the design of methods to simultaneously display signal and image data used in clinical epilepsy research is presented. Electrical sensors, spatially distributed into or over the head of the patient, are basic tools fo...
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(纸本)3540616497
the design of methods to simultaneously display signal and image data used in clinical epilepsy research is presented. Electrical sensors, spatially distributed into or over the head of the patient, are basic tools for epilepsy research. the considerable amount of sensors makes the interpretation of the acquired signals difficult when they are displayed as multiple electrical potentials vs. time curves. In addition, the dimension of the representation domain is increased after processingthe signals (e.g. time-scale or time-frequency representations). the anatomical reference is always required to understand the mechanisms underlying the brain electrical activity. the solutions reported here make use of two dimensional (2D) or three dimensional (3D) spatio-temporal mappings, surface cartographies projected onto the anatomical structures and compositions of depth/surface/morphology information.
this paper intends to present an integrated approach of constructing new spatio-temporal wavelets for discrete signal analysis. the main illustrative field of applications considered here stands as the analysis of dig...
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this paper intends to present an integrated approach of constructing new spatio-temporal wavelets for discrete signal analysis. the main illustrative field of applications considered here stands as the analysis of digital image sequences. Nevertheless, this can be readily extended to any kind of spatio-temporal signals. Continuous wavelet transforms, continuous series, discretized series and discrete transforms are considered here in an unified way. the analysis to be developed relies only on dynamic parameters like uniform translation and rotation, on kinematic parameters like velocity and speed and on structural parameters as scale and orientation. this digital processing intends to cover the detection and the focalization on motion-based regions of interest in order to perform tracking, classification, segmentation, multiscale trajectory construction and eventually a selective reconstruction of the useful content.
An extensible object-oriented MRI simulation system is presented. this simulator uses first-principle modelling based on the Bloch equations to implement a discrete-event simulation of NMR signal production. A model o...
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this paper presents a new technique for interpolating missing data in image sequences. A 3D autoregressive (AR) model is employed and a sampling based interpolator is developed in which reconstructed data is generated...
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A new lattice structure is described. It is capable of implementing all paraunitary two-channel filter banks where the filters have complex coefficients and yield symmetric wavelet bases. this lattice structure, while...
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A new lattice structure is described. It is capable of implementing all paraunitary two-channel filter banks where the filters have complex coefficients and yield symmetric wavelet bases. this lattice structure, while being a general design method, can also be used to actually design the filter bank. these filter banks are, in fact, a special case of multifilter banks and can also be related to Golay-Rudin-Shapiro complementary polynomial pairs. the applications of such filter banks are to be found in subband coding and communications systems.
In order to satisfy the needs of new applications in a multimedia environment the problem of object-oriented coding has to be addressed. In this paper two main approaches are presented to tackle this problem. First, a...
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In order to satisfy the needs of new applications in a multimedia environment the problem of object-oriented coding has to be addressed. In this paper two main approaches are presented to tackle this problem. First, an algorithm for shape coding is presented. It, is based on a chain coding algorithm where powerful modeling techniques are used to increase the compression ratio. Second, an algorithm for interior coding is described, It is based on an arbitrarily-shaped subband transform followed by a generalized embedded zerotree wavelet algorithm. It is shown in the paper that it achieves good compression results and has additional properties such as supporting arbitrarily shaped regions, being computationally efficient, keeping the same dimensionality in the transformed domain, allowing perfect reconstruction and an intrinsic rate control mechanism. the presented results show that the two algorithms build an efficient basis to design object-oriented video coding schemes.
We address the problem of bit allocation to wavelet subbands by extending the recursive optimal pruning algorithm of Kiang, Baker, Sullivan and Chiu (see IEEE Transactions on imageprocessing, vol.1, no.4, p.162-9, 19...
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We address the problem of bit allocation to wavelet subbands by extending the recursive optimal pruning algorithm of Kiang, Baker, Sullivan and Chiu (see IEEE Transactions on imageprocessing, vol.1, no.4, p.162-9, 1992) to bit allocation. We apply the algorithm to tree-structured vector quantizers used to code image subbands that result from the wavelet decomposition. We compare this method to the GBFOS algorithm, that is, the generalized Breiman, Friedman, Olshen, and Stone (1984) bit allocation, and show that it produces many additional bit allocations that lie close to the rate-distortion curve.
We present a region-based wavelet compression method for encoding video sequences at very low bit rates suitable for videophone applications. By selectively coding texture information in the regions of interest, we av...
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We present a region-based wavelet compression method for encoding video sequences at very low bit rates suitable for videophone applications. By selectively coding texture information in the regions of interest, we avoid spending bits in the unimportant regions and improve video quality. the embedded zerotree wavelet algorithm is extended to efficiently represent the wavelet coefficients within the regions of interest while exploiting redundancy between subbands. the locations of the regions of interest are selected during the motion estimation process and are transmitted as part of the macroblock type. this technique can provide better quality compared to the new H.263 videophone compression standard. this technique was also incorporated in a more general object-based compression scheme which obtained high scores during the recent MPEG-4 subjective quality evaluations.
We develop a new algorithm for multirate filter bank optimization, which finds application in subband coding or waveletsignal analysis. Although some impressive off-line algorithms have recently been developed for th...
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We develop a new algorithm for multirate filter bank optimization, which finds application in subband coding or waveletsignal analysis. Although some impressive off-line algorithms have recently been developed for this purpose, the computation demand of such algorithms often renders them prohibitive for real-time applications. In this vein, adaptive filtering solutions remain of interest. A simple gradient descent algorithm may be ill suited due to the nonquadratic nature of the cost function to be minimized, and accordingly non gradient algorithms may offer some attractive alternatives. the present paper describes a projection type algorithm, which aims to construct a lossless filter bank such that one of its impulse responses lies close to an extremal eigenvector of the input signal autocorrelation matrix. though a formal convergence proof of the algorithm is not offered, simulations show that the algorithm converges to an acceptable vicinity of the global minimum point of the cost function.
the wavelet transform provides a time-scale analysis that permits flexible pattern recognition, component identification, and detection of transients for time-varying neural signals such as the EEG, event-related pote...
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the wavelet transform provides a time-scale analysis that permits flexible pattern recognition, component identification, and detection of transients for time-varying neural signals such as the EEG, event-related potentials, neuromagnetic signals, and other neural signals and images. Many future applications to neural signals will benefit from choosing a mother waveletthat mimics neural waveform features. We use a recently developed algorithm to design physiologically realistic orthonormal Meyer wavelets, including 1) a waveletthat matches the prominent IV-V complex of the auditory brainstem evoked response used widely for clinical evaluation of hearing loss, and 2) a waveletthat matches ERPs containing prominent P300 components from control and alcoholic subjects. We also compare the relative naturalness of dyadic decompositions that use matched Meyer wavelets, the Haar wavelet, and Daubechies D4wavelet. Designer neural wavelets have broad potential to customize and improve neurometric imaging and clinical neurodiagnosis of sensory and cognitive dysfunction.
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