【作者】 马鸿泰；

【导师】 张家谋；

【作者基本信息】 北京邮电大学 ， 通信与信息系统， 2007， 硕士

【摘要】 当今社会，计算机和Internet技术在飞速发展，同时它也对其他各学科的发展起到了巨大的推动作用。天文学作为一门以观测为基础的学科也受到了它的很大影响。以往，天文观测者们需要在望远镜等观测设备旁边枯燥的记录收集观测数据，但由于新技术的出现极大的丰富了天文学研究的方法和手段，专业天文研究人员和天文爱好者们希望不需要守候在望远镜旁，而是通过网络就可以得到需要的信息。他们需要通过网络能够观测星图、快速获取星图文件，并且能够实时看到一些动态的视频。所以，国家天文台网站需要建立一个对静、动态图像压缩编码使之适应网络传输，并能够被用户点播和实时观看的流媒体传输平台，满足这些新的需求。针对上述要求，本论文研究了星图文件的特点，给出了国家天文台静、动态图像编码与传输的方案，并进行了软件实现。本论文具体的研究成果如下：首先，分析了星图图像和文件的特点，为了适应星图图像网络显示的需要，对星图文件进行了有损压缩，压缩比在10倍以上时依然有很好的视觉效果；为了适应星图图像存储传输的需要，对星图文件进行了无损压缩，提出了基于ZIP的分层压缩算法等，使压缩比由1.1～1.5倍提高到1.8～2.3倍，优于其他压缩算法，达到了较高要求；其次，利用微软的Windows Media SDK进行二次开发，将多幅静止的天文星图文件流化成一个视频文件，视频的码流速率、视频大小、每幅图像的显示间隔等都可以手动设置，并可以进行网络广播，还可以将生成的流实时推到流媒体视频服务器，由服务器分发进行网络视频点播。在国内天文界属于首创；第三，利用SOCKET网络编程技术实现了星图视频流化的远程控制系统，通过一个设置参数的客户端对远程的服务器进行控制，在服务器实现星图的流化和网络分发。最后，对工作进行了总结，并提出了下一步的改进意见。更多还原

【Abstract】 At present, the development of the computers and Internet technology are phenomenal, which is an impelling force for the population of other sciences such as the astronomy. We know astronomy is a science based on observation, in the past the professional astronomical researchers used to record and collect information with a telescope or other observation facilities personally, but now, many new technologies coming to the public improve methods and means for astronomy research. Both the professional and the amateur astronomical researchers hope to get the information and data they need through internet instead of standing by the telescopes and watching. Through internet they want to observe star images freely, get the star image files quickly and enjoy the real-time videos, so the National Astronomical Observatories consign us to build a streaming media transmission platform to serve the users, which can process the still images and videos to fit for the network transmission and be watched on demand by the orders.Based on the requirements mentioned above, the characters of star image files are studied and the still/dynamic image coding and transmission solution is proposed and realized in this paper. Concretely, the research achievements are as followed:Firstly, the characters of star images and files are analyzed. In order to adjust to the requirements of display of star image in internet, the star image files have been compressed with loss. The consequences show that there are still good performances for vision when the compression ratio is over 10 times; in order to adjust to the requirements of star images’ storage and transmission, the star image files has been compressed lossless. An algorithm of lossless delamination compression Based on ZIP has been proposed. The conclusion is that compression ratio is increased from 1.1～1.5 to 1.8～2.3 times and better than other algorithm of lossless compressions. The requirements can be satisfied better.Secondly, a original software application using the Windows Media SDK, which can stream the still star images to a video stream file is developed, the bit rate of video flow, the size of video, the display interval of each image and other parameters can be settled manually. The application can broadcast the streams and upload the generated media streams to the video servers, and then distribute them by the servers in the internet.Lastly, a remote control system for star images streaming is designed and implemented making use of socket internet programming technologies, which can control the remote servers to execute all kinds of functions by settling different parameters in the clients.At last, the paper sums up all the work, and give the next betterment idea.更多还原