In this paper speckle reduction is approached as a Wiener-like filtering performed in the wavelet domain by means of an adaptive shrinkage of the detail coefficients of an undecimated decomposition. The amplitude of e...
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ISBN:
(纸本)0819441929
In this paper speckle reduction is approached as a Wiener-like filtering performed in the wavelet domain by means of an adaptive shrinkage of the detail coefficients of an undecimated decomposition. The amplitude of each coefficient is divided by the variance ratio of the noisy coefficient to the noise-free one. All the above quantities are analytically calculated from the speckled image, the speckle variance, and the wavelet filters. On the test image Lenna corrupted by synthetic speckle, the proposed method outperforms Kuan's LLMMSE filtering by almost 3 dB SNR. Experiments carried out on true and synthetic speckled images demonstrate that the visual quality of the results is excellent in terms of both background smoothing and preservation of edge sharpness and textures. The absence of decimation in the wavelet decomposition avoids the typical ringing impairments produced by critically-subsampled wavelet-based denoising.
The patch clamp technique opened a new field in biological research and shed light on membrane permittivity for ionic currents. The key element in patch clamp measurements is the detection of the ionic currents in a s...
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ISBN:
(纸本)0819416274;9780819416278
The patch clamp technique opened a new field in biological research and shed light on membrane permittivity for ionic currents. The key element in patch clamp measurements is the detection of the ionic currents in a single biological channel. It is known that the channels open and close at random times, thus modulating the ionic currents. The measured current switches between two levels corresponding to the open and close states of the channel. Determining the statistics of the open and closed periods is of crucial importance to the experimenter, because it reflects the response of channel protein to drugs and other factors. The detected signal is strongly corrupted by instrumentation and other noises, rendering the detection of the opening and closing moments extremely difficult. We describe the use of the wavelet transform and its associated multiresolution (multiscale) analysis to detect the currents through single ionic channels corrupted with noise.
Discrete wavelet Transform (DWT) is widely applied to image watermarking applications because it decomposes a cover image into spatial domain as well as frequency domain simultaneously. Also, Singular Value Decomposit...
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ISBN:
(纸本)0769529941
Discrete wavelet Transform (DWT) is widely applied to image watermarking applications because it decomposes a cover image into spatial domain as well as frequency domain simultaneously. Also, Singular Value Decomposition (SVD) is suitable for watermarking applications since some largest singular values are sufficient to embed watermarks instead of using all singular values. We propose a hybrid blind watermarking scheme based on DWT and SVD for image data. The proposed scheme embeds watermarks by modifying log-scaled singular value of selected coefficients of all sub-bands. We have found two properties to be robust against malicious attacks commonly happened to images. We performed experiments to prove that the proposed scheme has the robustness against to a wide range of attacks such as JPEG compression, Gaussian noise addition, median filtering, blurring, histogram equalization, gamma correction, rescaling, shift, and rotation.
An algorithm for multidimensional nonlinear registration is proposed. The deformation field between two elastic bodies is represented by a multi-resolution separable wavelet. Using a progressive approach that reduces ...
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ISBN:
(纸本)0819450804
An algorithm for multidimensional nonlinear registration is proposed. The deformation field between two elastic bodies is represented by a multi-resolution separable wavelet. Using a progressive approach that reduces algorithm complexity the registration parameters are recovered in a coarse to fine order. A custom wavelet that approximates threefold orthogonality is developed. The performance of the algorithm is evaluated by the alignment of sections from mouse brains. The wavelet registration algorithm demonstrated on average fourfold improvement in section alignment over linear alignment.
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.
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.
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.
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.
Considering the forthcoming spaceborne imaging instruments, on-board image compression is now essential due to the limited on-board resources such as storage and telemetry. Meanwhile, the impact of compression on scie...
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ISBN:
(纸本)0780332598
Considering the forthcoming spaceborne imaging instruments, on-board image compression is now essential due to the limited on-board resources such as storage and telemetry. Meanwhile, the impact of compression on scientific data must be analyzed and characterized in detail. The commonly used JPEG technique (based on a Discrete Cosine Transform) produces an undesirable blocking effect. Therefore, this paper presents an on-board compression system based on wavelet transform.
wavelet transform is a main tool for imageprocessingapplications in modern existence. A Double Density Dual Tree Discrete wavelet Transform is used and investigated for image denoising. images are considered for the...
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wavelet transform is a main tool for imageprocessingapplications in modern existence. A Double Density Dual Tree Discrete wavelet Transform is used and investigated for image denoising. images are considered for the analysis and the performance is compared with discrete wavelet transform and the Double Density DWT. Peak signal to Noise Ratio values and Root Means Square error are calculated in all the three wavelet techniques for denoised images and the performance has evaluated. The proposed techniques give the better performance when comparing other two wavelet techniques.
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