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Defining a vibrotactile toolkit for digital musical instruments: characterizing voice coil actuators, effects of loading, and equalization of the frequency response
Abstract
The integration of vibrotactile feedback in digital music instruments (DMIs) is thought to improve the instrument’s response and make it more suitable for expert musical interactions. However, given the extreme requirements of musical performances, there is a need for solutions allowing for independent control of frequency and amplitude over a wide frequency bandwidth (40–1000 Hz) and low harmonic distortion, so that flexible and high-quality vibrotactile feedback can be displayed. In this paper, we evaluate cost-effective and portable solutions that meet these requirements. We first measure the magnitude–frequency and harmonic distortion characteristics of two vibrotactile actuators, where the harmonic distortion is quantified in the form of total harmonic distortion (THD). The magnitude–frequency and THD characteristics in two unloaded cases (actuator suspended freely or placed on a sandbag) are observed to be largely identical, with minor attenuation for actuators placed on the sandbag. Loading the actuator (when placed in a DMI) brings resonant features to its magnitude–frequency characteristics, increasing the output THD and imposing a dampening effect. To equalize the system’s frequency response, an autoregressive method that automatically estimates minimum-phase filter parameters is introduced, which by design, remains stable upon inversion A practical use of this method is demonstrated by implementing vibrotactile feedback in the poly vinyl chloride chassis of an unfinished DMI, the t-Stick. We finally compare the result of equalization by performing sinesweep measurements on the implementation and discuss the degree of equalization achieved using it.
... How to effectively retrieve the music information that people need has become an urgent problem to be dealt with by music information retrieval technology. Before the emergence of deep learning technology, the research on music classification mainly focused on the selection of feature sets and classifiers [5]. With the emergence of open music datasets, there are more and more research works in the field of music classification. ...
In recent years, the recommendation application of artificial intelligence and deep music has gradually become a research hotspot. As a complex machine learning algorithm, deep learning can extract features with value laws through training samples. The rise of deep learning network will promote the development of artificial intelligence and also provide a new idea for music score recognition. In this paper, the improved deep learning algorithm is applied to the research of music score recognition. Based on the traditional neural network, the attention weight value improved convolutional neural network (CNN) and high execution efficiency deep belief network (DBN) are introduced to realize the feature extraction and intelligent recognition of music score. Taking the feature vector set extracted by CNN-DBN as input set, a feature learning algorithm based on CNN&DBN was established to extract music score. Experiments show that the proposed model in a variety of different types of polyphony music recognition showed more accurate recognition and good performance; the recognition rate of the improved algorithm applied to the soundtrack identification is as high as 98.4%, which is significantly better than those of other classic algorithms, proving that CNN&DBN can achieve better effect in music information retrieval. It provides data support for constructing knowledge graph in music field and indicates that deep learning has great research value in music retrieval field.
... En comparaison, les vibreurs haut-parleur permettent un contrôle indépen-3. ang.ecological associations dant de ces deux dimensions, mais nécessitent un circuit électronique dédié beaucoup plus complexe pour être opéré [24]. Pour une comparaison plus en détail de ces modèles de vibreurs, vous pouvez vous référer au travail de Choi et al. [40]. ...
Cette thèse montre que « l’interaction directe d’un opérateur au cours de la mise en œuvre du procédé industriel de fabrication additive pour améliorer la fabrication est possible ». Aujourd’hui, la mise en œuvre de la Chaîne Numérique ne permet pas de réagir naturellement à l’apparition d’un aléa de fabrication. Or, il apparaît que la fabrication à la demande de produits engendre souvent des aléas durant le processus. La première section du mémoire est consacrée à un état de l’art sur la Fabrication Interactive à partir duquel nous proposons une boucle d’interaction Humain-Robot. Cette boucle permet l’interruption du processus automatique pour apporter une modification locale, directement depuis la cellule de fabrication. Un des verrous à lever est de permettre la perception des valeurs des critères de la fabrication par l’opérateur en temps réel et en mobilité. Pour cela, nous avons exploré les retours vibrotactiles. Ainsi, dans la seconde section du mémoire est présentée TacTool, une application web conçue et réalisée afin d’aider la conception de systèmes vibrotactiles. A partir d’une combinaison de 21 caractéristiques, sélectionnées interactivement et par catégories, l’utilisateur se voit proposer des recommandations sur la conception du dispositif de communication vibrotactile caractérisé. Ces recommandations sont sélectionnées dans un ensemble de 181 recommandations issues de la revue de 97 références comprises entre 1960 et 2020. Dans la dernière section, grâce à la conception d’un bracelet vibrotactile appelé ViMA (Vibrotactile Monitoring Armband), nous avons conçu 20 items vibrotactiles, dont nous avons évalué la capacité à être reconnus. Ainsi, cette évaluation et une enquête auprès de 27 experts de la fabrication additive, ont permis de définir 18 symboles vibrotactiles permettant d’informer un opérateur pour la surveillance des procédés automatisés de fabrication additive.
... The elemental representation is based on the study of the fundamental frequency cycles of human perception, a method also commonly referred to as the chromaticity vector method. In the vector, each element corresponds to one of the 12 traditional cycles [20]. The value obtained by finding the root mean square of the spectral energy is a physical quantity related to the intensity of the sound. ...
Digitization and analysis processing technology of music signals is the core of digital music technology. The paper studies the music signal feature recognition technology based on the mathematical equation inversion method, which is aimed at designing a method that can help music learners in music learning and music composition. The paper firstly studies the modeling of music signal and its analysis and processing algorithm, combining the four elements of music sound, analyzing and extracting the characteristic parameters of notes, and establishing the mathematical model of single note signal and music score signal. The single note recognition algorithm is studied to extract the Mel frequency cepstrum coefficient of the signal and improve the DTW algorithm to achieve single note recognition. Based on the implementation of the single note algorithm, we combine the note temporal segmentation method based on the energy-entropy ratio to segment the music score into single note sequences to realize the music score recognition. The paper then goes on to study the music synthesis algorithm and perform simulations. The benchmark model demonstrates the positive correlation of pitch features on recognition through comparative experiments and explores the number of harmonics that should be attended to when recognizing different instruments. The attention network-based classification model draws on the properties of human auditory attention to improve the recognition scores of the main playing instruments and the overall recognition accuracy of all instruments. The two-stage classification model is divided into a first-stage classification model and a second-stage classification model, and the second-stage classification model consists of three residual networks, which are trained separately to specifically identify strings, winds, and percussions. This method has the highest recognition score and overall accuracy.
The quantization of vibrotactile signals is generally performed in the same way as for audio signals. However, the specificities of the sense of touch may allow other choices for the digitization of vibrotactile signals, in particular on the number of quantization bits. The objective of this paper is to define the minimal number of quantization bits, ensuring an imperceptible digitization to touch. For this, a perceptual study is conducted on a set of signals for several quantization levels. For each signal, the total perceptible harmonic distortion (PTHD), taking into account the vibrotactile thresholds, is defined and calculated. PTHD seems to predict a threshold from which the quantization level of the vibrotactile signals is perceptible. This result was obtained by a perceptive study carried out on 29 subjects from pairwise comparison with vibrotactile signals emitted by an electrodynamic transducer placed in a wristband. If the PTHD of a vibrotactile signal is less than 35 dB, the digitization effect will be imperceptible. This suggests that 8-bit DACs may be sufficient to generate vibrotactile signals without the digitization effects being perceptible.
KeywordsVibrotactileQuantizationPerceptionPsychophysics
In order to provide convincing artifical touch sensations, humans should be presented with high quality haptic stimuli. In the vibrotactile domain, signals are usually displayed through mechanical actuators. Current high quality actuators exhibit a high dynamic range and have the ability to display a wide range of frequencies. However, fundamentally all actuators introduce distortions into the displayed signals. These distortions are usually nonlinear with additive noise components and they can be detrimental to some vibrotactile application scenarios that require high signal playback precision. To neutralize these distortions, we propose a signal-based equalization setup with adaptive filtering. Such a setup is very general and can be applied to any actuator in a straightforward manner. We introduce a novel adaptive filter based on Volterra and bilinear filter models that is nonlinear and more robust than previous approaches. In simulations and experiments we show that our filter model is able to consistently outperform existing adaptive filter models and equalize vibrotactile actuators efficiently.
Conventional loudspeakers are often heavy, require substantial design spaces and are hard to integrate into lightweight structures (e.g., panels). To overcome these drawbacks, this paper presents a novel extremely flat loudspeaker which uses dielectric elastomer actuators with natural rubber for the elastomeric layers and metal electrodes as transduction mechanism. To facilitate the deformation of the elastomer, the electrodes are perforated. The microscopic holes lead to a macroscopically compressible stack configuration despite the elastomer incompressibility. The design is developed and the materials are chosen to guarantee low mechanical and electrical losses and a high efficiency in the entire frequency range up to several kilohertz. The loudspeaker was designed, built and afterwards experimentally investigated and characterised. Laser measurements of the surface velocity were performed to find dynamic effects present at the diaphragm. To further characterise the device, a semi anechoic chamber as used. Sound pressure levels emitted by the device were recorded at different bias and alternating voltages to study their influence. The nonlinearity of the loudspeaker, which is inherent for this kind of actuators, was quantified considering the total harmonic distortion. Here, a dependence on the amplitude of the alternating voltage is observed. Further, the distortion decreases rapidly the higher the frequency is, which qualifies the loudspeaker concept to properly work at high frequencies. Transfer functions between supplied voltage and on-axis sound pressure were measured and showed in principle potential for high frequency application. Further, the behaviour of the diaphragm changing from rigid piston to resilient disk with respect to frequency for different configurations was observed. Additionally, the directivity of the loudspeaker was investigated at several frequencies, and was in accordance with previously found research outcomes. The results, especially in the high frequency range, prove the usability of this design concept for practical applications.
While a standard approach is more or less established for rendering basic vibratory cues in consumer electronics, the implementation of advanced vibrotactile feedback still requires designers and engineers to solve a number of technical issues. Several off-the-shelf vibration actuators are currently available, having different characteristics and limitations that should be considered in the design process. We suggest an iterative approach to design in which vibrotactile interfaces are validated by testing their accuracy in rendering vibratory cues and in measuring input gestures. Several examples of prototype interfaces yielding audio-haptic feedback are described, ranging from open-ended devices to musical interfaces, addressing their design and the characterization of their vibratory output.
This chapter introduces to the concept of musical haptics, its scope, aims, challenges, as well as its relevance and impact for general haptics and human–computer interaction. A brief summary of subsequent chapters is given.
We suggest that studies on active touch psychophysics are needed to inform the design of haptic musical interfaces and better understand the relevance of haptic cues in musical performance. Following a review of the previous literature on vibrotactile perception in musical performance, two recent experiments are reported. The first experiment investigated how active finger-pressing forces affect vibration perception, finding significant effects of vibration type and force level on perceptual thresholds. Moreover, the measured thresholds were considerably lower than those reported in the literature, possibly due to the concurrent effect of large (unconstrained) finger contact areas, active pressing forces, and long-duration stimuli. The second experiment assessed the validity of these findings in a real musical context by studying the detection of vibrotactile cues at the keyboard of a grand and an upright piano. Sensitivity to key vibrations in fact not only was highest at the lower octaves and gradually decreased toward higher pitches; it was also significant for stimuli having spectral peaks of acceleration similar to those of the first experiment, i.e., below the standard sensitivity thresholds measured for sinusoidal vibrations under passive touch conditions.
Haptics, and specifically vibrotactile-augmented interfaces, have been the object of much research in the music technology domain: In the last few decades, many musical haptic interfaces have been designed and used to teach, perform, and compose music. The investigation of the design of meaningful ways to convey musical information via the sense of touch is a paramount step toward achieving truly transparent haptic-augmented interfaces for music performance and practice, and in this chapter we present our recent work in this context. We start by defining a model for haptic-augmented interfaces for music, and a taxonomy of vibrotactile feedback and stimulation, which we use to categorize a brief literature review on the topic. We then present the design and evaluation of a haptic language of cues in the form of tactile icons delivered via vibrotactile-equipped wearable garments. This language constitutes the base of a “wearable score” used in music performance and practice. We provide design guidelines for our tactile icons and user-based evaluations to assess their effectiveness in delivering musical information and report on the system’s implementation in a live musical performance.
An experiment is presented that measured aspects of functionality, usability and user experience for four distinct types of device feedback. The goal was to analyse the role of haptic feedback in functional digital musical instrument (DMI) interactions. Quantitative and qualitative human–computer interaction analysis techniques were applied in the assessment of prototype DMIs that displayed unique elements of haptic feedback; specifically, full haptic (constant-force and vibrotactile) feedback, constant-force only, vibrotactile only and no feedback. From the analysis, data are presented that comprehensively quantify the effects of feedback in haptic interactions with DMI devices. The investigation revealed that the various types of haptic feedback applied had no significant functional effect upon device performance in pitch selection tasks; however, a number of significant effects were found upon the users’ perception of usability and their experiences with each of the different feedback types.
With a recent rise in the availability of affordable head mounted gear sets, various sensory stimulations (e.g., visual, auditory and haptics) are integrated to provide seamlessly embodied virtual experience in areas such as education, entertainment, therapy and social interactions. Currently, there is an abundance of available toolkits and application programming interfaces (APIs) for generating the visual and audio content. However, such richness in hardware technologies and software tools is missing in designing haptic experiences. Current solutions to integrate haptic effects are limited due to: i) a user's rigid adaptation to new hardware and software technologies, ii) limited scalability of the existing tools to incorporate haptic hardware and applications, iii) inflexible authoring capabilities, iv) missing infrastructure for storing, playback and distribution, and v) and unreliable hardware for long term usage.
Research of the audibility of loudspeaker nonlinear distortion has not shown good correlation between traditionally used metrics (harmonics and intermodulation) and subjective performance. The problem of sound fidelity-related methods to assess nonlinearity in transducers has not been solved. Wide application of low-bit rate compression systems (MP3, etc.) demanded the development of objective measurement methods based on perceptual models. These methods however have not been used for measurement of loudspeakers and they may not be optimal for that due to the different nature of the nonlinearity in transducers. Recently perceptual models created specifically for the assessment of nonlinearity in transducers have emerged. In this work analysis of the old and new methods, their comparison, and the prospects for future developments are discussed.
Digital Musical Instruments (DMIs) are musical instruments typically composed of a control surface where user interaction is measured by sensors whose values are mapped to sound synthesis algorithms. These instruments have gained interest among skilled musicians and performers in the last decades leading to artistic practices including musical performance, interactive installations and dance. The creation of DMIs typically involves several areas, among them: arts, design and engineering. The balance between these areas is an essential task in DMI design so that the resulting instruments are aesthetically appealing, robust, and allow responsive, accurate and repeatable sensing. In this paper, we review the use of sensors in the DMI community as manifested in the proceedings of the International Conference on New Interfaces for Musical Expression (NIME 2009-2013). Focusing on the sensor technologies and signal conditioning techniques used by the NIME community. Although it has been claimed that specifications for artistic tools are harder than those for military applications, this study raises a paradox showing that in most of the cases, DMIs are based on a few basic sensors types and unsophisticated engineering solutions, not taking advantage of more advanced sensing, instrumentation and signal processing techniques that could dramatically improve their response. We aim to raise awareness of limitations of any engineering solution and to assert the benefits of advanced electronics instrumentation design in DMIs. For this, we propose the use of specialized sensors such as strain gages, advanced conditioning circuits and signal processing tools such as sensor fusion. We believe that careful electronic instrumentation design may lead to more responsive instruments.
This paper discusses vibrotactile feedback in digital musical instruments. It compares the availability of intrinsic vibrotactile feedback in traditional acoustic musical instruments with the lack of vibrotactile feedback in most digital musical instruments. A short description of human sensory ability with regard to this form of feedback is given and the usefullness of vibrotactile feedback to musical performers is also briefly discussed. A number of devices are examined which can be used to provide vibrotactile feedback in a digital musical instruments and some experiments to evaluate these devices are also described. Finally, examples are given of a number of instruments which make use of some of these devices to provide vibrotactile feedback to the performer.
This paper presents a full-body vibrotactile display that can be used as a tool to help learning music performance. The system is composed of 10 vibrotactile actuators placed on different positions of the body as well as an extended and modified version of a software tool for generating tactile events, the Fast Afferent/Slow Afferent (FA/SA) applica-tion. We carried out initial tests of the system in the context of enhancing the learning process of novice guitar players. In these tests we asked the performers to play the guitar part over a drum and bass-line base track, either heard or felt by the performers through headphones and the tactile display they were wearing. Results show that it is possible to accurately render the representation of the audio track in the tactile channel only, therefore reducing the cognitive load in the auditory channel.
This paper presents a new approach to the integration of vibrotactile feedback into digital musical instruments. A design strategy for musical vibrotactile systems is devel- oped based on stimulator properties and neurophysiologi- cal studies of vibrotactile perception. A software vibration synthesizer driven by perceptual sound features extracted from audio feedback has been created based on these con- cepts. This framework will help to simplify integration of vibrotactile feedback into instrument designs by defining high-order tactile invariants, avoiding the need to explic- itly specify low-level vibration stimulus parameters. 1. MOTIVATION Touch has been vital to the development of musical skill for millennia, but the recent dominance of digital technol- ogy in composition and sound production techniques has separated embodiment from experiences of playing and listening (1). Electronic music culture has compensated for this missing element in various ways (11); however, technology is now sufficiently advanced that the haptic channel may be re-engaged. It is well known that acous- tic vibrations are utilized for self-monitoring in acous- tic performance (28, 8, 37), and that vibrotactile feed- back can considerably improve touch perception without adding significant complexity or cost to an interface (27). This combination of circumstances should make integra- tion of vibrotactile feedback systems into digital musical instruments (DMIs) (41) a top priority for instrument de- signers. Musical vibrotaction is a high-resolution, high- bandwidth perceptual system that promises nothing less than the reestablishment of embodied experience in elec- tronic musical discourse.
This paper describes the T-Stick, a new family of digital musical instruments. It presents the motivation behind the project, hardware and software design, and presents insights gained through collaboration with performers who have col-lectively practised and performed with the T-Stick for hun-dreds of hours, and with composers who have written pieces for the instrument in the context of McGill University's Dig-ital Orchestra project. Each of the T-Sticks is based on the same general structure and sensing platform, but each also differs from its siblings in size, weight, timbre and range.
Sine sweeps are employed since long time for audio and acoustics measurements, but in recent years (2000 and later) their usage became much larger, thanks to the computational capabilities of modern computers. Recent research results allow now for a further step in sine sweep measurements, particularly when dealing with the problem of measuring impulse responses, distortion and when working with systems which are neither time invariant, nor linear.
In this paper we outline the fundamentals for a tactile feedback system to be used in conjunction with open-air computer music performance devices. Some underlying physiological and perceptual mechanisms of haptics are examined, some currently available open-air controllers are reviewed, and previous technologies and experiments regarding haptic/tactile feedback are surveyed. Our VR/TX system is proposed as a solution for adding tactile feedback to open-air controllers; experiments show that the VR/TX vibrotactile stimulators provide invaluable perceptually-significant tactile feedback when used in conjunction with an open-air music controller. A typology of tactile sound events is also described, as well as the notion of a tactile simulation event (TSE).
This thesis deals with the study of performer-instrument interaction during the performance of novel digital musical instruments (DMIs). Unlike acoustic instruments, digital musical instruments have no coupling between the sound generation system and the physical interface with which the performer interacts. As a result of this, such instruments also lack the direct physical feedback to the performer which is present in an acoustic instrument. In fact in contrast to acoustic musical instruments, haptic and vibrotactile feedback is generally not present in a DMI contributing to a poor feel for the instrument. The main goal of this thesis is to propose ways to improve the overall feel of digital musical instruments through the study and design of its physical interface: the instrument body, sensors and feedback actuators. It includes a detailed study of the existing theory and practice of the design on physical interfaces for digital musical instruments, including a survey of 266 existing DMIs presented since the inception of the NIME conference. From this, a number of differences become apparent between the existing theory and practice, particularly in the areas of sensors and feedback. The research in this thesis then addresses these differences. It includes a series of experiments on the optimal choice of sensors for a digital musical instrument. This is followed by research into the provision of vibrotactile feedback in a digital musical instrument, including the choice of actuator, modification of actuator frequency response, and the effects of response modification on human vibrotactile frequency discrimination. Following this, a number of new digital musical instruments are presented, which were created during the course of this work. This includes an instrument designed specifically to follow the results of research in this thesis and also instruments designed as part of larger collaborative projects involving engineers, composers and performers. From the results obtained in this work, it is shown that a careful design of both the sensor and actuator aspects of the physical interface of a DMI can lead to an instrument which is more engaging and entertaining to play, offering an improved feel over that which is present in many digital musical instruments. Cette thèse porte sur l'étude de l'interaction ayant lieu, en situation de jeu,entre un(e) instrumentiste et un instrument musical numérique (IMN).A l'inverse des instruments acoustiques traditionnels, il n'existe aucun couplageentre le dispositif de production du son et l'interface sur laquelle agit l'instrumentistedans le cas des IMN. L'une des implications de cette observation est que cesinstruments ne procurent pas la rétroaction tactile normalement présente dans lesinstruments de musique traditionels. Par conséquent, les IMN sont souvent perçuspar leurs interprètes comme manquant d'âme, de personnalité.Le but de ce travail de thèse est d'avancer quelques solutions permettant d'insuer un peu plus âme à un instrument musical numérique. Le point focal de larecherche étant l'étude et la conception de l'interface physique (corps de l'instrument,capteurs et dispositifs de rétroaction utilisés) d'un tel instrument.Ce mémoire présente, en premier lieu, une étude détaillée de la théorie et de lapratique actuelles dans le domaine de la conception d'interfaces physiques pour lesIMN. L'inventaire des 266 instruments recensés depuis la création de la conférenceNIME constitue l'un des points majeurs de cette partie du travail. En effet, ce tour d'horizon permet de faire ressortir les incohérences entre théorie et pratique. Cesdifférences sont particulièrement frappantes en ce qui concerne les capteurs et lesdispositifs de rétroaction.Le travail de recherche de cette thèse a donc pour objectif de mieux comprendrecomment réduire ces incohérences. Des expériences portant sur le choix optimaldes capteurs à utiliser dans un IMN ont donc été menées. Différents dispositifs derétroaction vibrotactile ont aussi été étudiés en regardant d'abord quels actuateursutiliser, et en évaluant les effets de la modication de leur réponse en fréquencesur la discrimination fréquentielle de stimuli vibrotactiles chez des sujets humains.Des exemples d'applications pratiques de ces recherches sont ensuite détaillés.En effet, plusieurs IMN ont été construits lors de cette thèse : des dispositifs conçusdans le cadre des expérienes pré-citées ainsi que d'autres instruments s'inscrivantdans le cadre de projets collectifs regroupant des ingénieurs, des compositeurs etdes instrumentistes.A l'issue de ce travail, il apparaît clairement qu'une attention particulière portéeau choix des capteurs et des actuateurs de rétroaction utilisés lors de la conceptionde l'interface peut améliorer de façon considérable la perception que les interprètesont d'un instrument de musique numérique. Effectivement, les musicien(ne)s ayantjoué des instruments conçus lors de cette thèse ont généralement trouvé l'expérienceludique et agéable, pouvant mieux percevoir la personnalité des instruments.
A novel measurement technique of the transfer function of weakly not-linear, approximately time-invariant systems is presented. The method is implemented with low-cost instrumentation; it is based on an exponentially-swept sine signal. It is applicable to loudspeakers and other audio components, but also to room acoustics measurements. The paper presents theoretical description of the method and experimental verification in comparison with MLS. 1. Introduction The actual state-of-the art of audio measurements is represented by two different kinds of measurements: characterisation of the linear transfer function of a system, through measurement of its impulse response, and analysis of the nonlinearities through measurement of the harmonic distortion at various orders. These two measurements are actually well separated: for the impulse response measurement the most employed technique are MLS (Maximum Length Sequence) and TDS (Time-Delay Spectrometry). Both these methods are based on t...
This paper presents a wearable, wireless tactile display system which consists of individually controllable vibrotactile actuator devices, called Vibropixels. The design of the system is easily scalable and reconfigurable, allowing for implementation in a variety of applications. The system removes any limit on the number of actuator devices by avoiding both hand-shaking and packet acknowledgement functionality. The number of control messages required is minimized through the use of a exible two-part addressing scheme as well as functions allowing for the generation of multiple actuator envelopes on the devices. Created within an interdisciplinary art-science research project, 145 Vibropixels were utilized in the premier of the artistic installation Haptic Field. Recognizing that the artistic creation process often involves utilizing systems beyond their intended application, we designed our system to allow our collaborators to interact with and potentially modify the system on a hardware, firmware, or software level. Through interviews with our collaborators, we evaluated our system’s ability to support the artistic creation process in light of Shneiderman’s principles for creativity support tools. While our collaborators mostly used and modified the highest level software tools provided to them, we argue that supporting lower level modifications may still be useful depending upon available time and the knowledge of the user.
The relationship between nonlinear distortion measurements and nonlinearities is addressed - the physical causes for signal distortion in loudspeakers, headphones, microspeakers, and other transducers. Using simulation techniques characteristic symptoms are identified for each nonlinearity and presented systematically in a guide for loudspeaker diagnostics. This information is important for understanding the implications of nonlinear parameters and for performing measurements that describe the loudspeaker more comprehensively. Practical applications of the new technique are demonstrated on three different loudspeakers.
Information-Processing Channels in the Tactile Sensory System addresses the fundamental question of whether sensory channels, similar to those known to operate in vision and audition, also operate in the sense of touch. Based on the results of psychophysical and neurophysiological experimentation the authors make a powerful case that channels operate in the processing of mechanical stimulation of the highly sensitive glabrous skin of the hand. According to the multichannel model presented in this monograph, each channel, with its specific type of mechanoreceptor and afferent nerve fiber, responds optiimally to particular aspects of the tactile stimulus. It is further proposed that the tactile perception of objects results from the combined activity of the individual tactile channels. This work is important because it provides researchers and students in the field of sensory neuroscience with a comprehensive model that enhances our understanding of tactile perception.
The proposition that the performer of music can use vibrotactile sensations to supplement auditory cues as feedback signals in order to enhance tonal control of the instrument is examined. As a basis for evaluating this proposition, we present some fundamental characteristics of human vibrotactile sensation, including measurements at the threshold of detectability, at suprathreshold levels, and of subject variables that could affect sensation. It is reasonable to assume that the sensory capacities of skin could enable tactile feedback cues to be used by singers and some instrumentalists in controlling the tone of their instruments.
This paper reviews the technology and applications of vibrotactile display, an effective information transfer modality for the emerging area of haptic media. Our emphasis is on summarizing foundational knowledge in this area and providing implementation guidelines for application designers who do not yet have a background in haptics. Specifically, we explain the relevant human vibrotactile perceptual capabilities, detail the main types of commercial vibrotactile actuators, and describe how to build both monolithic and localized vibrotactile displays. We then identify exemplary vibrotactile display systems in application areas ranging from the presentation of physical object properties to broadcasting vibrotactile media content.
This paper places contemporary literature on the topic of unimodal, single-site display of information using complex tactile signals in the context of progress towards the achievement of transparent communication - placing minimal load on the user's attentional resources. We discuss recent evidence that more is possible with purely haptic display than is commonly believed, as well as procedural developments that support systematic design of transparent tactile information display; and we frame the advances required to realize significant benefits with the technology we have now. Examples used and objectives thus identified focus on establishing effective information representations, and outlining efficient tools and processes for perceptually guiding icon design. Our discussion is inspired by Weiser's vision of calm technology based on locatedness and seamless movement between center and periphery, and it is organized along the lines of potential utility, form and learning.
In this paper we present tactile feedback and stimulation design principles for applications in music technology and media. We discuss features and limitations of the human sense of touch, in the context of conveying musical content solely via the tactile sense. These factors should be firmly taken into account when designing a tactile-augmented interface. Applications of tactile displays in the field of music and media are then presented using a three-fold taxonomy of tactile feedback.
There has been many haptic devices proposed so far, but most of them are still in emerging stage. To attract the interest of potential users of haptics such as designers, educators, and students, it is necessary to provide easy-to-make and easy-to-use haptic device. We then developed an introductory haptic device named "TECHTILE toolkit". Current prototype is composed of haptic recorder, haptic reactor, and signal amplifier that is optimized to present not only zone of audibility but also low frequency vibrotactile sensation. This toolkit is intuitive to use and can be developed with low cost. We are currently holding a number of workshops to confirm that this device is suitable as an educational tool for learning possible applications of haptics design.
The coupled perception of sound and vibration is a well-known phenomenon during live pop or organ concerts. However, even during a symphonic concert in a classical hall, sound can excite perceivable vibrations at the body surface. However, the concert visitor might not be aware of those vibrations, because the tactile percept is integrated with the other senses into one multi-modal percept. This article discusses the influence of whole-body vibrations on the listener experience during the reproduction of concerts recordings. Four sequences were selected from classical and modern music, which include low frequency content (e.g., organ, kettledrum, contrabass). A stimulus length of 1.5 min was chosen in order to provide enough time for habituation. The audio signal was reproduced using a surround setup. Additional seat vibrations have been generated from the audio signal. Test participants were asked to rate the overall quality of the concert experience. The results show that vibrations have a significant influence on our perception of music. This finding is interesting in the context of audio reproduction, but also for the construction of concert venues.
In this paper, we extend the concept of the contrast sensitivity function—used to evaluate video projectors—to the evaluation of haptic devices. We propose using human observers to determine if vibrations rendered using a given haptic device are accompanied by artifacts detectable to humans. This determination produces a performance measure that carries particular relevance to applications involving texture rendering. For cases in which a device produces detectable artifacts, we have developed a protocol that localizes deficiencies in device design and/or hardware implementation. In this paper, we present results from human vibration detection experiments carried out using three commercial haptic devices and one high performance voice coil motor. We found that all three commercial devices produced perceptible artifacts when rendering vibrations near human detection thresholds. Our protocol allowed us to pinpoint the deficiencies, however, and we were able to show that minor modifications to the haptic hardware were sufficient to make these devices well suited for rendering vibrations, and by extension, the vibratory components of textures. We generalize our findings to provide quantitative design guidelines that ensure the ability of haptic devices to proficiently render the vibratory components of textures.
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Contenido: Introducción; Señales y sistemas en tiempo discreto; La transformada z y sus aplicaciones en el análisis de sistemas LTI; Análisis frecuencial de señales y sistemas; La transformada de Fourier discreta: sus propiedades y aplicaciones; Cálculo eficiente de la DFT: algoritmos para la transformada rápida de Fourier; Implementación de sistemas en tiempo discreto; Diseño de filtros digitales; Muestreo y reconstrucción de señales; Proceso digital de tasa múltiple; Predicción lineal y filtros lineales óptimos; Estimación espectral de potencia; Apéndices.
Vibrotactile thresholds on the finger have been compared using two alternative systems. One system prescribed the push force, the contact force, and the surround, while this was not defined for the other system. The experiment was performed with nine male subjects attending on three different days. It was found that the two systems yielded vibrotactile thresholds which were significantly different. The dependence of vibrotactile thresholds on the frequency of vibration, the area of contact with vibration, the conditions surrounding the contact area, the contact force, the push force, the finger temperature, and the distortion of waveform must be considered when quantifying vibrotactile thresholds.
The vibration motor is an actuator widely used for generating vibrations in haptic interaction, virtual reality, human-computer interaction, and gaming. Whereas the vibration motor has many advantages such as low price and small size, its internal structure brings a critical limitation: its output has correlated amplitude and frequency both controlled by voltage applied to the motor. Using the absolute magnitude estimation paradigm in psychophysics, we have previously obtained an Input-Output (I/O) relation from the applied voltage to vibration magnitude perceived by the user. Based on its inverse I/O relation, this paper addresses a vibration rendering method that allows the user to command the vibration motor in a perceptually transparent manner. Using the rendering method, the effects of vibration commands (in voltage) on the user's percept can be correctly understood, allowing more effective vibration design for haptic interaction. We have also implemented a prototype graphical vibration editor into which the perceptually transparent vibration rendering method is incorporated. The vibration editor can assist the user to easily design vibration effects for the vibration motor as s/he manipulates sounds with a graphical audio editor and to clearly predict the user's percept induced from the resulting vibrations as well.
Expressions of a common form will be given for the variance of spectral estimators which are either time or frequency averages over modified periodograms. A modified periodogram is a generalization of the usual periodogram in which the time sample is premultiplied by a data window. Such estimates include almost all in common use and this discussion should clarify the relationships between practical alternatives.
A summary of many of the new techniques developed in the last two decades for spectrum analysis of discrete time series is presented in this tutorial. An examination of the underlying time series model assumed by each technique serves as the common basis for understanding the differences among the various spectrum analysis approaches. Techniques discussed include the classical periodogram, classical Blackman-Tukey, autoregressive (maximum entropy), moving average, autotegressive-moving average, maximum likelihood, Prony, and Pisarenko methods. A summary table in the text provides a concise overview for all methods, including key references and appropriate equations for computation of each spectral estimate.
A spectral-flatness measure
- A H Gray
- J D Markel
A pre-characterized vibrotactile toolkit
- A T Bukkapatnam
Autoregressive parameter estimation for equalizing vibrotactile systems
- A T Bukkapatnam
- P Depalle
- M M Wanderley
A brief overview of the human somatosensory system
- V Hayward
Palm-area sensitivity to vibrotactile stimuli above 1 kHz
- L Wyse
- S Nanayakkara
- P Seekings
- S H Ong
- E A Taylor
Why and how to measure distortion in electroacoustic transducers
- S Temme