【作者】 王莹；

【导师】 王延杰；

【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】 图像末制导仿真系统可以作为外场武器的模拟跟踪和检测系统，还可以根据生成的特定仿真场景模拟对不易实验地区（例如城市）的作战试验。在虚拟仿真领域中，虚拟图像的实时生成速度以及虚拟场景的生成效果是衡量虚拟场景沉浸效果和程度的两个重要指标。对于数据量较小的虚拟仿真系统两个指标可以兼顾，但是对于大规模虚拟仿真系统场景的逼真度越高，系统的漫游速度可能越低，因此两个指标要权衡考虑。本课题针对虚拟仿真场景的这两个重要指标展开研究，主要包括以下几个方面的内容。在仿真系统中为了模拟真实感地形采用读取DEM高程数据渲染地形的方法，并对于不同飞行阶段的地形采用不同分辨率的真实图像作为地形纹理。为了避免相邻不同分辨率的纹理出现视觉跳跃的现象，采取了相应的图像融合策略生成过渡纹理的方法，逼真的模拟了导弹渐近的过程。对于卫星盲区地形，采用了基于ROAM算法的自适应地形算法生成的虚拟地形。将基本ROAM算法生成的地形作为基网格，计算下一级网格顶点的粗糙度以及与视点的距离等综合参数。通过给定阈值与综合参数的比较来判断是否继续细分。对于满足细分条件的顶点，通过进一步提取地形的特征采用Loop算法细分局部区域。最终对满足一定条件的边界顶点进行适当的几何优化以使仿真结果更加逼真。算法在场景仿真结果上比原始算法更加细腻，并且在实时漫游过程中漫游帧频平均值52.0303帧/秒，明显高于原始算法平均帧频36.187帧/秒。满足了虚拟仿真系统在漫游过程中对实时性的要求。对于经典的纹理调和映射算法，尽管保持了纹理映射的有效性但是算法复杂度高，不能满足仿真系统实时性。基于这个问题，提出了根据评估值自适应选取目标函数的约束纹理映射方法。结合模型的参数化平面，计算模型特征点三角化后每一个三角块内部顶点的评估值，根据与阈值比较后的结果自适应选择目标函数。对于不能直接应用两种目标函数的三角块进行迭代细分，计算下一级三角块的评估值。实验表明算法能够很好的保持纹理的有效性，具有很高的使用价值。在图像末制导仿真系统中，通过改变输入参数调整导弹的飞行姿态，伴随着图像出现平移、梯度变化等现象，并可以实现在指定帧图像出现特定渲染效果的目的。同时基于VC++和OpenGL完成了场景的调度绘制，实现了导弹末制导阶段虚拟场景的实时、动态模拟。为了实现基于虚拟场景的注入式仿真，搭建了以PC上位机、FPGA为核心的注入式仿真平台为主要设备的注入式仿真测试系统。通过上位机在产生虚拟场景的同时，利用旋转映射技术将虚拟仿真场景保存为BMP格式的二维图像，并经过PCIe总线发送到FPGA板卡，板卡将图像缓存到DDR3SDRAM中，然后将缓存的虚拟仿真图像通过Cameralink接口输出到图像处理平台。实现了基于虚拟仿真图像的注入式仿真测试。更多还原

【Abstract】 The virtual simulation technology on missiles homing phase is to simulated thescene of the missile terminal guidance stage. The simulation system can beconsiderded a tracking System or a detection system, and it can simulate somespecific simulation scenes for that never used to be combat simulation,like cities. Inthe field of virtual simulation, there are two important indicators to decidesimulation results of the virtual scene.One is the generation rate of virtual image,theother is the simulation results of simulation scenes.We can meet both ruquests for asimulation system with a small amount of data, but with regard to a simulationsystem with a large amount of data,things can be handled by another way. The morerealistic scenario, the slower the rendering speed. Thus, two factors should beweighed.The paper expands the research on these two indicators, and includes thesesevels aspects.In order to simulate realistic terrain in the simulation system, we generate terrainmodel by reading the DEM elevation data. At different phases of Missiles flight, weuse different terrain textures with different resolutions of real images. To avoid thephenomenon of visual jumps between adjacent resolution terrain, we use transitiontextures made by corresponding fusion strategy. This method is a realisticsimulation of missile gradual process. For satellite blind terrain, a simulation algorithm of adaptive realistic terrain generation method based on ROAM algorithmwas introduced. The terrain generated by ROAM is to be a base grid. Then wecomputer the integrated parameter Y of the lower grids. By comparison with a giventhreshold value to the Y parameters, determine whether to split or not. Extract thesharp features of the vertex that satisfy the conditions and split these vertexes withLoop algorithm. It generates a video stream by rotation mapping algorithm inreal-time roaming process and sends to the injection simulation system to the DVI.Experimental results show that: the average of roaming frame rate of proposedalgorithm is45.1303and the peak frame rate close to50. The frame rate is higherthan the average frame rate of the original algorithm. The proposed algorithmsatisfies the requirements of the injection simulation system and the average ofroaming frame rate is45.In order to improve the effectiveness of texture mapping, I propose a constrainttexture mapping method based on the evaluation value to determine which objectfunction to select. This algorithm computes evaluation value of internal vertices ofevery triangular block after the feature point’s triangulation in the parameter plane.For the triangle both the objective functions are not suitable, we conduct atriangulation iteratively and calculate the evaluation value of triangles next level.Experiments show that this algorithm is dropped an average more than75%of thetime than the classical algorithm.The model of this algorithm is loaded into thereal-time rendering system with high frame frequency. Experiments show that thealgorithm has good robustness; repeated experiments show that the proposedalgorithm can maintain good texture validity.In our virtual simulation system, the missiles fly at different positionscorresponding to different simulation scenarios.It can adjust the parameters of themissiles when the user change input data. Meanwhile, the virtual simulation scenechanges like translation, rotation or scaling.In this way, we can control the virtualsimulation scene at any time. For example, we can add some special renderingresults in any frame images. We use VC++and OPENGL finished the simulation of virtual scene. I realized the simulation of virtual scene about the missile terminalguidance stage.In order to achieve injection simulation on virtual image, I built a simulationplatform for injection.The platform includes PC、and FPGA. PC used to generate thevirtual scene, and in this process PC computer will save the virtual scene as BMPpictures by rotation mapping technology. Then, the virtual image will be sent toFPGA through PCIe. And then,the visual image will be sent to the image processingplatform of the missile. Experimental results show that the injection simulation testbased on virtual images is successful.更多还原