Correction method for lateral displacement optical system based on the analysis of aberration

2016 ◽  
Vol 45 (6) ◽  
pp. 0618005
Author(s):  
徐春梅 Xu Chunmei ◽  
刘秉琦 Liu Bingqi ◽  
黄富瑜 Huang Fuyu ◽  
张雏 Zhang Chu ◽  
沈洪斌 Shen Hongbin ◽  
...  
Keyword(s):  
Optical System ◽  
Lateral Displacement ◽  
Correction Method

A New Adaptive Background Correction Method Based on Pinhole Image Analysis in Optical System Modulation Transfer Function Measurement

2011 ◽  
Vol 31 (8) ◽  
pp. 0812008
Author(s):  
段亚轩 Duan Yaxuan ◽  
陈永权 Chen Yongquan ◽  
赵建科 Zhao Jianke ◽  
李坤 Li Kun ◽  
龙江波 Long Jiangbo
Keyword(s):  
Image Analysis ◽  
Transfer Function ◽  
Optical System ◽  
Modulation Transfer Function ◽  
Correction Method ◽  
Background Correction ◽  
Modulation Transfer ◽  
Function Measurement ◽  
Pinhole Image

Origin of and Compensation for the Baseline Errors in Fourier Transform Spectra

1998 ◽  
Vol 52 (4) ◽  
pp. 579-586 ◽  
Author(s):  
I. K. Salomaa ◽  
J. K. Kauppinen
Keyword(s):  
Fourier Transform ◽  
Optical System ◽  
Correction Method ◽  
Multicomponent Analysis ◽  
Absorbance Spectroscopy ◽  
Fourier Transform Spectra

In Fourier transform absorbance spectroscopy, several types of baseline errors may be caused by the variations in the optical system, especially in the interferometer. The nature and causes of these errors have been studied. Furthermore, a method to eliminate the effect of these errors on multicomponent analysis is introduced. The nature of the errors has been experimentally verified, and a practical example of the use of the correction method is presented.

A correction method for the axial maladjustment of transmission-type optical system based on aberration theory

2016 ◽  
Author(s):  
Chunmei Xu ◽  
Fu-yu Huang ◽  
Jian-ling Yin ◽  
Yu-dan Chen ◽  
Shao-juan Mao
Keyword(s):  
Optical System ◽  
Correction Method ◽  
Aberration Theory

Correction of CCD Camera Lens Vignetting

2013 ◽  
Vol 373-375 ◽  
pp. 603-607 ◽  
Author(s):  
Si Yu Chen ◽  
Shu Guang Dai ◽  
Ping An Mu
Keyword(s):  
Optical System ◽  
Ccd Camera ◽  
Correction Method ◽  
Good Stability ◽  
Measuring Error ◽  
Manufacturing Processes ◽  
Camera Lens ◽  
Two Factors ◽  
The Impact

Due to the impact of the lens optical system and the different manufacturing processes, there could be causing the vignetting when using a CCD camera to take pictures. This paper analyzes the causes of the lens vignetting and put forward a method for reducing this error to improve the accuracy of the intensity of illumination detection. Firstly, according to the analysis of the existing research on the camera lens, concluded that there are two factors that cause vignetting. Secondly, based on the conclusion, do large amounts of test in each case. Analyze for the influence of illumination test in each case. Finally, the article put forward a set of vignetting correction method to correct the image be collected in a fixed aperture. The result shows that the method can effectively reduce vignetting measuring error and has a good stability.

Misalignment correction method of space optical system on orbit

2009 ◽  
Author(s):  
Wei Zhang ◽  
Li-hong Lu ◽  
Fu-nian Long ◽  
Qing-yu Hou
Keyword(s):  
Optical System ◽  
Correction Method

A Field Emission System For Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 298-299
Author(s):  
Michel Troyonal ◽  
Huei Pei Kuoal ◽  
Benjamin M. Siegelal
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Optical System ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Electron Optical System ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Emission System

A field emission system for our experimental ultra high vacuum electron microscope has been designed, constructed and tested. The electron optical system is based on the prototype whose performance has already been reported. A cross-sectional schematic illustrating the field emission source, preaccelerator lens and accelerator is given in Fig. 1. This field emission system is designed to be used with an electron microscope operated at 100-150kV in the conventional transmission mode. The electron optical system used to control the imaging of the field emission beam on the specimen consists of a weak condenser lens and the pre-field of a strong objective lens. The pre-accelerator lens is an einzel lens and is operated together with the accelerator in the constant angular magnification mode (CAM).

Information and estimation in image processing

1987 ◽  
Vol 45 ◽  
pp. 14-17
Author(s):  
B. Roy Frieden
Keyword(s):  
Image Processing ◽  
Optical System ◽  
Large Amplitude ◽  
Communication Theory ◽  
Image Data ◽  
Direct Approach ◽  
Ill Posed

Despite the skill and determination of electro-optical system designers, the images acquired using their best designs often suffer from blur and noise. The aim of an “image enhancer” such as myself is to improve these poor images, usually by digital means, such that they better resemble the true, “optical object,” input to the system. This problem is notoriously “ill-posed,” i.e. any direct approach at inversion of the image data suffers strongly from the presence of even a small amount of noise in the data. In fact, the fluctuations engendered in neighboring output values tend to be strongly negative-correlated, so that the output spatially oscillates up and down, with large amplitude, about the true object. What can be done about this situation? As we shall see, various concepts taken from statistical communication theory have proven to be of real use in attacking this problem. We offer below a brief summary of these concepts.

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.

STEM and ELS Observation of Early Oxide Formation on the Surface of Cr Thin Films

1980 ◽  
Vol 38 ◽  
pp. 412-413
Author(s):  
Fumio Watari ◽  
J. M. Cowley
Keyword(s):  
Thin Films ◽  
Optical System ◽  
Room Temperature ◽  
Oxide Formation ◽  
Initial Nucleation ◽  
Diffraction Patterns ◽  
Relationship Of ◽  
Multiple Twinning ◽  
Moderately High Temperature

STEM coupled with the optical system was used for the investigation of the early oxidation on the surface of Cr. Cr thin films (30 – 1000Å) were prepared by evaporation onto the polished or air-cleaved NaCl substrates at room temperature and 45°C in a vacuum of 10−6 Torr with an evaporation speed 0.3Å/sec. Rather thick specimens (200 – 1000Å) with various preferred orientations were used for the investigation of the oxidation at moderately high temperature (600 − 1100°C). Selected area diffraction patterns in these specimens are usually very much complicated by the existence of the different kinds of oxides and their multiple twinning. The determination of the epitaxial orientation relationship of the oxides formed on the Cr surface was made possible by intensive use of the optical system and microdiffraction techniques. Prior to the formation of the known rhombohedral Cr2O3, a thin spinel oxide, probably analogous to γ -Al203 or γ -Fe203, was formed. Fig. 1a shows the distinct epitaxial growth of the spinel (001) as well as the rhombohedral (125) on the well-oriented Cr(001) surface. In the case of the Cr specimen with the (001) preferred orientation (Fig. 1b), the rings explainable by spinel structure appeared as well as the well defined epitaxial spots of the spinel (001). The microdif fraction from 20A areas (Fig. 2a) clearly shows the same pattern as Fig. Ia with the weaker oxide spots among the more intense Cr spots, indicating that the thickness of the oxide is much less than that of Cr. The rhombohedral Cr2O3 was nucleated preferably at the Cr(011) sites provided by the polycrystalline nature of the present specimens with the relation Cr2O3 (001)//Cr(011), and by further oxidation it grew into full coverage of the rest of the Cr surface with the orientation determined by the initial nucleation.

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