Wavelet and wavelet packet compression of electrocardiograms
01 May 1997-IEEE Transactions on Biomedical Engineering (IEEE Trans Biomed Eng)-Vol. 44, Iss: 5, pp 394-402
TL;DR: Pilot data from a blind evaluation of compressed ECG's by cardiologists suggest that the clinically useful information present in original ECG signals is preserved by 8:1 compression, and in most cases 16:1 compressed ECGs are clinically useful.
Abstract: Wavelets and wavelet packets have recently emerged as powerful tools for signal compression. Wavelet and wavelet packet-based compression algorithms based on embedded zerotree wavelet (EZW) coding are developed for electrocardiogram (ECG) signals, and eight different wavelets are evaluated for their ability to compress Holter ECG data. Pilot data from a blind evaluation of compressed ECG's by cardiologists suggest that the clinically useful information present in original ECG signals is preserved by 8:1 compression, and in most cases 16:1 compressed ECG's are clinically useful.
Citations
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01 Jan 2015
TL;DR: A time-evolving topology model and two-channel cryptography is formulated to design well-organized and non-interactive multilevel key exchange protocol for Bundle Protocol and reveals the security and provides enhancement in peculiarities, problems and opportunities a DTN network maintenance.
Abstract: Protected, low-overhead key establishment is vital to maintain the high level of confidence and security that are necessary in several categories of Delay Tolerant Networks (DTNs). A small number of works presenting solutions to DTN key establishment have concentrated principally on targeted networking atmospheres. In this work, to deal with the key establishment concern for Bundle Protocol (BP), a time-evolving topology model and two-channel cryptography is formulated to design well-organized and non-interactive multilevel key exchange protocol. A time-evolving model is employed to properly model the periodic and fixed behaviour patterns of space DTNs, and consequently, a node can plan when and to whom it should transmit its public key. In the meantime, the application of two-channel cryptography allows DTN nodes to exchange their public keys or revocation position information, with authentication assurance and in a non-interactive approach. This approach facilitates to set up a secure context to maintain BSP, tolerating huge delays, and unanticipated loss of connectivity of space DTNs. The experimental investigation reveals the security and provides enhancement in peculiarities, problems and opportunities a DTN network maintenance.
3 citations
Journal Article•
TL;DR: A new method which can be used for progressive transmission of electrocardiogram (ECG) using a discrete version of Radon Transform (DRT), which leads to transmit the most significant energy of the transformed image in Radon domain.
Abstract: The aim of this paper is to present a new method which can be used for progressive transmission of electrocardiogram (ECG). The idea consists in transforming any ECG signal to an image, containing one beat in each row. In the first step, the beats are synchronized in order to reduce the high frequencies due to inter-beat transitions. The obtained image is then transformed using a discrete version of Radon Transform (DRT). Hence, transmitting the ECG, leads to transmit the most significant energy of the transformed image in Radon domain. For decoding purpose, the receptor needs to use the inverse Radon Transform as well as the two synchronization frames. The presented protocol can be adapted for lossy to lossless compression systems. In lossy mode we show that the compression ratio can be multiplied by an average factor of 2 for an acceptable quality of reconstructed signal. These results have been obtained on real signals from MIT database. Keywords—Discrete Radon Transform, ECG compression, synchronization.
3 citations
12 Apr 1999
TL;DR: Wavelet compression issues and new signal-processing algorithm methodologies that can be integrated within the wireless design process to optimise the performance and to enhance the integration and adaptability of such systems under different mobility conditions are addressed.
Abstract: No study to date has addressed the integration issues of the wavelet-based compression techniques with the design and functionality issues of mobile telemedicine systems for real-time medical data transmission over cellular channels. This paper addresses such new hybrid methodologies, namely new wavelet compression methods integrated with the modular telecommunication design blocks and relevant hardware DSP structures for enhanced integrated wireless telemedical systems. I first describe wireless mobile communication in the health sector, discuss the trends in future personal communication services and highlight the actual uses of mobile communications and telematic services in the healthcare domain. The design and integration issues of mobile telemedicine applications based on European (GSM) and North American (IS-136) cellular telephone standards, detailing the modelling and design issues of a general modular structure of a GSM-based mobile telecardiology system are presented. I then address the wavelet compression issues and new signal-processing algorithm methodologies that can be integrated within the wireless design process to optimise the performance and to enhance the integration and adaptability of such systems under different mobility conditions. These concepts provide the telemedicine providers with a better understanding of the engineering aspects and the compatibility issues of future mobile standards and their integration with the next generation of mobile telemedicine applications for enhanced quality and better performance and flexibility of mobile telehealth systems.
3 citations
02 Apr 2015
TL;DR: In this article, simultaneous acquisition of PCG and PPG signals from the same subject with the aid of NIELVIS II+ DAQ and the signals are imported to MATLAB for further processing.
Abstract: Photoplethysmography (PPG) and Phonocardiography (PCG) are two important non-invasive techniques for monitoring physiological parameters of cardiovascular diagnostics. The PCG signal discloses information about cardiac function through vibrations caused by the working heart. PPG measures relative blood volume changes in the blood vessels close to the skin. This paper emphasizes on simultaneous acquisition of PCG and PPG signals from the same subject with the aid of NIELVIS II+ DAQ and the signals are imported to MATLAB for further processing. Heart rate is extracted from both the signals which are found to be distinctive. This analytical approach of processing these signals can abet for analysis of Heart rate variability (HRV) which is widely used for quantifying neural cardiac control and low variability is particularly predictive of death in patients after myocardial infarction.
3 citations
09 Jul 2009
TL;DR: Foveation enables the definition of a proper mask that will modulate the coefficients given by the Discrete Wavelet Transform of an ECG record and is combined with a lossless compression technique to provide high compression ratios at low reconstruction errors.
Abstract: Foveation enables the definition of a proper mask that will modulate the coefficients given by the Discrete Wavelet Transform of an ECG record. The mask is spatially selective and provides maximum accuracy around specific regions of interest. Subsequent denoising and coefficient quantization is further combined with a lossless compression technique in order to provide high compression ratios at low reconstruction errors. Experimental results reported on a number of MIT-BIH records show improved performances over existing solutions.
3 citations
References
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TL;DR: In this paper, it is shown that the difference of information between the approximation of a signal at the resolutions 2/sup j+1/ and 2 /sup j/ (where j is an integer) can be extracted by decomposing this signal on a wavelet orthonormal basis of L/sup 2/(R/sup n/), the vector space of measurable, square-integrable n-dimensional functions.
Abstract: Multiresolution representations are effective for analyzing the information content of images. The properties of the operator which approximates a signal at a given resolution were studied. It is shown that the difference of information between the approximation of a signal at the resolutions 2/sup j+1/ and 2/sup j/ (where j is an integer) can be extracted by decomposing this signal on a wavelet orthonormal basis of L/sup 2/(R/sup n/), the vector space of measurable, square-integrable n-dimensional functions. In L/sup 2/(R), a wavelet orthonormal basis is a family of functions which is built by dilating and translating a unique function psi (x). This decomposition defines an orthogonal multiresolution representation called a wavelet representation. It is computed with a pyramidal algorithm based on convolutions with quadrature mirror filters. Wavelet representation lies between the spatial and Fourier domains. For images, the wavelet representation differentiates several spatial orientations. The application of this representation to data compression in image coding, texture discrimination and fractal analysis is discussed. >
20,028 citations
Book•
01 May 1992TL;DR: This paper presents a meta-analyses of the wavelet transforms of Coxeter’s inequality and its applications to multiresolutional analysis and orthonormal bases.
Abstract: Introduction Preliminaries and notation The what, why, and how of wavelets The continuous wavelet transform Discrete wavelet transforms: Frames Time-frequency density and orthonormal bases Orthonormal bases of wavelets and multiresolutional analysis Orthonormal bases of compactly supported wavelets More about the regularity of compactly supported wavelets Symmetry for compactly supported wavelet bases Characterization of functional spaces by means of wavelets Generalizations and tricks for orthonormal wavelet bases References Indexes.
16,073 citations
TL;DR: In this article, the regularity of compactly supported wavelets and symmetry of wavelet bases are discussed. But the authors focus on the orthonormal bases of wavelets, rather than the continuous wavelet transform.
Abstract: Introduction Preliminaries and notation The what, why, and how of wavelets The continuous wavelet transform Discrete wavelet transforms: Frames Time-frequency density and orthonormal bases Orthonormal bases of wavelets and multiresolutional analysis Orthonormal bases of compactly supported wavelets More about the regularity of compactly supported wavelets Symmetry for compactly supported wavelet bases Characterization of functional spaces by means of wavelets Generalizations and tricks for orthonormal wavelet bases References Indexes.
14,157 citations
TL;DR: This work construct orthonormal bases of compactly supported wavelets, with arbitrarily high regularity, by reviewing the concept of multiresolution analysis as well as several algorithms in vision decomposition and reconstruction.
Abstract: We construct orthonormal bases of compactly supported wavelets, with arbitrarily high regularity. The order of regularity increases linearly with the support width. We start by reviewing the concept of multiresolution analysis as well as several algorithms in vision decomposition and reconstruction. The construction then follows from a synthesis of these different approaches.
8,588 citations
"Wavelet and wavelet packet compress..." refers methods in this paper
...In the work described in this paper, was chosen to be Daubechie's W6 wavelet [10], which is illustrated in Figure 1....
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TL;DR: The image coding results, calculated from actual file sizes and images reconstructed by the decoding algorithm, are either comparable to or surpass previous results obtained through much more sophisticated and computationally complex methods.
Abstract: Embedded zerotree wavelet (EZW) coding, introduced by Shapiro (see IEEE Trans. Signal Processing, vol.41, no.12, p.3445, 1993), is a very effective and computationally simple technique for image compression. We offer an alternative explanation of the principles of its operation, so that the reasons for its excellent performance can be better understood. These principles are partial ordering by magnitude with a set partitioning sorting algorithm, ordered bit plane transmission, and exploitation of self-similarity across different scales of an image wavelet transform. Moreover, we present a new and different implementation based on set partitioning in hierarchical trees (SPIHT), which provides even better performance than our previously reported extension of EZW that surpassed the performance of the original EZW. The image coding results, calculated from actual file sizes and images reconstructed by the decoding algorithm, are either comparable to or surpass previous results obtained through much more sophisticated and computationally complex methods. In addition, the new coding and decoding procedures are extremely fast, and they can be made even faster, with only small loss in performance, by omitting entropy coding of the bit stream by the arithmetic code.
5,890 citations
Additional excerpts
...algorithm was inspired by that in [28]....
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