Design of the Real-Time Autofocusing System for Collimator with Long Focus Length and Large Aperture

2011 ◽  
Vol 127 ◽  
pp. 25-31
Author(s):  
Xiang Li ◽  
Xiao Hui Zhang
Keyword(s):  
Computer Simulation ◽  
Semiconductor Lasers ◽  
Essential Role ◽  
Focal Length ◽  
Optical Devices ◽  
Plane Mirror ◽  
Large Aperture ◽  
Surrounding Environment ◽  
New Type ◽  
Common Problems

Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment, the large aperture collimator’s accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However, the process of adjusting the collimator is extremely complicated due to the collimator’s large aperture and long focal length. So it is difficult to ensure the measurement’s quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above, this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror, semiconductor lasers as light source and CCD sensor as receiver. The system is smaller, lighter, and more convenient when using. The computer simulation shows that the autofocusing system’s resolution could reach the accuracy of 40μm. If we use the relevant algorithms to execute the sub-pixel scanning, the resolution could reach the accuracy of 10μm. It shows that the system could satisfy the required testing precision of testing large aperture optical device.

Long focal length and large aperture zoom optical system

2021 ◽  
Author(s):  
Wei-jun Chang ◽  
Bo Zhang ◽  
Ge-ping Cao
Keyword(s):  
Optical System ◽  
Focal Length ◽  
Large Aperture

scholarly journals The Limits of Learning: Exploration, Generalization, and the Development of Learning Traps

2018 ◽  
Author(s):  
Alexander Rich ◽  
Todd Matthew Gureckis
Keyword(s):  
Decision Making ◽  
Computer Simulation ◽  
Adaptive Behavior ◽  
False Belief ◽  
Complex Environments ◽  
Extensive Experience ◽  
Present Evidence ◽  
Fundamental Limit ◽  
New Type ◽  
Series Of Experiments

Learning usually improves the accuracy of beliefs through the accumulation of experience. But are there limits to learning that prevent us from accurately understanding our world? In this paper we investigate the concept of a “learning trap”—the formation of a stable false belief even with extensive experience. Our review highlights how these traps develop though the interaction of learning and decision making in unknown environments. We further document a particularly pernicious learning trap driven by selective attention, a mechanism often assumed to facilitate learning in complex environments. Using computer simulation we demonstrate the key attributes of the agent and environment that lead to this new type of learning trap. Then, in a series of experiments we present evidence that people robustly fall into this trap, even in the presence of various interventions predicted to meliorate it. These results highlight a fundamental limit to learning and adaptive behavior that impacts individuals, organizations, animals, and machines.

Design of Long-Wave Infrared Scan System with Rotating Dual-Wedge Prism

2013 ◽  
Vol 552 ◽  
pp. 27-32
Author(s):  
Zhe Yuan Fan ◽  
Li Min Gao ◽  
Hong Tao Yang ◽  
Wei Ning Chen ◽  
Jian Zhong Cao ◽  
...  
Keyword(s):  
Focal Length ◽  
Chromatic Aberration ◽  
Energy Concentration ◽  
Large Field ◽  
Modulation Transfer ◽  
Sensing Element ◽  
Large Aperture ◽  
Long Wave ◽  
Good Imaging ◽  
Wedge Prism

Due to the possession of advantages of passivity working mode, good disguise, and easy observation, infrared systems are used in a wide variety of applications. This paper using 640×480 uncooled detector designed a long-wave scan optical system with large field and large aperture working at 8.0μm～12μm, the Pixel Dimensions of the detector is 30μm. The F number of this system is 1.4 and focal length is 17mm, FOV is 63.6°, which extended to 143° by adopting dual-wedge prism rotating, the paper also given the extended field theory by the dual-wedge prism. Because there are a limited number of lens materials used in LWIR spectral bands, Germanium material and three aspheric surfaces were adopted to balance sphere aberrations and chromatic aberration. All above mentioned are intending to ensure the system has good imaging quality. The results show that the optical performance approximates to the diffraction limit and the design has better achromatic performance. The modulation transfer function (MTF) is above 0.5 at spatial frequency of 20lp/mm, energy concentration ratio is greater than 70% within the sensing element of the detector and Root Mean Square (RMS) value of spot diameter is smaller than the Pixel Dimensions. The system has advantages of simple structure, large aperture, high image quality etc.

118 Long Focal Length Testing for Large Aperture Lens

2003 ◽  
Vol 2003 (0) ◽  
pp. 89-94
Author(s):  
Jian Bai ◽  
Changlun Hou ◽  
Xiyun Hou ◽  
Chen Sun ◽  
Guoguang Yang
Keyword(s):  
Focal Length ◽  
Large Aperture

scholarly journals Large-aperture laser differential confocal ultra-long focal length measurement and its system

2015 ◽  
Vol 23 (13) ◽  
pp. 17379 ◽  
Author(s):  
Weiqian Zhao ◽  
Zhigang Li ◽  
Lirong Qiu ◽  
Huan Ren ◽  
Rongjun Shao
Keyword(s):  
Focal Length ◽  
Length Measurement ◽  
Large Aperture

Optical Design of Very Large Four-Mirror Systems

2007 ◽  
Vol 364-366 ◽  
pp. 1231-1236 ◽  
Author(s):  
Li Rong Zhu ◽  
Wei Min Shen
Keyword(s):  
Focal Length ◽  
Optical Design ◽  
Diffraction Limit ◽  
Field Of View ◽  
Initial Structure ◽  
Entrance Pupil ◽  
Primary Mirror ◽  
Imaging Quality ◽  
Large Aperture ◽  
Design Idea

Four-mirror systems with a very large aperture and a long focal length were investigated and designed. Their design idea is given. Through the derivation of primary aberration formula, the aberration properties were analyzed and discussed, and the method to determine its initial structure is reported. As examples, two four-mirror systems with spherical and parabolic primary mirror, 100m focal length, and 10m entrance pupil were optimally designed. Their imaging quality approaches diffraction limit within field of view of 0.4 and 0.5 degrees respectively.

Numerical Simulations of Fractional Fourier Transform of Hypergeometric-Gaussian Beam

2013 ◽  
Vol 765-767 ◽  
pp. 780-784 ◽  
Author(s):  
Zhen Feng Yang ◽  
Wen Dan Miao ◽  
Zhen Jun Yang ◽  
Shu Min Zhang
Keyword(s):  
Fourier Transform ◽  
Numerical Simulations ◽  
Gaussian Beam ◽  
Intensity Distribution ◽  
Fractional Fourier Transform ◽  
Focal Length ◽  
Beam Width ◽  
Laser Beams ◽  
New Type ◽  
Lens Focal Length

The fractional Fourier transform (FRFT) of a new type of laser beams called the hypergeometric-Gaussian beam (HyGGB) is investigated in detail. The analytical expression for the FRFT of a HyGGB is derived. The properties of a HyGGB in the FRFT plane with different parameters are illustrated. The results show that the intensity distribution of a HyGGB in the FRFT plane strongly depends on the fractional order, the lens focal length and the initial beam width.

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