Determination of the ScaRaB FM1 broadband channel point spread functions

1999 ◽  
Vol 37 (4) ◽  
pp. 2004-2010 ◽  
Author(s):  
S. Dewitte ◽  
P. Boekaerts ◽  
F. Sirou
Keyword(s):  
Point Spread Functions ◽  
Point Spread

Spatial Sampling in Monostatic Subsurface Radar Imaging

2020 ◽  
Author(s):  
Maria Antonia Maisto ◽  
Rocco Pierri ◽  
Raffaele Solimene
Keyword(s):  
Sampling Strategy ◽  
Data Sampling ◽  
Subsurface Scattering ◽  
Point Spread Functions ◽  
Point Spread ◽  
Measurement Domain ◽  
Standard Sampling ◽  
The One ◽  
Space Case

<div>This paper deals with microwave subsurface imaging obtained by a migration-like inversion scheme, for a 2D monostatic scalar configuration and a two-layered background medium. The focus is on the determination of a data sampling strategy which allows to reduce the number of required measurements and at the same time keep the same performance in the reconstructions. To this end, the measurement points are determined in order to approximate the point-spread function corresponding to the ideal continuous case (i.e., the case in which the data space is not sampled at all). Basically, thanks to suitable variable transformations the point-spread functions is recast as a Fourier-like operator and this provides insight to devise the sampling scheme. It is shown that resulting measurement spatial positions are non-uniformly arranged across the measurement domain and their number can be much lower than the one provided by some literature standard sampling criteria. The study also contains a comparison with the free space case so as to highlight the role played by the half-space that schematized the subsurface scattering scenario on the number and the locations of the measurement points. Numerical examples are also included to check the theoretical arguments.</div>

scholarly journals An on Orbit Determination of Point Spread Functions for the Interface Region Imaging Spectrograph

Solar Physics ◽  
2018 ◽  
Vol 293 (9) ◽  
Author(s):  
Hans Courrier ◽  
Charles Kankelborg ◽  
Bart De Pontieu ◽  
Jean-Pierre Wülser
Keyword(s):  
Orbit Determination ◽  
Interface Region ◽  
Point Spread Functions ◽  
Point Spread ◽  
Imaging Spectrograph

scholarly journals High Precision Crowded Field Photometry

1989 ◽  
Vol 8 ◽  
pp. 651-656
Author(s):  
Peter Linde
Keyword(s):  
High Precision ◽  
List Type ◽  
Point Spread Functions ◽  
Error Sources ◽  
Point Spread ◽  
Spread Function ◽  
Star Group ◽  
Local Background ◽  
Definition Of

AbstractMethods have been developed for high precision photometry in crowded stellar fields. The procedure includes the following steps:• Determination of a two-dimensional point spread function• Definition of groups of stars with mutually overlapping images• Determination of local background for each star group• Simultaneous fitting of point spread functions, one for each star in the groupThe Lund approach emphasizes interactivity. Many fundamental procedures are facilitated by the use of an optimised image display. Extensive modelling has been done to study the influence of various error sources.

scholarly journals Spatial Sampling in Monostatic Subsurface Radar Imaging

2020 ◽  
Author(s):  
Maria Antonia Maisto ◽  
Rocco Pierri ◽  
Raffaele Solimene
Keyword(s):  
Sampling Strategy ◽  
Data Sampling ◽  
Subsurface Scattering ◽  
Point Spread Functions ◽  
Point Spread ◽  
Measurement Domain ◽  
Standard Sampling ◽  
The One ◽  
Space Case

<div>This paper deals with microwave subsurface imaging obtained by a migration-like inversion scheme, for a 2D monostatic scalar configuration and a two-layered background medium. The focus is on the determination of a data sampling strategy which allows to reduce the number of required measurements and at the same time keep the same performance in the reconstructions. To this end, the measurement points are determined in order to approximate the point-spread function corresponding to the ideal continuous case (i.e., the case in which the data space is not sampled at all). Basically, thanks to suitable variable transformations the point-spread functions is recast as a Fourier-like operator and this provides insight to devise the sampling scheme. It is shown that resulting measurement spatial positions are non-uniformly arranged across the measurement domain and their number can be much lower than the one provided by some literature standard sampling criteria. The study also contains a comparison with the free space case so as to highlight the role played by the half-space that schematized the subsurface scattering scenario on the number and the locations of the measurement points. Numerical examples are also included to check the theoretical arguments.</div>

Determination of the Point Spread Function of a Computer-Generated Lens Formed by a Phase Light Modulator

2020 ◽  
Vol 128 (7) ◽  
pp. 1036-1040 ◽  
Author(s):  
N. G. Stsepuro ◽  
G. K. Krasin ◽  
M. S. Kovalev ◽  
V. N. Pestereva
Keyword(s):  
Point Spread Function ◽  
Light Modulator ◽  
Point Spread ◽  
Spread Function

scholarly journals Axial localization and tracking of self-interference nanoparticles by lateral point spread functions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yongtao Liu ◽  
Zhiguang Zhou ◽  
Fan Wang ◽  
Günter Kewes ◽  
Shihui Wen ◽  
...  
Keyword(s):  
Mirror Image ◽  
Excitation Wavelength ◽  
Far Field ◽  
Point Spread Functions ◽  
Microscopy Imaging ◽  
Localization Accuracy ◽  
Field Patterns ◽  
Atomic Force ◽  
Point Spread ◽  
Sensing Technology

AbstractSub-diffraction limited localization of fluorescent emitters is a key goal of microscopy imaging. Here, we report that single upconversion nanoparticles, containing multiple emission centres with random orientations, can generate a series of unique, bright and position-sensitive patterns in the spatial domain when placed on top of a mirror. Supported by our numerical simulation, we attribute this effect to the sum of each single emitter’s interference with its own mirror image. As a result, this configuration generates a series of sophisticated far-field point spread functions (PSFs), e.g. in Gaussian, doughnut and archery target shapes, strongly dependent on the phase difference between the emitter and its image. In this way, the axial locations of nanoparticles are transferred into far-field patterns. We demonstrate a real-time distance sensing technology with a localization accuracy of 2.8 nm, according to the atomic force microscope (AFM) characterization values, smaller than 1/350 of the excitation wavelength.

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