In this paper, the dual tree complex wavelet transform, which is an important tool and recent advancement in signal and imageprocessing, has been generalized by coalescing dual tree complex wavelet transform and frac...
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In this paper, the dual tree complex wavelet transform, which is an important tool and recent advancement in signal and imageprocessing, has been generalized by coalescing dual tree complex wavelet transform and fractional Fourier transform. The new transform, i.e. the fractional dual tree complex wavelet transform (FrDT-CWT) inherits the excellent mathematical properties of dual tree complex wavelet transform and fractional Fourier transform. Possible applications of the proposed transform are in biometrics, image compression, image transmission, transient signalprocessing etc. In this paper, biometric is chosen as the primary application and hence a new technique is proposed for securing biometrics during communication and transmission over insecure channel. (C) 2010 Elsevier B.v. All rights reserved.
various imageprocessingapplications exploit a model of the human visual system (HvS). One element of HvSmodels describes the masking-effect, which is typically parameterized by psycho-visual experiments that employ ...
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various imageprocessingapplications exploit a model of the human visual system (HvS). One element of HvSmodels describes the masking-effect, which is typically parameterized by psycho-visual experiments that employ superimposed sinusoidal stimuli. Those stimuli are oversimplified with respect to real images and can capture only very elementary masking-effects. To overcome these limitations a new psycho-visual test method is proposed. It is based on natural scenery stimuli and operates in the wavelet domain. The collected psycho-visual data is finally used to evaluate the performance of various masking models under conditions as found in real imageprocessingapplications like compression. (C) 2002 Elsevier Science B.v. All rights reserved.
A new efficient image coding scheme, based on Quadtree Representation and Block Entropy Coding (QRBEC), for encoding the wavelet transform coefficients of images is presented. The property of HvS is also incorporated ...
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ISBN:
(纸本)0818679204
A new efficient image coding scheme, based on Quadtree Representation and Block Entropy Coding (QRBEC), for encoding the wavelet transform coefficients of images is presented. The property of HvS is also incorporated into the quantization process. In addition, how to flexibly control the quantization level as well as output bitrate of the coder is also investigated. The coding efficiency of the coder is quite competitive with the well-known EZW coder, and requires less computation burden. The proposed coding scheme can also be applied in image sequence coding, resulting in satisfactory performance.
A new approach to FPGA implementation of two-dimensional discrete wavelet transform is presented. This architecture allow high accurate and sampling rate DWT realization based on FIR filters of substantial length to b...
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ISBN:
(纸本)0819425915
A new approach to FPGA implementation of two-dimensional discrete wavelet transform is presented. This architecture allow high accurate and sampling rate DWT realization based on FIR filters of substantial length to be implemented on current generation FPGAs. The scheme is based on two parallel pipelined linear phase 17-tap FIR filters with common shift register, partial adders and look-up tables as coefficient multipliers with 4-stage pipelined architecture. The transform is realized in three stages controlled by the state machine, where temporary (L and H) and final subimages (LL, LH, HL, and HH) are created. High throughput (1050 MIPS) and external memory controller allow efficient concurrent cooperation with external processors.
We investigate three approaches to vLSI implementation of wavelet filters. The direct form structure, the lattice form structure, and an algebraic structure are used to derive different architectures for wavelet filte...
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ISBN:
(纸本)0819422134
We investigate three approaches to vLSI implementation of wavelet filters. The direct form structure, the lattice form structure, and an algebraic structure are used to derive different architectures for wavelet filters. The algebraic structure exploits conjugacy properties in number fields. All approaches are explained in detail for the Daubechies 4- tab filters. We outline the philosophy of a design method for integrated circuits.
The traditional mean-squared-error (MSE) or peak-signal-to-noise-ratio (PSNR) error measures are mainly focused on the pixel-by-pixel difference between the original and compressed images. Such metrics are improper fo...
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ISBN:
(纸本)0819425915
The traditional mean-squared-error (MSE) or peak-signal-to-noise-ratio (PSNR) error measures are mainly focused on the pixel-by-pixel difference between the original and compressed images. Such metrics are improper for subjective quality or fidelity assessment, since human perception is very sensitive to correlations between adjacent pixels. In this work, we explore the Haar wavelet to model the space-frequency localization property of human visual system (HvS). It is shown that the physical contrast in different resolutions can be easily represented in terms of transform coefficients. We model HvS with the Haar filter with several visual mechanisms and develop a subjective quality measure which is more consistent with human observation experience.
signal decomposition techniques are an important tool for analyzing nonstationary signals. The proper selection of time-frequency basis functions for the decomposition is essential to a variety of signalprocessing ap...
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ISBN:
(纸本)0819418447
signal decomposition techniques are an important tool for analyzing nonstationary signals. The proper selection of time-frequency basis functions for the decomposition is essential to a variety of signalprocessingapplications. The discrete wavelet transform (DWT) is increasingly being used for signal analysis, but not until recently has attention been paid to the time-frequency resolution property of wavelets. This paper describes additional results on our procedure to design wavelets with better time-frequency resolution. In particular, our optimal duration-bandwidth product wavelets (ODBW) have better duration-bandwidth product, as a function of wavelet-defining filter length N, than Daubechies' minimum phase and least- asymmetric wavelets, and Dorize and villemoes' optimum wavelets over the range N equals 8 to 64. Some examples and comparisons with these traditional wavelets are presented.
In this paper, a high-quality, space-frequency adaptive, trellis coded waveletimage codec is presented. The algorithm seeks jointly optimal space and frequency segmentation of an image. For this, first, wavelet packe...
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ISBN:
(纸本)0819422134
In this paper, a high-quality, space-frequency adaptive, trellis coded waveletimage codec is presented. The algorithm seeks jointly optimal space and frequency segmentation of an image. For this, first, wavelet packets are formed to localize the high-energy frequency bands. Then, the wavelet coefficients are further classified to maximize the coding gain. Design target is set to minimize Lagrangian cost functions which are formed with distortion in l2 norm being the cost and coding rate as constraint. Resultant mapping is used to quantize the wavelet coefficients with trellis code quantization. This is followed by adaptive arithmetic coding producing the final compressed bitstream. Described approach is tested on several ISO standard images and results are compared to other compression techniques. Representative examples are included.
Polarization in optical waveguides is always an aspect of optical loss and consequently impacts device performance. waveletimageprocessing allows a means to detect optical signals buried under noise. Orthogonality i...
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ISBN:
(纸本)0819445878
Polarization in optical waveguides is always an aspect of optical loss and consequently impacts device performance. waveletimageprocessing allows a means to detect optical signals buried under noise. Orthogonality is an essential element in wavelet bases. There are three primary types of multiresolution bases: orthogonal wavelet bases, semiorthogonal wavelet bases, and biorthogonal wavelet bases. waveletimageprocessing will be applied to laser beam propagation in lithium niobate and nonlinear polymer waveguides to achieve detection of signals below noise and a better understanding of polarization as an aspect of device performance.
Combined use of the X-ray (Radon) transform and the wavelet transform has proved to be useful in application areas such as diagnostic medicine and seismology. In the present paper, the wavelet X-ray transform is intro...
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ISBN:
(纸本)0819425915
Combined use of the X-ray (Radon) transform and the wavelet transform has proved to be useful in application areas such as diagnostic medicine and seismology. In the present paper, the wavelet X-ray transform is introduced. This transform performs one-dimensional wavelet transforms along lines in R-n, which are parameterized in the same fashion as for the X-ray transform. It is shown that the transform has the same convenient inversion properties as the wavelet transform. The reconstruction formula receives further attention in order to obtain usable discretizations of the transform. Finally, a connection between the wavelet X-ray transform and the filtered backprojection formula is discussed.
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