Results 1 - 10 of 2,778

Frame Reconstruction Of The Laplacian Pyramid

by Minh N. Do , Martin Vetterli , 2001
"... We study the Laplacian pyramid (LP) as a frame operator, and this reveals that the usual reconstruction is suboptimal. With orthogonal filters, the LP is shown to be a tight frame, thus the optimal linear reconstruction using the dual frame operator has a simple structure as symmetrical with the for ..."
Abstract - Cited by 4 (3 self) - Add to MetaCart
We study the Laplacian pyramid (LP) as a frame operator, and this reveals that the usual reconstruction is suboptimal. With orthogonal filters, the LP is shown to be a tight frame, thus the optimal linear reconstruction using the dual frame operator has a simple structure as symmetrical

Error analysis of frame reconstruction from noisy samples

by Akram Aldroubi, Qiyu Sun - λ∈Λ M. ZUHAIR NASHED AND QIYU SUN
"... Abstract — This paper addresses the problem of reconstructing a continuous function defined on R d from a countable collection of samples corrupted by noise. The additive noise is assumed to be i.i.d. with mean zero and variance σ 2. We sample the continuous function f on the uniform lattice 1 m Zd, ..."
Abstract - Cited by 8 (2 self) - Add to MetaCart
, and show for large enough m that the variance of the error between the frame reconstruction fε,m from noisy samples of f and the function f satisfy var(fε,m(x)−f(x)) ≈ σ2 md Cx where Cx is the best constant for every x ∈ R d. We also prove a similar result in the case that our data are weighted

Modified Frame Reconstruction Algorithm for Compressive Sensing

by Graeme Pope , 2009
"... Compressive sensing is a technique to sample signals well below the Nyquist rate using linear measurement operators. In this paper we present an algorithm for signal reconstruction given such a set of measurements. This algorithm generalises and extends previous iterative hard thresholding algorithm ..."
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Compressive sensing is a technique to sample signals well below the Nyquist rate using linear measurement operators. In this paper we present an algorithm for signal reconstruction given such a set of measurements. This algorithm generalises and extends previous iterative hard thresholding

Warped Optical-Flow Inter-Frame Reconstruction for Ultrasound Image Enhancement

by Balza Achmad, Mohd Marzuki Mustafa, Aini Hussain
"... Abstract: Problem statement: Optical flow inter-frame enhancement is one of the techniques to improve the quality of ultrasound images by reducing the speckle noise. The performance depends on accuracy of the optical flow inter-frame reconstruction which is a part of the technique. The speckle noise ..."
Abstract - Cited by 2 (0 self) - Add to MetaCart
Abstract: Problem statement: Optical flow inter-frame enhancement is one of the techniques to improve the quality of ultrasound images by reducing the speckle noise. The performance depends on accuracy of the optical flow inter-frame reconstruction which is a part of the technique. The speckle

New tight frames of curvelets and optimal representations of objects with piecewise C² singularities

by Emmanuel J. Candès, David L. Donoho - COMM. ON PURE AND APPL. MATH , 2002
"... This paper introduces new tight frames of curvelets to address the problem of finding optimally sparse representations of objects with discontinuities along C2 edges. Conceptually, the curvelet transform is a multiscale pyramid with many directions and positions at each length scale, and needle-shap ..."
Abstract - Cited by 428 (21 self) - Add to MetaCart
This paper introduces new tight frames of curvelets to address the problem of finding optimally sparse representations of objects with discontinuities along C2 edges. Conceptually, the curvelet transform is a multiscale pyramid with many directions and positions at each length scale, and needle

NOISE PROCESSING FOR SIMPLE LAPLACIAN PYRAMID SYNTHESIS BASED ON DUAL FRAME RECONSTRUCTION

by Aditya Mavlankar, David Chen, Sameh Zakhary, Markus Flierl, Bernd Girod
"... The Laplacian pyramid (LP) provides a frame expansion. Thus, there exist infinitely many synthesis operators which achieve perfect reconstruction in the absence of quantization. However, if the subbands are quantized in the open-loop mode then the dual frame synthesis operator, which is the pseudo-i ..."
Abstract - Cited by 1 (0 self) - Add to MetaCart
The Laplacian pyramid (LP) provides a frame expansion. Thus, there exist infinitely many synthesis operators which achieve perfect reconstruction in the absence of quantization. However, if the subbands are quantized in the open-loop mode then the dual frame synthesis operator, which is the pseudo

Super-resolution Frame Reconstruction Using Subpixel Motion Estimation

by unknown authors
"... When video data is used for forensic analysis, it may transpire that the level of detail available is insufficient. This is particularly the case when it is derived from sensors deployed in the field since they have limited resolution. For example, a vehicle license plate number may not be legible i ..."
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in video captured during a traffic violation. In such cases, it is desirable to enhance the resolution of selected frames. However, obtaining the maximum resolution possible is computationally prohibitive. Forensic analysts need a tool where the tradeoff between detail extracted and the running time can

Image Representation Using 2D Gabor Wavelets

by Tai Sing Lee - IEEE Trans. Pattern Analysis and Machine Intelligence , 1996
"... This paper extends to two dimensions the frame criterion developed by Daubechies for one-dimensional wavelets, and it computes the frame bounds for the particular case of 2D Gabor wavelets. Completeness criteria for 2D Gabor image representations are important because of their increasing role in man ..."
Abstract - Cited by 375 (4 self) - Add to MetaCart
formed an orthonormal basis. Approximating a "tight frame" generates redundancy which allows low-resolution neural responses to represent high-resolution images, as we illustrate by image reconstructions with severely quantized 2D Gabor coefficients. Index Terms---Gabor wavelets, coarse coding

Extraction of High-Resolution Frames from Video Sequences

by Richard R. Schultz, Robert L. Stevenson - IEEE Transactions on Image Processing , 1996
"... The human visual system appears to be capable of temporally integrating information in a video sequence in such a way that the perceived spatial resolution of a sequence appears much higher than the spatial resolution of an individual frame. While the mechanisms in the human visual system which do t ..."
Abstract - Cited by 264 (8 self) - Add to MetaCart
frame. A novel observation model based on motion compensated subsampling is proposed for a video sequence. Since the reconstruction problem is ill-posed, Bayesian restoration with a discontinuity-preserving prior image model is used to extract a high-resolution video still given a short low

Evaluation of a tight frame reconstruction algorithm for perfusion C-arm CT using a realistic dynamic brain phantom

by Michael Manhart, Andreas Fieselmann, Yu Deuerling-zheng - in Proc. of the Second International Conference on Image Formation in X-Ray Computed Tomography , 2012
"... Abstract—This work introduces and evaluates an iterative, compressed sensing (CS) reconstruction algorithm based on tight frame regularization for perfusion C-arm CT with a high C-arm rotation speed acquisition protocol. To allow a realistic evaluation, a digital 4D brain phantom was created by exte ..."
Abstract - Cited by 3 (3 self) - Add to MetaCart
Abstract—This work introduces and evaluates an iterative, compressed sensing (CS) reconstruction algorithm based on tight frame regularization for perfusion C-arm CT with a high C-arm rotation speed acquisition protocol. To allow a realistic evaluation, a digital 4D brain phantom was created
Results 1 - 10 of 2,778