期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
CT图像的计算机制全息三维重建 被引量:2
1
作者 杨上供 王辉 金洪震 《光电工程》 EI CAS CSCD 北大核心 2006年第12期23-26,共4页
提出用计算机制全息术实现CT图像的三维重建。首先研究了CT图像的三维信息融合,用计算机模拟CT图像的物光波,用菲涅耳计算全息图的方法,把CT图像的二维信息融合成三维信息,获得菲涅耳全息图。然后将计算机制全息与光学全息相结合,记录... 提出用计算机制全息术实现CT图像的三维重建。首先研究了CT图像的三维信息融合,用计算机模拟CT图像的物光波,用菲涅耳计算全息图的方法,把CT图像的二维信息融合成三维信息,获得菲涅耳全息图。然后将计算机制全息与光学全息相结合,记录彩虹全息图。最后用扩展的白光再现,获得逼真无畸变的真正的三维立体图像,充分发挥了计算机制全息与光学全息的优势。在全息图的计算中利用了快速傅里叶算法,大大缩短计算时间。根据不同的观察需要制作了两种不同效果的全息图,并给出了理论分析和实验结果。 展开更多
关键词 CT 三维重建 计算全息术 彩虹全息
下载PDF
彩色全息术的进展及未来发展 被引量:1
2
作者 刘海霞 栾晓宁 《光学技术》 CAS CSCD 北大核心 2007年第S1期249-252,254,共5页
对不同时期和采用各种技术制作的彩色全息图以及所使用的记录材料进行了较全面的介绍。这些技术包括光全息术、计算全息术和数字全息术。并对彩色全息术的未来发展进行了展望。
关键词 彩色全息术 计算全息术 数字全息术 彩色彩虹全息 彩色反射全息
原文传递
用计算全息法测量长焦透镜的透射波前 被引量:2
3
作者 魏小红 何宇航 +3 位作者 高波 徐凯源 李强 柴立群 《光学精密工程》 EI CAS CSCD 北大核心 2016年第12期3005-3011,共7页
为了高精度地检测长焦透镜的透射波前,提出了在Zygo干涉仪的平面光路中加入一个二元衍射元件提供参考波前的计算全息法(CGH)。介绍了计算全息法检测长焦透镜透射波前的理论,设计并研制了高精度计算全息板,并将其用于大口径长焦距透镜透... 为了高精度地检测长焦透镜的透射波前,提出了在Zygo干涉仪的平面光路中加入一个二元衍射元件提供参考波前的计算全息法(CGH)。介绍了计算全息法检测长焦透镜透射波前的理论,设计并研制了高精度计算全息板,并将其用于大口径长焦距透镜透射波前检测。理论分析和实际检测结果表明:该方法系统误差小,测量重复性精度优于0.004λ(2σRMS),与常规的菲索干涉法测量球面透镜透射波前得到的结果一致,从而验证了提出测量方法的可靠性。最后,详细分析了二元衍射元件的制造误差对透射波前检测的影响,得到测量误差(PV)小于λ/10。文中的结果表明提出的计算全息法可有效缩短光路,提高测量精度,对长焦透镜波前检测有重要的应用价值。 展开更多
关键词 长焦透镜 透射波前 光学检测 干涉检测 计算全息术 误差分析
下载PDF
菲涅耳非相干全息术3D全息成像探讨
4
作者 Author Joseph Rosen Barak Katz +1 位作者 Gary Brooker 何文(编译) 《中国印刷与包装研究》 CAS 2011年第1期60-64,共5页
全息成像提供了一种从单一观察点捕捉具有完整三维信息画面的可靠、快捷的方法。本文回顾了近期提出的单通道菲涅耳数字全息光学系统,该系统能获得由非相干光照射的三维实物体的全息图。在这一静态全息技术中,由三维物体反射或发射光,... 全息成像提供了一种从单一观察点捕捉具有完整三维信息画面的可靠、快捷的方法。本文回顾了近期提出的单通道菲涅耳数字全息光学系统,该系统能获得由非相干光照射的三维实物体的全息图。在这一静态全息技术中,由三维物体反射或发射光,在通过空间光调制器(SLM)后,用数码相机记录。SLM被用作单通道非相干干涉仪的分束器,使来自物体上各点的球面波被分成两束具有不同曲率半径的球面波。所有球面波干涉结果的非相干总和,即可生成被观测物体的三维菲涅耳全息图。在计算机中可再现该全息图,使其三维特征得以呈现。 展开更多
关键词 数字全息术 非相干全息术 计算全息术 合成孔径雷达 三维图像处理
下载PDF
漫话景物形象在电影电视中的三维显示(上) 被引量:1
5
作者 孙延禄 《现代电影技术》 2007年第12期38-42,共5页
本文分析了现行影视系统景物形象再现质量的不足,简述了真正三维显示方法的基本原理及研发状况。指出了计算机技术、数字技术为此项研究开辟了新途径。提出了将此项目纳入我国长期科技发展规划的建议。
关键词 光学全息 积成摄影 全息电影 全息电视计算全息术 电-全息术
下载PDF
Robust digital image watermarking against shearing based on Haar orthogonal function system 被引量:1
6
作者 DENGMing-hui HAOYan-ling SHENDong-hui 《Journal of Marine Science and Application》 2004年第1期75-80,共6页
In this paper, a robust digital watermarking method against shearing based on Haar orthogonal function system was introduced. The proposed method adopted the complete generalized orthogonal properties of Haar ortbogon... In this paper, a robust digital watermarking method against shearing based on Haar orthogonal function system was introduced. The proposed method adopted the complete generalized orthogonal properties of Haar ortbogonal function system to achieve the piece-based orthogonal transform on the image. The significant middle frequency coefficients in the transformation matrix are picked up, based on characteristics of the image visual system and the Haar orthogonal transform. The watermark is adoptively weighed to the middle frequency matrix. The method improves the validity of watermarking and shows excellent advantage against shearing attack. Experimental results show that the Haar orthogonal function system based watermark approach can provide an excellent protection under geometric attacks. 展开更多
关键词 digital watermarking Haar orthogonal function system shearing attack
下载PDF
Research on the Shrinking of 2-components Adhesive with Automatically Calculating Hologram
7
作者 WANG Wensheng (Changchun College of Optics and Fine Mechanics, Changchun 130022, CHN ) 《Semiconductor Photonics and Technology》 CAS 1998年第2期118-122,共5页
In this paper, used BSO(Bi12SiO(20)) crystal as a hologram recording material,TV-camera as a detector, and a holographic setup controlled by a computer, automatically calculating hologram of 3-interferograms method ... In this paper, used BSO(Bi12SiO(20)) crystal as a hologram recording material,TV-camera as a detector, and a holographic setup controlled by a computer, automatically calculating hologram of 3-interferograms method is theoretically and experimentally studied. This new holographic recording material and automatically calculating hologram make it possible to use real-time holography in an industry. As a practical example, the shrinking of 2-components adhesive in 4 h is measured. 展开更多
关键词 BSO Crystal Micro-computer Real-time Holography Shrinking of an Adhesive Layer TV-Camera
下载PDF
An entropy-based unsupervised anomaly detection pattern learning algorithm
8
作者 杨英杰 马范援 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2005年第1期81-85,共5页
Currently, most anomaly detection pattern learning algorithms require a set of purely normal data from which they train their model. If the data contain some intrusions buried within the training data, the algorithm m... Currently, most anomaly detection pattern learning algorithms require a set of purely normal data from which they train their model. If the data contain some intrusions buried within the training data, the algorithm may not detect these attacks because it will assume that they are normal. In reality, it is very hard to guarantee that there are no attack items in the collected training data. Focusing on this problem, in this paper, firstly a new anomaly detection measurement is proposed according to the probability characteristics of intrusion instances and normal instances. Secondly, on the basis of anomaly detection measure, we present a clustering-based unsupervised anomaly detection patterns learning algorithm, which can overcome the shortage above. Finally, some experiments are conducted to verify the proposed algorithm is valid. 展开更多
关键词 anomaly detection intrusion detection computer security pattern learning
下载PDF
Integrated criteria for covert channel auditing
9
作者 Chang-da WANG Shi-guang JU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2008年第6期737-743,共7页
A new concept, the security level difference of a covert channel, is presented, which means the security level span from the sender to the receiver of the covert channel. Based on this, the integrated criteria for cov... A new concept, the security level difference of a covert channel, is presented, which means the security level span from the sender to the receiver of the covert channel. Based on this, the integrated criteria for covert channel auditing are given. Whereas TCSEC (Trusted Computer System Evaluation Criteria) or CC (Common Criteria for Information Technology Security Evaluation) only use the bandwidth to evaluate the threat of covert channels, our new criteria integrate the security level difference, the bandwidth sensitive parameter, bandwidth, duration and instantaneous time of covert channels, so as to give a comprehensive evaluation of the threat of covert channels in a multilevel security system. 展开更多
关键词 Multilevel security Covert channel Covert channel auditing
下载PDF
Data Mining and Visualization of Grid-Based City Emergency System
10
作者 薛京生 孙济洲 +2 位作者 刘牧星 张旭 何宏 《Transactions of Tianjin University》 EI CAS 2005年第2期125-128,共4页
A cluster analyzing algorithm based on grids is introduced in this paper,which is applied to data mining in the city emergency system. In the previous applications, data mining was based on the method of analyzing poi... A cluster analyzing algorithm based on grids is introduced in this paper,which is applied to data mining in the city emergency system. In the previous applications, data mining was based on the method of analyzing points and lines, which was not efficient enough in dealing with the geographic information in units of police areas. The proposed algorithm maps an event set stored as a point set to a grid unit set, utilizes the cluster algorithm based on grids to find out all the clusters, and shows the results in the method of visualization. The algorithm performs well when dealing with high dimensional data sets and immense data. It is suitable for the data mining based on geogra-(phic) information system and is supportive to decision-makings in the city emergency system. 展开更多
关键词 GRID EMERGENCY data mining VISUALIZATION
下载PDF
Network security situation and development prospect
11
作者 Hua Du 《International Journal of Technology Management》 2013年第11期3-5,共3页
Network information security is an important issue mattering national security and sovereignty, social stability, cultural inheritance and development. Its importance is escalating with the accelerated pace of global ... Network information security is an important issue mattering national security and sovereignty, social stability, cultural inheritance and development. Its importance is escalating with the accelerated pace of global information. Information security is a comprehensive discipline involving computer science, network technology, communication technology, cryptography, information security technology, applied mathematics, number theory, information theory and other disciplines. It mainly refers to the condition that network hardware, software and system data are protected from destruction, change and divulgation from accidental or malicious reasons so that the system can run continuously and reliably with no interrupted network service. 展开更多
关键词 NETWORK SECURITY development prospect.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部