A Reducing Saturation Method for DMSP/OLS Nighttime Light Image Combining Landsat Data

Defense Meteorological Satellite Program/Operational Linescan System(DMSP/OLS)is one of the data sources,which can effectively reflect human activities of earth surfaces.During the past decade,DMSP/OLS had been extensively applied in urban extraction and extension study.In the recent year,the Vegetation Adjusted NTL Urban Index(VANUI)has been proposed and had proven to be a simple,convenient and high precision desaturation index to extract urban area.In VANUI method,negative values of imagery were directly eliminated to remove water body,which not only removed the bridge over the river and building but also extracted the aquaculture areas along the coast,thus,this method reduced the extraction accuracy.This paper proposed a new index\|RwNTLI,combining DMSP/OLS nighttime light data and the vegetation index (NDVI)and water index (MNDWI)which were constructed by Landsat data.In this study,Guangzhou was taken as experimental area.By comparing the VANUI index with the ability to identify ground objects as well as the ability to alleviate saturation regions,the result showed RwNTLI index could effectively solve the problem of VANUI as well as eliminate saturation effect of nighttime light imagery.Among them,the correlation between RwNTLI index and RCNTL is better than that of VANUI index and RCNTL.Therefore,RwNTLI index is a simple and effective index of luminous desaturation,which has more advantages than VANUI index in describing the characteristics of night lights of urban areas and will have higher application value in urban built\|up areas in the future.     

Analyzing Regional Inequality of Socioeconomic Development in China with Nighttime Light

Satellite\|derived nighttime light (NTL)data have been extensively used as an efficient proxy measure for monitoring urbanization dynamics and socioeconomic activity.This is because remotely sensed NTL signals can be quantitatively connected to demographic and socioeconomic variables.The recently composited cloud\|free NTL imagery derived from the Visible Infrared Imaging Radiometer Suite (VIIRS)provides spatially detailed observations of human settlements.We quantitatively estimated socioeconomic development inequalities across 30 provinces andmunicipalities in mainland China using VIIRS NTL data associated with both regional gross domestic product (GDP)and population census data.We quantitatively investigated relations between NTL,GDP,and population using a linear regression model.Our results suggest that NTL have significant positive correlations with GDP and population at different levels.Several inequality coefficients were derived from VIIRS data and statistical data at multiple spatial scales.NTL\|derived inequality coefficients enabled us to elicit more detailed information on differences in regional development at multiple levels.Our study of provinces and municipalities revealed that county\|level inequality was more significant than city\|level.The results of population\|weighted NTL inequality indicate an obvious regional disparity with NTL distribution being more unequal in China’s undeveloped western regions compared with eastern regions.Our findings suggest that given the timely and spatially explicit advantages of VIIRS,NTL data are capable of providing comprehensive information regarding inequality at multiple levels,which is not possible through the use of traditional statistical sources.     

一种改进的DCT域数字音频水印算法

针对现有数字音频水印算法不能同时满足隐蔽性与鲁棒性的问题,在添加水印之前,先将水印的二值图像与随机密钥进行加密操作,再对载体进行三级小波变化和DCT变换,最后对比加密后的水印信息与载体信号,得到密钥值,并将密钥嵌入到载体音频的DCT中频系数中。实验结果表明,该算法能在隐蔽性和鲁棒性之间达到一个较好的平衡。     

Efficient region-aware large graph construction towards scalable multi-label propagation

With fast growing number of images on photo-sharing websites such as Flickr and Picasa, it is in urgent need to develop scalable multi-label propagation algorithms for image indexing, management and retrieval. It has been well acknowledged that analysis in semantic region level may greatly improve image annotation performance compared to that in the holistic image level. However, region level approach increases the data scale to several orders of magnitude and proposes new challenges to most existing algorithms. In this work, we present a novel framework to effectively compute pairwise image similarity by accumulating the information of semantic image regions. Firstly, each image is encoded as Bag-of-Regions based on multiple image segmentations. Secondly, all image regions are separated into buckets with efficient locality-sensitive hashing (LSH) method, which guarantees high collision probabilities for similar regions. The k-nearest neighbors of each image and the corresponding similarities can be efficiently approximated with these indexed patches. Lastly, the sparse and region-aware image similarity matrix is fed into the multi-label extension of the entropic graph regularized semi-supervised learning algorithm [1]. In combination they naturally yield the capability of handling large-scale dataset. Extensive experiments on NUS-WIDE (260k images) and COREL-5k datasets validate the effectiveness and efficiency of our proposed framework for region-aware and scalable multi-label propagation.     

基于Xilinx System Generator的PID算法快速硬件实现

介绍了利用Xilinx System Generator平台构建模型化数字PID控制算法,并通过FPGA将数字PID算法结合传感器与实际硬件控制对象快速建立控制模型,构成完整的闭环控制。通过对控制效果的实验验证,证明了其控制方法的可行性。     

一种JPEG图像的DCT域隐写分析方法

提出了一种基于JPEG图像DCT系数差分矩阵统计特征的隐写分析方法。该算法保留了以往算法选用的DCT系数水平和竖直方向的差分矩阵相关特征,通过增加其主副对角线方向上差分矩阵来提取和计算特征向量,进而利用SVM分类器进行分类。实验结果表明,该方法能够有效地对JPEG图像进行检测,并且具有较高的检测正确率。     

基于WebKit的嵌入式浏览器关键技术研究与实现

随着嵌入式设备的大量普及,具有自主知识产权嵌入式浏览器的研究也逐步深入.通过对WebKit的基本框架的分析,研究了其关键技术,并针对特定的硬件平台进行了移植和裁剪,实验表明该研究为自主知识产权浏览器的开发提供了重要的参考价值.     

使用Visual C++实现多媒体电子出版物中的矢量电子地图

该文介绍在基于光盘的多媒体电子出版物中实现矢量电子地图的关键技术。使用VisualC＋＋和面向对象的方法实现了一个矢量电子地图引擎。     

基于图像特征配准的数字血管减影算法

数字减影血管成象(DSA)是一种在医学诊断以及介入治疗中起重要作用的技术。在临床应用中,由于能源能量的波动、设备噪声、病人移动、器官蠕动等,通常的数字减影结果常常出现伪影。伪影消除问题成为数字减影技术中的难点,也是引起关注的热点。文章提出了消除伪影的一套新的算法———基于图像局部特征消除伪影。包括建立排除模板、控制点判定准则与方法、位移向量优化、配准方法等。该方法已用VC编制成软件,并且装备数字化X-射线装置,在计算机试验及临床实验中都取得了满意的效果。     

防火墙及其安全策略

本文论述了Firewall技术的基本特征及安全方面的策略。