基于混合Contourlet变换和主成分变换的高光谱图像融合

针对高光谱图像波段多、存在噪声干扰等特点,提出了一种混合Contourlet和主成 分 分析（principal component analysis, 简称PCA）变换的高光谱图像融合方法。首先将多 个波段的高光谱图像进行Contourlet变换,得到系列多尺度、方向各异的子带系数,然后利 用PCA变换对各子带系数分别进行自适应融合处理。实验结果表明该算法可以有效地进行高 光谱图像融合,消除噪声干扰,获得比直接应用Contourlet变换和PCA变换更好的融合效果 。〖JP〗     

光电干扰箔片云团运动规律的仿真研究

鉴于自燃箔片云团对红外成像导引头光电干扰有效的试验结果,针对气动阻力大的箔片云团,采取常用的气动阻力公式f=-kv2来描述运动规律,引入匀降速度u,分别推导出水平方向和垂直方向上升段和下降段的速度、位移的计算公式.结合图象分析对云团的运动规律进行仿真研究,还讨论了采用不同气动阻力公式对拟合系数和拟合相似度的影响.该方法可推广应用于大气层内亚声速质点运动轨迹的解析方法.     

海天背景舰船红外目标识别技术研究

通过对舰船红外目标特性与识别方法的讨论,给出了图像序列目标识别算法流程以及仿真实验的结果,并对工程实现自动目标识别的硬件、算法和软件设计进行了讨论,具有较好的理论和应用价值。     

气动热试验中稳态热流测量技术研究

高超声速飞行器热防护系统防热结构、防热材料的地面防热试验研究中,模型表面热流大小是关键参数之一。介绍了防热试验研究中瞬态热流测量技术,详细分析和论述了将红外热图测试技术和水卡量热计测试技术相结合,利用动态换热平衡和能量守恒原理实现防热试验中稳态热流测量的基本理论和测试方法,并给出初步试验结果。该技术的建立,为地面防热材料筛选和材料防热机理研究提供了有效、可行的测试手段。     

飞船返回舱红外跟踪

提出一种联合大底检测的改进的Mean-Shift（均值移位）算法,将其应用于返回舱红外跟踪。新算法采用非均匀量化加权直方图构造目标特征矢量,以提高目标描述的准确性。为避免跟踪到大底上去,使用＂滑窗式＂大底检测算法实时修正Mean-Shift跟踪坐标。通过对飞船返回实况判读验证,提出的新算法处理速度达到20帧/s以上,并且能够可靠和准确地跟踪返回舱。     

细缝裁减和非均匀映射结合的图像自适应方法

采用将细缝裁减和非均匀映射相结合的图像尺寸自适应框架,提出了一种基于内容的图像重要信息变形的度量方法.首先提取原始图像的重要性像素点,利用细缝裁减去掉一条像素细缝后,相应的重要性像素点会被更新.对于图像中保留的重要性像素点,计算它们的子图像平均偏差(ADSI,Average Difference of Sub Images);对于被移除的重要性像素点,计算它们的平均丢失能量(ALE,Average Lost Energy).通过ADSI和ALE可计算出重要信息变形的度量函数(IIDF,Important Information Deformation Function)的值,通过分析IIDF的趋势得到细缝裁减的终止条件,然后改用非均匀映射方法(non-homogeneous warping)将图像自适应到目标尺寸.实验结果证明,新方法处理的结果图像重要区域变形较小,并且计算效率比较高.     

Spiral eddies in the Baltic,Black and Caspian seas as seen by satellite radar data

Despite spiral eddies were first seen on the sea surface more than 40 years ago, there is still a lot of uncertainty concerning these eddies. The present paper is aimed to provide the comprehensive results on the occurrence and statistics of small-scale eddies in the three inner seas (the Baltic, Black and Caspian) using satellite synthetic aperture radar (SAR) images. The dataset used includes over 2000 medium resolution Envisat ASAR and ERS-2 SAR images obtained in 2009–2010 in the different parts of the seas mentioned. As a result of the analysis performed ∼14,000 vortical structures were detected. 71% of them were visualized due to surfactant films (“black” eddies), while 29% due to wave/current interactions (“white” eddies). Practically all the eddies detected were cyclonically rotating. Their diameter was within 1–20 km. Characteristic size of the “black” eddies in all the basins was discovered to be less than that of the “white” eddies. Characteristic eddy size for the Baltic, Black and Caspian seas proved to be strictly proportional to the values of the baroclinic Rossby radius of deformation typical for these basins. The “black” eddies did not demonstrate a significant connection with the basin- and meso-scale surface circulation of the seas. Most of the “white” eddies detected were attributed to the zones with the most intense drift currents, i.e. those along the western boundaries and (in the Baltic Sea only) in the elongated parts of the basin.     

Relationships between soil properties of the abandoned fields and spectral data derived from the advanced spaceborne thermal emission and reflection radiometer (ASTER)

The structural transformation of Polish agriculture after 1989 has been leading to significant changes in land use. As a result a large part of formerly ploughed fields lies abandoned and they occur across considerable variability in soil typological units. Accurate information about soil conditions within the abandoned fields facilitates proper management in the new socio-economic situation. Such information can be collected using satellite images since the structure and condition of the vegetation growing on the abandoned fields reflects soil properties. The objective of this study is to evaluate the relationships between physical and chemical attributes of soil within the abandoned fields and spectral reflectance patterns recorded by ASTER sensors onboard Terra Satellite. Soil samples were collected at five abandoned fields which have not been ploughed since 2000 and analyzed in the laboratory to determine their physical and chemical properties. Nine ASTER nearly cloud-free pictures were used for this study in order to derive the remote-sensing attributes of the abandoned fields. In order to evaluate the relationships between soil fertility and remotely sensed data, partial least-squares (PLS) and a multiple linear regression (MLR) analysis between these two datasets were carried out. In the regression analysis, only soil TEB (total exchangeable bases) stock in the whole profile displayed the highest correlation with remotely sensed data acquired in April and May and the best predictors were NDVI and LSWI vegetation indices.     

进动锥体目标散射特性仿真及实验分析

目标微动及结构参数的获取有助于弹道目标的识别。准确获得进动锥体目标散射特性的时频分布(TFD)、一维距离像及二维逆合成孔径雷达(ISAR)像分布是获取锥体目标微动及结构参数的关键。分析了进动锥体在窄带及宽带条件下的目标散射特性,总结了锥体目标强散射源在时频分布、距离像序列和ISAR像序列中的理论表现形式,并分析了存在锥面镜面散射时锥体目标散射特性,构建了进动锥体目标电磁回波仿真方法及微波暗室动态测试系统,通过仿真及测试数据得到了典型条件下锥体目标的散射特性,对比表明仿真及测试结果均与本文散射特性理论分布相一致,说明了本文所提散射特性理论分布与散射特性分析方法的正确性,可为分析弹道目标散射特性研究提供参考。