基于几何矩预分类的无人机遥感图像自动配准方法

图像配准技术是近些年来图像处理领域发展迅速的研究方向之一.在遥感领域内,图像配准更是实现图像融合、运动检测、图像校正、图像拼接等应用的一个关键步骤.尽管国内外目前在图像配准方面提出了很多方法,但不同方法适用的图像范围不同,很多时候需要人工干预进行方法的选择.尤其对于无人机这种快速、实时获取图像的新型遥感平台,如何集合不同方法的优点以实现图像自动配准成为了关键性问题.本文在比较分析了基于SIFT和SURF特征提取图像配准方法的各自优势后,提出基于几何矩的方法对图像进行预先分类,从而决定将其分配给何种方法进行配准,实现全程自动化.实验证明,这种图像自动配准方法在拓宽了图像应用范围的同时保证了良好的配准效果.     

无人机多光谱传感器场地绝对辐射定标研究

2010年10月14日无人机遥感载荷验证场科学实验在内蒙古乌拉特前旗展开,这是我国首个航空遥感定标验证场的首次科学实验。通过验证场实验数据及制作的朗伯特性好的六块高光谱辐射特性靶标,采用反射率基法对搭载在无人机平台上的宽视场多光谱相机进行了场地绝对辐射定标。结果显示,对于成功获取影像的绿光、红光及近红外通道的绝对定标结果中,计数值(DN值)与辐射传输计算得出的表观辐亮度之间的线性相关系数优于99%。经误差分析得到不确定度为5.19%,优于验证场课题要求的6%。定标结果表示,验证场所配备之高光谱辐射特性靶标适用于机载多光谱载荷的场地绝对定标,且定标结果可靠,可以用于地物参数的反演。     

Topological phase boundary in a generalized Kitaev model

We study the effects of the next-nearest-neighbor hopping and nearest-neighbor interactions on topological phases in a one-dimensional generalized Kitaev model. In the noninteracting case, we define a topological number and calculate exactly the phase diagram of the system. With addition of the next-nearest-neighbor hopping, the change of phase boundary between the topological and trivial regions can be described by an effective shift of the chemical potential. In the interacting case, we obtain the entanglement spectrum, the degeneracies of which correspond to the topological edge modes, by using the infinite time-evolving block decimation method. The results show that the interactions change the phase boundary as adding an effective chemical potential which can be explained by the change of the average number of particles.     

Vertical GaN Shottky barrier diode with thermally stable TiN anode

Vertical GaN Schottky barrier diodes with Ti N anodes were fabricated to investigate the electrical performance. The turn-on voltage and specific on-resistance of diodes are deduced to be approximately 0.41 V and 0.98 m?·cm2, respectively.The current-voltage curves show rectifying characteristics under different temperatures from 25℃ to 200℃, implying a good thermal stability of Ti N/Ga N contact. The low-frequency noise follows a 1/f behavior due to the multiple traps and/or barrier inhomogeneous at Ti N/Ga N interface. The trapping/de-trapping between traps and Fermi level causes the slight capacitance dispersion under reverse voltage.     

汉传佛教寺院声环境安静度评价及其影响因素研究*

本文通过在4个汉传佛教寺院的调查和分析,对寺院声环境安静度评价及其主客观影响因素进行研究。首先实地测量各寺院的总体声环境,并针对寺院声环境及安静度评价的各个因素,在寺院内发放调查问卷。研究结果表明4个寺院全天平均声级差别不大,70%的人对寺院声环境总体评价为安静或比较安静。客观因素中实测A声级和不同寺院环境同声安静度评价显著相关,当寺院的声级超过61dBA时大部分人会有造成吵闹的感觉,且声级和安静度评价的相关性大幅提高。被调查者特征中年龄、职业、教育程度、信仰因素同其对寺院内声安静度评价显著相关,性别和来寺院的次数对声安静度评价没有显著相关。