Reproducing the Velocity Vectors in the Listening Region

This paper proposes a sound field reproduction algorithm based on matching the velocity vectors in a spherical listening region. Using the concept of sound field translation, the spherical harmonic coefficients of the velocity vectors in a spherical region are derived from the desired pressure distribution. The desired pressure distribution can either correspond to sources such as plane waves and point sources, or be obtained from measurements using a spherical microphone array. Unlike previous work in which the velocity vectors are only controlled on the boundary of the listening region or at discrete sweet spots, this work directly manipulates the velocity vectors in the whole listening region, which is expected to improve the perception of the desired sound field at low frequencies.Comment:

Spatial Acoustic Vector Based Sound Field Reproduction

Spatial sound field reproduction aims to recreate an immersive sound field over a spatial region. The existing sound pressure based approaches to spatial sound field reproduction focus on the accurate approximation of original sound pressure over space, which ignores the perceptual accuracy of the reproduced sound field. The acoustic vectors of particle velocity and sound intensity appear to be closely linked with human perception of sound localization in literature. Therefore, in this thesis, we explore the spatial distributions of the acoustic vectors, and seek to develop algorithms to perceptually reproduce the original sound field over a continuous spatial region based on the vectors. A theory of spatial acoustic vectors is first developed, where the spatial distributions of particle velocity and sound intensity are derived from sound pressure. To extract the desired sound pressure from a mixed sound field environment, a 3D sound field separation technique is also formulated. Based on this theory, a series of reproduction techniques are proposed to improve the perceptual performance. The outcomes resulting from this theory are: (i) derivation of a particle velocity assisted 3D sound field reproduction technique which allows for non-uniform loudspeaker geometry with a limited number of loudspeakers, (ii) design of particle velocity based mixed-source sound field translation technique for binaural reproduction that can provide sound field translation with good perceptual experience over a large space, (iii) derivation of an intensity matching technique that can reproduce the desired sound field in a spherical region by controlling the sound intensity on the surface of the region, and (iv) two intensity based multizone sound field reproduction algorithms that can reproduce the desired sound field over multiple spatial zones. Finally, these techniques are evaluated by comparing to the conventional approaches through numerical simulations and real-world experiments

Multizone wideband sound field reproduction

This thesis deals with the problem of multizone wideband sound field reproduction using an array of loudspeakers. A pressure matching approach is researched to control the sound field within the zones through the calculation of loudspeaker weights. The loudspeaker weights are computed first using a regularized least-squares (LS) approach and then a least-absolute shrinkage and selection operator (Lasso). It is demonstrated that the single-stage LS technique outperforms the single-stage Lasso in multizone wideband sound field reproduction, while the single-stage Lasso enables the judicious placement of loudspeakers. To improve the multizone sound reproduction performance of wideband sources using a limited number of loudspeakers, it is assumed that the virtual sources are fixed in positions. A new two-stage Lasso-LS pressure matching approach is then proposed to optimize both the loudspeaker locations and weights. In the first stage, a Lasso algorithm is used to select the loudspeakers' positions for all sources and frequency bands. A second stage then optimizes reproduction using all selected loudspeakers on the basis of a regularized LS algorithm. The results show that a horizontal array of limited number of loudspeakers (e.g. 52) can be used to effectively create personal audio spaces for multiple users of variable heights. The proposed method is then extended to a nested Lasso-LS method which employs harmonic nested arrays in the first stage Lasso to reduce the computational complexity. Effectively, the nested arrays provide a priori knowledge of prospective loudspeaker locations based on the frequency bands of interest. The final loudspeaker locations and weightings are then estimated during the two-stage Lasso-LS optimization

Spatial Multizone Soundfield Reproduction Design

It is desirable for people sharing a physical space to access different multimedia information streams simultaneously. For a good user experience, the interference of the different streams should be held to a minimum. This is straightforward for the video component but currently difficult for the audio sound component. Spatial multizone soundfield reproduction, which aims to provide an individual sound environment to each of a set of listeners without the use of physical isolation or headphones, has drawn significant attention of researchers in recent years. The realization of multizone soundfield reproduction is a conceptually challenging problem as currently most of the soundfield reproduction techniques concentrate on a single zone. This thesis considers the theory and design of a multizone soundfield reproduction system using arrays of loudspeakers in given complex environments. We first introduce a novel method for spatial multizone soundfield reproduction based on describing the desired multizone soundfield as an orthogonal expansion of formulated basis functions over the desired reproduction region. This provides the theoretical basis of both 2-D (height invariant) and 3-D soundfield reproduction for this work. We then extend the reproduction of the multizone soundfield over the desired region to reverberant environments, which is based on the identification of the acoustic transfer function (ATF) from the loudspeaker over the desired reproduction region using sparse methods. The simulation results confirm that the method leads to a significantly reduced number of required microphones for an accurate multizone sound reproduction compared with the state of the art, while it also facilitates the reproduction over a wide frequency range. In addition, we focus on the improvements of the proposed multizone reproduction system with regard to practical implementation. The so-called 2.5D multizone oundfield reproduction is considered to accurately reproduce the desired multizone soundfield over a selected 2-D plane at the height approximately level with the listener’s ears using a single array of loudspeakers with 3-D reverberant settings. Then, we propose an adaptive reverberation cancelation method for the multizone soundfield reproduction within the desired region and simplify the prior soundfield measurement process. Simulation results suggest that the proposed method provides a faster convergence rate than the comparative approaches under the same hardware provision. Finally, we conduct the real-world implementation based on the proposed theoretical work. The experimental results show that we can achieve a very noticeable acoustic energy contrast between the signals recorded in the bright zone and the quiet zone, especially for the system implementation with reverberation equalization

Active Noise Control at low frequencies for Open Air events

Щороку в місті, поблизу житлових районів, проводяться все більше і більше open air заходів та великих концертів. Головною проблемою цього є шумове забруднення прилежних районів. З іншого боку, невід'ємною частиною таких концертів є високий рівень звукового тиску. Створення звукових зон є одним з можливих шляхів вирішення цієї проблеми. У даній роботі ми розглянемо та охарактеризуємо основні способи створення звукових зон: акустичний контраст, pressure matching та комбінований метод. Розглянуто також класичний метод активного контролю шуму на основі алгоритму найменших квадратів. Для всіх методів отримані кінцеві вирази для розрахунку оптимальних комплексних об'ємних швидкостей гучномовців. Описано значення параметрів регуляції цих методів. Для обчислення звукових зон використовуються виміряні або змодельовані передатні характеристики розповсюдження звуку. У цій роботі вивчається вплив навколишнього середовища та атмосферних умов. Моделювання всіх методів проводилося у середовищі MATLAB. Порівняння результатів проводилося за розрахунковими показниками продуктивності та за частотною характеристикою розрахованих оптимальних ваг. Важливість параметрів регулювання показана при моделюванні різних методів. Для досліджуваної системи обраний оптимальний метод. В цілому метою цієї роботи є порівняння та пошук оптимального методу створення звукових зон, який використовується для управління великими зонами в межах open air події; а також зробити оцінку можливого впливу атмосферних умов на точність і надійність цих методів.Every year more and more open-air events and large concerts are held in the city, near residential areas. The main problem of this is noise pollution in nearby areas. On the other hand, an integral part of such concerts is a high SPL. Creating sound zones is one possible solution to this problem. In this paper, we examine and characterize the main methods of creating sound zones: Acoustic Contrast, Pressure Matching and combined method. The classical method of active noise control based on the LMS algorithm is also considered. For all methods, final expressions are derived for calculating the optimal complex volume velocities of the loudspeakers. The meaning of regularization parameters of these methods is described. To calculate the sound zones, measured or modeled propagation transfer functions are used. The effect of the environment and atmospheric conditions is studied in this work and their impact is evaluated. Simulations of all methods were performed at MATLAB. Comparison of the results was carried out on the calculated performance metrics and on the frequency response of the calculated optimal weights. The importance of the regulation parameters has been shown when simulating various methods. The optimal method was chosen for the system under study. In general, this work aimed to make a comparison and search for the optimal method for creating sound zones, which is used to control large zones within an open air event; and also make an assessment of the possible influence of atmospheric conditions on the accuracy and robustness of these methods.Ежегодно в городе, вблизи жилых районов, проводятся все больше и больше open air мероприятий и больших концертов. Главной проблемой этого является шумовое загрязнение прилегающей районов. С другой стороны, неотъемлемой частью таких концертов является высокий уровень звукового давления. Создание звуковых зон является одним из возможных путей решения этой проблемы. В данной работе мы рассмотрим и охарактеризуем основные способы создание звуковых зон: акустический контраст, pressure matching и комбинированный метод. Рассмотрены также классический метод активного контроля шума на основе алгоритма наименьших квадратов. Для всех методов полученные конечные выражения для расчета оптимальных комплексных объемных скоростей громкоговорителей. Описаны значения параметров регуляции этих методов. Для вычисления звуковых зон используются измеренные или смоделированы передаточные характеристики распространения звука. В этой работе изучается влияние окружающей среды и атмосферных условий. Моделирование всех методов проводилось в среде MATLAB. Сравнение результатов проводилось по расчетным показателям производительности и по частотной характеристикой рассчитанных оптимальных весов. Важность параметров регулирования показана при моделировании различных методов. Для исследуемой системы выбран оптимальный метод. В целом целью этой работы является сравнение и поиск оптимального метода создания звуковых зон, который используется для управления большими зонами в пределах open air события; а также сделать оценку возможного воздействию атмосферных условий на точность и надежность этих методов

Local sound field synthesis

This thesis investigates the physical and perceptual properties of selected methods for (Local) Sound Field Synthesis ((L)SFS). In agreement with numerical sound field simulations, a specifically developed geometric model shows an increase of synthesis accuracy for LSFS compared to conventional SFS approaches. Different (L)SFS approaches are assessed within listening experiments, where LSFS performs at least as good as conventional methods for azimuthal sound source localisation and achieves a significant increase of timbral fidelity for distinct parametrisations.Die Arbeit untersucht die physikalischen und perzeptiven Eigenschaften von ausgewählten Verfahren zur (lokalen) Schallfeldsynthese ((L)SFS). Zusammen mit numerischen Simulationen zeigt ein eigens entwickeltes geometrisches Modell, dass LSFS gegenüber konventioneller SFS zu einer genauere Synthese führt. Die Verfahren werden in Hörversuchen evaluiert, wobei LSFS bei der horizontalen Lokalisierung von Schallquellen eine Genauigkeit erreicht, welche mindestens gleich der von konventionellen Methoden ist. Für bestimmte Parametrierung wird eine signifikant verbesserte klangliche Treue erreicht

Toward enhancement of deep learning techniques using fuzzy logic: a survey

Deep learning has emerged recently as a type of artificial intelligence (AI) and machine learning (ML), it usually imitates the human way in gaining a particular knowledge type. Deep learning is considered an essential data science element, which comprises predictive modeling and statistics. Deep learning makes the processes of collecting, interpreting, and analyzing big data easier and faster. Deep neural networks are kind of ML models, where the non-linear processing units are layered for the purpose of extracting particular features from the inputs. Actually, the training process of similar networks is very expensive and it also depends on the used optimization method, hence optimal results may not be provided. The techniques of deep learning are also vulnerable to data noise. For these reasons, fuzzy systems are used to improve the performance of deep learning algorithms, especially in combination with neural networks. Fuzzy systems are used to improve the representation accuracy of deep learning models. This survey paper reviews some of the deep learning based fuzzy logic models and techniques that were presented and proposed in the previous studies, where fuzzy logic is used to improve deep learning performance. The approaches are divided into two categories based on how both of the samples are combined. Furthermore, the models' practicality in the actual world is revealed

Towards Artificial General Intelligence (AGI) in the Internet of Things (IoT): Opportunities and Challenges

Artificial General Intelligence (AGI), possessing the capacity to comprehend, learn, and execute tasks with human cognitive abilities, engenders significant anticipation and intrigue across scientific, commercial, and societal arenas. This fascination extends particularly to the Internet of Things (IoT), a landscape characterized by the interconnection of countless devices, sensors, and systems, collectively gathering and sharing data to enable intelligent decision-making and automation. This research embarks on an exploration of the opportunities and challenges towards achieving AGI in the context of the IoT. Specifically, it starts by outlining the fundamental principles of IoT and the critical role of Artificial Intelligence (AI) in IoT systems. Subsequently, it delves into AGI fundamentals, culminating in the formulation of a conceptual framework for AGI's seamless integration within IoT. The application spectrum for AGI-infused IoT is broad, encompassing domains ranging from smart grids, residential environments, manufacturing, and transportation to environmental monitoring, agriculture, healthcare, and education. However, adapting AGI to resource-constrained IoT settings necessitates dedicated research efforts. Furthermore, the paper addresses constraints imposed by limited computing resources, intricacies associated with large-scale IoT communication, as well as the critical concerns pertaining to security and privacy

Extending BIM for air quality monitoring

As we spend more than 90% of our time inside buildings, indoor environmental quality is a major concern for healthy living. Recent studies show that almost 80% of people in European countries and the United States suffer from SBS (Sick Building Syndrome), which affects physical health, productivity and psychological well-being. In this context, environmental quality monitoring provides stakeholders with crucial information about indoor living conditions, thus facilitating building management along its lifecycle, from design, construction and commissioning to usage, maintenance and end-of-life. However, currently available modelling tools for building management remain limited to static models and lack integration capacities to efficiently exploit environmental quality monitoring data. In order to overcome these limitations, we designed and implemented a generic software architecture that relies on accessible Building Information Model (BIM) attributes to add a dynamic layer that integrates environmental quality data coming from deployed sensors. Merging sensor data with BIM allows creation of a digital twin for the monitored building where live information about environmental quality enables evaluation through numerical simulation. Our solution allows accessing and displaying live sensor data, thus providing advanced functionality to the end-user and other systems in the building. In order to preserve genericity and separation of concerns, our solution stores sensor data in a separate database available through an application programming interface (API), which decouples BIM models from sensor data. Our proof-of-concept experiments were conducted with a cultural heritage building located in Bled, Slovenia. We demonstrated that it is possible to display live information regarding environmental quality (temperature, relative humidity, CO2, particle matter, light) using Revit as an example, thus enabling end-users to follow the conditions of their living environment and take appropriate measures to improve its quality.Pages 244-250

Two-Dimensional Spatial Control using Multiple Circular Loudspeaker Arrays and Elliptical Loudspeaker Array

電気通信大学202