Wavelet transform inversion with prior scale information

Geophysics ◽  
1996 ◽  
Vol 61 (5) ◽  
pp. 1379-1385 ◽  
Author(s):  
Xin-Gong Li ◽  
Mauricio D. Sacchi ◽  
Tadeusz J. Ulrych
Keyword(s):  
Wavelet Transform ◽  
Prior Information ◽  
A Priori ◽  
Wavelet Basis ◽  
Wavelet Domain ◽  
Central Importance ◽  
Traveltime Inversion ◽  
Data Inversion ◽  
Damped Least Squares ◽  
Special Case

The concept of scale is of central importance in all problems related to the interpretation of earth data. Inversion of geophysical data does not at present, however, allow the incorporation of scale‐dependent information directly. This article presents an application of the wavelet transform to traveltime inversion where we are specifically concerned with the selection and application of a priori scale information in the wavelet domain to reconstruct tomographic models. Because of the nature of the problem, the wavelet basis chosen for this example is the Haar basis. The results are compared with the classic damped least‐squares (DLS) method, which is a special case of the wavelet transform approach when all the scales are treated equally. We show that with scale‐dependent prior information, most of the artifacts created by the DLS technique are diminished considerably.

Multifocus image fusion based on coefficient significance of redundant discrete wavelet transform

2019 ◽  
Vol 46 (3) ◽  
pp. 377-383
Author(s):  
Jianhua Liu ◽  
Peng Geng ◽  
Hongtao Ma
Keyword(s):  
Wavelet Transform ◽  
Image Fusion ◽  
Discrete Wavelet Transform ◽  
Fusion Rule ◽  
Discrete Wavelet ◽  
Wavelet Domain ◽  
Content Type ◽  
Ripplet Transform ◽  
Detail Coefficient ◽  
Redundant Discrete Wavelet Transform

Purpose This study aims to obtain the more precise decision map to fuse the source images by Coefficient significance method. In the area of multifocus image fusion, the better decision map is very important the fusion results. In the processing of distinguishing the well-focus part with blur part in an image, the edge between the parts is more difficult to be processed. Coefficient significance is very effective in generating the better decision map to fuse the multifocus images. Design/methodology/approach The energy of Laplacian is used in the approximation coefficients of redundant discrete wavelet transform. On the other side, the coefficient significance based on statistic property of covariance is proposed to merge the detail coefficient. Findings Due to the shift-variance of the redundant discrete wavelet and the effectiveness of fusion rule, the presented fusion method is superior to the region energy in harmonic cosine wavelet domain, pixel significance with the cross bilateral filter and multiscale geometry analysis method of Ripplet transform. Originality/value In redundant discrete wavelet domain, the coefficient significance based on statistic property of covariance is proposed to merge the detail coefficient of source images.

De Verwerving Van Morfologische Regels in Schrift (III)

1999 ◽  
Vol 61 ◽  
pp. 97-110
Author(s):  
Marjolein van Dort-Slijper ◽  
Gert Rijlaarsdam ◽  
Eva Breedveld
Keyword(s):  
Negative Transfer ◽  
Empirical Studies ◽  
A Priori ◽  
Recognition Task ◽  
Past Tense ◽  
Production Task ◽  
The Past ◽  
Verb Inflection ◽  
Group 6 ◽  
Special Case

In order to provide textbook authors with empirical data on the acquisition in Dutch of written morphology in nouns, verbs and adjectives, several empirical studies have been undertaken. In this article, the third study reports on the performance of the morpheme -e in a special case of adjectives in Dutch: the adjectives derived from participles. The study tries to determine the possible interference between the morphological rules for verb inflection (past tense) and adjective declension in reading and writing. Five classes of adjectives were distinguished according to order of relative difficulty established a priori. Subjects (n=157, grade 6, 7 and 8 from two schools) individually completed a compre-hension and a production task in which factors were systematically varied. Also a recognition test on the spelling of the past tense of verbs was administered. The results showed an effect of categories of verbal adjectives in the production task, but only for groups 7 and 8; group 6 was not sensitive to the differences between the categories. In the recognition task, no effect of type of adjective (verbal or normal) was found for groups 7 and 8; but for group 6, performance on verbal adjectives was lower for the three most difficult categories of adjectives. In the production task, all three groups performed lower on verbal adjectives than normal adjectives in the two most difficult categories of adjectives. It turned out that groups which acquired spelling rules for the past tense of verbs to a higher level, made more errors in the spelling of verbal adjectives, especially in the two categories of adjectives which related the strongest to the spelling of verbs. It was concluded that indications were found that negative transfer or interference is present. Authors recommend changing the order of phases in which spelling rules are trained: from 'adjective declension-verb inflection (past tense)-verbal adjective declension' to 'adjective declension (including verbal adjective declension)-verb declension (past tense).

XXIV.—On the Equation of Motion of a Free Particle in the Expanding Universe of Kinematical Relativity

1943 ◽  
Vol 61 (3) ◽  
pp. 288-297
Author(s):  
E. A. Milne
Keyword(s):  
Additional Assumption ◽  
A Priori ◽  
Free Particle ◽  
Equation Of Motion ◽  
Expanding Universe ◽  
Image Position ◽  
Special Case

In a recent paper in these Proceedings, Dr G. C. McVittie has published some criticisms of kinematical relativity. These criticisms are to a large extent based on his formula (4.10), namely,It must be stated at the outset that McVittie's interpretation of his derivation of (1) as a derivation of “Milne's formula for the acceleration of a ‘free particle moving in the presence of a substratum,’ for the special case of one spatial co-ordinate only” is wrong. McVittie does not derive the result, as he claims, from what he calls the “axioms of kinematical relativity” alone; he deduces it from these axioms together with an additional assumption, which is equivalent to begging the answer to the whole problem it was my object to solve. Instead of considering a free particle, as I did—that is, a particle whose motion we do not a priori know—he prescribes a priori the motion of his particle as being constrained to obey the rule, in his notation,

scholarly journals A Guaranteed Deterministic Approach to Superhedging—The Case of Convex Payoff Functions on Options

Mathematics ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 1246 ◽  
Author(s):  
Sergey Smirnov
Keyword(s):  
A Priori ◽  
Contingent Claim ◽  
Mixed Strategies ◽  
Deterministic Approach ◽  
Deterministic Problem ◽  
History Of ◽  
Game Theoretic ◽  
Payoff Functions ◽  
Special Case ◽  
Problem Setting

This paper considers super-replication in a guaranteed deterministic problem setting with discrete time. The aim of hedging a contingent claim is to ensure the coverage of possible payoffs under the option contract for all admissible scenarios. These scenarios are given by means of a priori given compacts that depend on the history of prices. The increments of the price at each moment in time must lie in the corresponding compacts. The absence of transaction costs is assumed. The game–theoretic interpretation of pricing American options implies that the corresponding Bellman–Isaacs equations hold for both pure and mixed strategies. In the present paper, we study some properties of the least favorable (for the “hedger”) mixed strategies of the “market” and of their supports in the special case of convex payoff functions.

Digital Watermarking of High Security Based on Holography

2013 ◽  
Vol 333-335 ◽  
pp. 1051-1055
Author(s):  
Chao Han ◽  
Meng Meng Li ◽  
Wei Wu
Keyword(s):  
Wavelet Transform ◽  
White Noise ◽  
Digital Watermarking ◽  
Reference Beam ◽  
Shear Resistance ◽  
Wavelet Domain ◽  
Phase Information ◽  
Excellent Performance ◽  
Host Image ◽  
High Security

Aiming at the problem that security of digital watermarking is imperfect, a new digital watermarking algorithm based on holography is put forward. In embedment watermarking stage, first, original watermarking information is divided into two parts: amplitude and phase information. Then, a hologram which will be used as new watermarking information is generated by interference of the phase information light and the reference beam, and the amplitude information will be the key when original watermarking is extracted. At last, host image is transformed by the multilevel structures wavelet transform, and the new watermarking information is embedded into its suitable wavelet domain. In extraction watermarking information stage, the original watermarking information is obtained by the extracted watermarking information combined with the amplitude information. The theory and simulation show our algorithm has excellent performance in security, shear resistance and anti interference of white noise.

scholarly journals Wavelet transform and cyclic cumulant based modulation classification in wireless network

2019 ◽  
Vol 15 (12) ◽  
pp. 155014771989545
Author(s):  
Wenwen Li ◽  
Zheng Dou ◽  
Lin Qi
Keyword(s):  
Wavelet Transform ◽  
Wireless Network ◽  
Prior Information ◽  
Ad Hoc ◽  
Multipath Channel ◽  
Modulation Scheme ◽  
Modulation Classification ◽  
Embedded Devices ◽  
Correct Communication ◽  
Classification Probability

With the development of Internet of things, a large number of embedded devices are interconnected by ad hoc and wireless network. The embedded devices can work correctly, only by ensuring correct communication between them. Identifying modulation scheme is the precondition to ensure the correct communication between embedded devices. However, in the multipath channel, ensuring the correct communication between embedded devices is a great challenge. Multipath channel always exists in the wireless network. However, most of the available modulation classification algorithms are based on ideal channel. It leads to the low-modulation classification probability in multipath channel. To resolve this problem, we propose a novel modulation classification algorithm. The proposed algorithm can classify signal without prior information about multipath channel. We calculate feature by high-order cyclic cumulant and wavelet transform. The feature is robust to multipath channel. The simulation results show that the proposed algorithm can achieve the much better classification accuracy than the available method in multipath channel.

scholarly journals Statistical Method to Extract Evoked Potentials from Noise

2020 ◽  
Vol 170 ◽  
pp. 02005
Author(s):  
Besma Benchabane ◽  
Moncef Benkherrat ◽  
Salah Djelel
Keyword(s):  
Wavelet Transform ◽  
Evoked Potentials ◽  
A Priori ◽  
Brain Regions ◽  
Statistical Test ◽  
A Priori Information ◽  
Time Frequency ◽  
Priori Information ◽  
Electrical Activities ◽  
The Brain

Evoked Potentials are induced by visual or auditory stimulation. The Evoked Potentials represent transient electrical activities of some limited brain regions. The signal-noise ratio (SNR) of the EPs is typically around -10 dB. In order to study brain activities related to information processing in the brain, one has to “extract” the single EPs from the noise. We propose a method does not require a priori information concerning the characteristics (time, frequency) of the signal and does not use a template. The method proposed in this work use the wavelet transform associated with a statistical test.

KINETIC THEORY AND HYDRODYNAMICS FOR A LOW DENSITY GRANULAR GAS

2001 ◽  
Vol 04 (04) ◽  
pp. 397-406 ◽  
Author(s):  
JAMES W. DUFTY
Keyword(s):  
Kinetic Theory ◽  
Hard Spheres ◽  
A Priori ◽  
Inelastic Collisions ◽  
Low Density ◽  
Qualitative And Quantitative ◽  
Granular Gas ◽  
Rapid Flow ◽  
Special Case ◽  
Domain Of Validity

Many features of real granular fluids under rapid flow are exhibited as well by a system of smooth hard spheres with inelastic collisions. For such a system, it is tempting to apply standard methods of kinetic theory and hydrodynamics to calculate properties of interest. The domain of validity for such methods is a priori uncertain due to the inelasticity, but recent systematic studies continue to support the utility of kinetic theory and hydrodynamics as both qualitative and quantitative descriptions for many physical states. The basis for kinetic theory and hydrodynamic descriptions is discussed briefly for the special case of a low density gas.

DETECTION OF TRACKS IN AERIAL PHOTOS BY THE GIBBS SAMPLER

2003 ◽  
Vol 17 (01) ◽  
pp. 1-16 ◽  
Author(s):  
A. TETERUKOVSKIY
Keyword(s):  
Prior Knowledge ◽  
Cell Size ◽  
Bayesian Approach ◽  
Gibbs Sampler ◽  
Prior Information ◽  
A Priori ◽  
A Priori Knowledge ◽  
Gray Level ◽  
Aerial Photos ◽  
Positive Results

A problem of automatic detection of tracks in aerial photos is considered. We adopt a Bayesian approach and base our inference on an a priori knowledge of the structure of tracks. The probability of a pixel to belong to a track depends on how the pixel gray level differs from the gray levels of pixels in the neighborhood and on additional prior information. Several suggestions on how to formalize the prior knowledge about the shape of the tracks are made. The Gibbs sampler is used to construct the most probable configuration of tracks in the area. The method is applied to aerial photos with cell size of 1 sq. m. Even for detection of trails of width comparable with or smaller than the cell size, positive results can be achieved.

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