检索结果-内蒙古大学图书馆

conference on Lasers and electro-Optics (CLEO)

作者： Marcos Dantus Igor Pastirk BioPhotonic Solutions Inc. Okemos MI USA

Breakthrough technology in remote femtosecond pulse characterization and accurate delivery of ultrashort shaped pulses to distances greater than 30 meters is being used to develop remote detection of explosives as wel... 详细信息

关键词： chemical technology Explosives Ultrafast optics optical pulse shaping optical receivers optical scattering Biomedical optical imaging optical sensors Laser noise Pulse measurements

来源：评论

学校读者我要写书评

暂无评论

remote concealed weapon detection in the millimeterwave region:: Active and passive

Remote concealed weapon detection in the millimeterwave regi...

引用

conference on electro-optical remote Sensing ii

作者： Stanko, Stephan Kloeppel, Frank Huck, Johann Noetel, Denis Haegelen, Manfred Briese, Gunnar Gregor, Alexander Erukulla, Sreenivas Fuchs, Hans-Hellmuth Essen, Helmut Pagels, Anke FGAN Res Inst High Frequency Phys & Radar Tech Neuenahrer Str 20 D-53343 Wachtberg Germany

ISBN: (纸本)9780819464941

Sensors used for Security purposes have to cover the non-invasive inspection of persons, baggage and letters with the aim to detect weapons, explosives and chemical or biological threat material. Currently, emphasis is placed on system concepts and technologies for this type of applications, employing millimeterwave-, submillimeterwave- and terahertz sensors. This is based on the capability of these frequency bands to look through textiles and the possibility to achieve a geometric resolution which is sufficient to resolve critical items within the necessary range. Using multiple frequencies promises to give more detailed information about the structure of the observed objects. Furthermore, to overcome the limitations of passive millimeter- and submillimeterwave sensors which depend on indirect illumination, systems using miniaturized mmw-radar modules are applied as well.

关键词： concealed weapon detection millimeterwaves radiometry synthetic aperture radar

来源：评论

学校读者我要写书评

暂无评论

Forward modeling of linear mixing in thermal IR ground leaving radiance spectra

Forward modeling of linear mixing in thermal IR ground leavi...

引用

conference on electro-optical remote Sensing ii

作者： Balick, Lee K. Gillespie, Alan R. McCabe, Matthew F. Mushkin, Amit Los Alamos Natl Lab Space & Remote Sensing Sci Grp M-S B244POB 1663 Los Alamos NM 87545 USA Univ Washington Dept Earth & Space Sci Seattle WA 98195 USA

ISBN: (纸本)9780819464941

Hyperspectral thermal IR remote sensing is an effective tool for the detection and identification of gas plumes and solid materials. Virtually all remotely sensed thermal IR pixels are mixtures of different materials or temperatures. As sensors improve and hyperspectral thermal IR remote sensing becomes more quantitative, the concept of homogeneous pixels becomes inadequate. The contributions of the constituents to the pixel spectral ground leaving radiance are weighted by their spectral emissivity as well as their temperature, or more correctly, temperature distributions, because real pixels are rarely thermally homogeneous. Planck's Law defines a relationship between temperature and radiance that is strongly wavelength dependent, even for blackbodies. Spectral ground leaving radiance (GLR) from mixed pixels is temperature and wavelength dependent and the relationship between observed radiance spectra from mixed pixels and library emissivity spectra of mixtures of 'pure' materials is indirect. This paper presents results from a simple model of linear mixing of pixel spectral GLR. A pixel consists of one or more materials each with a temperature distribution and an emissivity spectrum. Temperature distributions consistent with high resolution thermal images are used as inputs to the model. The impact of spatial-temporal fluctuation of skin temperature on skin temperature variability will be discussed. The results show the strong sensitivity of spectral GLR at shorter wavelengths to temperature and significant variation of radiance mixture proportions with wavelength in the mid-infrared (3-5 mu m). Spectral GLR of mixtures in the 8-12 mu m domain are more modestly impacted but the impact of subpixel mixing and variability is still significant. A demonstration of the effects of linear mixing on linear un-mixing is also presented.

关键词： hyperspectral thermal IR spectral remote sensing linear mixing model

来源：评论

学校读者我要写书评

暂无评论

Hyperspectral multiple approach fusion for the long range detection of low observable objects:TB MUF2

Hyperspectral multiple approach fusion for the long range de...

引用

conference on electro-optical remote Sensing ii

作者： Yuen, Peter W. T. Bishop, G. BAE SYST Ctr Adv Technol Sowerby BldgFPC 267POB 5 Bristol BS34 7QW Avon England

ISBN: (纸本)9780819464941

Highly efficient target detection algorithms in hyperspectral remote sensing technology, particularly for the long range detection of very low observable objects which exhibit extremely small detection cross sections, are in great demand. This is more so for a near or real time application. This paper is concerned with global anomaly detections (GAD), and conventional methods to achieve better detection using multiple approach fusion (MAF), which fuses detection outputs from various detectors using either logical operators, or, via a model based estimation of the joint detection statistics from all detectors, is found to be not good enough. This work emphasises the need to integrate a more comprehensive background modelling into the GAD to develop a robust anomaly detector (AD). Then, the detection output from this detector is fused with other detectors via MAF for a further improvement of detection performance. The MUF2 algorithm is formulated exactly using this 2-level fusion mechanism, in which mixture modelling and spectral unmixing fusion have been employed. The significance of background modelling in GAD has been highlighted in this work using real data. The result has shown a factor of 2-5 reduction in detection performance when a very small amount of target pixels (-0.1%) is misclassified as background. This is because anomalies are defined with reference to a model of the background, and subsequently two new background classification techniques have been proposed in this work. The effectiveness of the MUF2 has been assessed using three representative data sets which contain various different types of targets, ranging from vehicles to small plates embedded in backgrounds with various degrees of homogeneity. The performance of MUF2 has been shown to be more superior than the conventional GAD frequently in orders of magnitude, regardless of the background homogeneity and target types. The current version of the MUF2 is run under Matlab and it takes -2 minutes

关键词： hyperspectral background characterisation near real time detection spectral unmixing multiple fusion

来源：评论

学校读者我要写书评

暂无评论

Hyperspectral imaging: Gem identification and authentication

Hyperspectral imaging: Gem identification and authentication

引用

conference on Multispectral and Hyperspectral remote Sensing Instruments and Applications ii

作者： Gomez, RB Del Re, N George Mason Univ Sch Computat Sci Fairfax VA 22030 USA

ISBN: (纸本)0819456160

Through the centuries gem materials have been highly prized and sought after. The varieties of gem materials run into the hundreds if not thousands, characterized by a gamut of material classes running from organic to inorganic and from crystalline to amorphous. All consisting of numerous chemical compositions and characterized by various physical and optical properties. In addition, most gem materials have been subject to numerous modifications to enhance and imitate the most pleasing of esthetic qualities, e.g., dyeing, impregnation, heating, reconstruction, high pressure and temperature, irradiation, and diffusion. Of concern is the ability not only to identify the gem material in question, but if applicable, the treatment. Up until recent, the main instruments utilized to detect these have been simple but quite effective such as a binocular microscope, refractometer, hand spectroscope, dichroscope, and measuring of specific gravity. New gem materials and techniques involved in treatments have become increasingly sophisticated such as ultraviolet-visible-infrared and Raman spectroscopy. In certain cases, some of the most recent techniques have become time consuming and expensive. Here is the opportunity to overview and utilize a powerful technology found in the field of remote sensing, i.e., Hyperspectral Imaging. This technology has been in effect for many years but only recently has it been used to focus on areas similar to the ones in this paper. In particular, hyperspectral imaging technology and its potential application to gem identification and authentication are covered in this paper.

关键词： hyperspectral imaging gems gemstones remote sensing classification

来源：评论

学校读者我要写书评

暂无评论

detection and identification of toxic air pollutants using airborne LWIR hyperspectral imaging

Detection and identification of toxic air pollutants using a...

引用

conference on Multispectral and Hyperspectral remote Sensing Instruments and Applications ii

作者： Williams, DJ Feldman, BL Williams, TJ Pilant, D Lucey, PG Worthy, LD US EPA Res Triangle Pk NC 27711 USA

ISBN: (纸本)0819456160

Airborne longwave infrared (LWIR) hyperspectral imagery was utilized to detect and identify gaseous chemical release plumes at sites in southern Texas. The Airborne Hyperspectral Imager (AHI), developed by the University of Hawai'i, was flown over a petrochemical facility and a confined animal feeding operation on a modified DC-3 during April, 2004. Data collected by the AM system was successfully used to detect and identify numerous plumes at both sites. Preliminary results indicate the presence of benzene and ammonia and several other organic compounds. Emissions were identified using regression analysis on atmospherically compensated data. Data validation was conducted using facility emission inventories. This technology has great promise for monitoring and inventorying facility emissions, and may be used as means to assist ground inspection teams to focus on actual fugitive emission points.

关键词： Long wavelength infrared Calibration Hyperspectral imaging Inspection Imaging systems remote sensing chemical analysis Infrared imaging Infrared sensors Sensors

来源：评论

学校读者我要写书评

暂无评论

Chip-scale photonics with plasmonic components

Chip-scale photonics with plasmonic components

引用

Frontiers in Optics, FiO 2005

作者： Atwater, Harry A. Thomas J. Watson Laboratory of Applied Physics California Institute of Technology MS 128-95 Pasadena CA 91125 United States

ISBN: (纸本)1557527970

Historically, optical device size has been limited by diffraction. Today's photonic devices are composed of dielectric materials with modest dielectric constants, and are much bigger than the smallest electronic devices for this reason. However subwavelength spatial confinement of light at dimensions down to less than 10% of the free-space wavelength is possible using plasmonic components. Ultimately it may be possible to employ plasmonic components to form the building blocks of a chip-based optical device technology that is scaleable to molecular dimensions, with potential imaging, spectroscopy and interconnection applications in computing, communication and chemical/biological detection. In this talk we will describe recent opportunities presented by plasmonics for chip-scale integration of photonic and electronic devices, including i)design of metal-insulator-metal plasmon waveguides that optimize the trade-off between mode localization and propagation loss in the visible and near-infrared ii) on-chip Si CMOS compatible light near-infrared light sources for coupling into plasmonic networks iii) plasmon-enhanced emission from quantum dots, and iv) opportunities for active plasmonic devices based on electro-optic and all-optical modulation of plasmon propagation.

关键词： Light sources Near infrared radiation Photonic devices Plasmon waveguides Quantum dots Spectroscopy

来源：评论

学校读者我要写书评

暂无评论

Application of THz imaging in security screening

Application of THz imaging in security screening

引用

Frontiers in Optics, FiO 2005

作者： Bandyopadhyay, Aparajita Sengupta, Amartya Barat, Robert B Gary, Dale E Michalopoulou, Zoi-Heleni Federici, John F Department of Physics New Jersey Institute of Technology Newark NJ 07103 United States Otto York Dep't of Department of Chemical Engineering New Jersey Institute of Technology Newark NJ 07103 United States Department of Mathematical Sciences New Jersey Institute of Technology Newark NJ 07102 United States

Non - contact detection of concealed lethal agents using Terahertz radiation is described. Applying interferometric techniques, synthetic images are reconstructed at different frequencies. Aspects affecting image iden... 详细信息

ISBN: (纸本)1557527970

关键词： Terahertz waves

来源：评论

学校读者我要写书评

暂无评论

Chip-scale photonics with flasmonic components

Chip-scale photonics with flasmonic components

引用

International Quantum electronics conference 2005

作者： Atwater, Harry A. Sweatlock, Luke A. Dionne, Jennifer A. Walters, Robert J. Biteen, Julie S. Sungjee, Kim Lezec, Henri Thomas J. Watson Laboratory of Applied Physics California Institute of Technology MS 128-95 Pasadena CA 91125

ISBN: (纸本)078039240X

Since the development of the light microscope in the 16th century, optical device size and performance has been limited by diffraction. Photonic devices of today are composed of dielectric materials with modest dielectric constants, and are much bigger than the smallest electronic devices for this reason. However subwavelength spatial confinement of light at dimensions down to less than 10% of the free-space wavelength is possible using plasmonic components. Ultimately it may be possible to employ plasmonic components to form the building blocks of a chip-based optical device technology that is scaleable to molecular dimensions, with potential imaging, spectroscopy and interconnection applications in computing, communication and chemical/biological detection. In this talk we will describe recent opportunities presented by plasmonics for chip-scale integration of photonic and electronic devices, including i) design of metal-insulator-metal plasmon waveguides that optimize the trade-off between mode localization and propagation loss in the visible and near-infrared ii) on-chip Si CMOS compatible light near-infrared light sources for coupling into plasmonic networks iii) plasmon-enhanced emission from quantum dots, and iv) opportunities for active plasmonic devices based on electro-optic and all-optical modulation of plasmon propagation.

关键词： Chip scale packages

来源：评论

学校读者我要写书评

暂无评论

Demonstration of an uncooled LiTaO3-detector-based differential absorption radiometer for remote sensing of chemical effluents

引用

optical ENGINEERING 2004年第10期43卷 2303-2311页

作者： Holland, SK Krauss, RH Laufer, G Univ Virginia Dept Mech & Aerosp Engn Charlottesville VA 22904 USA Rammatek LLC Charlottesville VA 22901 USA

Differential absorption radiometers (DARs) using uncooled detectors are introduced as a simple method for low-cost remote sensing of chemical vapors for domestic security. A DAR consisting of a pair of uncooled LiTaO3 pyroelectric detectors integrated with bandpass filters selected to detect methanol, a simulant of many hazardous vapors, was demonstrated. At a signal-to-noise ratio (SNR) greater than or equal to5, the measured detection limit for methanol was 0.014 atm cm. This corresponds to a detection limit of 5.70 x 10(-4) atm cm (31.5 Mg m(-2)) for dimethyl methylphosphonate (DMMP). For comparison, a DAR consisting of a pair of cryogenically cooled HgCdTe (MCT) detectors was also tested. The detector-limited noise equivalent temperature differential (NETD) of the MCT detectors was measured to be 0.38 mK, whereas for the pyroelectric detector it was 115 mK. Despite the much lower detector noise, the MCT-based DAR provided a detection limit of only 0.005 atm cm for methanol, corresponding to 2.04 x 10-4 atm cm (11.25 mg m(-2)) for DMMP. The relatively poor sensitivity of the MCT-based DAR was shown to be limited by small temperature gradients of 15 mK across the noncoincident fields of view of the detectors in the DAR and by environmental fluctuations, which contributed a total NETD = 37 mK. (C) 2004 Society of Photo-optical Instrumentation Engineers.

关键词： Sensors Signal detection Absorption Pyroelectric detectors Temperature metrology remote sensing Bandpass filters Infrared sensors Signal to noise ratio Target detection

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：