1,720,970 research outputs found
Multi-sensory design, physical computing and experimental validation of virtual buttons and knobs for professional appliances
Full text linkTouch screens have become the most popular computer interface in our daily life. Although they respond to finger contact, most of them are able to provide only a visual representation of standard physical controls such as buttons, sliders, and knobs. Indeed, tactile and auditory feedback is neutralized by a touch screen into an interaction with a flat surface. Among other issues that occur during this interaction, the lack of multimodal sensory cues inevitably unbalances the cognitive load toward vision.
This thesis targets the design, realization and validation of user interfaces for the professional appliances domain. In such a specific working environment, populated by multiple and cooperative human activities that frequently and sometimes unexpectedly trigger attendance by the operator, the use of touch screens is generally problematic because often the visual attention must be switched from a machine interface to an emerging task, without suspending any activity in between. In this context, new designs and implementations providing rich auditory and tactile information can contribute to more reliable and robust interactions capable of restoring, partially or absolutely, the multisensory essence of physical controllers hence improving effectiveness and safety of the working environment.
To such an end, this thesis discusses three interface prototypes reproducing the multimodal feedback of two fundamental physical controllers: buttons and knobs. The proposed research starts from the peculiar interaction with professional appliances, and aims at 1) designing and 2) prototyping audio-haptic interfaces that combine innovative haptic and force actuators, as well as 3) evaluating such interfaces through rigorous experiments involving human participants.
The first part of the thesis deals with surface haptics --- a research field studying the reproduction of tactile effects on touch surfaces. This part provides a series of experiments on auditory and tactile surface perception, together with the development of a mock up aimed at testing and improving the reliability and robustness of interaction with professional appliances controlled by touch screen interfaces. The second part of the thesis deals with rotary controllers with haptic feedback. As opposed to touch screens, knob controllers do not require visual attention, thus allowing a user to perform multiple actions simultaneously. In this part,
the design of two innovative knob controllers is presented, each providing specific haptic features: while the first device essentially consists of a technology improvement in the form of a programmable haptic knob exposing a low-cost force resistance technology, the second device, called "Non-a-knob'', affords a new interaction primitive in which rotation gestures are operated over a motionless cylinder. Along with its machine learning-based sensing algorithm, a validation experiment is presented aiming at studying objective and subjective parameters of the user interaction.
Finally, the third part of the thesis shows some hardware and software tools that were developed in the context of this research
DEVELOPMENT OF REAL-TIME AUDIO APPLICATIONS USING PYTHON
No full textThe development of real-time audio applications for general purpose OS like Linux or MS Windows is a well-known and not trivial problem. Several real-time audio software with libraries for multi-purposes programming languages like C, C++ or Java have been developed. Although these solutions provide portability through multiple OS, they often introduce problems related to dependencies and versions alignment over the time. In the present article, the process to build a framework for real-time audio relying on the programming language Python is described. We selected Python because it offers a fast learning rate coupled with several modules that can be used inside real-time
audio projects. The advantages of this programming language but also the limitations in terms of execution time imposed by the interpreted code are both discussed. In particular, a procedure of code refactoring to obtain the real-time execution is presented. This procedure involves the inclusion of compiled code generated by Cython and C language, only where strictly needed. In the last part, some case studies related to the implementation of Virtual Analog models are presented introducing different amounts of compiled code and measuring the execution time
Designing on subjective tolerance to approximated piano reproductions
Full text linkResults from three experiments are presented, showing that the perceived acoustic and vibrotactile quality of a reproduced piano does not require models simulating every aspect of the original instrument with great accuracy. It was found that high-quality loudspeaker array passive listening at the pianist's position admits distortions of the sound field. Furthermore, pianists during playing seem to compensate for errors in the auditory scene description. Finally, they are particularly sensitive to the existence of vibrotactile feedback on their fingers meanwhile tolerant about the precision with which this feedback is reproduced. Based on these results we are currently working on a lightweight portable physics-based digital piano design, that should improve upon the experience a pianist with no keyboards at hand makes when interacting with a touch-screen piano software running on smartphones and laptops
Confronto tra sistemi di rilevamento del gesto basati su sensori a infrarossi o ultrasuoni per applicazioni di pianoforte virtuale
Full text linkPresentiamo una tastiera virtuale che mira a sostituire quella del pianoforte con dei tasti in realtà aumentata. Lo sforzo maggiore è stato compiuto nel rilevamento accurato nonché rapido dei movimenti delle mani. Per raggiungere questo obiettivo sono stati confrontati un dispositivo di rilevamento a infrarossi ed uno a ultrasuoni, valutandone pro e contro nell’impiego specifico. Abbiamo poi realizzato un sistema di feedback multimodale riprendendo le azioni delle mani dell’esecutore mediante la fotocamera posteriore di un comune dispositivo mobile, e presentandole all’utente unite alla visualizzazione di una tastiera di pianoforte animata. Connettendo il dispositivo Leap Motion, responsabile del rilevamento a infrarossi, e altri dispositivi hardware per la generazione di stimoli audio e vibrotattili, il prototipo promette potenziali applicazioni come interfaccia musicale mobile a basso costo, trasformando un comune tavolo in uno scenario di realtà aumentata dove possono essere eseguiti semplici esercizi con buona accuratezza e una risposta realistica in assenza di una tastiera reale
Infrared vs. ultrasonic finger detection on a virtual piano keyboard
Full text linkAn immaterial digital keyboard is presented, aiming at testing possibilities to substitute physical with augmented piano keys during the performance. The main effort has been made around the realization of an accurate meanwhile fast detection of the hands movement. To achieve this goal we have tested low-cost infrared as well as ultrasonic capture devices, whose current pros and cons are presented in either cases. Multimodal feedback has been realized by filming the hands’ action with the rear camera of a consumer’s tablet PC, and then projecting this action on its screen; furthermore this projection has been layered over the image of
a piano keyboard reacting to the hands’ action. Especially in connection with a Leap Motion system in charge of doing the infrared-based detection, and other light hardware for the sonic and vibrotactile rendering of the feedback,
the proposed prototype promises potential application as an inexpensive mobile music interface transforming a normal table in an augmented reality scenario, where a pianist can perform simple musical tasks by relying on reasonably
accurate and realistic feedback even in absence of a hardware keyboard
Interacting with digital audio effects through a haptic knob with programmable resistance
Full text linkLive music performances and music production often involve the manipulation of several parameters during sound generation, processing, and mixing. In hardware layouts, those parameters are usually controlled using knobs, sliders and buttons. When these layouts are virtualized, the use of physical (e.g. MIDI) controllers can make interaction easier and reduce the cognitive load associated to sound manipulation. The addition of haptic feedback can further improve such interaction by facilitating the detection of the nature (continuous / discrete) and value of a parameter. To this end, we have realized an endless-knob controller prototype with programmable resistance to rotation, able to render various haptic effects. Ten subjects assessed the effectiveness of the provided haptic feedback in a target-matching task where either visual-only or visual-haptic feedback was provided; the experiment reported significantly lower errors in presence of haptic feedback. Finally, the knob was configured as a multi-parametric controller for a real-time audio effect software written in Python, simulating the voltage-controlled filter aboard the EMS VCS3. The integration of the sound algorithm and the haptic knob is discussed, together with various haptic feedback effects in response to control actions
Haptics
Full text linkIn vision, Augmented Reality (AR) allows the superposition of digital content on real-world visual information, relying on the well-established See-through paradigm. In the haptic domain, a putative Feel-through wearable device should allow to modify the tactile sensation without masking the actual cutaneous perception of the physical objects. To the best of our knowledge, a similar technology is still far to be effectively implemented. In this work, we present an approach that allows, for the first time, to modulate the perceived softness of real objects using a Feel-through wearable that uses a thin fabric as interaction surface. During the interaction with real objects, the device can modulate the growth of the contact area over the fingerpad without affecting the force experienced by the user, thus modulating the perceived softness. To this aim, the lifting mechanism of our system warps the fabric around the fingerpad in a way proportional to the force exerted on the specimen under exploration. At the same time, the stretching state of the fabric is controlled to keep a loose contact with the fingerpad. We demonstrated that different softness perceptions for the same specimens can be elicited, by suitably controlling the lifting mechanism of the system
A low-cost endless knob controller with programmable resistive force feedback for multimedia production
Full text linkMultimedia production involves the editing of several tracks (e.g., audio, MIDI, video) and related parameter control envelopes. This activity unfolds through several
iterations, each consisting of repetitive tasks. In such scenario, the use of an input controller providing multimodal feedback can reduce the cognitive load associated to task
execution. In particular, tactile feedback can reinforce visual information to facilitate the detection of specific features in a waveform.
We present an endless knob controller prototype with programmable resistive force feedback to rotation. Its use in supporting basic audio editing operations is then informally tested in a pilot software environment developed in Processing
Tactile and auditory feedback of virtual buttons
No full textAuditory and tactile feedback were respectively recorded with an Audio-Technica AT4050 condenser microphone placed 40 cm far from the screen, and by attaching a Wilcoxon Model 736 accelerometer on top of the touchscreen, between the displayed buttons. Signals have been recorded with RME Babyface PRO (0dBFS @ +8dBu, gain: 0dB). Auditory feedback have been normalized to -3dB. A video demo shows a finger operating the four buttons in sequence.</p
Auditory and tactile example of virtual buttons
No full textMaterials related to the characterization of the test virtual buttons </p
- …
