Showing papers on "Wavelet published in 1970"
Patent•
07 Dec 1970
TL;DR: For each seismic receiver location n multi-transmission signals, which are similar in form but differ in peak frequency within a frequency range of interest, are time-compressed by cross-correlating the received signals containing it with each transmitted signal alone, weighting the resulting n correlation functions to produce for each event arrival the simplest compressed central wavelet when added with zero-lag times in coincidence, summing the weighted correlogram traces, and Wiener filtering the summation trace to reduce its amplitudes substantially to zero outside of said central wavelets as mentioned in this paper.
Abstract: For each seismic receiver location n multi-transmission signals, which are similar in form but differ in peak frequency within a frequency range of interest, are time-compressed by cross-correlating the received signals containing it with each transmitted signal alone, weighting the resulting n correlation functions to produce for each event arrival the simplest compressed central wavelet when said n correlation functions are added with zero-lag times in coincidence, summing the weighted correlogram traces, and Wiener filtering the summation trace to reduce its amplitudes substantially to zero outside of said central wavelets.
25 citations
TL;DR: A modified version of Lind Boze and Gray algorithm using Partial Search Partial Distortion (PSPD) is presented for coding the wavelet coefficients to speed up the codebook generation and the search required for nearest neighbour codevector of input image.
Abstract: The fast development of computing multimedia has led to the demand of using digital images. The manipulation, storage and transmission of these images in their raw form is very expensive, it significantly slows the transmission and makes storage costly. In this paper, a brief review of wavelet transform theory is given using filters as examples to show the related multiresolution analysis. Advantages over Fourier transform is investigated and several results are derived. The pyramid algorithm is also presented and some features of wavelets in image data compression are given. A modified version of Lind Boze and Gray (LBG) algorithm using Partial Search Partial Distortion (PSPD) is presented for coding the wavelet coefficients to speed up the codebook generation and the search required for nearest neighbour codevector of input image. The proposed scheme can save 70 - 80 % of the Vector Quantization (VQ) encoding time as compared to fully search VQ and reduced arithmetic complexity with less sacrificing performance. Key Words: Image compression, Wavelets transform, Vector qQuantization
5 citations
TL;DR: In this paper, the behavior of amplitude and waveform as a function of common depth point, offset, shot position, and receiver position is extracted from the wavelet maps and used to provide a basis for amplitude control and corrections as functions of time and space.
Abstract: Wavelet maps are special displays of reflection seismograms. Seismic wavelets from a reflecting horizon are gathered and displayed in each of 4 data organizations: common depth point, common shot position, common receiver position, and common offset. In each of these organizations, the wavelets are aligned relative to their estimated traveltimes, thereby removing the structural and the hyperbolic normal moveout effects. By suitable averaging and analysis of the wavelets, we may extract information from each reflector relating to (1) the behavior of amplitude and waveform as a function of common depth point, offset and shot and receiver locations, and (2) the residual traveltime, referred to hyperbolic normal moveout, as a function of offset, shot position, and receiver position. This information can be used to provide a basis for (1) amplitude control and corrections as functions of time and space, (2) surface‐consistent static corrections, (3) shot characteristics, (4) indication of thin‐bed, complex, in...
2 citations
DOI•
01 Jan 1970
TL;DR: In this article, the wavelet analysis has been used as a possible candidate as turbulent structure detection method, overcoming any empirical approach, and an application of this mathematical tool to a near wall boundary layer velocity signal is shown.
Abstract: Classical eduction schemes for turbulent boundary layer bursting processes are based on the assumption of empirical threshold constants. The wavelet analysis has been recently considered to be a possible candidate as turbulent structure detection method, overcoming any empirical approach. An application of this mathematical tool to a near wall boundary layer velocity signal is shown. Comparison with classical VITA detection scheme is presented.
TL;DR: A survey of the most recent work in the field of surface metrology by using wavelet theory is provided in this paper, where the basic theory, algorithm and properties of these models are discussed.
Abstract: The needs of modem surface metrology assessment cover not only the extraction of roughness, waviness, but also identification of surface texture or the multiscalar properties of a surface topography. In answer to this, the newly developing wavelet theory has been introduced into surface characterisation in 1994. Wavelet analysis employs time-frequency windows and offers the relevant time-frequency analysis, as a result, it can divide surface topography into different frequency components, and then study each component with the multiresolution. This paper provides a survey of the most recent work in the field of surface metrology by using wavelet theory. The major wavelet models used in surface metrology will be introduced and the basic theory, algorithm and the properties of these models will also be discussed.