We discuss the utility of wavelet transform methods in signalprocessing in general, and in particular, demonstrate the technique in optoacoustic applications. In several optoacoustic experiments with different sample...
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ISBN:
(纸本)0819435325
We discuss the utility of wavelet transform methods in signalprocessing in general, and in particular, demonstrate the technique in optoacoustic applications. In several optoacoustic experiments with different samples, we have successfully enhanced the signal to noise ratios. wavelet transforms optimize resolution by utilizing a tailored, variable time-window in different frequency regions. The technique's great advantage lies in the fact that the wavelet transform adds some redundancy to the original signal, and some desired features can be enhanced in the transformed space. In addition, proper choice of the basis set allows a sparse representation of the signal. Therefore, even when some components are suppressed in the transformed space, the signal itself can maintain its fidelity. This technique has great potential in biomedical optoacoustics, such as medical imageprocessing and signal denoising. We use the wavelet transform technique to resolve acoustic echoes in the time-dilation space (equivalent to the time-frequency space). White noise was removed by the wavelet shrinkage method. This processing was used to analyze several experimental results. These include optoacoustic measurements in solid samples as well as in biological tissues.
In order to satisfy the needs of new multimedia applications, the problem of content-based coding has to be addressed. In this paper a new approach of object interior coding is proposed. It is based on an arbitrarily-...
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ISBN:
(纸本)0780331923
In order to satisfy the needs of new multimedia applications, the problem of content-based coding has to be addressed. In this paper a new approach of object interior coding is proposed. It is based on an arbitrarily-shaped subband transform followed by a generalized embedded zerotree wavelet algorithm. It is shown that the proposed technique achieves good compression results and has additional properties such as being computationally efficient, keeping the same dimensionality in the transformed domain, being perfect reconstruction, and allowing a perfect rate control. In addition a lossless mode can be defined by using an appropriate filter bank.
In this work, we present a new family of image compression algorithms derived from Shapiro's embedded zerotree wavelet (EZW) coder. These new algorithms introduce robustness to transmission errors into the bit str...
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Continuous wavelet transforms (CWT) and frames have always been useful for noise suppression, edge detection and medical signalprocessing. However these transforms are generally shied away from since computational co...
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ISBN:
(纸本)0819437646
Continuous wavelet transforms (CWT) and frames have always been useful for noise suppression, edge detection and medical signalprocessing. However these transforms are generally shied away from since computational complexity prevents their widespread use. However, recently developed processor technology that uses analog rather than digital signalprocessing hardware may be the ideal means to implement and apply these algorithms. It is then appropriate to consider new types of frames and continuous wavelet systems. We propose two families of tunable continuous wavelet systems with widely varying frame bounds and scaling behavior, and illustrate examples of computations involving these systems.
The proliferation of digital cameras, wireless networks and distributed computing make sharing of visual data easier than ever. Such casual exchange of data, however, has increasingly raised questions on how sensitive...
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ISBN:
(纸本)9781467325332;9781467325349
The proliferation of digital cameras, wireless networks and distributed computing make sharing of visual data easier than ever. Such casual exchange of data, however, has increasingly raised questions on how sensitive visual information can be protected. Encrypted-domain signalprocessing techniques based on homomorphic encryption and garbled circuits are increasingly applied for such applications. Their high computation and communication complexity, however, are not suitable for pixel-level processing. In this paper, we propose an alternative approach of using information-theoretically secure protocols over multiple non-colluding semi-honest computing agents. The proposed protocols are based on classical Shamir's secret sharing scheme which supports multiplication and addition in the random-share domain. We extend the sharing scheme to handle other fundamental signalprocessing operations and use them to develop a novel privacy-protected wavelet denoising scheme over three computing agents. Our experimental results demonstrate the viability of using information-theoretic secure protocols to safeguard privacy in distributed pixel-level processing.
wavelet transform-based methods are currently used in a variety of image and video processingapplications and are popular candidates for future image and video processing standards (e.g., JPEG 2000, MPEG 7). Very lit...
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ISBN:
(纸本)0819437646
wavelet transform-based methods are currently used in a variety of image and video processingapplications and are popular candidates for future image and video processing standards (e.g., JPEG 2000, MPEG 7). Very little, however, has been done to develop efficient and simple stochastic models for waveletimage data. In this paper we review some existing modeling approaches for waveletimage data. Inspired by our recent Estimation-Quantization image coder, we introduce an efficient graphical stochastic model for waveletimage coefficients. Specifically, we propose to model waveletimage coefficients as Gaussian random variables with parameters determined by an underlying hidden Markov-type process. This stochastic model is defined using a factor graph framework. We test our model for denoising images corrupted by additive Gaussian noise. Our results are among the state-of-the-art in the held and they indicate the promise of the proposed model.
As a powerful technique, sparse coding was adopted by several researchers in different approaches. Particularly in imageprocessing, it has attracted a considerable attention. It can be widely used for representation,...
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ISBN:
(纸本)9781538635810
As a powerful technique, sparse coding was adopted by several researchers in different approaches. Particularly in imageprocessing, it has attracted a considerable attention. It can be widely used for representation, compression, denoising and separation of all type of signal. Recent works have confirmed that the use of a predefined dictionary is less efficient than a dictionary from training data. According to this idea, this paper proposes a new technique based on wavelet network to create a dictionary to ameliorate the representation and classification of image using sparse coding technique.
The wavelet transform is a powerful tool for image and video processing, useful in a range of applications. This paper is concerned with the efficiency of a certain fast-wavelet-transform (FWT) implementation and seve...
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ISBN:
(纸本)9780819467010
The wavelet transform is a powerful tool for image and video processing, useful in a range of applications. This paper is concerned with the efficiency of a certain fast-wavelet-transform (FWT) implementation and several wavelet filters, more suitable for constrained devices. Such constraints are typically found on mobile (cell) phones or personal digital assistants (PDA). These constraints can be a combination of;limited memory, slow floating point operations (compared to integer operations, most often as a result of no hardware support) and limited local storage. Yet these devices are burdened with demandino, tasks such as processing a live video or audio signal through on-board capturing sensors. In this paper we present a new wavelet software library, Heat Wave, that can be used efficiently for image/video processing/analysis tasks on mobile phones and PDA's. We will demonstrate that HeatWave is suitable for real-time applications with fine control and range to suit transform demands. We shall present experimental results to substantiate these claims. Finally this library is intended to be of real use and applied, hence we considered several well known and common embedded operating system platform differences;such as a lack of common routines or functions, stack limitations, etc. This makes HeatWave suitable for a range of applications and research projects.
Major spin-offs from NASA's multi- and hyperspectral imaging remote sensing technology developed for Earth resources monitoring, are creative techniques that combine and integrate spectral with spatial methods. Su...
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ISBN:
(纸本)0819436828
Major spin-offs from NASA's multi- and hyperspectral imaging remote sensing technology developed for Earth resources monitoring, are creative techniques that combine and integrate spectral with spatial methods. Such techniques are finding use in medicine, agriculture, manufacturing, forensics, and an ever expanding list of other applications. Many such applications are easier to implement using a sensor design different from the pushbroom or whiskbroom air- or space-borne counterparts. This need is met by using a variety of electronically tunable filters that are mounted in front of a monochrome camera to produce a stack of images at a sequence of wavelengths, forming the familiar "image cube". The combined spectral/spatial analysis offered by such image cubes takes advantage of tools borrowed from spatial imageprocessing, chemometrics and specifically spectroscopy, and new custom exploitation tools developed specifically for these applications. Imaging spectroscopy is particularly useful for non homogeneous samples or scenes. Examples include spatial classification based on spectral signatures, use of spectral libraries for material identification, mixture composition analysis, plume detection, etc. This paper reviews available tunable filters, system design considerations, general analysis techniques for retrieving the intrinsic scene properties from the measurements, and applications and examples.
We propose a new image compression scheme based on fractal coding of a wavelet transform coefficients using a fast non-iterative algorithm for the codebook generation. The original image is first decomposed into subba...
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ISBN:
(纸本)0818679204
We propose a new image compression scheme based on fractal coding of a wavelet transform coefficients using a fast non-iterative algorithm for the codebook generation. The original image is first decomposed into subbands containing information indifferent spatial directions and different scales, using an orthogonal wavelet filter bank. Subbands are encoded using local Iterated Function Systems (LIFS) with range and domain blocks presenting horizontal or vertical directionalities. Their sizes are estimated according to the correlation lengths and resolution of each subband. The computational complexity is greatly decreased by using subband decomposition. In addition a fast non-iterative algorithm is implemented for the blocks classification. This algorithm creates progressively the codebook during only one scanning of the training set. We proves the efficiency of the proposed approach both in terms of PSNR/bit rate and computation time.
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