A perceptual sound space for auditory displays based on sung-vowel synthesis

When designing displays for the human senses, perceptual spaces are of great importance to give intuitive access to physical attributes. Similar to how perceptual spaces based on hue, saturation, and lightness were constructed for visual color, research has explored perceptual spaces for sounds of a given timbral family based on timbre, brightness, and pitch. To promote an embodied approach to the design of auditory displays, we introduce the Vowel-Type-Pitch (VTP) space, a cylindrical sound space based on human sung vowels, whose timbres can be synthesized by the composition of acoustic formants and can be categorically labeled. Vowels are arranged along the circular dimension, while voice type and pitch of the vowel correspond to the remaining two axes of the cylindrical VTP space. The decoupling and perceptual effectiveness of the three dimensions of the VTP space are tested through a vowel labeling experiment, whose results are visualized as maps on circular slices of the VTP cylinder. We discuss implications for the design of auditory and multi-sensory displays that account for human perceptual capabilities

Internal representations of auditory frequency: behavioral studies of format and malleability by instructions

Research has suggested that representational and perceptual systems draw upon some of the same processing structures, and evidence also has accumulated to suggest that representational formats are malleable by instructions. Very little research, however, has considered how nonspeech sounds are internally represented, and the use of audio in systems will often proceed under the assumption that separation of information by modality is sufficient for eliminating information processing conflicts. Three studies examined the representation of nonspeech sounds in working memory. In Experiment 1, a mental scanning paradigm suggested that nonspeech sounds can be flexibly represented in working memory, but also that a universal per-item scanning cost persisted across encoding strategies. Experiment 2 modified the sentence-picture verification task to include nonspeech sounds (i.e., a sound-sentence-picture verification task) and found evidence generally supporting three distinct formats of representation as well as a lingering effect of auditory stimuli for verification times across representational formats. Experiment 3 manipulated three formats of internal representation (verbal, visuospatial imagery, and auditory imagery) for a point estimation sonification task in the presence of three types of interference tasks (verbal, visuospatial, and auditory) in an effort to induce selective processing code (i.e., domain-specific working memory) interference. Results showed no selective interference but instead suggested a general performance decline (i.e., a general representational resource) for the sonification task in the presence of an interference task, regardless of the sonification encoding strategy or the qualitative interference task demands. Results suggested a distinct role of internal representations for nonspeech sounds with respect to cognitive theory. The predictions of the processing codes dimension of the multiple resources construct were not confirmed; possible explanations are explored. The practical implications for the use of nonspeech sounds in applications include a possible response time advantage when an external stimulus and the format of internal representation match.Ph.D.Committee Chair: Walker, Bruce; Committee Member: Bonebright, Terri; Committee Member: Catrambone, Richard; Committee Member: Corso, Gregory; Committee Member: Rogers, Wend

Sonification as a Reliable Alternative to Conventional Visual Surgical Navigation

Despite the undeniable advantages of image-guided surgical assistance systems in terms of accuracy, such systems have not yet fully met surgeons' needs or expectations regarding usability, time efficiency, and their integration into the surgical workflow. On the other hand, perceptual studies have shown that presenting independent but causally correlated information via multimodal feedback involving different sensory modalities can improve task performance. This article investigates an alternative method for computer-assisted surgical navigation, introduces a novel sonification methodology for navigated pedicle screw placement, and discusses advanced solutions based on multisensory feedback. The proposed method comprises a novel sonification solution for alignment tasks in four degrees of freedom based on frequency modulation (FM) synthesis. We compared the resulting accuracy and execution time of the proposed sonification method with visual navigation, which is currently considered the state of the art. We conducted a phantom study in which 17 surgeons executed the pedicle screw placement task in the lumbar spine, guided by either the proposed sonification-based or the traditional visual navigation method. The results demonstrated that the proposed method is as accurate as the state of the art while decreasing the surgeon's need to focus on visual navigation displays instead of the natural focus on surgical tools and targeted anatomy during task execution

Using Sound to Represent Uncertainty in Spatial Data

There is a limit to the amount of spatial data that can be shown visually in an effective manner, particularly when the data sets are extensive or complex. Using sound to represent some of these data (sonification) is a way of avoiding visual overload. This thesis creates a conceptual model showing how sonification can be used to represent spatial data and evaluates a number of elements within the conceptual model. These are examined in three different case studies to assess the effectiveness of the sonifications. Current methods of using sonification to represent spatial data have been restricted by the technology available and have had very limited user testing. While existing research shows that sonification can be done, it does not show whether it is an effective and useful method of representing spatial data to the end user. A number of prototypes show how spatial data can be sonified, but only a small handful of these have performed any user testing beyond the authors’ immediate colleagues (where n > 4). This thesis creates and evaluates sonification prototypes, which represent uncertainty using three different case studies of spatial data. Each case study is evaluated by a significant user group (between 45 and 71 individuals) who completed a task based evaluation with the sonification tool, as well as reporting qualitatively their views on the effectiveness and usefulness of the sonification method. For all three case studies, using sound to reinforce information shown visually results in more effective performance from the majority of the participants than traditional visual methods. Participants who were familiar with the dataset were much more effective at using the sonification than those who were not and an interactive sonification which requires significant involvement from the user was much more effective than a static sonification, which did not provide significant user engagement. Using sounds with a clear and easily understood scale (such as piano notes) was important to achieve an effective sonification. These findings are used to improve the conceptual model developed earlier in this thesis and highlight areas for future research

Investigating perceptual congruence between information and sensory parameters in auditory and vibrotactile displays

A fundamental interaction between a computer and its user(s) is the transmission of information between the two and there are many situations where it is necessary for this interaction to occur non-visually, such as using sound or vibration. To design successful interactions in these modalities, it is necessary to understand how users perceive mappings between information and acoustic or vibration parameters, so that these parameters can be designed such that they are perceived as congruent. This thesis investigates several data-sound and data-vibration mappings by using psychophysical scaling to understand how users perceive the mappings. It also investigates the impact that using these methods during design has when they are integrated into an auditory or vibrotactile display. To investigate acoustic parameters that may provide more perceptually congruent data-sound mappings, Experiments 1 and 2 explored several psychoacoustic parameters for use in a mapping. These studies found that applying amplitude modulation — or roughness — to a signal, or applying broadband noise to it resulted in performance which were similar to conducting the task visually. Experiments 3 and 4 used scaling methods to map how a user perceived a change in an information parameter, for a given change in an acoustic or vibrotactile parameter. Experiment 3 showed that increases in acoustic parameters that are generally considered undesirable in music were perceived as congruent with information parameters with negative valence such as stress or danger. Experiment 4 found that data-vibration mappings were more generalised — a given increase in a vibrotactile parameter was almost always perceived as an increase in an information parameter — regardless of the valence of the information parameter. Experiments 5 and 6 investigated the impact that using results from the scaling methods used in Experiments 3 and 4 had on users' performance when using an auditory or vibrotactile display. These experiments also explored the impact that the complexity of the context which the display was placed had on user performance. These studies found that using mappings based on scaling results did not significantly impact user's performance with a simple auditory display, but it did reduce response times in a more complex use-case

Real-Time Electroencephalogram Sonification for Neurofeedback

Electroencephalography (EEG) is the measurement via the scalp of the electrical activity of the brain. The established therapeutic intervention of neurofeedback involves presenting people with their own EEG in real-time to enable them to modify their EEG for purposes of improving performance or health. The aim of this research is to develop and validate real-time sonifications of EEG for use in neurofeedback and methods for assessing such sonifications. Neurofeedback generally uses a visual display. Where auditory feedback is used, it is mostly limited to pre-recorded sounds triggered by the EEG activity crossing a threshold. However, EEG generates time-series data with meaningful detail at fine temporal resolution and with complex temporal dynamics. Human hearing has a much higher temporal resolution than human vision, and auditory displays do not require people to focus on a screen with their eyes open for extended periods of time – e.g. if they are engaged in some other task. Sonification of EEG could allow more rapid, contingent, salient and temporally detailed feedback. This could improve the efficiency of neurofeedback training and reduce the number and duration of sessions for successful neurofeedback. The same two deliberately simple sonification techniques were used in all three experiments of this research: Amplitude Modulation (AM) sonification, which maps the fluctuations in the power of the EEG to the volume of a pure tone; and Frequency Modulation (FM) sonification, which uses the changes in the EEG power to modify the frequency. Measures included, a listening task, NASA task load index; a measure of how much work it was to do the task, Pre & post measures of mood, and EEG. The first experiment used pre-recorded single channel EEG and participants were asked to listen to the sound of the sonified EEG and try and track the activity that they could hear by moving a slider on a computer screen using a computer mouse. This provided a quantitative assessment of how well people could perceive the sonified fluctuations in EEG level. The tracking accuracy scores were higher for the FM sonification but self-assessments of task load rated the AM sonification as easier to track. The second experiment used the same two sonifications, in a real neurofeedback task using participants own live EEG. Unbeknownst to the participants the neurofeedback task was designed to improve mood. A Pre-Post questionnaire showed that participants changed their self-rated mood in the intended direction with the EEG training, but there was no statistically significant change in EEG. Again the FM sonification showed a better performance but AM was rated as less effortful. The performance of sonifications in the tracking task in experiment 1 was found to predict their relative efficacy at blind self-rated mood modification in experiment 2. The third experiment used both the tracking as in experiment 1 and neurofeedback tasks as in experiment 2, but with modified versions of the AM and FM sonifications to allow two-channel EEG sonifications. This experiment introduced a physical slider as opposed to a mouse for the tracking task. Tracking accuracy increased, but this time no significant difference was found between the two sonification techniques on the tracking task. In the training task, once more the blind self-rated mood did improve in the intended direction with the EEG training, but as again there was no significant change in EEG, this cannot necessarily be attributed to the neurofeedback. There was only a slight difference between the two sonification techniques in the effort measure. In this way, a prototype method has been devised and validated for the quantitative assessment of real-time EEG sonifications. Conventional evaluations of neurofeedback techniques are expensive and time consuming. By contrast, this method potentially provides a rapid, objective and efficient method for evaluating the suitability of candidate sonifications for EEG neurofeedback

INTERACTIVE SONIFICATION STRATEGIES FOR THE MOTION AND EMOTION OF DANCE PERFORMANCES

The Immersive Interactive SOnification Platform, or iISoP for short, is a research platform for the creation of novel multimedia art, as well as exploratory research in the fields of sonification, affective computing, and gesture-based user interfaces. The goal of the iISoP’s dancer sonification system is to “sonify the motion and emotion” of a dance performance via musical auditory display. An additional goal of this dissertation is to develop and evaluate musical strategies for adding layer of emotional mappings to data sonification. The result of the series of dancer sonification design exercises led to the development of a novel musical sonification framework. The overall design process is divided into three main iterative phases: requirement gathering, prototype generation, and system evaluation. For the first phase help was provided from dancers and musicians in a participatory design fashion as domain experts in the field of non-verbal affective communication. Knowledge extraction procedures took the form of semi-structured interviews, stimuli feature evaluation, workshops, and think aloud protocols. For phase two, the expert dancers and musicians helped create test-able stimuli for prototype evaluation. In phase three, system evaluation, experts (dancers, musicians, etc.) and novice participants were recruited to provide subjective feedback from the perspectives of both performer and audience. Based on the results of the iterative design process, a novel sonification framework that translates motion and emotion data into descriptive music is proposed and described