scholarly journals Power Phase Apodization Study on Compensation Defocusing and Chromatic Aberration in the Imaging System

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1327
Author(s):  
Svetlana N. Khonina ◽  
Sergey G. Volotovskiy ◽  
Alexey P. Dzyuba ◽  
Pavel G. Serafimovich ◽  
Sergey B. Popov ◽  
...  
Keyword(s):  
Imaging System ◽  
Color Image ◽  
Chromatic Aberration ◽  
Spot Size ◽  
Light Spot ◽  
Depth Of Field ◽  
Nonlinear Relationship ◽  
Point Spread ◽  
Spread Function ◽  
High Degree

We performed a detailed comparative study of the parametric high degree (cubic, fourth, and fifth) power phase apodization on compensation defocusing and chromatic aberration in the imaging system. The research results showed that increasing the power degree of the apodization function provided better independence (invariance) of the point spread function (PSF) from defocusing while reducing the depth of field (DOF). This reduction could be compensated by increasing the parameter α; however, this led to an increase in the size of the light spot. A nonlinear relationship between the increase in the DOF and spot size was shown (due to a small increase in the size of the light spot, the DOF can be significantly increased). Thus, the search for the best solution was based on a compromise of restrictions on the circle of confusion (CoC) and DOF. The modeling of color image formation under defocusing conditions for the considered apodization functions was performed. The subsequent deconvolution of the resulting color image was demonstrated.

New Aspects in the Design of Electron Optical Magnification Systems

1972 ◽  
Vol 30 ◽  
pp. 606-607
Author(s):  
Willem H.J. Andersen
Keyword(s):  
Electron Microscope ◽  
Imaging System ◽  
Chromatic Aberration ◽  
Research Tool ◽  
Energy Losses ◽  
Objective Lens ◽  
Theoretical Limit ◽  
Optical Magnification ◽  
Chromatic Aberrations ◽  
High Degree

Electron microscope design, and particularly the design of the imaging system, has reached a high degree of perfection. Present objective lenses perform up to their theoretical limit, while the whole imaging system, consisting of three or four lenses, provides very wide ranges of magnification and diffraction camera length with virtually no distortion of the image. Evolution of the electron microscope in to a routine research tool in which objects of steadily increasing thickness are investigated, has made it necessary for the designer to pay special attention to the chromatic aberrations of the magnification system (as distinct from the chromatic aberration of the objective lens). These chromatic aberrations cause edge un-sharpness of the image due to electrons which have suffered energy losses in the object.There exist two kinds of chromatic aberration of the magnification system; the chromatic change of magnification, characterized by the coefficient Cm, and the chromatic change of rotation given by Cp.

Near-infrared fundus imaging system with light illumination from an electronic contact lens

2022 ◽  
Vol 15 (2) ◽  
pp. 027001
Author(s):  
Yang Cui ◽  
Taiki Takamatsu ◽  
Koichi Shimizu ◽  
Takeo Miyake
Keyword(s):  
Contact Lens ◽  
Near Infrared ◽  
Imaging System ◽  
Low Cost ◽  
Light Illumination ◽  
Fundus Images ◽  
Fundus Imaging ◽  
Point Spread ◽  
Spread Function ◽  
Dependent Point

Abstract As for the diagnosis and treatment of eye diseases, an ideal fundus imaging system is expected to be portability, low cost, and high resolution. Here, we demonstrate a non-mydriatic near-infrared fundus imaging system with light illumination from an electronic contact lens (E-lens). The E-lens can illuminate the retinal and choroidal structures for capturing the fundus images when voltage is applied wirelessly to the lens. And we also reconstruct the images with a depth-dependent point-spread function to suppress the scattering effect that eventually visualizes the clear fundus images.

Measurement of the Point Spread Function of a Photoacoustic Imaging System using Step Method

2013 ◽  
Vol 33 (4) ◽  
pp. 0411002
Author(s):  
周红仙 Zhou Hongxian ◽  
周有平 Zhou Youping ◽  
王毅 Wang Yi
Keyword(s):  
Point Spread Function ◽  
Imaging System ◽  
Photoacoustic Imaging ◽  
Step Method ◽  
Point Spread ◽  
Spread Function

Point Spread Function Model of Grating Imaging System Based on Boltzmann Function Edge Fitting

2020 ◽  
Vol 40 (14) ◽  
pp. 1405003
Author(s):  
卢泉 Lu Quan ◽  
张泽昊 Zhang Zehao ◽  
张卫平 Zhang Weiping ◽  
刘诣荣 Liu Yirong
Keyword(s):  
Point Spread Function ◽  
Imaging System ◽  
Function Model ◽  
Point Spread ◽  
Boltzmann Function ◽  
Spread Function

Point Spread Function of Pinhole Imaging System for Deviating from Center of Incident γ-Ray

2015 ◽  
Vol 44 (3) ◽  
pp. 311004
Author(s):  
马庆力 MA Qing-li ◽  
唐世彪 TANG Shi-biao ◽  
吴彦华 WU Yan-hua
Keyword(s):  
Point Spread Function ◽  
Imaging System ◽  
Point Spread ◽  
Spread Function ◽  
Pinhole Imaging ◽  
Γ Ray

scholarly journals Estimation of Ultrasound Echogenicity Map from B-Mode Images Using Convolutional Neural Network

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4931
Author(s):  
Che-Chou Shen ◽  
Jui-En Yang
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Imaging System ◽  
Speckle Pattern ◽  
Image Resolution ◽  
Post Processing ◽  
Point Spread ◽  
Spread Function ◽  
In Silico Simulation ◽  
Tissue Structures

In ultrasound B-mode imaging, speckle noises decrease the accuracy of estimation of tissue echogenicity of imaged targets from the amplitude of the echo signals. In addition, since the granular size of the speckle pattern is affected by the point spread function (PSF) of the imaging system, the resolution of B-mode image remains limited, and the boundaries of tissue structures often become blurred. This study proposed a convolutional neural network (CNN) to remove speckle noises together with improvement of image spatial resolution to reconstruct ultrasound tissue echogenicity map. The CNN model is trained using in silico simulation dataset and tested with experimentally acquired images. Results indicate that the proposed CNN method can effectively eliminate the speckle noises in the background of the B-mode images while retaining the contours and edges of the tissue structures. The contrast and the contrast-to-noise ratio of the reconstructed echogenicity map increased from 0.22/2.72 to 0.33/44.14, and the lateral and axial resolutions also improved from 5.9/2.4 to 2.9/2.0, respectively. Compared with other post-processing filtering methods, the proposed CNN method provides better approximation to the original tissue echogenicity by completely removing speckle noises and improving the image resolution together with the capability for real-time implementation.

Effect of point spread function position bias in wavefront coding infrared imaging system

2020 ◽  
Vol 22 (2) ◽  
pp. 025703
Author(s):  
Bin Feng ◽  
Zelin Shi ◽  
Haizheng Liu ◽  
Yaohong Zhao ◽  
Jianlei Zhang
Keyword(s):  
Point Spread Function ◽  
Infrared Imaging ◽  
Imaging System ◽  
Position Bias ◽  
Point Spread ◽  
Infrared Imaging System ◽  
Wavefront Coding ◽  
Spread Function
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