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小、暗、多、快目标的近距离测量关键技术研究

Research on Key Technology of Close Measurement for Small, Dark, Rapid, and Multi Targets

【作者】 吕耀文

【导师】 王建立;

【作者基本信息】 中国科学院研究生院(长春光学精密机械与物理研究所) , 机械电子工程, 2014, 博士

【摘要】 现代靶场为适应武器系统快速发展的需要,提出了对小、暗、多、快目标测量的新要求。由于目标具有小、多、不发光和速度快等特点,要获取目标的清晰图像,相应的光学测量设备必须具有高帧频、高灵敏度和大视场的特性。基于对成本和安全性的要求,光学测量设备的布站位置距目标相对较远,因此无法给出对小、暗、多、快目标作用过程的细节。本文结合现代电子通信技术与摄像测量方法从低成本高速CMOS摄像机设计、图像采集存储、摄像机标定和目标测量等关键技术对该问题进行了深入的研究。本文的研究内容主要集中在以下几个方面:(1)根据测量要求并考虑研制成本,本文设计了一款分辨率为2K×1K、最高帧频为280帧、曝光可调的低成本高速CMOS摄像机,并详细说明了高速摄像机设计中的关键技术,尤其对高速数据采集中的位对齐和字对齐技术做了重点论述。为了适应测量设备小型化、便携化和低功耗的发展趋势,本文设计了一套基于高速SATA传输接口的嵌入式图像存储系统。实验结果表明,该图像存储系统最高图像存储速度可以达到294MB/s。(2)摄像机标定算法在本文中做了详细讨论和深入研究。以平面棋盘为标定工具,采用平面标定算法标定测量系统摄像机的内外参数,并针对该算法在实际标定中标定结果不收敛的问题,在随机抽样一致性(RANSAC)算法的基础上,提出了一种改进的标定算法。实验结果表明,改进的标定算法与传统方法相比,在降低算法迭代次数,优化算法运行效率的同时,标定精度提高了35%。(3)根据小、暗、多、快目标测量的实际需求,本文采用平面摄像测量方法单目测量目标的脱靶量和落点坐标,该方法具有测量简便、灵活性高的优点。在此基础上,针对点目标抛物线运动测量的问题,证明了二次抛物线的射影几何性质,并提出了一种针对抛物线运动目标三维信息测量的单目测量方法。通过仿真和实际小球投掷实验,验证了方法的正确性和可行性。该方法与双目测量结果比较,小球三维坐标测量误差在1.2%以内。(4)针对更一般的交汇测量任务,本文首先详细介绍了交汇测量中的关键技术,包括三维欧式重构、立体匹配与外参数标定等;其次,重点分析了外参数对测量精度的影响,通过仿真得到了最优的结构参数;最后,针对小、暗、多、快目标的落点测量问题,提出了一种无需标定的平面交汇测量方法,该方法可以应用于大范围、远距离、粗测量的场合。

【Abstract】 With the rapid development of weapons systems, new requirements are raisedfor measurement of small, dark, rapid, multi targets in modern shooting ranges.Since the rapid, multi targets are smalland non-luminous, to get clear pictures of thetargets, corresponding optical measurement equipment must have the characteristicsof high frame rate, high sensitivity and large field of view. For reasons of safety andcost, optical measurement equipments are posited far from the targets, thereforedetails of the targets movement are missed. Based on modern electroniccommunication technology and camera measurement technique, image acquisitionand storage, camera calibration and targets measurement are taken into considerationthis problem in this dissertation. The main works are summed in follows:(1) A new low-cost high speed camera is designed with the consideration ofmeasurement requirements and hardware costs. The image resolution is2Kx1K andthe maximum frame frequency is up to280fps under the condition of full resolution.Exposure of the camera can adjust to application environment. The key technologiesof camera design are explained in details, especially for bit alignment and wordalignment technique in the process of high-speed data acquisition. Under theminiaturization of the measuring device, trend of better portability and low powerconsumption, an embedded image storage system is also designed with thehigh-speed SATA interface. The experimental results indicate that the bandwidth of storage system can reach294MB/s。(2) In this paper, the camera calibration technology is in-depth researched. Theexternal and internal parameters of camera are estimated using the plane calibrationalgorithm with planar checkerboard. The plane calibration algorithm is easy andflexible, but sometimes the algorithm is not convergent in practice when the numberof calibration imagesis more than10. A modified method is proposed to ensurecalibration convergence. The modified method divides the calibration images intocorrect images and false images using Random Sample Consensus(RANSAC)algorithm, and calibrates camera only for good images. The experimental resultsshow that the robust modified method can reduce the number of iteration, andcalibration precision increase by35%.(3) To satisfy actual demand for the measurement of small, dark, rapid, multitargets, planar imaging measurement, easy and high flexibly, is used to monocularmeasure the miss distance and drop point coordinates of targets in this paper. On thisbasis, nature of the projective geometry of parabola is proved and a novel monocularmeasurement method is proposed for parabolic motion of point targets. Bothcomputer simulation and real data have been used to verify the feasibility of thismethod.. Practical globule throwing experiments show that the measurement erroris less than1.2%compared with binocular measurement methods.(4) For general measurement tasks, the key technologies for intersectionmeasuring are firstly introduced, which include3D European reconstruction, stereomatching and external parameters calibration, etc. Secondly, the influence ofexternal structure parameters on the accuracy of measurement is analyzedemphatically, and the optimal parameters are achieved by numerical simulation.Finally, Aiming at measurement of the small, dark, rapid, multi targets drop point, anovel plane intersection method is raised and it can be applied in large view field,long distance and coarse measurement occasions.

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