Rapid matching algorithm for hyperspectral image based on norm sifting

We propose a rapid spectral matching method by lowering number of comparisons, processing time can be saved. Firstly, 1-norm is chosen as length measure of spectrum, and with this criterion, a 1-norm database is built. Secondly, a subspace is constructed from the whole reference library by retaining the references with the most similar 1-norm values. Finally, matching operations are performed in the subspace to obtain the match result. Simulations of geological mapping with ASTER spectral library show that the proposed method can significantly reduce processing time and enhance accuracy compared with traditional and dimension reduction methods.     

基于生物光学算法的海洋赤潮监测

机载海洋激光雷达具有高效搜索的能力,已成为海洋环境监测的重要手段。以机载蓝绿激光雷达监测海洋赤潮为研究应用背景,通过检测海洋中叶绿素的质量浓度来实现对海洋赤潮消长信息的获取。在分析海水固有光学性质的基础上,基于生物光学算法,构建了机载蓝绿激光雷达后向散射信号检测的的叶绿素质量浓度监测模型。仿真计算证明该模型能够有效探测出叶绿素质量浓度的大小,为机载海洋赤潮监测增加了一种方法。     

基于赋权连接图的增量式运动恢复结构算法北大核心CSCD

运动恢复结构算法(structure from motion, SfM)是一种通过计算图像匹配关系,恢复出相机位姿和目标三维结构的重建算法。提出一种基于赋权视角连接图的增量式运动恢复结构算法。首先建立基于图像对立体匹配质量的赋权连接图,量化了图像两两之间的匹配关系;其次在赋权连接图中边的权重的基础上,搜索度数感知的最佳初始种子对;最后根据已重建顶点的连通性构建下一张最佳图像候选集,设计了基于顶点度数与特征点分布的下一张最佳图像评价算法。在公开数据集上实验结果显示,本文算法在重建质量、相机校准率和点云生成数量的表现优于现有先进的运动恢复结构算法,相比基准对比算法,本文算法在不同数据集上平均重建耗时至少降低了19%,点云生成速率至少提升了21%。     

Accuracy analysis on Rayleigh lidar measurements of atmospheric temperature based on spectroscopy

We make a detailed analysis on the linearity and accuracy of the relationship between the full-width at half-height （FWHH） of the atmosphere molecules Rayleigh scattering spectrum and the square root of the atmospheric temperature. A simulation of the FWHH of the atmosphere molecules Rayleigh scattering spectrum is made based on the S6 Atmosphere Model and U.S. Standard Atmosphere Model. The calcu- lated temperature is compared with the initial simulation temperature. The result shows that the FWHH of the atmosphere molecules Rayleigh scattering spectrum is nearly proportional to the atmospheric temperature. The goodness-of-fit index of the fitting curve is 0.9977 and the maximum absolute error of measured atmospheric temperature is about 2 K.     

基于布里渊后向散射的海水温度与盐度同步测量研究

基于布里渊散射信号的检测可实现对海水温度等参量的监测.由于海水的布里渊频移量是关于温度和盐度的二元函数,故无法仅通过布里渊散射频移量的检测实现对海水温度和盐度两个独立变量的精确测定.研究表明布里渊信号的功率也是关于温度和盐度的二元函数,所以文章提出通过测量布里渊频移量和接收布里渊信号功率大小,通过两个二元函数反演出海水的温度与盐度数值,实现对海水温度和盐度两个独立变量的同步测量.     

基于布里渊散射信号检测的大气探测模型

以激光信号在传输介质中的布里渊散射频移量模型为基础,依据相关大气数据建立基于布里渊散射信号检测的大气探测模型。该模型中布里渊频移量只与大气高度相关,详细描述了低空大气范围内布里渊频移量的连续分布状态。结果表明在086 km的海拔高度范围内,大气的布里渊散射频移量分布在1.01.3 GHz之间。与有关数据相比,该模型与实际情况非常符合,同时具有很好的连续性和普适性。     

基于机载激光雷达监测海洋赤潮模型研究

提出了基于机载激光雷达应用于海洋赤潮的监测与预报方法,以检测激光水下后向散射光信号,实现对海洋赤潮藻密度信息的获取.引入赤潮藻散射系数的概念,建立了机载激光雷达的赤潮藻散射系数探测模型.通过仿真计算,证明该模型可以有效评估出赤潮藻密度的大小,进而实现对赤潮消长过程的判断.     

Novel averaging window filter for SIFT in infrared face recognition

The extraction of stable local features directly affects the performance of infrared face recognition algorithms.Recent studies on the application of scale invariant feature transform(SIFT) to infrared face recognition show that star-styled window filter(SWF) can filter out errors incorrectly introduced by SIFT.The current letter proposes an improved filter pattern called Y-styled window filter(YWF) to further eliminate the wrong matches.Compared with SWF,YWF patterns are sparser and do not maintain rotation invariance;thus,they are more suitable to infrared face recognition.Our experimental results demonstrate that a YWF-based averaging window outperforms an SWF-based one in reducing wrong matches,therefore improving the reliability of infrared face recognition systems.     

基于对称变换的人脸图像眼睛定位方法

利用图像灰度分布的特性,从计算对称值的角度出发,利用梯度对称变换,实现了一种自动定位人脸图像中眼睛的算法。经计算机模拟实验表明,它对一定程度的背景干扰以及光照的变化不敏感,对正面人脸且在眼睛张开的情况下,对称变换的定位准确率可以达到95%以上。     

水下无线光OOK信道误码率分析

现有的矢量辐射输运（VRT）理论无法分析有限孔径条件下水下无线光通信信道特征,因此VRT误码率计算结果并不能很好地与实际系统相符。在分析水下光OOK信号激光传输模型的基础上,根据水下有限孔径光信道的特征,对三类海水中可见光水下通信系统的误码率进行了仿真和评估。仿真结果表明,水下光OOK系统可靠视频传输距离上限分别为远洋108m,近海65m和海湾11m,该结果为水下实时高码率激光通信系统设计提供了参考。