空间CCD相机的高速多通道图像高可靠光纤传输系统     

李进  金龙旭  李国宁  张柯  韩双丽  朱鹏 《遥感学报》2012,16(5):909-927

为了提高空间CCD相机中数字视频图像信息的传输带宽,增强图像传输抗电磁干扰能力并提高光纤链路的整体性能,开发了应用于大视场空间相机的数字视频图像信息高可靠光纤传输系统。首先,根据CCD成像单元特点和相机在轨工作环境得出了传输系统的输入速率,在此基础上并结合CCD视频处理结构设计并实现了9通道CCD图像数据光纤并行传输系统。然后,阐述了系统设计思想,并说明了高速串化器和光模块的设计理念。接着,提出了(16,8)纠错编码算法,阐述了该算法思想和实现电路。最后,在XX-X空间多光谱相机样机的传输系统上进行了试验验证。实验结果表明:该传输系统图像传输正确、工作稳定、可靠性高、实时强、无误码,单路有效数据率达到2.44Gbit/s。(16,8)纠错编码算法纠错能力强、易于硬件实现、占用资源少。纠错算法在3043Byte内可以纠正191bit错误。该传输系统满足了空间相机图像传输的要求。  相似文献   

“天绘一号”卫星工程建设与应用   总被引：1，自引：1，他引：0  

王任享  胡莘  王新义  杨俊峰 《遥感学报》2012,16(S1):2-5

概括“天绘一号”卫星工程的建设历程和卫星系统的使命任务;介绍了卫星系统和相机载荷的能力与技术参数;重点阐述了“天绘一号”卫星无地面控制条件下的摄影测量关键技术, 包括LMCCD相机体制、航天摄影测量相机参数在轨标定技术以及无地面控制点条件的三线阵EFP影像平差技术等的运用, 通过工程实践, 达到了工程技术指标要求;最后介绍数据应用情况, 提出“天绘一号”卫星的发展设想, 为了解“天绘一号”卫星工程提供了基本参考。  相似文献   

Simultaneous optical and electrical observations on the initial processes of altitude-triggered negative lightning     

Weitao Lu  Yijun Zhang  Xiuji Zhou  Xiushu Qie  Dong Zheng  Qing Meng  Ming Ma  Shaodong Chen  Fei Wang  Xiangzhen Kong 《Atmospheric Research》2009,91(2-4):353-359

Using a high-speed camera system and two electric field antenna systems, we have documented the initial processes of an altitude-triggered negative lightning (ATNL). The optical records clearly show that ATNL begins with the inception and propagation of an upward positive leader (UPL) and then a simultaneous propagation of UPL and downward negative leader (DNL), known as the bidirectional leader process, follows. Based on the optical records, it is inferred that (1) the triggering height is about 371 m; (2) the two-dimensional (2D) propagation speed of the UPL in its inception phase is about 3.8–5.5 × 10⁴ m s^− 1 during its propagation from about 393 to 452 m above the ground; (3) the grey levels of the DNL are about one order of magnitude higher than that of the UPL in their inception phase; (4) a discharge phenomenon propagating along the elevated triggering wire part of the lightning channel occurs after the mini-return stroke (MRS), with a 2D propagation speed of about 1.6–2.0 × 10⁵ m s^− 1. Combined with the simultaneous electric field change records, it is further inferred that (1) the UPL incepts about 932 μs earlier than the unstable DNL and about 4.1 ms earlier than the stable DNL; (2) the unstable DNL propagates downward intermittently three times with a time interval of about 1 ms, and each propagation contains a different number of steps with an average step length of about 7 m; (3) the stable DNL incepts at the tip of the unstable one, with a 2D propagation speed of about 1.9 × 10⁵ m s^− 1, an average step length of about 3 m, and a stepping time interval varying from 6 to 31 µs with a mean value of 15 µs.  相似文献   

Field testing of robotic technologies to support ground ice prospecting in martian polygonal terrain     

Timothy D. Barfoot  Paul T. Furgale  Nadeem Ghafoor 《Planetary and Space Science》2010,58(4):671-681

Polygonal terrain, a landform commonly associated with the presence of ground ice, is widespread throughout the high latitudes on Mars. In this paper, we present the results of field testing a potential mission concept for the robotic prospecting of ground ice in polygonal terrain. The focus of the paper is on the key robotic technologies that could be used to implement the concept and the engineering lessons we learned (as opposed to the specific scientific findings of our field tests). In particular, we have found that a lander- or rover-mounted lidar and a rover-borne stereo camera/ground-penetrating radar suite are two important scientific tools that may be used to help pin-point ground ice prior to subsurface sampling. We field tested some aspects of this mission concept on a previously - unstudied polygonal terrain site on Devon Island in the Canadian High Arctic (a common Mars/Moon analogue site) during the summer of 2008. This unique collaboration between technological and scientific communities has led to a deeper understanding of how such a science-driven mission could actually be implemented robotically.  相似文献   

GPS辅助光束法区域网平差—太原试验场GPS航摄飞行试验结果   总被引：8，自引：2，他引：8  

李德仁  袁修孝 《测绘学报》1995,24(2):1-7

本文简要介绍了ＧＰＳ辅助光束法区域网平差的基本原理和方法，详细讨论了太原航摄机动态试验场实际ＧＰＳ航摄飞行试验的结果。利用联合平差程序ＷｕＣＡＰＳ系统对试验区进行ＧＰＳ辅助光束法区域网平差，用分米级精度的ＧＰＳ摄站坐标获得了实地上平面为±７．９ｃｍ、高程为±１８．１ｃｍ的加密精度，充分显示了动态ＧＰＳ定位技术在航空遥感定位中的广阔应用前景。  相似文献   

Rapid texture mapping from image sequences for building geometry model     

ZHANGZuxun WUJun ZHANGJianqing 《地球空间信息科学学报》2003,6(3):8-15

An effective approach,mapping the texture for building model based on the digital photogrammetric theory, is proposed. The easily-ac-quired image sequences from digital video camera on helicopter are used as texture resource, and the correspon-dence between the space edge in build-ing geometry model and its line feature in image sequences is determined semi-automatically. The experimental re-sults in production of three-dimension-al data for car navigation show us an attractive future both in efficiency and effect.  相似文献   

首次回击具有双接地点的地闪光学和电学特征的个例分析   总被引：10，自引：4，他引：6  

孔祥贞  郄秀书  王才伟  张义军  王怀斌  张翠华 《高原气象》2003,22(3):259-267

利用成像率为1000幅／s的数字化高速摄像系统和时间分辨率为1μs的快、慢天线闪电电场变化测量仪在广州附近观测到一次首次回击具有两个接地点的负极性地闪。两个分支到达地面的时间间隔约为30μs;在发生回击R2时,其中一个分支的直窜先导发展成为企图先导。观测发现M一分量的发光要比梯级先导强;回击间的K一变化与云中的在击穿和通道的延伸有关,但不引起云地间通道的发光。光学和电场变化的同步观测证实了直窜一梯级先导的发展速度与前一次回击的时间间隔有关,较快的先导发展速度对应于较短的回击时间间隔,较慢的发展速度对应于较长的回击时间间隔。另外,本文在资料分析的基础上,提出了产生双接地点的四种可能原因。  相似文献   

Assessing plantation canopy condition from airborne imagery using spectral mixture analysis and fractional abundances     

《International Journal of Applied Earth Observation and Geoinformation》2005,7(1):11-28

Pine plantations in Australia are subject to a range of abiotic and biotic damaging agents that affect tree health and productivity. In order to optimise management decisions, plantation managers require regular intelligence relating to the status and trends in the health and condition of trees within individual compartments. Remote sensing technology offers an alternative to traditional ground-based assessment of these plantations. Automated estimation of foliar crown health, especially in degraded crowns, can be difficult due to mixed pixels when there is low or fragmented vegetation cover. In this study we apply a linear spectral unmixing approach to high spatial resolution (50 cm) multispectral imagery to quantify the fractional abundances of the key image endmembers: sunlit canopy, shadow, and soil. A number of Pinus radiata tree crown attributes were modelled using multiple linear regression and endmember fraction images. We found high levels of significance (r² = 0.80) for the overall crown colour and colour of the crown leader (r² = 0.79) in tree crowns affected by the fungal pathogen Sphaeropsis sapinea, which produces both needle necrosis and chlorosis. Results for stands associated with defoliation and chlorosis through infestation by the aphid Essigella californica were lower with an r² = 0.33 for crown transparency and r² = 0.31 for proportion of crown affected. Similar analysis of data from a nitrogen deficient site produced an outcome somewhat in between the other two damaging agents. Overall the sunlit canopy image fraction has been the most important variable used in the modelling of forest condition for all damaging agents.  相似文献   

高分辨率数字航测相机现状和思考   总被引：4，自引：0，他引：4  

常本义 《测绘科学与工程》2005,25(3):1-4

本文根据国内外数字航测相机发展的实际情况，对于新型数字航测相机视场角、影像分辨率、像移补偿、摄影间隔和影像存贮器容量、相机系统的动态定位与定向以及真彩色与多光谱摄影等技术问题进行了分析并给出了相应的结论。  相似文献   

应用数字近景摄影测量提取岩体裂隙迹长信息方法研究   总被引：5，自引：0，他引：5  

王凤艳  陈剑平  庞贺民 《世界地质》2006,25(1):39-42

针对传统以皮尺为主要工具的岩体裂隙迹长测量方法精度及效率较低、尤其是遇有危险场地不能遥测等缺点,研究应用数字近景摄影测量的方法获取岩体裂隙迹长信息,以普通非量测数码相机为主要工具,以JX-4A数字摄影测量工作站为依托进行信息处理,可以快速获取隧道施工掌子面裂隙迹线图。经实验比较分析,数字近景摄影测量方法获取岩体裂隙信息在精度和效率方面都优于传统方法。  相似文献