干涉光谱数据处理技术研究进展

干涉光谱成像技术是一类同时具有成像、光谱测量功能的新型信息获取技术,由于干涉光谱成像仪获取的数据是目标的干涉数据,是一种中间数据,不能为用户直接所用,必须通过数据处理技术进行处理才能得到高质量的光谱数据,最终为用户所用.文章将干涉光谱数据处理技术分为通用型和专用型两大类,首先介绍了通用型干涉光谱数据处理技术的发展历程,然后针对干涉光谱成像技术的分类,介绍了不同类型干涉光谱数据的提取方式,对近些年来国内外专用型干涉光谱数据处理技术的发展进行了分析介绍.最后,对干涉光谱数据处理技术的发展趋势进行了展望.     

用于拼接子镜相位误差检测的低相干光谱干涉系统分析

针对大口径望远镜拼接式主镜,提出一种基于迈克尔逊干涉原理的低相干光谱干涉检测系统.应用该系统对拼接子镜间相位失调误差进行实时检测,进而对失调子镜进行相应校正,以实现拼接子镜的共面排布.子镜间相位误差通过干涉图形间的不匹配性进行提取.给出了该低相干光谱干涉检测系统的具体结构,叙述了该干涉检测系统的检测原理.针对该系统的干涉条纹对比度V及系统的最低信噪比SNRdBmin进行了分析,论证了通过该低相干光谱干涉检测系统进行子镜间相位误差检测的可行性.     

空间调制干涉光谱成像仪数据误差修正方法

针对空间调制干涉光谱成像仪获取数据的特殊性,提出一种数据误差修正方法,修正了干涉数据的探测器误差和光学系统误差.对于光学系统导致的光场分布不均匀误差,采用多项式拟合的方法从干涉数据中直接获取误差修正数据.利用实际仪器获取的数据对上述方法进行了计算机仿真,得到了较好的误差修正结果.     

基于ROI编码的干涉超光谱图像近无损压缩

针对干涉超光谱成像仪所成图像的特点，提出了一种基于ROI（Region of Interest，感兴趣区域）编码的干涉超光谱图像序列压缩方法.利用帧内差值变换，结合矩形ROI编码，在提高遥感图像压缩比的同时，使压缩后的重建图像质量达到近无损的技术要求.实验结果表明，这种压缩方法在干涉超光谱图像压缩中当相对光谱二次误差为2.04％时，干涉图像的压缩比达到9.66∶1.     

空间调制型干涉光谱成像仪数据压缩方法研究

干涉型光谱成像技术是一种新型的光谱成像技术,近些年来发展迅速。在星载使用时,由于卫星数据传输容量的限制,需要对干涉成像光谱仪获得的原始干涉数据进行压缩,然后经过数据传输,到地面进行解压缩,再进行光谱复原处理,才能交给用户使用,干涉数据的压缩是一项新的技术,国内外很少有专门的文献进行介绍,基于该单位对此技术多年的研究,针对空间调制型干涉光谱成像仪数据的特点,结合环境与灾害监测预报小卫星星座A星超光谱成像仪的数据,提出了一种针对空间调制型干涉成像光谱仪的数据压缩方法,获得了很好的结果。     

对称楔形干涉高光谱成像的光谱复原方法

干涉型高光谱成像技术可以探测目标的空间信息以及光谱特性,在生物医学、材料分析、食品安全和文物考古等领域发挥着重要作用。基于对称楔形干涉腔的高光谱成像方法为光谱探测提供了一种新的技术途径,通过分析系统的干涉原理和工作方式,研究其光谱复原方法。提出干涉图像的校正补偿算法,较好地消除了像面暗斑对光谱复原的影响。针对系统整体推扫的工作方式,研究了基于局部相位相关的快速亚像素图像配准算法,能准确提取目标点干涉数据。对系统光谱传递矩阵进行讨论,提出基于矩阵反演的光谱复原方法。研制原理样机,对场景目标进行光谱成像实验,得到了初步的复原结果。     

一种干涉高光谱图像的3DSPIHT结合ROI压缩算法

针对大孔径静态干涉成像光谱仪的成像特点,提出了一种基于三维小波变换的3DSPIHT算法结合ROI的图像压缩方案.对干涉高光谱图像序列进行了三维非对称离散小波变换.采用ROI方法对主要的光谱系数进行提升,以保护光谱信息.最后,对3DSPIHT算法进行改进,以有效编码干涉高光谱图像的小波变换系数.实验结果表明,该方法在8:1压缩比下可获得大于40dB的峰值信噪比,同时有效地保护了光谱信息.     

空间调制干涉光谱成像仪光谱定标技术研究

为了对干涉光谱成像仪进行光谱定标,针对空间调制该仪器的原理,得出了其光程差和光谱分辨率的计算方法,并分析了仪器的线型函数.在实验中使用多种单色光源(波长范围:450～950 nm)和扩束准直镜(焦距120 mm、口径50 mm)进行光谱定标测试.结果表明:影响实验室光谱定标不确定度的主要因素为d/f的测量误差和标准光谱的误差.     

一种干涉高光谱图像的3DSPIHT结合ROI压缩算法

 针对大孔径静态干涉成像光谱仪的成像特点,提出了一种基于三维小波变换的3DSPIHT算法结合ROI的图像压缩方案.对干涉高光谱图像序列进行了三维非对称离散小波变换.采用ROI方法对主要的光谱系数进行提升,以保护光谱信息.最后,对3DSPIHT算法进行改进,以有效编码干涉高光谱图像的小波变换系数.实验结果表明,该方法在8:1压缩比下可获得大于40 dB的峰值信噪比,同时有效地保护了光谱信息.     

空间调制型干涉光谱成像仪数据处理方法

干涉型光谱成像技术是一种新型的光谱成像技术,近些年来发展迅速。干涉成像光谱仪获得的是间接数据干涉图,不能被用户直接使用,需要进行干涉数据反演处理,包括数据预处理(干涉图修正)、切趾、相位修正、傅里叶变换、光谱辐射定标等一系列复杂的处理,目前国内外尚未有文献对干涉数据处理技术进行全面的分析,文章基于作者单位对此技术多年的研究,针对空间调制型干涉光谱成像仪的数据处理方法,结合环境与灾害卫星超光谱成像仪的数据,提出了一套有效的数据反演方法和流程,获得了很好的数据反演结果。     

Aerial Video Trackers Review

Target tracking technology that is based on aerial videos is widely used in many fields; however, this technology has challenges, such as image jitter, target blur, high data dimensionality, and large changes in the target scale. In this paper, the research status of aerial video tracking and the characteristics, background complexity and tracking diversity of aerial video targets are summarized. Based on the findings, the key technologies that are related to tracking are elaborated according to the target type, number of targets and applicable scene system. The tracking algorithms are classified according to the type of target, and the target tracking algorithms that are based on deep learning are classified according to the network structure. Commonly used aerial photography datasets are described, and the accuracies of commonly used target tracking methods are evaluated in an aerial photography dataset, namely, UAV123, and a long-video dataset, namely, UAV20L. Potential problems are discussed, and possible future research directions and corresponding development trends in this field are analyzed and summarized.     

Binary encoding method to encrypt Fourier-transformed information of digital images

An encoding method is used to encrypt the Fourier-transformed information of a hidden (covert) digital image in an overt image, while the Fourier-transformed information must be encoded with binary codes. All of the pixels in an overt image are classified into five groups that are called identification, type, tracing, dimension, and information codes. Identification codes are used to judge if the overt image contains codes that belong to the proposed encoding method or not; type codes are used to judge the encoding type; tracing codes are used to judge the encoding trace; dimension codes are used to judge the size of the hidden information; and information codes are used to decode the hidden information. Applying the proposed encoding method is rather easy, and host images corresponding to overt images are not needed for decoding work. The experiment has demonstrated four types of encoding for the proposed encoding method to reconstruct covert images without any distortion or only with a little distortion.     

外电场下BN分子的结构及性质

采用QCISD方法研究了BN基态分子在不同场强条件下的稳定构型及激发态性质。分析了外电场对BN分子键长、总能量、能级、谐振频率和红外谱强度以及对BN分子前10个激发态的激发能、振子强度等的影响。结果表明随着正向电场的逐渐增大, BN分子键长先减小后增大;分子总能量则先增大后减小;分子电偶极矩 增大;费米能级和能隙均减小。谐振频率及红外谱强度均随正向电场的增大而增大。由基态到第1激发态的波长减小,激发能增大,而基态至第2-10激发态的波长增大而激发能减小。     

外电场下BN分子的结构及性质

采用QCISD方法研究了BN基态分子在不同场强条件下的稳定构型及激发态性质。分析了外电场对BN分子键长、总能量、能级、谐振频率和红外谱强度以及对BN分子前10个激发态的激发能、振子强度等的影响。结果表明随着正向电场的逐渐增大, BN分子键长先减小后增大;分子总能量则先增大后减小;分子电偶极矩μ增大;费米能级和能隙均减小。谐振频率及红外谱强度均随正向电场的增大而增大。由基态到第1激发态的波长减小,激发能增大,而基态至第2－10激发态的波长增大而激发能减小。     

物理实验中类似图形现象的对比分析

在迈克尔逊干涉实验和牛顿圈干涉实验中，虽然图形类似，但研究问题的出发点、研究方法、物理特征及其变化规律明显不同。本文应用类比的分析方法，从理论上对两个实验进行了系统的比较分析，使学生对两实验从本质上有了清楚的认识。     

Nano organic carbon and soot in turbulent non-premixed ethylene flames

Spectral optical techniques are combined to characterise the distribution of large-molecule soot precursors, nanoparticles of organic carbon, and soot in two turbulent non-premixed ethylene flames with differing residence times. Laser-induced fluorescence, laser-induced incandescence and light scattering are used to define distributions across the particle size distribution. From the scattering and laser-induced emission measurements it appears that two classes of particles are formed. The first ones are preferentially formed in the fuel-rich region of the flame closer to the nozzle, have sizes of the order of few nanometers but are not fully solid particles, because the constituent molecules still maintain their individual identity exhibiting strong broadband fluorescence in the UV. The second class of particles constituted by solid particles, with sizes of the order of tens of nanometers are able to absorb a sufficient number of photons to be heated to incandescent temperatures. These larger particles are formed at larger residence times in the flame since they are the result of slow growth processes such as coagulation or carbonization. The flames are also modeled in order to produce mixture fraction maps. A new discovery is that nanoparticles of organic carbon concentration, unlike soot, does correlate well with mixture fraction, independent of position in the flame. This is likely to be a significant benefit to future modelling of soot inception processes in turbulent non-premixed flames.     

Patterns and Symmetries in the Visual Cortex and in Natural Images

As borders between different entities, lines are an important element of natural images. Indeed, the neurons of the mammalian visual cortex are tuned to respond best to lines of a given orientation. This preferred orientation varies continuously across most of the cortex, but also has vortex-like singularities known as pinwheels. In attempting to describe such patterns of orientation preference, we are led to consider underlying rotation symmetries: Oriented segments in natural images tend to be collinear; neurons are more likely to be connected if their preferred orientations are aligned to their topographic separation. These are indications of a reduced symmetry requiring joint rotations of both orientation preference and the underlying topography. This is verified by direct statistical tests in both natural images and in cortical maps. Using the statistics of natural scenes we construct filters that are best suited to extracting information from such images, and find qualitative similarities to mammalian vision. PACS84.35+i 89.70.+c 87.57.Nk     

Interactions of rare gas cations with lighter rare gas atoms

High-level ab initio calculations are employed to generate potential energy curves for rare gas cations, RG⁺, interacting with neutral atoms of other rare gases, RG′, that are lighter (RG′ = Ne–Rn). The calculations employ the RCCSD(T) method, with doubly-augmented basis sets of quintuple-ζ quality. The interaction potential curves, with the full counterpoise correction applied, are calculated point-by-point. Spin-orbit coupling is applied analytically in an atom-based model. The potentials are used to calculate spectroscopic parameters, which are then compared to recent experimental work, and the very limited previous theoretical work. In addition, the potentials are used to calculate ion transport properties and the ion mobilities are compared to the few experimental data available.