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	On a Certain Sum-product Estimate in Fields of Prime Order 期刊论文 OAI收割 ACTA MATHEMATICA SINICA-ENGLISH SERIES, 2014, 卷号: 30, 期号: 11, 页码: 1861-1866 作者: Xue Bo Qing \| 收藏 \| 浏览/下载：12/0 \| 提交时间：2021/01/14 SUBSETS Sum-product estimate different sets fields of prime order
	Simulation test research of using the Ritchey-Common method for the detection of large flat mirror (EI CONFERENCE) 会议论文 OAI收割 2012 International Conference on Frontiers of Advanced Materials and Engineering Technology, FAMET 2012, January 4, 2012 - January 5, 2012, Xiamen, China 作者: Zhang X.; Zhang X.; Zhang X. 收藏 \| 浏览/下载：22/0 \| 提交时间：2013/03/25 In the detection of large flat mirror the Ritchey-Common test can achieve high accuracy measurement. A method which expands the compressed images due to Ritchey Angle and rotates the plane under test is presented achieve two sets of influence functions through this we can built two equations according to two different angular positions we can solve the equations by least squares method. Then through fitting the coefficients we can get the flat errors this paper describe the simulation test of the method in order to prove the feasibility and reliability of this method. (2012) Trans Tech Publications.
	Design and image restoration research of a cubic-phase-plate system (EI CONFERENCE) 会议论文 OAI收割 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, April 26, 2010 - April 29, 2010, Dalian, China 作者: Zhang J.; Zhang J.; Zhang J.; Shi G.; Zhang X. 收藏 \| 浏览/下载：31/0 \| 提交时间：2013/03/25 Wave-front coding technology is a novel jointly optical and digital imaging technology which can greatly extend the depth of focus of optical systems. The image restoration process is an important part of wave-front coding technology. Using wave-front coding makes the modulation transfer function(MTF) values of the optical systems change little over a range of several times the depth of focus which means the system MTF is quite insensitive to defocus and there is no zero in the passband. So we can design a single filter for the restoration of images in different defocus positions. However it's hard to avoid noise during image acquisition and transmission processes. These noises will be amplified in the image restoration especially in the high frequency part when the MTF drop is relatively low. The restoration process significantly reduces the system signal to noise ratio this way. Aimed at the problem of noise amplification a new algorithm was proposed which incorporated wavelet denoising into the iterative steps of Lucy-Richardson algorithm. Better restoration results were obtained through the new algorithm effectively solving the noise amplification problem of original LR algorithm. Two sets of identical triplet imaging systems were designed in one of which the cubic-phase-plate was added. Imaging experiments of the manufactured systems were carried and the images of a traditional system and a wave-front coded system before and after decoding were compared. The results show that the designed wave-front coded system can extend the depth of focus by 40 times compared with the traditional system while maintaining the light flux and the image plane resolution. 2010 Copyright SPIE - The International Society for Optical Engineering.
	Intelligent MRTD testing for thermal imaging system using ANN (EI CONFERENCE) 会议论文 OAI收割 ICO20: Remote Sensing and Infrared Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China Sun J.; Ma D. 收藏 \| 浏览/下载：32/0 \| 提交时间：2013/03/25 The Minimum Resolvable Temperature Difference (MRTD) is the most widely accepted figure for describing the performance of a thermal imaging system. Many models have been proposed to predict it. The MRTD testing is a psychophysical task for which biases are unavoidable. It requires laboratory conditions such as normal air condition and a constant temperature. It also needs expensive measuring equipments and takes a considerable period of time. Especially when measuring imagers of the same type the test is time consuming. So an automated and intelligent measurement method should be discussed. This paper adopts the concept of automated MRTD testing using boundary contour system and fuzzy ARTMAP but uses different methods. It describes an Automated MRTD Testing procedure basing on Back-Propagation Network. Firstly we use frame grabber to capture the 4-bar target image data. Then according to image gray scale we segment the image to get 4-bar place and extract feature vector representing the image characteristic and human detection ability. These feature sets along with known target visibility are used to train the ANN (Artificial Neural Networks). Actually it is a nonlinear classification (of input dimensions) of the image series using ANN. Our task is to justify if image is resolvable or uncertainty. Then the trained ANN will emulate observer performance in determining MRTD. This method can reduce the uncertainties between observers and long time dependent factors by standardization. This paper will introduce the feature extraction algorithm demonstrate the feasibility of the whole process and give the accuracy of MRTD measurement.
	Towards a problem of E. van Douwen and A. Miller 期刊论文 OAI收割 MATHEMATICAL LOGIC QUARTERLY, 1999, 卷号: 45, 期号: 2, 页码: 183-188 作者: Yi, Z \| 收藏 \| 浏览/下载：18/0 \| 提交时间：2018/07/30 eventually different functions almost disjoint sets maximal almost disjoint family Martin's axiom continuum hypothesis