scholarly journals Non-Rotationally Symmetric Field Mapping for Back-Scanned Step/Stare Imaging System

2020 ◽  
Vol 10 (7) ◽  
pp. 2399
Author(s):  
Qiang Fu ◽  
Xin Zhang ◽  
Jianping Zhang ◽  
Guangwei Shi ◽  
Shangnan Zhao ◽  
...  
Keyword(s):  
Optical System ◽  
Imaging System ◽  
Optical Design ◽  
Mapping Method ◽  
Focal Plane Arrays ◽  
Image Motion ◽  
Field Point ◽  
Field Mapping ◽  
Symmetric Field ◽  
Rotationally Symmetric

Step/stare imaging with focal plane arrays (FPAs) has become the main approach to achieve wide area coverage and high resolution imaging for long range targets. A fast steering mirror (FSM) is usually utilized to provide back-scanned motion to compensate for the image motion. However, the traditional optical design can just hold one field point relatively stable, typically the central or on-axis field point, on the FPA during back-scanning; all other field points may wander during the exposure due to imaging distortion characteristics of the optical system, which reduces the signal to noise ratio (SNR) of the target. Aiming toward this problem, this paper proposes a non-rotationally symmetric field mapping method for the back-scanned step/stare imaging system, which can make all field points stable on the FPA during back-scanning. First of all, the mathematical model of non-rotationally symmetric field mapping between object space and image space is established. Then, a back-scanned step/stare imaging system based on the model is designed, in which this non-rotationally symmetric mapping can be implemented with an afocal telescope including freeform lenses. Freeform lenses can produce an anamorphic aberration to adjust distortion characteristics of the optical system to control image wander on an FPA. Furthermore, the simulations verify the effectiveness of the method.

scholarly journals Optical Design of a Shortwave Infrared Dual Camera CASSI Based on Improved Offner-Wynne Imaging Spectrometer

2021 ◽  
Vol 2112 (1) ◽  
pp. 012021
Author(s):  
Chong Song ◽  
Lipeng Huo ◽  
Yong Huang ◽  
Yangdong Yan ◽  
Gang Wang ◽  
...  
Keyword(s):  
Optical System ◽  
Imaging System ◽  
Optical Measurement ◽  
Focal Length ◽  
Optical Design ◽  
Optical Transmittance ◽  
Coded Aperture ◽  
Visual Axis ◽  
Imaging Spectrometer ◽  
Shortwave Infrared

Abstract Based on the optical system characteristics of coded aperture snapshot spectral imager (CASSI), an optimized optical system of shortwave infrared dual camera CASSI was designed based on improved Offner-Wynne imaging spectrometer. The operating wavelength of the optical system ranges from 900nm to 1700nm, and the focal length is 1200mm. It consists of two parts: the two dimensional imaging system and the multispectral CASSI imaging system. The key technical parameters of the two parts are the same and there is no visual axis difference. Therefore, the optimized optical system can effectively improve real-time performance, optical transmittance and compactness of the dual camera shortwave infrared CASSI, which is conducive to the application in optical measurement scenes in the shooting range.

scholarly journals Optical Aberration Calibration and Correction of Photographic System Based on Wavefront Coding

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4011
Author(s):  
Chuanwei Yao ◽  
Yibing Shen
Keyword(s):  
Imaging System ◽  
Optical Design ◽  
Computational Imaging ◽  
Large Field ◽  
Wavefront Aberration ◽  
Imaging Method ◽  
Image Deconvolution ◽  
Pupil Function ◽  
Wavefront Coding ◽  
Blurred Images

The image deconvolution technique can recover potential sharp images from blurred images affected by aberrations. Obtaining the point spread function (PSF) of the imaging system accurately is a prerequisite for robust deconvolution. In this paper, a computational imaging method based on wavefront coding is proposed to reconstruct the wavefront aberration of a photographic system. Firstly, a group of images affected by local aberration is obtained by applying wavefront coding on the optical system’s spectral plane. Then, the PSF is recovered accurately by pupil function synthesis, and finally, the aberration-affected images are recovered by image deconvolution. After aberration correction, the image’s coefficient of variation and mean relative deviation are improved by 60% and 30%, respectively, and the image can reach the limit of resolution of the sensor, as proved by the resolution test board. Meanwhile, the method’s robust anti-noise capability is confirmed through simulation experiments. Through the conversion of the complexity of optical design to a post-processing algorithm, this method offers an economical and efficient strategy for obtaining high-resolution and high-quality images using a simple large-field lens.

scholarly journals Design and Implementation Guidelines for a Modular Spectral-Domain Optical Coherence Tomography Scanner

2018 ◽  
Vol 2018 ◽  
pp. 1-22 ◽  
Author(s):  
Farid Atry ◽  
Israel Jacob De La Rosa ◽  
Kevin R. Rarick ◽  
Ramin Pashaie
Keyword(s):  
Optical Coherence Tomography ◽  
Imaging System ◽  
Optical Design ◽  
Spectral Domain ◽  
Design Parameters ◽  
Optical Coherence ◽  
Custom Made ◽  
Essential Knowledge ◽  
Sd Oct

In the past decades, spectral-domain optical coherence tomography (SD-OCT) has transformed into a widely popular imaging technology which is used in many research and clinical applications. Despite such fast growth in the field, the technology has not been readily accessible to many research laboratories either due to the cost or inflexibility of the commercially available systems or due to the lack of essential knowledge in the field of optics to develop custom-made scanners that suit specific applications. This paper aims to provide a detailed discussion on the design and development process of a typical SD-OCT scanner. The effects of multiple design parameters, for the main optical and optomechanical components, on the overall performance of the imaging system are analyzed and discussions are provided to serve as a guideline for the development of a custom SD-OCT system. While this article can be generalized for different applications, we will demonstrate the design of a SD-OCT system and representative results for in vivo brain imaging. We explain procedures to measure the axial and transversal resolutions and field of view of the system and to understand the discrepancies between the experimental and theoretical values. The specific aim of this piece is to facilitate the process of constructing custom-made SD-OCT scanners for research groups with minimum understanding of concepts in optical design and medical imaging.

An extended depth-of-field imaging system with a non-rotationally symmetric phase mask

2018 ◽  
Vol 89 (10) ◽  
pp. 103101 ◽  
Author(s):  
Hongbo Xie ◽  
Lirong He ◽  
Lei Yang ◽  
Chensheng Mao ◽  
Meng Zhu ◽  
...  
Keyword(s):  
Imaging System ◽  
Phase Mask ◽  
Depth Of Field ◽  
Rotationally Symmetric ◽  
Extended Depth Of Field ◽  
Field Imaging ◽  
Symmetric Phase

scholarly journals Optical Design of Improved Offner Imaging Spectrometer

2021 ◽  
Vol 2112 (1) ◽  
pp. 012007
Author(s):  
Chong Song ◽  
Yong Huang ◽  
Yangdong Yan ◽  
Dongsen Cui ◽  
Gang Wang ◽  
...  
Keyword(s):  
Optical System ◽  
Optical Design ◽  
Annular Region ◽  
Practical Application ◽  
Imaging Spectrometer ◽  
Imaging Quality ◽  
Lens Position ◽  
Operating Wavelength ◽  
The Stability ◽  
System Characteristics

Abstract An improved Offner imaging spectrometer was proposed based on the optical system characteristics of Offner imaging spectrometer, which can ensure perfect imaging quality in a wider annular region. The operating wavelength of the improved Offner imaging spectrometer ranges from 900nm to 1700nm, and the magnification is 1. Improved Offner imaging spectrometer can be obtained by changing the meniscus lens position and further optimizing the design. The results indicate that the improved Offner imaging spectrometer can effectively improve compactness and lightweight, and reduce the difficulty of optical adjustment, which is conducive to the stability of practical application.

scholarly journals Space Variant PSF – Deconvolution of Wide-Field Astronomical Images

10.14311/1023 ◽  
2008 ◽  
Vol 48 (3) ◽  
Author(s):  
M. Řeřábek
Keyword(s):  
Optical System ◽  
Imaging System ◽  
Real Data ◽  
Wavefront Aberration ◽  
Wide Field ◽  
Optical Aberrations ◽  
Optical Aberration ◽  
Transfer Characteristics ◽  
Astronomical Images ◽  
Space Variant

The properties of UWFC (Ultra Wide-Field Camera) astronomical systems along with specific visual data in astronomical images contribute to a comprehensive evaluation of the acquired image data. These systems contain many different kinds of optical aberrations which have a negatively effect on image quality and imaging system transfer characteristics, and reduce the precision of astronomical measurement. It is very important to figure two main questions out. At first: In which astrometric depend on optical aberrations? And at second: How optical aberrations affect the transfer characteristics of the whole optical system. If we define the PSF (Point Spread Function) [2] of an optical system, we can use some suitable methods for restoring the original image. Optical aberration models for LSI/LSV (Linear Space Invariant/Variant) [2] systems are presented in this paper. These models are based on Seidel and Zernike approximating polynomials [1]. Optical aberration models serve as suitable tool for estimating and fitting the wavefront aberration of a real optical system. Real data from the BOOTES (Burst Observer and Optical Transient Exploring System) experiment is used for our simulations. Problems related to UWFC imaging systems, especially a restoration method in the presence of space variant PSF are described in this paper. A model of the space variant imaging system and partially of the space variant optical system has been implemented in MATLAB. The “brute force” method has been used for restoration of the testing images. The results of different deconvolution algorithms are demonstrated in this paper. This approach could help to improve the precision of astronomic measurements. 

Optical Design of Decentered Aperture-Divided Polarization Imaging System

2013 ◽  
Vol 33 (6) ◽  
pp. 0622005 ◽  
Author(s):  
贺虎成 He Hucheng ◽  
季轶群 Ji Yiqun ◽  
周建康 Zhou Jiankang ◽  
赵知诚 Zhao Zhicheng ◽  
沈为民 Shen Weimin
Keyword(s):  
Imaging System ◽  
Optical Design ◽  
Polarization Imaging

Optical Design of Off-Axis Four-Mirror Optical System with Wide Field of View

2013 ◽  
Vol 33 (10) ◽  
pp. 1022002
Author(s):  
刘军 Liu Jun ◽  
刘伟奇 Liu Weiqi ◽  
康玉思 Kang Yusi ◽  
吕博 Lü Bo ◽  
冯睿 Feng Rui ◽  
...  
Keyword(s):  
Optical System ◽  
Optical Design ◽  
Field Of View ◽  
Wide Field ◽  
Wide Field Of View

Optical Design and Stray-Light Analysis of Urban Night-Light Remote Sensing Imaging System

2020 ◽  
Vol 57 (1) ◽  
pp. 012201
Author(s):  
姜守望 Jiang Shouwang ◽  
夏振涛 Xia Zhentao ◽  
孙永雪 Sun Yongxue ◽  
王珂 Wang Ke
Keyword(s):  
Remote Sensing ◽  
Imaging System ◽  
Optical Design ◽  
Stray Light
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