Discrete Wavelet Transforms

The discrete wavelet transform (DWT) algorithms have a firm position in processing of signals in several areas of research and industry. As DWT provides both octave-scale frequency and spatial timing of the analyzed signal, it is constantly used to solve and treat more and more advanced problems. The present book: Discrete Wavelet Transforms: Algorithms and Applications reviews the recent progress in discrete wavelet transform algorithms and applications. The book covers a wide range of methods (e.g. lifting, shift invariance, multi-scale analysis) for constructing DWTs. The book chapters are organized into four major parts. Part I describes the progress in hardware implementations of the DWT algorithms. Applications include multitone modulation for ADSL and equalization techniques, a scalable architecture for FPGA-implementation, lifting based algorithm for VLSI implementation, comparison between DWT and FFT based OFDM and modified SPIHT codec. Part II addresses image processing algorithms such as multiresolution approach for edge detection, low bit rate image compression, low complexity implementation of CQF wavelets and compression of multi-component images. Part III focuses watermaking DWT algorithms. Finally, Part IV describes shift invariant DWTs, DC lossless property, DWT based analysis and estimation of colored noise and an application of the wavelet Galerkin method. The chapters of the present book consist of both tutorial and highly advanced material. Therefore, the book is intended to be a reference text for graduate students and researchers to obtain state-of-the-art knowledge on specific applications

Spatial impression in multichannel surround sound systems

Spatial impression in both concert halls and reproduced sound has been identified as an important attribute of the listening experience. In this study, the synthesis and objective measurement of spatial impression in reproduced sound is examined. A novel, multichannel spatializing technique for musical synthesis has been developed that entailed the separation of the individual harmonics of a musical note that were spatially distributed over multichannel surround systems. Subjective testing of the techniques revealed that the perceived degree of spatial impression significantly increased as the angular spread of harmonics increased, however, extending the spatial spread beyond 90° did not significantly increase the perception of spatial impression. The concert hall measure of spatial impression, the interaural cross correlation coefficient (IACC) was used to objectively measure the effects of the spatializing techniques. The IACC measurements displayed a strong correlation to the subjective results. Further examination of the IACC measurement indicated the possibility of it’s adaptation to multichannel surround sound in general. A method of adapting IACC to reproduced sound was further developed that involved comparing IACC measurements taken in a concert hall to IACC measurements taken in reproduced versions of the same concert hall. The method was first conducted as a simulation using basic auralisation techniques. Real concert hall measurements and reproduction systems were then employed. Results showed that the method was able to discriminate between the spatial capabilities of a number of different surround sound systems and rank them in a predictable order. The results were further validated by means of a subjective test. In an attempt to sensitise the IACC measurement, the frequency dependency of IACC was investigated by means of a subjective test. The results indicated that a perceptually more accurate indication of spatial impression may be gained by applying a frequency-dependent weighting to IACC measurements. This may be useful in the spatial measurement of both reproduced sound and concert halls.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Spatial impression in multichannel surround sound systems

Spatial impression in both concert halls and reproduced sound has been identified as an important attribute of the listening experience. In this study, the synthesis and objective measurement of spatial impression in reproduced sound is examined.A novel, multichannel spatializing technique for musical synthesis has been developed that entailed the separation of the individual harmonics of a musical note that were spatially distributed over multichannel surround systems. Subjective testing of the techniques revealed that the perceived degree of spatial impression significantly increased as the angular spread of harmonics increased, however, extending the spatial spread beyond 90° did not significantly increase the perception of spatial impression.The concert hall measure of spatial impression, the interaural cross correlation coefficient (IACC) was used to objectively measure the effects of the spatializing techniques. The IACC measurements displayed a strong correlation to the subjective results. Further examination of the IACC measurement indicated the possibility of it’s adaptation to multichannel surround sound in general.A method of adapting IACC to reproduced sound was further developed that involved comparing IACC measurements taken in a concert hall to IACC measurements taken in reproduced versions of the same concert hall. The method was first conducted as a simulation using basic auralisation techniques. Real concert hall measurements and reproduction systems were then employed. Results showed that the method was able to discriminate between the spatial capabilities of a number of different surround sound systems and rank them in a predictable order. The results were further validated by means of a subjective test.In an attempt to sensitise the IACC measurement, the frequency dependency of IACC was investigated by means of a subjective test. The results indicated that a perceptually more accurate indication of spatial impression may be gained by applying a frequency-dependent weighting to IACC measurements. This may be useful in the spatial measurement of both reproduced sound and concert halls

Scalable and perceptual audio compression

This thesis deals with scalable perceptual audio compression. Two scalable perceptual solutions as well as a scalable to lossless solution are proposed and investigated. One of the scalable perceptual solutions is built around sinusoidal modelling of the audio signal whilst the other is built on a transform coding paradigm. The scalable coders are shown to scale both in a waveform matching manner as well as a psychoacoustic manner. In order to measure the psychoacoustic scalability of the systems investigated in this thesis, the similarity between the original signal\u27s psychoacoustic parameters and that of the synthesized signal are compared. The psychoacoustic parameters used are loudness, sharpness, tonahty and roughness. This analysis technique is a novel method used in this thesis and it allows an insight into the perceptual distortion that has been introduced by any coder analyzed in this manner

Optimization and improvements in spatial sound reproduction systems through perceptual considerations

[ES] La reproducción de las propiedades espaciales del sonido es una cuestión cada vez más importante en muchas aplicaciones inmersivas emergentes. Ya sea en la reproducción de contenido audiovisual en entornos domésticos o en cines, en sistemas de videoconferencia inmersiva o en sistemas de realidad virtual o aumentada, el sonido espacial es crucial para una sensación de inmersión realista. La audición, más allá de la física del sonido, es un fenómeno perceptual influenciado por procesos cognitivos. El objetivo de esta tesis es contribuir con nuevos métodos y conocimiento a la optimización y simplificación de los sistemas de sonido espacial, desde un enfoque perceptual de la experiencia auditiva. Este trabajo trata en una primera parte algunos aspectos particulares relacionados con la reproducción espacial binaural del sonido, como son la escucha con auriculares y la personalización de la Función de Transferencia Relacionada con la Cabeza (Head Related Transfer Function - HRTF). Se ha realizado un estudio sobre la influencia de los auriculares en la percepción de la impresión espacial y la calidad, con especial atención a los efectos de la ecualización y la consiguiente distorsión no lineal. Con respecto a la individualización de la HRTF se presenta una implementación completa de un sistema de medida de HRTF y se introduce un nuevo método para la medida de HRTF en salas no anecoicas. Además, se han realizado dos experimentos diferentes y complementarios que han dado como resultado dos herramientas que pueden ser utilizadas en procesos de individualización de la HRTF, un modelo paramétrico del módulo de la HRTF y un ajuste por escalado de la Diferencia de Tiempo Interaural (Interaural Time Difference - ITD). En una segunda parte sobre reproducción con altavoces, se han evaluado distintas técnicas como la Síntesis de Campo de Ondas (Wave-Field Synthesis - WFS) o la panoramización por amplitud. Con experimentos perceptuales se han estudiado la capacidad de estos sistemas para producir sensación de distancia y la agudeza espacial con la que podemos percibir las fuentes sonoras si se dividen espectralmente y se reproducen en diferentes posiciones. Las aportaciones de esta investigación pretenden hacer más accesibles estas tecnologías al público en general, dada la demanda de experiencias y dispositivos audiovisuales que proporcionen mayor inmersión.[CA] La reproducció de les propietats espacials del so és una qüestió cada vegada més important en moltes aplicacions immersives emergents. Ja siga en la reproducció de contingut audiovisual en entorns domèstics o en cines, en sistemes de videoconferència immersius o en sistemes de realitat virtual o augmentada, el so espacial és crucial per a una sensació d'immersió realista. L'audició, més enllà de la física del so, és un fenomen perceptual influenciat per processos cognitius. L'objectiu d'aquesta tesi és contribuir a l'optimització i simplificació dels sistemes de so espacial amb nous mètodes i coneixement, des d'un criteri perceptual de l'experiència auditiva. Aquest treball tracta, en una primera part, alguns aspectes particulars relacionats amb la reproducció espacial binaural del so, com són l'audició amb auriculars i la personalització de la Funció de Transferència Relacionada amb el Cap (Head Related Transfer Function - HRTF). S'ha realitzat un estudi relacionat amb la influència dels auriculars en la percepció de la impressió espacial i la qualitat, dedicant especial atenció als efectes de l'equalització i la consegüent distorsió no lineal. Respecte a la individualització de la HRTF, es presenta una implementació completa d'un sistema de mesura de HRTF i s'inclou un nou mètode per a la mesura de HRTF en sales no anecoiques. A mès, s'han realitzat dos experiments diferents i complementaris que han donat com a resultat dues eines que poden ser utilitzades en processos d'individualització de la HRTF, un model paramètric del mòdul de la HRTF i un ajustament per escala de la Diferencià del Temps Interaural (Interaural Time Difference - ITD). En una segona part relacionada amb la reproducció amb altaveus, s'han avaluat distintes tècniques com la Síntesi de Camp d'Ones (Wave-Field Synthesis - WFS) o la panoramització per amplitud. Amb experiments perceptuals, s'ha estudiat la capacitat d'aquests sistemes per a produir una sensació de distància i l'agudesa espacial amb que podem percebre les fonts sonores, si es divideixen espectralment i es reprodueixen en diferents posicions. Les aportacions d'aquesta investigació volen fer més accessibles aquestes tecnologies al públic en general, degut a la demanda d'experiències i dispositius audiovisuals que proporcionen major immersió.[EN] The reproduction of the spatial properties of sound is an increasingly important concern in many emerging immersive applications. Whether it is the reproduction of audiovisual content in home environments or in cinemas, immersive video conferencing systems or virtual or augmented reality systems, spatial sound is crucial for a realistic sense of immersion. Hearing, beyond the physics of sound, is a perceptual phenomenon influenced by cognitive processes. The objective of this thesis is to contribute with new methods and knowledge to the optimization and simplification of spatial sound systems, from a perceptual approach to the hearing experience. This dissertation deals in a first part with some particular aspects related to the binaural spatial reproduction of sound, such as listening with headphones and the customization of the Head Related Transfer Function (HRTF). A study has been carried out on the influence of headphones on the perception of spatial impression and quality, with particular attention to the effects of equalization and subsequent non-linear distortion. With regard to the individualization of the HRTF a complete implementation of a HRTF measurement system is presented, and a new method for the measurement of HRTF in non-anechoic conditions is introduced. In addition, two different and complementary experiments have been carried out resulting in two tools that can be used in HRTF individualization processes, a parametric model of the HRTF magnitude and an Interaural Time Difference (ITD) scaling adjustment. In a second part concerning loudspeaker reproduction, different techniques such as Wave-Field Synthesis (WFS) or amplitude panning have been evaluated. With perceptual experiments it has been studied the capacity of these systems to produce a sensation of distance, and the spatial acuity with which we can perceive the sound sources if they are spectrally split and reproduced in different positions. The contributions of this research are intended to make these technologies more accessible to the general public, given the demand for audiovisual experiences and devices with increasing immersion.Gutiérrez Parera, P. (2020). Optimization and improvements in spatial sound reproduction systems through perceptual considerations [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/142696TESI

AXMEDIS 2008

The AXMEDIS International Conference series aims to explore all subjects and topics related to cross-media and digital-media content production, processing, management, standards, representation, sharing, protection and rights management, to address the latest developments and future trends of the technologies and their applications, impacts and exploitation. The AXMEDIS events offer venues for exchanging concepts, requirements, prototypes, research ideas, and findings which could contribute to academic research and also benefit business and industrial communities. In the Internet as well as in the digital era, cross-media production and distribution represent key developments and innovations that are fostered by emergent technologies to ensure better value for money while optimising productivity and market coverage

The augmented tonoscope towards a deeper understanding of the interplay between sound and image in visual music

This thesis presents the theoretical, technical and aesthetic concerns in realising a harmonic complementarity and more intimate perceptual connection between music and moving image. It explores the inspirations and various processes involved in creating a series of artistic works - attached as a portfolio and produced as the research. This includes the Cymatic Adufe (v1.1) - a sound-responsive, audiovisual installation; Stravinsky Rose (v2.0) - an audiovisual short in Dome format; and the live performance works of Whitney Triptych (v1.2), Moiré Modes (v1.1) and Stravinsky Rose (v3.0). The thesis outlines an approach towards realising a deeper understanding of the interplay between sound and image in Visual Music - through applying: the Differential Dynamics of pioneering, computer-aided, experimental animator John Whitney Sr.; alternate musical tunings based on harmonic consonance and the Pythagorean laws of harmony; and sound’s ability to induce physical form and flow via Cymatics - the study of wave phenomena and vibration - a term coined by Dr. Hans Jenny for his seminal research into these effects in the 1960s and 70s, using a device of his own design - the ʻtonoscopeʼ. The thesis discusses the key method for this artistic investigation through the design, fabrication and crafting of a hybrid analogue/digital audiovisual instrument - a contemporary version of Jenny’s sound visualisation tool - The Augmented Tonoscope. It details the developmental process which has realised a modular performance system integrating sound making, sound analysis, analogue outputs, virtual systems, musical interface and recording and sequencing. Finally, the thesis details the impact of this system on creating audiovisualisation of a distinct quality through: a formalist, minimal, decluttered aesthetic; a direct, elemental and real-time correspondence between sound and image; a mirroring of music’s innate movement and transition within the visual domain; and an underlying concord or harmony between music and moving image