Denoising by singularity detection

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Improved speech presence probability estimation based on wavelet denoising

A reliable estimator for speech presence probability (SPP) can significantly improve the performance of many speech enhancement algorithms. Previous work showed that a good SPP estimator can be obtained by using a smooth a-posteriori signal to noise ratio (SNR) function, which can be achieved by reducing the noise variance when estimating the speech power spectrum. In this paper, a wavelet based denoising algorithm is proposed for such purpose. We first apply the wavelet transform to the periodogram of a noisy speech signal to generate an oracle for indicating the locations of the noise floor in the periodogram. We then make use of that oracle to selectively remove the wavelet coefficients of the noise floor in the log multitaper spectrum (MTS) of the noisy speech. The remaining wavelet coefficients are then used to reconstruct a denoised MTS and in turn generate a smooth a-posteriori SNR function. Simulation results show that the new SPP estimator outperforms the traditional approaches and enables a significantly improvement in the quality and intelligibility of the enhanced speeches. © 2012 IEEE.published_or_final_versio

Recording of natural head position using stereophotogrammetry: A new technique and reliability study

The purpose of this study was to develop a technique to record physical references and orient digital mesh models to natural head position (NHP) using stereo-photogrammetry (SP). The first step was to record the digital mesh model of a hanging reference board placed at the capturing position of the SP machine. The board was aligned to the true vertical using a plumb bob. It was also aligned with laser plane parallel to the hanging mirror which was located at the center of the machine. Parameter derived from the digital mesh model of the board was then used to adjust the roll, pitch and yaw of the subsequent captures of subjects. This information was valid until the next machine calibration. The board placement was repeatable with standard deviation of less than 0.1 degrees for both pitch and yaw; 0.15 degrees for roll angles.postprin

Efficient blind image restoration using discrete periodic Radon transform

Author name used in this publication: Daniel P. K. LunAuthor name used in this publication: David Dagan FengCentre for Multimedia Signal Processing, Department of Electronic and Information Engineering2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Efficient fringe image enhancement based on dual-tree complex wavelet transform

Author name used in this publication: William W. L. Ng2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

The difference between registered natural head position and estimated natural head position in three dimensions

This study determined the intra-rater and inter-rater reliability of re-orientating three-dimensional (3D) facial images into the estimated natural head position. Three-dimensional facial images of 15 pre-surgical class III orthognathic patients were obtained and automatically re-orientated into natural head position (RNHP) using a 3D stereophotogrammetry system and in-house software. Six clinicians were asked to estimate the NHP of these patients (ENHP); they re-estimated five randomly selected 3D images after a 2-week interval. The differences in yaw, roll, pitch, and chin position between RNHP and ENHP were measured. For intra-rater reliability, the intra-class correlation coefficient (ICC) values ranged from 0.55 to 0.77, representing moderate reliability for roll, yaw, pitch, and chin position, while for inter-rater reliability, the ICC values ranged from 0.38 to 0.58, indicating poor to moderate reliability. The median difference between ENHP and RNHP was small for roll and yaw, but larger for pitch. There was a tendency for the clinicians to estimate NHP with the chin tipped more posteriorly (6.3 ± 5.2 mm) compared to RNHP, reducing the severity of the skeletal deformity in the anterior–posterior direction

Corpo-oralidades y territorio en la dramaturgia de Felipe Vergara, de la experiencia del conflicto al correlato artístico

Dissertação apresentada ao Programa de Pós- Graduação em Literatura Comparada da Universidade Federal da Integração Latino- Americana, como requisito parcial à obtenção do título de Mestre em Literatura Comparada. Orientador: Andrea Ciacchi (Pós-Doutor Universidade Estadual de Campinas , Doutor em Iberistica, Università di Bologn , a Mestro em Letras, Universidade Federal da Paraíba , Graduação em Antropologia, Università di Roma)Propongo una lectura de la poética teatral de Felipe Vergara desde el estudio de tres piezas: Kilele, una epopeya artesanal; Arimbato, el camino del árbol; y Coragyps Sapiens, partiendo por considerar el teatro como un encuentro vital entre los artistas y su público, que instala escrituras permeadas por el tiempo, la historia y el contexto de su surgimiento. En ese sentido planteo que la dramaturgia Vergara funciona como un correlato que revive el rastro de la experiencia de guerra de las comunidades del Pacífico colombiano, a la vez que toma una posición autónoma de resistencia artística, social y cultural, y que porta en su discurso las versiones silenciadas históricamente, las versiones subterráneas. Para el análisis abordo: la relación indisoluble de las comunidades con su territorio, manifiesta en las obras; las representaciones de cuerpo y su fragmentación tanto a nivel individual como colectivo; y su reconstrucción a través de los duelos que se encarnan en transmisiones rituales, corporales y orales, en actos de memoria viva. Presento así un recorrido por la propuesta artística de Felipe Vergara y un acercamiento a algunas propuestas teatrales las comunidades del Pacífico colombiano, en las que curiosamente, Vergara trabajó de la mano de Inge Kleutgens, Catalina Medina y otros colaboradores. Retomaremos tres obras de Vergara, así como tres de las creaciones colectivas de las comunidades con las que , rastreando en ellas los procesos y procedimientos para la reconstrucción de una porción de los relatos alternativos de la historia social de las vivencias del conflicto social y armado colombiano, traducidas en las relaciones entre los imaginarios y las representaciones simbólicas de las obras, que asocian las gamas de sentido del texto y de la puesta en escena, con el cauce efectivo que propicia su escritura.Proponho uma leitura da poesia teatral de Felipe Vergara a partir do estudo de três obras: Kilele, una epopeya artesanal; Arimbato, el camino del árbol; y Coragyps Sapiens, começando por considerar o teatro como um encontro vital entre os artistas e seu público, que instala escritos permeados pelo tempo, pela história e pelo contexto de seu surgimento. Nesse sentido, proponho que a dramaturgia de Vergara funcione como um correlato que revive o traço da experiência de guerra das comunidades do Pacífico colombiano, ao mesmo tempo em que assume uma posição autônoma de resistência artística, social e cultural, e que carrega em seu discurso as versões silenciadas historicamente, as versões subterrâneas. Pela análise a bordo: a relação indissolúvel das comunidades com seu território, manifestada nos trabalhos; representações corporais e sua fragmentação individual e coletiva; e sua reconstrução através dos duelos que se encarnam em transmissões rituais, corporais e orais, em atos de memória viva. Apresento um encontro com a proposta artística de Felipe Vergara, propostas teatrais das comunidades do Pacífico colombiano, nas quais curiosamente, Vergara trabalhou com Inge Kleutgens, Catalina Medina e outros colaboradores. Retornaremos a três obras de Vergara, bem como a três das criações coletivas das comunidades com as quais traçamos os processos e procedimentos para a reconstrução de uma parte dos relatos alternativos da história social das experiências do conflito social e armado colombiano , traduzido nas relações entre o imaginário e as representações simbólicas das obras, que associam as faixas de significado do texto e da encenação, ao canal efetivo que propicia sua escrit

A Generalized Orthogonal Symmetric Prefilter Banks for Discrete Multiwavelet Transforms

Prefilters are generally applied to the discrete multiwavelet transform (DMWT) for processing scalar signals. To fully utilize the benefit given by the multiwavelets, we have recently shown a maximally decimated orthogonal prefilter which preserves the linear phase property and the approximation power of the multiwavelets. However, such design requires the point of symmetry of each channel of the prefilter to match with the scaling functions of the target multiwavelet system. A compatible filter bank structure can be very difficult to find or simply does not exist, e.g. for multiplicity 2 multiwavelets. In this paper, we suggest a new DMWT structure in which the prefilter is combined with the first stage of DMWT. The advantage of the new structure is twofold: First, the computational complexity can be greatly reduced. Second, additional design freedom allows maximally decimated, orthogonal and symmetric prefilters even for low multiplicity. We evaluated the computational complexity and energy compaction capability of the new DMWT structure. Satisfactory results are obtained in comparing with the traditional approaches.Department of Electronic and Information EngineeringRefereed conference pape

Marker encoded fringe projection profilometry for efficient 3D model acquisition

This paper presents a novel marker encoded fringe projection profilometry (FPP) scheme for efficient 3-dimensional (3D) model acquisition. Traditional FPP schemes can introduce large errors to the reconstructed 3D model when the target object has an abruptly changing height profile. For the proposed scheme, markers are encoded in the projected fringe pattern to resolve the ambiguities in the fringe images due to that problem. Using the analytic complex wavelet transform, the marker cue information can be extracted from the fringe image, and is used to restore the order of the fringes. A series of simulations and experiments have been carried out to verify the proposed scheme. They show that the proposed method can greatly improve the accuracy over the traditional FPP schemes when reconstructing the 3D model of objects with abruptly changing height profile. Since the scheme works directly in our recently proposed complex wavelet FPP framework, it enjoys the same properties that it can be used in real time applications for color objects.Department of Electronic and Information Engineerin