Quantitative Relationship Between Multi-Angle Polarized Reflectance and BRDF of Rock

1 IntroductionWhile the multi-spectral, multi-temporal andhyper-spectral remote sensing data are applied toenhance the ability to recognize the targets onground, more and more investigators have realizedthe influence and contribution of the angle informa-tion, namely the 3D spectrum characteristics of thetargets in 2π space, for recognizing and classifyingimages in remote sensing. The traditional unidirec-tional remote sensing can only obtain one directionprojection of targets; therefore it l…     

探地雷达探测隐伏岩溶的可行性与实例分析

介绍了探地雷达在地下介质中的传播原理,对影响探测工作的关键参数进行了分析;论证了探地雷达探测隐伏岩溶的可行性,结合现场实例总结出不同形态的隐伏岩溶在雷达剖面图上的波形特征,讨论了现场探测工作中应注意的一些问题.实践证明,应用探地雷达探测隐伏岩溶是一种快速、高效、经济、可靠的物探方法.     

半导体材料少子寿命测试仪的研制开发

少数载流子寿命(简称少子寿命)是半导体材料的一项重要参数，它对半导体器件的性能、太阳能电池的效率都有重要的影响。我们采用微波反射光电导衰减法研制了一台半导体材料少子寿命测试仪，本文将对测试仪的实验装置、测试原理及程序计算进行了较详细的介绍，并与国外同类产品的测试进行比较，结果表明本测试仪测试结果准确、重复性高，适合少子寿命的实验室研究和工业在线测试。     

Comparison of Particle Size Distributions Measured Using Different Techniques

In this article, particle size distributions (PSDs) measured by different techniques, including image analysis (IA), laser diffraction (LD), ultrasonic attenuation spectroscopy (UAS), and focused-beam reflectance measurement (FBRM), are compared for spherical glass beads and nonspherical silica flakes. It is shown that particle shape strongly affects the results obtained by different techniques. For spheres, the PSDs obtained by IA, LD, and UAS agree well. There is no consistent result among different particle measurement techniques for nonspherical particles. The conversion between PSDs obtained by IA, LD, and UAS has been based on particle shape factors. Caution must be exercised when a measured chord length distribution (CLD) is used to indicate the PSD during a process because the CLD result obtained by FBRM is complex, depending not only on the PSD, but also on particle optical properties and shape.     

Estimation of vegetation water content and photosynthetic tissue area from spectral reflectance: a comparison of indices based on liquid water and chlorophyll absorption features

Because of the high water content of vegetation, water absorption features dominate spectral reflectance of vegetation in the near-infrared region of the spectrum. In comparison to indices based on chlorophyll absorption features (such as the normalized difference vegetation index (NDVI)), indices based on the water absorption bands are expected to “see” more deeply into thick canopies and have a preferential sensitivity to thin as opposed to thick tissues. These predictions are based on the much lower absorption coefficients for water in the short wavelength water bands as compared to chlorophyll. Thus, the water bands may have advantages over NDVI for remote sensing of photosynthetic tissues. Previous studies have primarily related water band indices (WI) to leaf area index (LAI). Here we expand the definition of photosynthetic tissues to include thin green stems and fruits and measure a wide range of species to determine the influence of variable tissue morphologies and canopy structures on these relationships. As expected, indices based on reflectance in the water absorption bands in the near infrared were best correlated with the water content of thin tissues (less than 0.5-cm thickness). The choice of wavelength for a water index was much more important for thick than for thin canopies, and the best wavelengths were those where water absorptance was weak to moderate. We identified three wavelength regions (950-970, 1150-1260 and 1520-1540 nm) that produced the best overall correlations with water content. Comparison of these wavelength regions with the atmospheric “windows” where water vapor absorption is minimal suggests that the 1150-1260 and 1520-1540 nm regions would be the best wavelengths for satellite remote sensing of water content. We also developed and tested a new Canopy Structure Index (CSI) that combines the low absorptance water bands with the simple ratio vegetation index (SR) to produce an index with a wider range of sensitivity to photosynthetic tissue area at all canopy thicknesses. CSI was better than either WI or SR alone for prediction of total area of photosynthetic tissues. However, SR was best for prediction of leaf area when other green tissues were excluded. All of these relationships showed good generality across a wide range of species and functional types.     

Simulation of hyperspectral and directional radiance images using coupled biophysical and atmospheric radiative transfer models

Future remote sensing satellite missions exploring the earth will feature advanced hyperspectral and directional optical imaging instruments. Given the complex nature of the data to be expected from these missions, a thorough preparation for them is essential and this can be accomplished by realistic simulation of the imagery data, years before the actual launch. Based on given spectral and directional capabilities of the instrument, and in combination with biophysical land surface properties obtained from existing imagery, the spectral and directional responses of several types of vegetation and bare soil have been simulated pixel by pixel using the radiative transfer models PROSPECT (for hyperspectral leaf reflectance and transmittance), GeoSAIL (for two-layer canopy bidirectional spectral reflectance), and MODTRAN4 (for atmospheric hyperspectral and directional effects). In this way, one obtains realistically simulated hyperspectral and directional top-of-atmosphere spectral radiance images, with all major effects included, such as heterogeneity of the landscape, non-Lambertian reflectance of the land surface, the atmospheric adjacency effect, and the limited spatial resolution of the instrument. The output of the image simulations can be used to demonstrate the capabilities of future earth observation missions. In addition, instrument specifications and image acquisition strategies might be optimized on the basis of simulated image analysis results, and new advanced data assimilation procedures could be validated with realistic inputs under controlled circumstances. This paper describes the applied methodology, the study area with the input images, the set-up of the actual image simulations, and discusses the final results obtained.     

泛光照明中光源光色与节能研究

泛光照明中，被照体的亮度大小、颜色变化等视觉效果不但与电光源的功率和光色有关，而且还与物体色（即光谱反射比）等有关，所以在进行照明设计时，应选择光源色和物体色相匹配的光源，这样才有可能使泛光照明效果较好，而且达到照明节能的目的。     

不同含水量黄棕壤反射光谱特征研究

采用多光谱辐射仪(MSR～16R)对自然条件下不同水分含量黄棕壤光谱特征进行了研究，试验结果表明在可见光部分(460～710nm)，土壤含水量与光谱反射率相关性差，而在红外部分(760～1650nm）土壤含水量与光谱反射率达到极显著负相关，模式方程拟合度都在0．86以上，因此通过测定土壤光谱反射率来推算土壤含水量是可行的。应用地面光谱测量试验的结果，本文讨论了由地面光谱测量来推算土壤含水量向由卫星遥感影像反演土壤含水量过渡的可能性，进而对采用TM遥感影像对黄棕壤分布区土壤水分状况实施遥感监测的可行性作了一些探访。     

Automated metrology system including VUV spectroscopic ellipsometry and X-ray reflectometry for 300 mm silicon microelectronics

Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. Instrumentation for the next generation of VUV lithography at 157 nm requires special optical setup since O₂ and H₂O are extremely absorbing below 190 nm. A new system has been developed which works into a purged glove box to reduce the oxygen and water contamination in the part per million range. Ellipsometric and photometric measurements vs. wavelength and angle of incidence can be performed. Grazing X-ray option has been added on the same instrument to provide a better picture of the analyzed samples. This paper presents in detail the new system with its two measurement methods, and includes experimental results gate dielectrics layers and high k dielectrics.