Results 251 to 260 of about 465,610 (291)
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Journal of Modern Optics, 2003
Abstract It is shown that the cross-spectral density at a plane in the Fresnel—Fraunhofer domain can be expressed as a certain diffraction pattern, which is generated by the superposition of second-order spatial coherence wavelets that emerge from the aperture. The amplitude of each coherence wavelet exhibits units of power density (average energy) and
Roman Castaneda, Jorge Garcia-Sucerquia
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Abstract It is shown that the cross-spectral density at a plane in the Fresnel—Fraunhofer domain can be expressed as a certain diffraction pattern, which is generated by the superposition of second-order spatial coherence wavelets that emerge from the aperture. The amplitude of each coherence wavelet exhibits units of power density (average energy) and
Roman Castaneda, Jorge Garcia-Sucerquia
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Holographic features of spatial coherence wavelets
Journal of the Optical Society of America A, 2008The behavior of the marginal power spectrum as a two-channel-multiplexed hologram is analyzed. Its "negative energies" make it quite different from the conventional holograms, i.e., it is not recordable in general and the objects to be reconstructed (the cross-spectral densities at both the aperture and the observation planes) are virtual.
Roman, Castaneda +2 more
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Comparative study on wavelet coherence and HHT coherence
2014 7th International Congress on Image and Signal Processing, 2014Classic coherence analysis has been commonly used as a effective method for the analysis of stationary signals. To study the instantaneous coherence between non-stationary signals, we extended the concept of coherence to time-varying coherence using some time-frequency analysis methods.
Zheng Zhang +4 more
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Radiometry and spatial coherence wavelets
Optics Communications, 2005An alternative approach to the relationship between the radiometry and the optical spatial coherence is proposed. It is based on the concepts of classes of radiator pairs and the marginal power spectrum, recently introduced in the framework of the Wigner optics.
Roman Castaneda, Jorge Garcia-Sucerquia
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Transient Detection With Cross Wavelet Transforms and Wavelet Coherence
IEEE Transactions on Signal Processing, 2007Effective detection of unknown, transient oscillations in strong, colored, time varying noise and clutter has remained a signal processing challenge. Recently we presented a self-normalized wavelet detector for this purpose. Here, we revisit this detection problem for the case of a tapered, complex, transient oscillation observed coherently in two time
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Multiple wavelet coherence analysis
SPIE Proceedings, 2006We propose a method for analysis of localised relationships between multiple two-dimensional signals, or images, that naturally treats the local phase structure and local orientation of any variation in the observed images. The method is based on using several non-separable wavelet decompositions of the images.
Sofia C. Olhede, Georgios Metikas
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Wavelet Transform of Even- and Odd-Coherent States
International Journal of Theoretical Physics, 2010zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Song, Jun, Fan, Hong-yi
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Wavelet Coherence for Certain Nonstationary Bivariate Processes
IEEE Transactions on Signal Processing, 2011A previous study considered the estimation of wavelet coherence from jointly stationary time series via time-domain smoothing and use of a single Morlet wavelet. The form of the asymptotic (Goodman's) distribution was derived. In this paper we extend this approach to nonstationary time series where the nonstationarity is induced by various types of ...
Ed A. K. Cohen, Andrew T. Walden
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A Comment on “Transient Detection With Cross Wavelet Transforms and Wavelet Coherence”
IEEE Transactions on Signal Processing, 2008An explicit expression is derived for the probability density function (pdf) of the square magnitude of the normalized cross wavelet spectrum for the self-normalized Morlet cross wavelet spectrum (NCM) detector considered for Plett. The expression involves the well-known Gauss hypergeometric function.
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Young's experiment with electromagnetic spatial coherence wavelets
Journal of the Optical Society of America A, 2006We discuss Young's experiment with electromagnetic random fields at arbitrary states of coherence and polarization within the framework of the electric spatial coherence wavelets. The use of this approach for the electromagnetic spatial coherence theory allows us to envisage the existence of polarization domains inside the observation plane.
Roman, Castaneda +2 more
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