors features and some gradient-related information from the reconstructed object-shape image for the final recognition in corresponding four classes of objects viz. planar, one-edged object, two-edged object and cylindrical objects. The hybrid strategy achieves 97.62% classification accuracy, while the conventional recognition scheme reaches only to 92.60%. Moreover, the proposed algorithm has been proved to be less noise prone and more statistically robust.

Low-Resolution Tactile Image Recognition for Automated Robotic Assembly Using Kernel PCA-Based Feature Fusion and Multiple Kernel Learning-Based Support Vector Machine

In this paper, we propose a robust tactile sensing image recognition scheme for automatic robotic assembly. First, an image reprocessing procedure is designed to enhance the contrast of the tactile image. In the second layer, geometric features and Fourier descriptors are extracted from the image. Then, kernel principal component analysis (kernel PCA) is applied to transform the features into ones with better discriminating ability, which is the kernel PCA-based feature fusion. The transformed features are fed into the third layer for classification. In this paper, we design a classifier by combining the multiple kernel learning (MKL) algorithm and support vector machine (SVM). We also design and implement a tactile sensing array consisting of 10-by-10 sensing elements. Experimental results, carried out on real tactile images acquired by the designed tactile sensing array, show that the kernel PCA-based feature fusion can significantly improve the discriminating performance of the geometric features and Fourier descriptors. Also, the designed MKL-SVM outperforms the regular SVM in terms of recognition accuracy. The proposed recognition scheme is able to achieve a high recognition rate of over 85% for the classification of 12 commonly used metal parts in industrial applications.

The process of graphic image creation in the conditions of non-seeing

This article explores the problem of depiction in tactile images, aiming to further existing understanding of what else, besides any tangible marks that may happen to be a feature of a particular image, can be said to belong to the image’s tactility. The answer to this question is sought using examples of creative practice incorporating varieties of touch perception. Analysing the examples, it emerges that the sense of touch is involved in the creation of drawings to a greater extent than tactile sensations (sensorial qualities that are conveyed during the contact). Touch enters the image area through tactile–kinaesthetic imagery based on descriptive gesture that is also shown to manifest itself in situations of non-seeing. It is also suggested that the drawing image, created using descriptive gesture, is capable of displaying intelligible links between the depicted object and the perceptual information associated with it.

Two-Dimensional Direction Recognition Using Uniaxial Tactile Arrays

To allow intuitive communication in human-robot cooperation through tactile information, this paper presents a method to recognize human intended direction in 2-D using a handlebar equipped with uniaxial tactile arrays. The method first extracts various features from the tactile images aiming to reduce computation complexity and increase recognition robustness. A support vector machines classifier was implemented for classifying the intended direction of humans using the extracted features. The algorithm efficiency of using different combinations of features has been investigated and compared through human user studies. In total, five human users in the project team were involved in this research. Experimental results show that the proposed method can achieve 91.7% recognition accuracy if both the training data and validation data contain tactile images from all the users. The method could still achieve 77.5% recognition accuracy when the training and validation data share no common user.