scholarly journals Ionogram RFI Rejection Using an Autoregressive Interpolation Process

Radio Science ◽  
2019 ◽  
Vol 54 (1) ◽  
pp. 135-150 ◽  
Author(s):  
Mike D. E. Turley ◽  
Andrew J. Heitmann ◽  
Robert S. Gardiner-Garden
Keyword(s):  
Interpolation Process

Image Interpolation Algorithm Based on Edge Features

2011 ◽  
Vol 50-51 ◽  
pp. 564-567
Author(s):  
Yun Feng Yang ◽  
Xiao Guang Wei ◽  
Zhi Xun Su
Keyword(s):  
Interpolation Method ◽  
Spline Interpolation ◽  
Weighted Average ◽  
Image Interpolation ◽  
Interpolation Process ◽  
Edge Information ◽  
B Spline ◽  
Interpolation Methods ◽  
Distance Weighted ◽  
Edge Features

Image interpolation is used widely in the computer vision. Holding edge information is main problem in the image interpolation. By using bilinear and bicubic B-spline interpolation methods, a novel image interpolation approach was proposed in this paper. Firstly, inverse distance weighted average method was used to reduce image’s noise. Secondly, edge detection operator was used to extract image's edges information. It can help us to select different interpolation methods in the image interpolation process. Finally, we selected bilinear interpolation approach at non-edge regions, and bicubic B-spline interpolation method was used near edges regions. Further more, control vertexes were computed from pixels with calculation formula which has been simplified in the B-spline interpolation process. Experiments showed the interpolated image by the proposed method had good vision results for it could hold image's edge information effectively.

scholarly journals Big ray‐tracing and eikonal solver on unstructured grids: Application to the computation of a multivalued traveltime field in the Marmousi model

Geophysics ◽  
1999 ◽  
Vol 64 (1) ◽  
pp. 230-239 ◽  
Author(s):  
Rémi Abgrall ◽  
Jean‐David Benamou
Keyword(s):  
Phase Space ◽  
Point Source ◽  
Numerical Computation ◽  
Ray Tracing ◽  
Eikonal Equation ◽  
Unstructured Grids ◽  
Unstructured Meshes ◽  
Interpolation Process ◽  
Local Solutions

This paper presents a numerical computation of the multivalued traveltime field generated by a point‐source experiment in the Marmousi model. Two methods are combined to achieve this goal: a method called big ray tracing, used to compute multivalued traveltime fields, and an eikonal solver, designed to work on unstructured meshes. Big ray tracing is based on a combination of ray tracing and local solutions of the eikonal equation. Classical ray tracing first discretizes the phase space and defines local zones that possibly overlap where the traveltime field is multivalued. Then an eikonal solver computes traveltimes in these zones called big rays. It acts as an exact interpolation process between rays associated with different branches of the traveltime field. The geometry of big rays may be complicated and is better discretized using unstructured meshes. An eikonal solver designed to work on unstructured meshes is used.

scholarly journals Interpolation process between standard diffusion and fractional diffusion

2018 ◽  
Vol 54 (3) ◽  
pp. 1731-1757
Author(s):  
Cédric Bernardin ◽  
Patrícia Gonçalves ◽  
Milton Jara ◽  
Marielle Simon
Keyword(s):  
Fractional Diffusion ◽  
Interpolation Process

Hermite-Fejér interpolation with Jacobi weights

2011 ◽  
Vol 48 (3) ◽  
pp. 408-420
Author(s):  
G. Mastroianni ◽  
J. Szabados
Keyword(s):  
Error Estimates ◽  
Sufficient Conditions ◽  
Continuous Functions ◽  
Necessary And Sufficient Conditions ◽  
Interpolation Process ◽  
Weighted Norm ◽  
Jacobi Weights ◽  
Jacobi Weight ◽  
Necessary And Sufficient

We consider the weighted Hermite-Fejér interpolation process based on Jacobi nodes for classes of locally continuous functions defined by another Jacobi weight. Necessary and sufficient conditions for the weighted norm boundedness and for the convergence, as well as error estimates of the approximation, are given.

On: “A Method to minimize edge effects in two‐dimensional discrete Fourier transforms” by Yanick Ricard and Richard J. Blakely (GEOPHYSICS, 53, 1113–1117, August 1988).

Geophysics ◽  
1990 ◽  
Vol 55 (11) ◽  
pp. 1514-1514 ◽  
Author(s):  
Kenneth F. Sprenke
Keyword(s):  
Continuous Spectrum ◽  
Edge Effects ◽  
Fourier Transforms ◽  
Interpolation Process ◽  
Two Dimensional ◽  
Discrete Fourier Transforms ◽  
Sampling Grid ◽  
Valuable Method ◽  
Sampling Window ◽  
Rotational Transform

The authors of this paper have created a very valuable method for approximating the two‐dimensional continuous spectrum by repeatedly rotating a rectangular sampling grid and averaging the resulting spectra. The authors state that their rotational transform “eliminates artifacts associated with the orientation of the rectangular sampling window.” However, I believe that one aspect of their method, the interpolation process, actually creates artifacts:

scholarly journals On Berman's phenomenon in interpolation theory

1975 ◽  
Vol 12 (3) ◽  
pp. 457-465 ◽  
Author(s):  
W. Lyle Cook ◽  
T.M. Mills
Keyword(s):  
Higher Order ◽  
Interpolation Process ◽  
Divergence Theorem ◽  
Interpolation Theory ◽  
Open Problems ◽  
Chebyshev Nodes

In 1965, D.L. Berman established an interesting divergence theorem concerning Hermite-Fejér interpolation on the extended Chebyshev nodes. In this paper it is shown that this phenomenon is not an isolated incident. A similar divergence theorem is proved for a higher order interpolation process. The paper closes with a list of several related open problems.

Visual hyperacuity: spatiotemporal interpolation in human vision

1981 ◽  
Vol 213 (1193) ◽  
pp. 451-477 ◽  
Keyword(s):  
Constant Velocity ◽  
Receptive Fields ◽  
Spatial Separation ◽  
Human Vision ◽  
Interpolation Process ◽  
Vernier Acuity ◽  
Optimal Velocity ◽  
Temporal Properties ◽  
Wide Range ◽  
Temporal Offset

Stroboscopic presentation of a moving object can be interpolated by our visual system into the perception of continuous motion. The precision of this interpolation process has been explored by measuring the vernier discrimination threshold for targets displayed stroboscopically at a sequence of stations. The vernier targets, moving at constant velocity, were presented either with a spatial offset or with a temporal offset or with both. The main results are: (1) vernier acuity for spatial offset is rather invariant over a wide range of velocities and separations between the stations (see Westheimer & McKee 1975); (2) vernier acuity for temporal offset depends on spatial separation and velocity. At each separation there is an optimal velocity such that the strobe interval is roughly constant at about 30 ms; optimal acuity decreases with increasing separation; (3) blur of the vernier pattern decreases acuity for spatial offsets, but improves acuity for temporal offsets (at high velocities and large separations); (4) a temporal offset exactly compensates the equivalent (at the given velocity) spatial offset only for a small separation and optimal velocity; otherwise the spatial offset dominates. A theoretical analysis of the interpolation problem suggests a computational scheme based on the assumption of constant velocity motion. This assumption reflects a constraint satisfied in normal vision over the short times and small distances normally relevant for the interpolation process. A reasonable implementation of this scheme only requires a set of independent, direction selective spatiotemporal channels, that is receptive fields with the different sizes and temporal properties revealed by psychophysical experiments. It is concluded that sophisticated mechanisms are not required to account for the main properties of vernier acuity with moving targets. It is furthermore suggested that the spatiotemporal channels of human vision may be the interpolation filters themselves. Possible neurophysiological implications are briefly discussed.

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