Research & Development on High-Speed Digital Video Recording System

在弹道学和爆炸力学的研究中，高速数字图像数据的获取有着重要的意义。为了准确地实时地获得图像数据，必须保证在规定的时间内系统有足够的传输速度和存储空间。由于高速图像流对带宽占用率高（课题项目提出50MB/s），接近于总线传输的饱和极限，对实时记录存储造成很大的难度。本论文所研究设计的数字图像记录系统可以很好地完成上述工作。 本论文针对武器性能测试系统中，高速数字图像实时记录器的设计与实现进行了研究。主要研究工作如下： ⑴研究制定了基于SMP服务器处理器结构和SCSI磁盘阵列的计算机硬件体系结构的解决方案。该硬件平台适合于高速图像采集与存储。 ⑵为了减轻传输带宽及存储空间的压力，并且针对武器测试系统对图像无损压缩的要求，给出了差分变长游程无损压缩算法。把该算法应用于图像序列仿真测试，得出此压缩算法具有压缩比率大，复杂度低，实时性强的特点。 ⑶分析研究了Windows 2000非实时性问题，它对记录系统实时性产生较大的影响。为此根据图像记录实时性的特有的要求，对Windows 2000某些方面做出了调整和优化，最终减少非实时性的影响。 ⑷在系统实现中，采用多线程异步I/O的方式实现系统的采集和记录功能。针对多线程出现的问题，采用资源复用的思想，构造线程池和I/O完成端口，对多线程程序设计进行优化。最终使得系统对记录任务有较高的吞吐率和实时响应能力。 ⑸研究制定了图像记录系统的性能检测方案。对整个系统以及系统的各个模块进行全面的丢帧率测试，并将整个系统置于相机不同的工作模式下，进行丢帧率测试。然后对存在丢帧的情况，查明原因并做了改进。 最后测试本系统可以稳定地工作在相机速度200频/s（分辨率512×512，图像深度8位的灰度图像），保证不丢帧。采集速度突破了50MB/s。该系统成功试运行于导弹姿态测量中，被证明是一个有用的可靠的记录高速数字图像数据的应用平台。High–speed digital video acquisition is very important for the image inspection in ballistic trajectory and explosive mechanics. So in order to get enough data during dead time, it request that a system must be of high-speed data transferring and a large mount of memory. High-speed video stream occupy full of bandwidth(50MB/s), close to saturated utmost of transmission, which elicit difficulty of real-time storage. The recording system designed in this thesis is a good resolution for the above programs. This thesis research designing and implementing of high-speed digital video recording against weapon performance testing. The main content of this paper is as follow: ⑴Establish hardware configuration system of computer based on SMP sever architecture and SCSI disk array, which is fit for high-speed video recording. ⑵In order to alleviate stress of transmission bandwidth and storage space, and to meet lossless compression of image in weapon performance testing, propose lossless compression algorithms of difference run-length coding. ⑶Research on non-real-time of windows 2000, operation system’s non-real-time characteristic reduces performance of acquisition and storage system. To enhance performance, this paper probes into the problems about why and where these non-real-time mechanisms appear and provide some techniques to avoid its influence. ⑷System adopts multi-thread and Asynchronous I/O technology to realize acquisition and storage. Contraposing to flaw of multi-thread, thread pool and I/O completion ports technology are introduce to this system. ⑸Establish performance inspection scheme, and test the whole system and all of module in system at different work mode of camera. In case of image losing, finding out reason and ameliorate it. This recording system can work steadily under the condition of camera’s velocity 200fps(resolution 512×512, 8bir pixel), and not lose image. Grabbing velocity break through 50MBps. This recording system had already applied on bomb pose measurement, which proved this recorder can provide useful and credible serving