Poor directional selectivity, a major disadvantage of the separable 2D discrete wavelet transform (DWT), has previously been circumvented either by using highly redundant, nonseparable wavelet transforms or by using r...
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ISBN:
(纸本)0819437646
Poor directional selectivity, a major disadvantage of the separable 2D discrete wavelet transform (DWT), has previously been circumvented either by using highly redundant, nonseparable wavelet transforms or by using restrictive designs to obtain a pair of wavelet. trees. In this paper, we demonstrate that superior directional selectivity may be obtained with no redundancy in any separable wavelet transform. We achieve this by projecting the wavelet coefficients to separate approximately the positive and negative frequencies. Subsequent decimation maintains nonredundancy. A novel reconstruction step guarantees perfect reconstruction within this critically-sampled framework. Although our transform generates complex-valued coefficients, it may be implemented with a fast algorithm that uses only real arithmetic. We also explain how redundancy may be judiciously introduced into our transform to benefit certain applications. To demonstrate the efficacy of our projection technique, we show that it achieves state-of-the-art performance in a seismic image-processing application.
Efficient image watermarking techniques have been developed in the wavelet domain. Similar to other wavelet-based imageprocessing, the choice of wavelet filters generally affects the performance of a wavelet-based wa...
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Efficient image watermarking techniques have been developed in the wavelet domain. Similar to other wavelet-based imageprocessing, the choice of wavelet filters generally affects the performance of a wavelet-based watermarking system. In this paper, we evaluate the performance of a set of biorthogonal integer wavelets under a multiresolution-watermarking framework. Biorthogonal integer wavelets have been extensively used for imageapplications because they possess the linear-phase property and can be efficiently implemented. We find that the widely adopted 9/7-F wavelet achieves the best robustness performance. Further investigation is conducted to show that the superiority of the 9/7-F wavelet is primarily owing to its being nearly orthogonal.
Discrete wavelet transform of finite-length signals must necessarily handle the signal boundaries. The state-of the-art approaches treat such boundaries in a complicated and inflexible way, using special prolog or epi...
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ISBN:
(纸本)9781509023776
Discrete wavelet transform of finite-length signals must necessarily handle the signal boundaries. The state-of the-art approaches treat such boundaries in a complicated and inflexible way, using special prolog or epilog phases. This holds true in particular for images decomposed into a number of scales, exemplary in JPEG 2000 coding system. In this paper, the state-of-the-art approaches are extended to perform the treatment using a compact streaming core, possibly in multi-scale fashion. We present the core focused on CDF 5/3 wavelet and the symmetric border extension method, both employed in the JPEG 2000. As a result of our work, every input sample is visited only once, while the results are produced immediately, i.e. without buffering.
A perspective invariant function has been derived. It is based on analyzing the object boundary using the dyadic wavelet transform. Five dyadic wavelet transform levels are used to define the invariant function. The s...
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ISBN:
(纸本)0819437646
A perspective invariant function has been derived. It is based on analyzing the object boundary using the dyadic wavelet transform. Five dyadic wavelet transform levels are used to define the invariant function. The selection of the dyadic levels is discussed. Experimental results test the recognition power of the proposed invariant function. In addition: the stability of the invariant function is examined.
Mathematical morphology, as originally described by Matheron and Serra, consists of the application of set theoretical operations between the image set X and a structure element set B. image skeletons are very efficie...
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ISBN:
(纸本)0819418447
Mathematical morphology, as originally described by Matheron and Serra, consists of the application of set theoretical operations between the image set X and a structure element set B. image skeletons are very efficient representations of shape, and can be directly derived using the morphological operations of erode and open. If done at full image resolution, derivation of a skeleton can be very time consuming without dedicated signalprocessing hardware. This paper presents an alternative to the standard approach that relies on morphological operations within the wavelet coefficient space. In particular, the skeleton transformation can be done very efficiently at the reduced resolution of the coarse wavelet coefficient levels. We investigate the relationship between waveletimage compression and morphological transforms for the derivation of skeletons. We also report the results of some experimental studies on binary and gray scale images.
The objective of this investigation is to apply waveletimageprocessing to Four-Wave Mixing (FWM) for the purpose of defining beam interaction both within and outside the nonlinear crystal. This will allow a better u...
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ISBN:
(纸本)0819443670
The objective of this investigation is to apply waveletimageprocessing to Four-Wave Mixing (FWM) for the purpose of defining beam interaction both within and outside the nonlinear crystal. This will allow a better understanding of beam quality and allow for better performance of potential devices.
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.
This paper provides an overview of subband and wavelet theories. It emphasizes their strong relations. The practical merits of these decomposition techniques in signalprocessing are examined. The current status of th...
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ISBN:
(纸本)0819412236
This paper provides an overview of subband and wavelet theories. It emphasizes their strong relations. The practical merits of these decomposition techniques in signalprocessing are examined. The current status of this active research field is summarized and it concludes with the discussion of potential extensions for future study.
We introduce a pose estimation method for synthetic aperture radar (SAR) imagery using the 2-D continuous wavelet transform (CWT). The computational complexity of the new approach is comparable to other image-based ap...
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ISBN:
(纸本)0819437646
We introduce a pose estimation method for synthetic aperture radar (SAR) imagery using the 2-D continuous wavelet transform (CWT). The computational complexity of the new approach is comparable to other image-based approaches such as ones that incorporate principle component analysis (PCA). Using the public domain MSTAR database, we show that the CWT-based method provides a better pose estimate than the PCA method.
We describe a formalism that allows us to study space (or time)-scale correlations in multiscale processes. This method, based on the continuous wavelet transform, is particularly well suited to study multiplicative r...
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ISBN:
(纸本)0819437646
We describe a formalism that allows us to study space (or time)-scale correlations in multiscale processes. This method, based on the continuous wavelet transform, is particularly well suited to study multiplicative random cascades for which the correlation functions take very simple expressions. This two-point space-scale statistical analysis is illustrated on synthetic multifractal signals and then applied to financial time series and fully developed turbulence data.
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