COMPLEX CROSS-CORRELATION PARAMETERS FOR MULTI-CHANNEL AUDIO

2012 ◽  
Vol 132 (6) ◽  
pp. 4091
Author(s):  
Sanjeev Mehrotra ◽  
Wei-Ge Chen
Keyword(s):  
Cross Correlation ◽  
Complex Cross ◽  
Correlation Parameters

scholarly journals Fregion plasma density estimation at Jicamarca using the complex cross-correlation of orthogonal polarized backscatter fields

Radio Science ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Zhaomei Feng ◽  
Erhan Kudeki ◽  
Ronald F. Woodman ◽  
Jorge Chau ◽  
Marco Milla
Keyword(s):  
Density Estimation ◽  
Plasma Density ◽  
Cross Correlation ◽  
Complex Cross

A GaAs Power Detector Design for $C$ -Band Wideband Complex Cross Correlation Measurement

2020 ◽  
Vol 69 (8) ◽  
pp. 5673-5683
Author(s):  
Chen Chen ◽  
Ghulam Mehdi ◽  
Chao Wang ◽  
Umar Dilshad ◽  
Anyong Hu ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Correlation Measurement ◽  
Complex Cross ◽  
Power Detector ◽  
Detector Design

A Single Bit RF Domain Complex Cross-Correlation Velocity Estimator for Color Flow Mapping

1997 ◽  
Vol 19 (3) ◽  
pp. 180-194 ◽  
Author(s):  
Peter J. Brands ◽  
Arnold P.G. Hoeks ◽  
Léon A.F. Ledoux
Keyword(s):  
Cross Correlation ◽  
Dynamic Range ◽  
Hardware Complexity ◽  
Flow Mapping ◽  
Color Flow ◽  
Mean Frequency ◽  
Color Flow Mapping ◽  
Complex Cross ◽  
Frequency Estimator ◽  
Full Dynamic Range

This paper evaluates the performance of a one bit mean frequency estimator to estimate blood flow velocity for ultrasound color flow mapping. This one bit mean frequency estimator, referred to as BC3 estimator, is derived from the recently introduced complex cross-correlation model (C3M) employing the full dynamic data range. The C3M velocity estimator is not suitable for application in color flow mapping because of its high hardware complexity and associated computational load. The BC3 estimator estimates the mean blood flow velocity using only two complex cross-correlation coefficients. For this purpose the latter are computed by means of a complex one bit cross-correlation operation. Each sample of the RF signals is converted into an one bit representation based on the sign of the real and imaginary part of the RF samples. A full derivation and mathematical description of the BC3 estimator is presented. In addition, a thorough performance evaluation of the BC3 estimator in comparison with the full dynamic range C3M velocity estimator is carried out by means of signal simulations to document the effect of signal to noise ratio, sample frequency and bandwidth. For the specific simulation conditions considered the standard deviation of both estimators (C3M and BC3) is comparable. The bias of the BC3 estimator appears to be a function of velocity, while the full dynamic range C3M velocity estimator exhibits no bias. The simulation results are confirmed by evaluation of data from an in vivo measurement. Taking into account the low hardware complexity and computational load in combination with the achieved precision, it may be concluded that the BC3 estimator is well suited for implementation in color flow mapping.

Directed Transport in Symmetrically Periodic Potentials Induced by Cross-Correlation among Colored Gaussian Noises

2019 ◽  
Vol 20 (2) ◽  
pp. 105-114
Author(s):  
Igor Alexandrovich Knyaz’
Keyword(s):  
Correlation Time ◽  
Cross Correlation ◽  
Periodic Potential ◽  
Brownian Particle ◽  
System Parameters ◽  
Directed Transport ◽  
Periodic Potentials ◽  
Spatially Periodic ◽  
Correlation Parameters

AbstractWe study the noise induced directed transport of an inertial Brownian particle moving in a symmetric spatially periodic potential and is subjected to correlated colored noises. Under the assumption of small correlation times of colored fluctuations we obtain an analytical expression for resulting current in overdamped systems. Our analytical and numerical calculations indicate the directed current is controlled by the correlation parameters. It has been pointed out that the nonzero correlation time makes an important contribution to current only at large enough values of noise intensities. The role of other system parameters is investigated from the viewpoint of optimization the current amplitude.

Artefact in 20Å-Resolution Electron Images of Negatively Stained Twodimensional Membrane Protein Crystals

1982 ◽  
Vol 40 ◽  
pp. 92-93
Author(s):  
Douglas L. Dorset ◽  
Barbara Moss
Keyword(s):  
Electron Scattering ◽  
Cross Correlation ◽  
Transmission Function ◽  
Group Symmetry ◽  
Asymmetric Structure ◽  
Object Model ◽  
Phase Object ◽  
Computing Systems ◽  
Resolution Electron ◽  
Plane Group

A number of computing systems devoted to the averaging of electron images of two-dimensional macromolecular crystalline arrays have facilitated the visualization of negatively-stained biological structures. Either by simulation of optical filtering techniques or, in more refined treatments, by cross-correlation averaging, an idealized representation of the repeating asymmetric structure unit is constructed, eliminating image distortions due to radiation damage, stain irregularities and, in the latter approach, imperfections and distortions in the unit cell repeat. In these analyses it is generally assumed that the electron scattering from the thin negativelystained object is well-approximated by a phase object model. Even when absorption effects are considered (i.e. “amplitude contrast“), the expansion of the transmission function, q(x,y)=exp (iσɸ (x,y)), does not exceed the first (kinematical) term. Furthermore, in reconstruction of electron images, kinematical phases are applied to diffraction amplitudes and obey the constraints of the plane group symmetry.

Application of cross correlation to HREM images of surfaces

1987 ◽  
Vol 45 ◽  
pp. 754-755
Author(s):  
D. E. Luzzi ◽  
L. D. Marks ◽  
M. I. Buckett
Keyword(s):  
Cross Correlation ◽  
A Priori ◽  
Matrix Material ◽  
Correlation Method ◽  
Accurate Knowledge ◽  
Complex Image ◽  
Fourier Filtering ◽  
The Matrix ◽  
Low Pass ◽  
Data Reduction Technique

As the HREM becomes increasingly used for the study of dynamic localized phenomena, the development of techniques to recover the desired information from a real image is important. Often, the important features are not strongly scattering in comparison to the matrix material in addition to being masked by statistical and amorphous noise. The desired information will usually involve the accurate knowledge of the position and intensity of the contrast. In order to decipher the desired information from a complex image, cross-correlation (xcf) techniques can be utilized. Unlike other image processing methods which rely on data massaging (e.g. high/low pass filtering or Fourier filtering), the cross-correlation method is a rigorous data reduction technique with no a priori assumptions.We have examined basic cross-correlation procedures using images of discrete gaussian peaks and have developed an iterative procedure to greatly enhance the capabilities of these techniques when the contrast from the peaks overlap.

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