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1.
为使高光谱成像技术能够在大幅面绘画类文物研究和保护中充分发挥面分析的优势,研制了大幅面高光谱扫描系统,同时建立了传统颜料数据库。与以往高光谱成像技术对文物进行的局部分析相比,该系统不仅提高了分析效率,而且可对绘画文物整体进行颜料鉴别和相对浓度分布研究,可以为绘画中复杂调色工艺的研究提供巨大的帮助。目前,已使用该系统对故宫博物院东华门天花彩画、纸本书画《丁观鹏画不二尊者图轴》、绢本书画《沈庆兰画贴落》和唐卡《吉祥天母画佛像》进行分析研究,并将其用于文物隐藏病害、隐藏墨迹、底稿线等信息的提取与增强,颜料成分鉴别和混合颜料工艺研究等方面,取得了良好的效果,对绘画类文物的研究与保护具有重要的意义。 相似文献
2.
为了深入开展航空光学测绘装备的研制,通过文献调研对该领域主流装备系统的产品性能、系统配置、发展趋势以及关键技术进行研究。研究表明,5~6μm的5~20 k大面阵多光谱数字相机是目前测绘相机的主流配置。机载LiDAR(light detection and ranging)已发展成为航空测绘装备系统的重要一员,数千米工作高度下的测量精度可达厘米级别,最大测量速度优于250 kHz。为满足更多新兴测绘任务需求,达到优势互补效果,测绘相机与机载LiDAR相结合已成为必然趋势。以30~50 k超大面阵测绘相机为主,机载LiDAR、高光谱成像设备相结合的多传感器测绘平台,是未来的重要发展方向。在高性能多传感器航空光学测绘平台搭建中,存在LiDAR数据效率提升、视场拼接、像移补偿、数据处理等多项关键技术。 相似文献
3.
J. B. Varesi A. A. Buell R. E. Bornfreund W. A. Radford J. M. Peterson K. D. Maranowski S. M. Johnson D. F. King 《Journal of Electronic Materials》2002,31(7):815-821
We are continuing to develop our growth and processing capabilities for HgCdTe grown on 4-in. Si substrates by molecular beam
epitaxy (MBE). Both short-wave and mid-wave infrared (SWIR and MWIR) double-layer hetero-junctions (DLHJs) have been fabricated.
In order to improve the producibility of the material, we have implemented an in-situ growth composition-control system. We
have explored dry etching the HgCdTe/Si wafers and seen promising results. No induced damage was observed in these samples.
Detector results show that the HgCdTe/Si devices are state-of-the-art, following the diffusion-limited trend line established
by other HgCdTe technologies. Focal-plane array (FPA) testing has been performed in order to assess the material over large
areas. The FPA configurations range from 128×128 to 1,024×1,024, with unit cells as small as 20 μm. The MWIR responsivity
and NEDT values are comparable to those of existing InSb FPAs. Pixel operabilities well in excess of 99% have been measured.
We have also explored the role of growth macrodefects on diode performance and related their impact to FPA operability. The
SWIR HgCdTe/Si shows similar results to the MWIR material. Short-wave IR FPA, median dark-current values of less than 0.1
e−/sec have been achieved. 相似文献
4.
提出了整体复合阈值方法,成功实现了高精度图像高速/高品质矢量化转换,制作了首台基于多线阵CCD的大幅面拼接型高精度一次性成像扫描仪。实验及测试结果表明:制作的大幅面扫描仪最大幅面为A0,分辨率高达1200dpi,扫描速度达到2.54cm/s,扫描后拼接精度能达到±3pixel,单张高分辨率图像最大容量达到5Gbit左右,并在此大容量图像条件下,高速/高品质矢量化转换得以有效实现,1.4Gbit容量时,时长控制在了0.4s以内。大容量高速高品质矢量化转换在大幅面扫描装备的成功实施,解决了在基于多线阵CCD的大幅面拼接性高精度一次性成像扫描仪的诸多难题,填补了该领域的应用空白。 相似文献
5.
M. F. Vilela A. A. Buell M. D. Newton G. M. Venzor A. C. Childs J. M. Peterson J. J. Franklin R. E. Bornfreund W. A. Radford S. M. Johnson 《Journal of Electronic Materials》2005,34(6):898-904
Middle wave infrared (MWIR) HgCdTe p-on-n double-layer heterojunctions (DLHJs) for infrared detector applications have been
grown on 100-mm Si (112) substrates by molecular beam epitaxy (MBE) for large format 2,560×512 focal plane arrays (FPAs).
In order to meet the performance requirements needed for these FPAs, cutoff and doping uniformity across the 100-mm wafer
are crucial. Reflection high-energy electron diffraction (RHEED), secondary ion mass spectrometry (SIMS), Fourier transform
infrared spectrometry (FTIR), x-ray, and etch pit density (EPD) were monitored to assess the reproducibility, uniformity,
and quality of detector material grown. Material properties demonstrated include x-ray full width half maximum (FWHM) as low
as 64 arc-sec, typical etch pit densities in mid-106 cm−2, cutoff uniformity below 5% across the full wafer, and typical density of macrodefects <1000 cm−2. The detector quality was established by using test structure arrays (TSAs), which include miniarray diodes with the similar
pitch as the detector array for easy measurement of critical parameters such as diode I-V characteristics and detector quantum
efficiency. Typical I-V curves show excellent R0A products and strong reverse breakdown characteristics. Detector quantum efficiency was measured to be in the 60–70% range
without an antireflection coating. 相似文献
6.
Performance of molecular-beam epitaxy-grown midwave infrared HgCdTe detectors on four-inch Si substrates and the impact of defects 总被引:4,自引:0,他引:4
J. B. Varesi A. A. Buell J. M. Peterson R. E. Bornfreund M. F. Vilela W. A. Radford S. M. Johnson 《Journal of Electronic Materials》2003,32(7):661-666
We are continuing development of the growth of midwave infrared (MWIR) HgCdTe by molecular-beam epitaxy (MBE) on 4-in. Si
substrates and the fabrication of state-of-the-art detectors and focal plane arrays (FPAs). Array formats of up to 2048 ×
2048 and unit cells as small as 20 μm have been made. We regularly measure response operability values in excess of 99% on
these arrays. These values typically exceed expectations, with the number of outages corresponding to as-grown defect densities
four times lower than what we measure. We have investigated this operability discrepancy and now can account for it. Comparisons
of measured properties were used to establish trends between defect occurrence and pixel operability. These correlations show
that a combination of defect removal and low-impact defects provide the explanation. Having this knowledge will allow for
better operability predictions and assist in efforts to reduce defect impact on FPA performance. 相似文献
7.
8.
J. B. Varesi R. E. Bornfreund A. C. Childs W. A. Radford K. D. Maranowski J. M. Peterson S. M. Johnson L. M. Giegerich T. J. de Lyon J. E. Jensen 《Journal of Electronic Materials》2001,30(6):566-573
We have developed the capability to grow HgCdTe mid-wave infrared radiation double-layer heterojunctions (MWIR DLHJs) on 4″
Si wafers by molecular beam epitaxy (MBE), and fabricate devices from these wafers that are comparable to those produced by
mature technologies. Test data show that the detectors, which range in cutoff wavelength over 4–7 μm, are comparable to the
trendline performance of liquid phase epitaxy (LPE)-grown material. The spectral characteristics are similar, with a slight
decrease in quantum efficiency attributable to the Si substrate. With respect to R0A, the HgCdTe/Si devices are closer to the theoretical radiative-limit than LPE-grown detectors. Known defect densities in
the material have been correlated to device performance through a simple model. Slight 1/f noise increases were measured in
comparison to the LPE material, but the observed levels are not sufficient to significantly degrade focal plane array (FPA)
performance. In addition to discrete detectors, two FPA formats were fabricated. 128×128 FPAs show MWIR sensitivity comparable
to mature InSb technology, with pixel operability values in excess of 99%. A 640×480 FPA further demonstrates the high-sensitivity
and high-operability capabilities of this material. 相似文献
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10.
森林防火的关键是通过火灾实时监测系统有效预测森林各区域的火灾风险。通过分析无人机在森林防火中的应用,提出了一种基于无人机的森林火灾实时监测中波红外相机系统。该系统的焦距为75 mm,工作波段为3.7~4.8 μm,F数为2.0,可匹配像元尺寸为12 μm×12 μm的1280×1024元制冷型中波红外焦平面阵列探测器。在光学设计中采用3种红外光学材料(硅、硒化锌和锗)的组合,并引入3个偶次非球面。通过优化设计实现了光学被动无热化功能。设计结果表明,在-60~100℃温度范围内,空间频率41.7 lp/mm处各视场的调制传递函数(Modulation Transfer Function, MTF)均大于或接近0.4,成像质量良好。这种中波红外系统的成像质量与分辨率高,视场范围大,具有宽温度范围的自适应性,结构紧凑且易装调,在森林防火领域有着广泛的应用前景。 相似文献