Recently, wavelet analysis has gained an established role in signal and imageprocessingapplications. In this paper, we present a discrete wavelet transform algorithm based on the lifting scheme. The Haar wavelet tra...
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Recently, wavelet analysis has gained an established role in signal and imageprocessingapplications. In this paper, we present a discrete wavelet transform algorithm based on the lifting scheme. The Haar wavelet transformed and decimated signals are lifted by the ladder-type network. A unique lifting filter is designed for in-place computation. The present algorithm is especially suitable for microprosessor and VLSI applications since it can be implemented by integer arithmetics using only register shifts and summations.
The classical Shannon sampling theorem has resulted in many applications and generalizations. From a multiresolution point of view, it provides the sine scaling function. In this case, for a band-limited signal, its w...
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The classical Shannon sampling theorem has resulted in many applications and generalizations. From a multiresolution point of view, it provides the sine scaling function. In this case, for a band-limited signal, its wavelet series transform (WST) coefficients below a certain resolution level can be exactly obtained from the samples with a sampling rate higher than the Nyquist rate. In this research, we study the properties of cardinal orthogonal scaling functions (COSF), which provide the standard sampling theorem in multiresolution spaces with scaling functions as interpolants. We show that COSF with compact support have and only have one possibility which is the Haar pulse. We present a family of COSF with exponential decay, which are generalizations of the Haar function. With these COSF, an application is the computation of WST coefficients of a signal by the Mallat algorithm. We present some numerical comparisons for different scaling functions to illustrate the advantage of COSF. For signals which are not in multiresolution spaces, we estimate the aliasing error in the sampling theorem by using uniform samples.
signalprocessing in the encrypted domain is a new technology with the goal of protecting valuable signals from insecure signalprocessing. In this paper, we propose a method for implementing discrete wavelet transfor...
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signalprocessing in the encrypted domain is a new technology with the goal of protecting valuable signals from insecure signalprocessing. In this paper, we propose a method for implementing discrete wavelet transform (DWT) and multiresolution analysis (MRA) in homomorphic encrypted domain. We first suggest a framework for performing DWT and inverse DWT (IDWT) in the encrypted domain, then conduct an analysis of data expansion and quantization errors under the framework. To solve the problem of data expansion, which may be very important in practical applications, we present a method for reducing data expansion in the case that both DWT and IDWT are performed. With the proposed method, multilevel DWT/IDWT can be performed with less data expansion in homomorphic encrypted domain. We propose a new signalprocessing procedure, where the multiplicative inverse method is employed as the last step to limit the data expansion. Taking a 2-D Haar wavelet transform as an example, we conduct a few experiments to demonstrate the advantages of our method in secure imageprocessing. We also provide computational complexity analyses and comparisons. To the best of our knowledge, there has been no report on the implementation of DWT and MRA in the encrypted domain.
We develop a Generalized Gaussian scale mixture (GGSM) model of the wavelet coefficients of natural and distorted images. The GGSM model, which is more general than and which subsumes the Gaussian scale mixture (GSM) ...
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We develop a Generalized Gaussian scale mixture (GGSM) model of the wavelet coefficients of natural and distorted images. The GGSM model, which is more general than and which subsumes the Gaussian scale mixture (GSM) model, is shown to be a better representation of the statistics of the wavelet coefficients of both natural as well as distorted images. We demonstrate the utility of the model by applying it to various imageprocessingapplications, including blind distortion identification and no reference image quality assessment (NR-IQA). Similar to the GSM model, the GGSM model is useful for motivating the use of local divisive energy normalization, especially when the wavelet coefficients are computed on distorted pictures. We show that the GGSM model can lead to improved performance in distortion-related applications, while providing a more principled approach to the statistical processing of distorted imagesignals. The software release of a GGSM-based NR-IQA approach called DIIviNE-GGSM is available online at http://***/research/quality/*** for further experimentation.
We consider an extension of the 1-D concept of analytical wavelet to n-D which is by construction compatible with rotations. This extension, called a monogenic wavelet, yields a decomposition of the wavelet coefficien...
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We consider an extension of the 1-D concept of analytical wavelet to n-D which is by construction compatible with rotations. This extension, called a monogenic wavelet, yields a decomposition of the wavelet coefficients into amplitude, phase, and phase direction. The monogenic wavelet is based on the hypercomplex monogenic signal which is defined using Riesz transforms and perfectly isotropic wavelets frames. Employing the new concept of Clifford frames, we can show that the monogenic wavelet generates a wavelet frame. Furthermore, this approach yields wavelet frames that are steerable with respect to direction. applications to descreening and contrast enhancement illustrate the versatility of this approach to image analysis and reconstruction.
The application of wavelet transform can improve discrimination capability and signal-to-noise ratio of the correlation outputs with respect to the classical one. The concept of the associative storage in a photorefra...
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ISBN:
(纸本)0819429139
The application of wavelet transform can improve discrimination capability and signal-to-noise ratio of the correlation outputs with respect to the classical one. The concept of the associative storage in a photorefractive material offers suitable methods to design multichannel correlators for fingerprint identification. An optical system that employs holographic recording in a F-e: LiNbO3 crystal is proposed and experimentally demonstrated for the physical implementation of multichannel wavelet matched correlator. The scale of wavelet filter is optimized according to the robustness to the noise and discriminability of the filter. The photorefractive correlator is used as a ROM in the recognition. When the object beam with an input fingerprint is used for recovering, a set of correlation outputs are obtained in parallel along the directions of the reference beams, and detected by a CCD camera. Experimental results are promising for further use in the practice.
By using the wavelet transform, we develop a hierarchical planar curve descriptor that decomposes a curve into components of different scales so that the coarsest scale components carry the global approximation inform...
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By using the wavelet transform, we develop a hierarchical planar curve descriptor that decomposes a curve into components of different scales so that the coarsest scale components carry the global approximation information while the finer scale components contain the local detailed information, We show that the wavelet descriptor has many desirable properties such as multiresolution representation, invariance, uniqueness, stability, and spatial localization, A deformable wavelet descriptor is also proposed by interpreting the wavelet coefficients as random variables, The applications of the wavelet descriptor to character recognition and model-based contour extraction from low SNR images are examined, Numerical experiments are performed to illustrate the performance of the wavelet descriptor.
We explore the filtering properties of wavelets functions in order to develop accurate and efficient numerical algorithms for image Restoration problems. We propose a parallel implementation for MIMD distributed memor...
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ISBN:
(纸本)0819429139
We explore the filtering properties of wavelets functions in order to develop accurate and efficient numerical algorithms for image Restoration problems. We propose a parallel implementation for MIMD distributed memory environments. The key insight of our approach is the use of distributed versions of Level 3 Basic Linear Algebra Subprograms as computational building blocks and the use of Basic Linear Algebra Communication Subprograms las communication building blocks for advanced architecture computers. The use of these low-level mathematical software libraries garantees the development of efficient, portable and scalable high-level algorithms and hides many details of the parallelism from the user's point of view. Numerical experiments on a simulated image restoration applications are shown. The parallel software has been tested on a 12 nodes IBM SP2 available at the Center for Research on Parallel Computing and Supercomputers in Naples (Italy).
In this correspondence paper, the wavelet transform, which is an important tool in signal and imageprocessing, has been generalized by coalescing wavelet transform and fractional random transform. The new transform, ...
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In this correspondence paper, the wavelet transform, which is an important tool in signal and imageprocessing, has been generalized by coalescing wavelet transform and fractional random transform. The new transform, i.e., fractional random wavelet transform (FrRnWT) inherits the excellent mathematical properties of wavelet transform and fractional random transform. Possible applications of the proposed transform are in biometrics, image compression, image transmission, transient signalprocessing, etc. In this correspondence paper, biometrics is chosen as the primary application;and hence, a new technique is proposed for securing fingerprints during communication and transmission over insecure channel.
The article provides arguments in favor of an alternative approachthat uses splines, which is equally justifiable on a theoretical basis,and which offers many practical advantages. To reassure the reader whomay be afr...
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The article provides arguments in favor of an alternative approachthat uses splines, which is equally justifiable on a theoretical basis,and which offers many practical advantages. To reassure the reader whomay be afraid to enter new territory, it is emphasized that one is notlosing anything because the traditional theory is retained as aparticular case (i.e., a spline of infinite degree). The basiccomputational tools are also familiar to a signalprocessing audience(filters and recursive algorithms), even though their use in the presentcontext is less conventional. The article also brings out the connectionwith the multiresolution theory of the wavelet transform. This articleattempts to fulfil three goals. The first is to provide a tutorial onsplines that is geared to a signalprocessing audience. The second is togather all their important properties and provide an overview of themathematical and computational tools available; i.e., a road map for thepractitioner with references to the appropriate literature. The thirdgoal is to give a review of the primary applications of splines insignal and imageprocessing
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