分块DPCM与5/3整数小波变换结合的天文图像无损压缩     

朱贵富  邓辉  王锋  季凯帆 《天文研究与技术》2011,8(1)

针对海量的天文图像数据与有限的存储空间和带宽资源之间矛盾日益突出这一问题,提出一种无损压缩方法,首先将超大天文图像分块,再使用差分脉冲编码调制和5/3整数小波变换,最后使用霍夫曼算法编码。对该方法的原理和具体实现做了详细的分析与介绍,通过实验验证该方法比天文中常用的tar、PKZip、WinZip、WinRar软件在压缩比上分别提高了30%、29%、26%、2%,压缩速度远大于WinZip和WinRar;且该算法实现简单,适合硬件实现和利于并行处理。  相似文献   

月表虹湾Hurst指数分析          下载免费PDF全文

奚晓旭  刘少峰  韦蔚  李珂  焦中虎  李力 《地学前缘》2012,19(6):137-143

月球遥感是在登月技术还不完善的情况下,利用遥感数据,通过各种分析来研究月球演化、内部结果和表面特征的方法。粗糙度是地表隆升、沉降、侵蚀和火山喷射物覆盖在行星表面留下的记录,因此对行星表面粗糙度的定量分析可以精确反映其地质演化过程。而Hurst指数则是粗糙度的精确反映。文中利用LOLA制作的DEM,以月球正面虹湾为例,选取水平方向的12条剖面和垂直方向的15条剖面对其各粗糙度参数进行计算,并结合月表成熟度对Hurst指数与底层年龄的相关性进行了分析,得出如下结论:(1)在1km的剖面长度上,虹湾地区均方根高程的平均值在3m左右;在0.2～3km研究尺度范围内,虹湾地区的坡度不超过2°,说明该地表起伏度小。(2)虹湾地区的Hurst指数跨度比较大,尤其在垂直方向(南北)上,在0.4到0.9之间,表明其构造样式丰富。(3)在0.2～3km研究尺度范围内,Hurst指数自北往南增大、自西往东增大,表示在虹湾地区粗糙度自西北向东南方向增大。(4)虹湾地区地质年龄为自西北向东南方向变小,与Hurst指数增大方向一致。(5)在月表年轻撞击坑地区月表成熟度与Hurst指数大致呈负相关关系。  相似文献   

High-contrast coronagraph for ground-based imaging of Jupiter-like planets     

Jiang-Pei Dou    De-Qing Ren    Yong-Tian Zhu  National Astronomical Observatories / Nanjing Institute of Astronomical Optics & Technology  Chinese Academy of Sciences  Nanjing  China  Key Laboratory of Astronomical Optics & Technology  Nanjing Institute of Astronomical Optics & Technology  China Physics & Astronomy Department  California State University Northridge  Nordhoff Street  Northridge  California – 《中国天文和天体物理学报》2010,10(2)

We propose a high-contrast coronagraph for direct imaging of young Jupiter-like planets orbiting nearby bright stars. The coronagraph employs a steptransmission filter in which the intensity is apodized with a finite number of steps with identical transmission in each step. It should be installed on a large ground-based telescope equipped with a state-of-the-art adaptive optics system. In this case, contrast ratios around 10-6 should be accessible within 0.1 arcsec of the central star. In recent progress, a...  相似文献   

The CCD photometric study of the newly identified RS CVn binary star DV Piscium     

Liyun Zhang  Xiliang Zhang  Zhongzhong Zhu 《New Astronomy》2010,15(4):362-366

This paper presents new CCD BVRI light curves of the newly discovered RS CVn eclipsing binary star DV Psc. From the asymmetric light curves outside the eclipse, we find there are two depressions in the phase ranges 0.3–0.45 and 0.6–0.9, respectively. By analyzing the light curves using the Wilson–Devinney program, the four photometric solutions of the system are obtained and the starspot parameters are also derived. It turns out that the case of two spots being on the primary is most successful in reproducing the light curve distortion of DV Psc. Moreover, analysis the longitudes of spots suggests that there are two active longitude belts (one is about 90°, the other is about 270°). At the same time, on 22 November 2008, the first flare-like event was detected on DV Psc at phase 0.35 whose duration was about 13.5 min. These findings reveal that DV Psc has a high degree of magnetic activity.  相似文献   

Scientific Objectives of China-Russia Joint Mars Exploration Program YH-1     

Ji Wu  Guang-Wu Zhu  Hua Zhao  Chi Wang  Lei Li  Yue-Qiang Sun  Wei Guo  Cheng-Li Huang 《Chinese Astronomy and Astrophysics》2010

Compared with other planets, Mars is a planet most similar with the earth and most possible to find the extraterrestrial life on it, and therefore especially concerned about by human beings. In recent years, some countries have launched Mars probes and announced their manned Mars exploration programs. China has become the fifth country in the world to launch independently artificial satellites, and the third country able to carry out an independent manned space program. However, China is just at the beginning of deep space explorations. In 2007, China and Russia signed an agreement on a joint Mars exploration program by sending a Chinese micro-satellite Yinghuo-1 (YH-1) to the Mars orbit. Once YH-1 enters its orbit, it will carry out its own exploration, as well as the joint exploration with the Russian Phobos-Grunt probe. This paper summarizes the scientific background and objectives of YH-1 and describes briefly its payloads for realizing these scientific objectives. In addition, the main exploration tasks of YH-1 and a preliminary prospect on its exploration results are also given.  相似文献   

The Key Techniques and Design Features of YH-1 Mars Probe     

Chang-Ya Chen  Jian-Wen Hou  Guang-Wu Zhu 《Chinese Astronomy and Astrophysics》2010

In this paper, the function and composition as well as the key techniques (ultra-long distance communication, attitude determination and control, thermal control, ultra-low temperature acclimatization, etc.) of China's first Mars probe are analyzed. In combination with practical engineering conditions, the solutions of these key techniques are given. The design features of the probe are summarized, as a reference for developing the probes of the subsequent related missions in China.  相似文献   

基于影像和矢量数据的三调界线数据更新方法     

彭云璐  王新鹏  王晶晶  翟曦  赵婷婷  邸欣丽 《北京测绘》2022,36(4):423-428

针对第三次全国国土调查界线数据存在的拓扑不一致问题,基于影像和矢量数据,通过构建拓扑规则,对不同来源、不同时期的三调界线数据进行质量检查与更新,并针对更新中出现的11类特殊问题,分别给出了不同的处理方法.基于以上方法完成了第三次全国国土调查行政区域界线、零米线等矢量数据的更新工作.  相似文献   

杭州L波段和59-701高空探测系统资料对比分析   总被引：1，自引：0，他引：1  

朱兰娟  华行祥 《气象科技》2007,35(5):750-754

为比较L波段高空探测系统和59-701高空探测系统的资料异同,采用平均差、均方差比较的方法分析了杭州站平行观测一个月资料的温压湿资料,比较其异同及产生原因,为更好利用高空探测资料、改进L波段高空探测系统提供参考。通过比较发现:L波段高空探测系统比59-701高空探测系统所测的温度、高度资料更稳定、离散率更小,对提高预报准确率有利。两套系统的温度差值在70 hPa层出现明显拐点,其原因有待进一步研究。  相似文献   

Erratum to: Iron isotope variations in spinel peridotite xenoliths from North China Craton: implications for mantle metasomatism     

Xinmiao Zhao  Hongfu Zhang  Xiangkun Zhu  Suohan Tang  Yanjie Tang 《Contributions to Mineralogy and Petrology》2010,160(1):15-14

Iron isotopes, together with mineral elemental compositions of spinel peridotite xenoliths and clinopyroxenites from Hannuoba and Hebi Cenozoic alkaline basalts, were analyzed to investigate iron isotopic features of the lithospheric mantle beneath the North China Craton. The results show that the Hannuoba spinel peridotite xenoliths have small but distinguishable Fe isotopic variations. Overall variations in δ⁵⁷Fe are in a range of −0.25 to 0.14‰ for olivine, −0.17 to 0.17‰ for orthopyroxene, −0.21 to 0.27‰ for clinopyroxene, and −0.16 to 0.26‰ for spinel, respectively. Clinopyroxene has the heaviest iron isotopic ratio and olivine the lightest within individual sample. No clear linear relationships between the mineral pairs on “δ-δ” plot suggest that iron isotopes of mineral separates analyzed have been affected largely by some open system processes. The broadly negative correlations between mineral iron isotopes and metasomatic indexes such as spinel Cr#, (La/Yb)_N ratios of clinopyroxenes suggest that iron isotopic variations in different minerals and peridotites were probably produced by mantle metasomatism. The Hebi phlogopite-bearing lherzolite, which is significantly modified by metasomatic events, appears to be much heavier isotopically than clinopyroxene-poor lherzolite. This study further confirms previous conclusions that the lithospheric mantle has distinguishable and heterogeneous iron isotopic variations at the xenoliths scale. Mantle metasomatism is the most likely cause for the iron isotope variations in mantle peridotites.  相似文献   

Iron isotope variations in spinel peridotite xenoliths from North China Craton: implications for mantle metasomatism   总被引：2，自引：1，他引：1  

Xinmiao Zhao  Hongfu Zhang  Xiangkun Zhu  Suohan Tang  Yanjie Tang 《Contributions to Mineralogy and Petrology》2010,160(1):1-14

Iron isotopes, together with mineral elemental compositions of spinel peridotite xenoliths and clinopyroxenites from Hannuoba and Hebi Cenozoic alkaline basalts, were analyzed to investigate iron isotopic features of the lithospheric mantle beneath the North China Craton. The results show that the Hannuoba spinel peridotite xenoliths have small but distinguishable Fe isotopic variations. Overall variations in δ⁵⁷Fe are in a range of ?0.25 to 0.14‰ for olivine, ?0.17 to 0.17‰ for orthopyroxene, ?0.21 to 0.27‰ for clinopyroxene, and ?0.16 to 0.26‰ for spinel, respectively. Clinopyroxene has the heaviest iron isotopic ratio and olivine the lightest within individual sample. No clear linear relationships between the mineral pairs on “δ-δ” plot suggest that iron isotopes of mineral separates analyzed have been affected largely by some open system processes. The broadly negative correlations between mineral iron isotopes and metasomatic indexes such as spinel Cr#, (La/Yb)_N ratios of clinopyroxenes suggest that iron isotopic variations in different minerals and peridotites were probably produced by mantle metasomatism. The Hebi phlogopite-bearing lherzolite, which is significantly modified by metasomatic events, appears to be much heavier isotopically than clinopyroxene-poor lherzolite. This study further confirms previous conclusions that the lithospheric mantle has distinguishable and heterogeneous iron isotopic variations at the xenoliths scale. Mantle metasomatism is the most likely cause for the iron isotope variations in mantle peridotites.  相似文献