We present planar curve descriptors that allow a hierarchical representation of curves. The descriptors are based on wavelet and multiwavelet transforms and they decompose a curve into components of different scales.
ISBN:
(纸本)0819429139
We present planar curve descriptors that allow a hierarchical representation of curves. The descriptors are based on wavelet and multiwavelet transforms and they decompose a curve into components of different scales.
We define and characterize a frame-like stable decomposition for subspaces in a separable Hilbert space. We call in pseudoframes for subspaces (PFFS). Properties of PFFS are discussed. A necessary and sufficient condi...
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ISBN:
(纸本)0819429139
We define and characterize a frame-like stable decomposition for subspaces in a separable Hilbert space. We call in pseudoframes for subspaces (PFFS). Properties of PFFS are discussed. A necessary and sufficient condition for the construction is provided. An analytical formula for the construction of PFFS is also derived. An example is studied both as a motivation of the theoretical study of such pseudoframes and as an actual construction. Potential applications of PFFS are discussed.
Fast algorithms performing time-scale analysis of multivariate functions are discussed. The algorithms employ univariate wavelets and involve a directional parameter, namely the angle of rotation. Both the rotation st...
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ISBN:
(纸本)0819429139
Fast algorithms performing time-scale analysis of multivariate functions are discussed. The algorithms employ univariate wavelets and involve a directional parameter, namely the angle of rotation. Both the rotation steps and the wavelet analysis/synthesis steps in the algorithms require a number of computations proportional to the number of data involved. The rotation and wavelet techniques are used for the segregation of wanted and unwanted components in a seismic signal. As an illustration, the rotation and wavelet methods are applied to a synthetic shot record.
High-resolution optical mapping is an emerging technique to record the activation and propagation of transmembrane potential on the surface of cardiac tissues. Important electrodynamic information previously not avail...
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ISBN:
(纸本)0819429139
High-resolution optical mapping is an emerging technique to record the activation and propagation of transmembrane potential on the surface of cardiac tissues. Important electrodynamic information previously not available from extracellular electric recording could be extracted from these detailed optical recordings. The noise contamination in the images is a major obstacle that prohibits higher level of information extraction. Because the patterns of interest contain sharp wavefronts and structures that we wish to detect and track in a series of: flames, we seek to perform denoising based on wavelet decomposition approaches. Among the wavelet denoise methods that were tested in this preliminary study, the wavelet packet produced the best results that could be extended to denoise the entire image sequence for multi-dimensional information processing.
The main contribution of this work is a new paradigm for image compression. We describe a new multi-layered representation technique for images. An image is encoded as the superposition of one main approximation, and ...
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ISBN:
(纸本)0819429139
The main contribution of this work is a new paradigm for image compression. We describe a new multi-layered representation technique for images. An image is encoded as the superposition of one main approximation, and a sequence of residuals. The strength of the multi-layered method comes from the fact that we use different bases to encode the main approximation and the residuals. For instance, we can use: - a wavelet basis to encode a coarse main approximation of the image, - wavelet packet bases to encode textured patterns, - brushlet bases to encode localized oriented textured features, etc.
We address the problem of improving the performance of wavelet based fractal image compression by applying efficient triangulation methods. We construct iterative function systems (IFS) in the tradition of Barnsley an...
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ISBN:
(纸本)0819429139
We address the problem of improving the performance of wavelet based fractal image compression by applying efficient triangulation methods. We construct iterative function systems (IFS) in the tradition of Barnsley and Jacquin, using non-uniform triangular range and domain blocks instead of uniform rectangular ones. We search for matching domain blocks in the manner of Zhang and Chen, performing a fast wavelet transform on the blocks and eliminating low resolution mismatches to gain speed. We obtain further improvements by the efficiencies of binary triangulations (including the elimination of affine and symmetry calculations and reduced parameter storage), and by pruning the binary tree before construction of the IFS. Our wavelets are triangular Haar wavelets and "second generation" interpolation wavelets as suggested by Sweldens' recent work.
The discrete wavelet transform (DWT) gives a compact multiscale representation of signals and provides a hierarchical structure for signalprocessing. It has been assumed the DWT can fairly well decorrelate real-world...
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ISBN:
(纸本)0780362934
The discrete wavelet transform (DWT) gives a compact multiscale representation of signals and provides a hierarchical structure for signalprocessing. It has been assumed the DWT can fairly well decorrelate real-world signals. However a residual dependency structure still remains between wavelet coefficients. It. has been observed magnitudes of wavelet coefficients are highly correlated, both across the scale and at neighboring spatial locations. In this paper we present, a wavelet folding technique, which folds wavelet coefficients across the scale and removes the across-the-scale dependence to a larger extent. It produces an even more compact signal representation and the energy is more concentrated in a few large, coefficients. It has a great potential in applications such as image compression.
image Registration, one of the scene encoding approaches, is a very active research topic in computer vision and computer graphics community. This paper presents a robust image registration scheme that employs complex...
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ISBN:
(纸本)0819429139
image Registration, one of the scene encoding approaches, is a very active research topic in computer vision and computer graphics community. This paper presents a robust image registration scheme that employs complex wavelet pyramid and the human visual perceptive thresholding techniques. Complex wavelet transform guarantees not only a global optimal solution, but also the scale and translation invariance for the image alignment. Applying the HVS (Human visual System) thresholding for wavelet coefficients shows that image can be compressed significantly (30-100:1 ratio) while the detail of the structured information can be retained so that the transformation obtained from the threshholded waveletimages is sufficiently accurate when applying on the original images. The transformation can be progressively refined on the multiresolution decomposition. This guarantees the robustness of the scheme with a better performance than the traditional registration techniques. Moreover, the scheme registers images taken directly by hand-held digital camera without knowing camera motion and any intrinsic parameters of camera.
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