نتایج جستجو برای: wavelet coefficients

تعداد نتایج: 138766  

2001
İbrahim Öz Cemil Öz Nejat Yumuşak

Wavelet is a recently developed compression technique in image compression. In this study, after multiple level 2-D wavelet transform of images, approximation and detail coefficients are obtained. These coefficients are quantized that more important coefficients are represented with higher accuracy and retained coefficients are represented with less accuracy or they are neglected. Afterward the...

2006
V. Bruni B. Piccoli D. Vitulano

In this paper a wavelet based model for image de-noising is presented. Wavelet coefficients are modelled as waves that grow while dilating along scales. The model establishes a precise link between corresponding modulus maxima in the wavelet domain and then allows to predict wavelet coefficients at each scale from the first one. This property combined with the theoretical results about the char...

Synthetic Aperture Radar (SAR) images are inherently affected by a multiplicative noise-like phenomenon called speckle, which is indeed the nature of all coherent systems. Speckle decreases the performance of almost all the information extraction methods such as classification, segmentation, and change detection, therefore speckle must be suppressed. Despeckling can be applied by the multilooki...

1997
François G. Meyer Amir Averbuch Ronald R. Coifman

We construct a new algorithm for motion compensation of wavelet coefficients. The new approach outperforms standard block matching techniques both in terms of higher PSNR, and better perceptual quality. The algorithm works directly in the wavelet coefficients domain and has been successfully used for wavelet based very low bit rate video coding.

This article presents an analytic approach to study admissibility conditions related to classical full wavelet systems over finite fields using tools from computational harmonic analysis and theoretical linear algebra. It is shown that for a large class of non-zero window signals (wavelets), the generated classical full wavelet systems constitute a frame whose canonical dual are classical full ...

2004
Zohreh Azimifar Paul W. Fieguth Ed Jernigan

This paper presents an empirical study of the joint wavelet statistics for textures and other random imagery. There is a growing realization that modeling wavelet coefficients as independent, or at best correlated only across scales, assuming independence within a scale, may be a poor assumption. While recent developments in wavelet-domain Hidden Markov Models (notably HMT-3S) account for withi...

Journal: :CoRR 2009
G. Kheder Abdennaceur Kachouri M. Ben Massoued Mounir Samet

In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtai...

Journal: :CoRR 2011
Atefeh Elahian Mehdi Khalili Shahriar B. Shokouhi

Digital watermarking is an effective way to protect copyright. In this paper, a robust watermarking algorithm based on wavelet transformation is proposed which can confirm the copyright without original image. The wavelet transformation technique is effective in image analyzing and processing. Thus the color-image watermark algorithm based on discrete wavelet transformation (DWT) begins to draw...

2008
S. J. Park

In this paper, Haar wavelet based identification of a continuous-time linear time-varying (LTV) system is proposed. For that purpose, input and output data are analyzed to derive an algebraic equation, leading to estimation of Haar wavelet coefficients for the impulse response. Finally, it is demonstrated that an LTV system can be effectively identified by solving the algebraic equation and by ...

Journal: :JCS 2014
G. M. Rajathi R. Rangarajan R. Haripriya R. Nithya

The image data is normally corrupted by additive noise during acquisition. This reduces the accuracy and reliability of any automatic analysis. For this reason, denoising methods are often applied to restore the original image. In proposed method a wavelet shrinkage algorithm based on fuzzy logic and the DT-DWT scheme is used. In particular, intra-scale dependency within wavelet coefficients is...

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