scholarly journals Randomly Multiplexed Diffractive Lens and Axicon for Spatial and Spectral Imaging

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 437 ◽  
Author(s):  
Vijayakumar Anand ◽  
Tomas Katkus ◽  
Saulius Juodkazis
Keyword(s):  
Intensity Distribution ◽  
Point Spread Function ◽  
Fresnel Zone ◽  
Spherical Wave ◽  
Optical Element ◽  
Intensity Pattern ◽  
Object Space ◽  
Point Spread ◽  
Spread Function ◽  
Complicated Object

A new hybrid diffractive optical element (HDOE) was designed by randomly multiplexing an axicon and a Fresnel zone lens. The HDOE generates two mutually coherent waves, namely a conical wave and a spherical wave, for every on-axis point object in the object space. The resulting self-interference intensity distribution is recorded as the point spread function. A library of point spread functions are recorded in terms of the different locations and wavelengths of the on-axis point objects in the object space. A complicated object illuminated by a spatially incoherent multi-wavelength source generated an intensity pattern that was the sum of the shifted and scaled point spread intensity distributions corresponding to every spatially incoherent point and wavelength in the complicated object. The four-dimensional image of the object was reconstructed using computer processing of the object intensity distribution and the point spread function library.

Influence of optimum balanced linear coma on disk spread functions

1978 ◽  
Vol 56 (1) ◽  
pp. 12-16
Author(s):  
A. K. Gupta ◽  
R. N. Singh ◽  
K. Singh
Keyword(s):  
Intensity Distribution ◽  
Point Spread Function ◽  
Optical Systems ◽  
Point Spread ◽  
Spread Function ◽  
Special Case ◽  
Optimum Balance

Disk spread functions are evaluated to study the performance of optical systems in the presence of linear coma. Optimum balance among various coma terms based on Strehl intensity criterion is used and the applicability of this balance to imaging of extended objects is examined. Graphical results of intensity distribution in the paraxial receiving plane for the diffraction images of extended circular targets for various sizes and azimuths are presented. Results for the point spread function in presence of optimum balanced linear coma come out as a special case and are also included.

scholarly journals Recognition of wavefront aberrations types corresponding to single Zernike functions from the pattern of the point spread function in the focal plane using neural networks

2020 ◽  
Vol 44 (6) ◽  
pp. 923-930
Author(s):  
I.A. Rodin ◽  
S.N. Khonina ◽  
P.G. Serafimovich ◽  
S.B. Popov
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Point Spread Function ◽  
Focal Plane ◽  
Prediction Errors ◽  
Intensity Pattern ◽  
Data Set ◽  
Point Spread ◽  
The Neural Network ◽  
Spread Function

In this work, we carried out training and recognition of the types of aberrations corresponding to single Zernike functions, based on the intensity pattern of the point spread function (PSF) using convolutional neural networks. PSF intensity patterns in the focal plane were modeled using a fast Fourier transform algorithm. When training a neural network, the learning coefficient and the number of epochs for a dataset of a given size were selected empirically. The average prediction errors of the neural network for each type of aberration were obtained for a set of 15 Zernike functions from a data set of 15 thousand PSF pictures. As a result of training, for most types of aberrations, averaged absolute errors were obtained in the range of 0.012 – 0.015. However, determining the aberration coefficient (magnitude) requires additional research and data, for example, calculating the PSF in the extrafocal plane.

scholarly journals Spherical Aberration of Point Spread Function with Asymmetric Pupil Mask

2016 ◽  
Vol 2016 ◽  
pp. 1-5
Author(s):  
Naresh Kumar Reddy Andra ◽  
Karuna Sagar Dasari
Keyword(s):  
Point Spread Function ◽  
Spherical Aberration ◽  
Spherical Wave ◽  
Super Resolution ◽  
Central Peak ◽  
Phase Mask ◽  
One Dimensional ◽  
Point Spread ◽  
Spread Function ◽  
Wave Aberration

Point spread function underneath spherical wave aberration with antiphase apodization has been obtained by one-dimensional pupil mask functions. In the presence of spherical aberration, suppression of optical side-lobes has increased on one side of the point spread function with the width of the periphery strips within the pupil mask. On introducing wave aberration effect, there exists dependence of the lateral resolution of central peak of the asymmetric point spread function on the amount of amplitude masking. However, the magnitude of intensity of central peak is originated be to amplified by the highest degree of amplitude and phase masking. Additionally, for aberrated asymmetric PSF, FWHM increases and it further decreases with the control parameters of amplitude and phase mask. The magnitude of this corollary can quantify the super resolution of diffracted structures under spherical aberration.

scholarly journals An Hα Image of Nova V1500 Cygni Twelve Years After Outburst

1990 ◽  
Vol 122 ◽  
pp. 195-196 ◽  
Author(s):  
Richard A. Wade ◽  
R. Ciardullo ◽  
J.B. DeVeny ◽  
G.H. Jacoby ◽  
W.E. Schoening
Keyword(s):  
Intensity Distribution ◽  
Point Spread Function ◽  
Data Reduction ◽  
Narrow Band ◽  
Central Object ◽  
Point Spread ◽  
Spread Function ◽  
Flat Field ◽  
Bias Level ◽  
The Mean

We obtained a narrow band Hα image of V1500 Cyg during an engineering run at the R-C focus of the KPNO 4 m telescope on UT 1987 July 19. Our detector was an 800 × 800 format TI CCD, which yielded a plate scale of 0.1013 arcsec/pixel. The exposure was 2000 sec and was made through a 75 Å wide filter centered at 6563 Å. The seeing was ~ 1.2 arcsec.Our reductions were accomplished with the DAOPHOT photometry package (Stetson 1987) and IRAF data reduction facility. After performing standard bias level subtraction and flat field division, we used DAOPHOT to find the frame’s normalized point spread function (PSF) by summing the images of several field stars. We then scaled the PSF to calculate the instrumental magnitudes of the stars and of V1500 Cyg. This procedure overestimates the brightness of the nova, since the nebula contributes extra light to the central object and modifies the expected intensity distribution. (This is especially true in the narrow Hα bandpass.) Hence, in a frame where the PSF has been used to remove the fitted images, all the stars have satisfactorily small residuals around the mean sky level, except the nova itself. The image of V1500 Cyg shows sky level at the center, but a halo that rises from the center and then falls away.

Point spread function based feature optimization and fusion for underwater objet recognition

2013 ◽  
Vol 26 (11) ◽  
pp. 944-952 ◽  
Author(s):  
Huibin Wang ◽  
Rong Zhang ◽  
Zhe Chen ◽  
Lizhong Xu ◽  
Jie Shen
Keyword(s):  
Point Spread Function ◽  
Point Spread ◽  
Spread Function ◽  
Feature Optimization

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

Accurate point spread function (PSF) estimation for coded aperture cameras

2014 ◽  
Author(s):  
Jingyu Yang ◽  
Bin Jiang ◽  
Jinlong Ma ◽  
Yi Sun ◽  
Ming Di
Keyword(s):  
Point Spread Function ◽  
Coded Aperture ◽  
Point Spread ◽  
Spread Function ◽  
Psf Estimation
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