scholarly journals Optimal PSF Estimation for Simple Optical System Using a Wide-Band Sensor Based on PSF Measurement

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3552 ◽  
Author(s):  
Yunda Zheng ◽  
Wei Huang ◽  
Yun Pan ◽  
Mingfei Xu
Keyword(s):  
Image Quality ◽  
Optical System ◽  
Estimation Method ◽  
Wide Band ◽  
Optical Systems ◽  
Blind Estimation ◽  
Image Deconvolution ◽  
Color Channel ◽  
Spread Function ◽  
Psf Estimation

Simple optical system imaging is a method to simplify optical systems by removing aberrations using image deconvolution. The point spread function (PSF) used in deconvolution is an important factor that affects the image quality. However, it is difficult to obtain optimal PSFs. The blind estimation of PSFs relies heavily on the information in the image. Measured PSFs are often misused because real sensors are wide-band. We present an optimal PSF estimation method based on PSF measurements. Narrow-band PSF measurements at a single depth are used to calibrate the optical system; these enable the simulation of real lenses. Then, we simulate PSFs in the wavelength pass range of each color channel all over the field. The optimal PSFs are computed according to these simulated PSFs. The results indicated that the use of the optimal PSFs significantly reduces the artifacts caused by misuse of PSFs, and enhances the image quality.

Design of Athermalized Infrared Telephoto Lens

2013 ◽  
Vol 552 ◽  
pp. 8-13
Author(s):  
Yu Zhang ◽  
Ji Yang Shang ◽  
Yue Xu ◽  
Wen Sheng Wang
Keyword(s):  
Image Quality ◽  
Optical System ◽  
Power Distribution ◽  
Focal Length ◽  
Diffraction Limit ◽  
Field Of View ◽  
Optical Systems ◽  
Modulation Transfer ◽  
Full Field ◽  
Telephoto Lens

IR optical system is much more appropriate to be applied in cluttered and formidable conditions. The change of temperature could degrade image quality of the infrared optical system. So the athermalization becomes the difficult part and key factor in the designing of MWIR optical systems for working under temperature range of -40°C~60°C. In this paper, the infrared telephoto lens is designed; it meets the designing requirements and has good image quality. The effective focal length is 240mm and the F-number is 2.The full field of view is 3.2°. In order to balance the chromatic aberration, an aspherical surface is used in the athermalized infrared optical system. Through carefully selected optical material and reasonable optical power distribution, passive optical athermalization can be realized. The curve of MTF is close to diffraction limit. Within the working temperature, the value of MTF at 30cy/mm is always large than 0.6. The results show that the modulation transfer function (MTF) of optical system in all field of view approaches the diffraction limit at different temperature, and 80% energy concentrates in 1 pixel.

scholarly journals Wavefront Parameters Recovering by Using Point Spread Function

2020 ◽  
pp. short47-1-short47-7
Author(s):  
Olga Kalinkina ◽  
Tatyana Ivanova ◽  
Julia Kushtyseva
Keyword(s):  
Optical System ◽  
Point Spread Function ◽  
Optical Systems ◽  
Adjustment Process ◽  
Substantial Part ◽  
Zernike Polynomials ◽  
Reconstruction Algorithms ◽  
Point Spread ◽  
Spread Function

At various stages of the life cycle of optical systems, one of the most important tasks is quality of optical system elements assembly and alignment control. The different wavefront reconstruction algorithms have already proven themselves to be excellent assistants in this. Every year increasing technical capacities opens access to the new algorithms and the possibilities of their application. The paper considers an iterative algorithm for recovering the wavefront parameters. The parameters of the wavefront are the Zernike polynomials coefficients. The method involves using a previously known point spread function to recover Zernike polynomials coefficients. This work is devoted to the research of the defocusing influence on the convergence of the algorithm. The method is designed to control the manufacturing quality of optical systems by point image. A substantial part of the optical systems can use this method without additional equipment. It can help automate the controlled optical system adjustment process.

Atomic Resolution in Crystal Aperture Stem

1990 ◽  
Vol 48 (1) ◽  
pp. 236-237
Author(s):  
J T Fourie
Keyword(s):  
Optical System ◽  
Spherical Aberration ◽  
Three Dimensional ◽  
Transmission Function ◽  
Optical Systems ◽  
Bragg Angle ◽  
Electron Optical System ◽  
Intimate Contact ◽  
Diffraction Effects ◽  
Design Aspect

The attempts at improvement of electron optical systems to date, have largely been directed towards the design aspect of magnetic lenses and towards the establishment of ideal lens combinations. In the present work the emphasis has been placed on the utilization of a unique three-dimensional crystal objective aperture within a standard electron optical system with the aim to reduce the spherical aberration without introducing diffraction effects. A brief summary of this work together with a description of results obtained recently, will be given.The concept of utilizing a crystal as aperture in an electron optical system was introduced by Fourie who employed a {111} crystal foil as a collector aperture, by mounting the sample directly on top of the foil and in intimate contact with the foil. In the present work the sample was mounted on the bottom of the foil so that the crystal would function as an objective or probe forming aperture. The transmission function of such a crystal aperture depends on the thickness, t, and the orientation of the foil. The expression for calculating the transmission function was derived by Hashimoto, Howie and Whelan on the basis of the electron equivalent of the Borrmann anomalous absorption effect in crystals. In Fig. 1 the functions for a g220 diffraction vector and t = 0.53 and 1.0 μm are shown. Here n= Θ‒ΘB, where Θ is the angle between the incident ray and the (hkl) planes, and ΘB is the Bragg angle.

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

Optimization of PET/CT image quality using the GE ‘Sharp IR’ point-spread function reconstruction algorithm

2017 ◽  
Vol 38 (6) ◽  
pp. 471-479 ◽  
Author(s):  
Nicholas J. Vennart ◽  
Nicholas Bird ◽  
John Buscombe ◽  
Heok K. Cheow ◽  
Ewa Nowosinska ◽  
...  
Keyword(s):  
Image Quality ◽  
Point Spread Function ◽  
Reconstruction Algorithm ◽  
Ct Image ◽  
Point Spread ◽  
Pet Ct ◽  
Spread Function ◽  
Ct Image Quality ◽  
Function Reconstruction

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.

Sign in / Sign up

Export Citation Format

Share Document