摘要:The Digital Signal Processor ( DSP ) is specially designed for signal processing. In recent years, the DSP has found wide application in signal processing, image processing,communication, traffic and aerospace etc. As a practical part of image processing, the image haze removal has been researched for decades. During the research and development of haze removal algorithm, the Matlab and C programming language were usually used, and were supported by DSP. Yet, the efficiency was too low by simply running the source code. To solve this problem, a novel algorithm is proposed for optimizing the algorithm and improving the processing effect. The multi-core DSP and development tool of TI Company are used for real-time optimization of C code and parallel processing. A fine optimization effect is obtained,which shows that the method can be used for processing hazy images with low resolution ratio in realtime.%数字信号处理器( DSP)专门针对信号处理而设计,以其独特的特点在信号处理、图形图像处理、通信、交通、航空航天等领域得到越来越广泛的应用。在图形图像处理领域中,图像去雾一直是研究热点,开发时多使用Matlab和C语言仿真,将其直接移植到DSP中运行效率通常较低,难以做到实时处理。针对该问题,提出一种快速有效的图像去雾算法,优化算法过程,获得更好的处理结果;利用TI公司的多核DSP和开发工具,对C代码进行实时优化和并行处理,取得很好的优化效果,能够对低分辨率进行图像去雾的实时处理。
摘要:针对单目视觉系统中载体纯旋转运动引起的估计退化问题,结合运动参数约束条件,提出了一种基于OPA的时空约束单目视觉位姿估计方法。该方法利用OPA算法在估计本质矩阵和平移方向之前判断载体的运动形式,检测修正估计退化问题,并结合摄像机在运动过程中的时间相关约束及图像特征点在空间中的相关约束,实现单目视觉系统的位姿估计。两组对比实验结果分析表明,新算法相比于传统的估计算法具有更高的精度和稳定性。%Considering the estimation degradation caused by the pure rotational movement in the monocular vision system and the motion parameter constraints, we proposed an OPA-based spatial-time constraint pose estimation algorithm for monocular vision systems. The OPA algorithm was used to detect and correct the estimation degradation before estimating the essential matrix and translational direction vector. Combined with the time-related constraints of camera in motion process and the space-related constraints of image feature point, the estimation to navigation parameters of the monocular vision system were obtained. Comparative analysis of two sets of experimental results shows that the proposed algorithm has higher accuracy and stability compared with the conventional estimation algorithm.
摘要:Generally, the aviation communication system has some constraints, such as power, bandwidth and latency. To satisfy its requirements of high coding gain and low latency to channel coding, the paper derives the theoretical Shannon limit on the minimum SNR required for coded system, especially for the binary communication system. And then, the performance of several typical kinds of channel coding is analyzed through simulation. Finally, qualitative analysis is made to the application scope of the different channel coding methods with consideration of the technical indicators of them. The conclusion has engineering significance for the selection of channel coding in aviation communication systems.%一般地,航空通信系统具有功率受限、带宽受限、时延受限的特点。针对航空通信系统对信道编码高增益和低时延的要求,首先理论推导通信系统(特别是二进制通信系统)应用r码率信道编码获得编码增益的香农极限值,并仿真对比分析几类典型信道编码的编码性能,最后结合工程实现考虑的技术指标对几类信道编码的应用范围进行了定性分析,其对航空通信系统的信道编码选取具有工程指导意义。
摘要:Using digital zenith instrument for positioning the observation station is an astronomical positioning method with high accuracy. In calculating the position of observation station, there lacks an effective method for screening the star data. Direct processing of the star data obtained from experiment always has an influence on the final positioning accuracy. In order to solve the above problems, a method for star screening is proposed. With residual error as the object of study, it uses Grubbs criterion for repeating screening of star data in iterative computation, and then uses the least square algorithm for calculation. The processed result of experimental data has rejected the stars with gross error and improved the reliability of calculated data, which can improve the positioning accuracy by about 5 m.%运用数字天顶仪对测站点位置进行定位是一种高精度的天文定位方法。在对测站点位置解算的过程中,缺少一种对星点数据进行有效筛选的方法。往往直接对实验获得的星点数据进行处理,影响了最终的定位精度。为了解决上述问题,提出了一种星点筛选的方法,该方法以残差为研究对象,运用格罗布斯准则,在迭代计算的过程中反复对星点数据进行筛选,然后再使用最小二乘算法进行解算。实验数据的处理结果剔除了部分含有粗大误差的星点,提高了解算数据的可靠性,使定位的精度提高了大约5m。
摘要:A distributed control method for formation of quadrotor UAVs is presented with introductions on the fundamental knowledge of graph theory and consensus of swarm system. The quadrotor UAV is described as a second-order integrator dynamic system, and the relative position is used to describe the UAV formation shape. The quadrotor UAV formation is modeled based on the communication topology relationship of quadrotors. The strategy of follower-leader method integrated with graph-based method is explored. A second-order consensus algorithm is presented, with which the fleet can complete formation gathering and formation maneuvering. Finally, the effectiveness of this algorithm is shown through the simulation results.%介绍了图论和群体系统一致性的相关理论,提出一种分布式四旋翼无人机编队控制方法,将四旋翼无人机描述为二阶积分器动力系统,采用相对位置偏差描述编队队形;根据四旋翼无人机之间通信拓扑关系将四旋翼无人机编队建模为图,探索了领航跟随法和基于图论法的融合策略,给出一种有领航者的二阶一致性算法。在该算法下,编队可以完成编队集结和编队机动等行为,最后通过仿真实验验证了该方法的有效性。
摘要:目标威胁评估是进行空战任务规划的重要一环。针对传统评估模型中指标信息的不确定性和模糊性,以多机空战编队整体为出发点,提出了优化广义回归神经网络的目标威胁评估模型及算法。该优化算法通过遍历散布系数区间内的值,能迅速找到最优散布系数从而使模型达到最优仿真输出结果。考虑到目前空战多以编队作战为主,选择目标对我方编队整体的威胁程度作为评价指标,提高了评估结果的可靠性。最后通过引入实例,验证了该优化模型的有效性和正确性。%Target threat assessment is very important for air combat mission planning. Due to the uncertainty and fuzziness of target information in traditional assessment model, the model and algorithm for target threat assessment based on improved Generalized Regression Neural Network ( GRNN) are proposed, with multi-aircraft air-combat formation as the starting point. This optimization algorithm can quickly find the optimal scatter coefficient through traversing values within the scatter coefficient interval, thus enabling the model to reach the optimal simulation output. Considering that most of the current air-combats are formation operation, the overall threat level of targets to our formation is selected as the assessment criteria, which improves the reliability of assessment results. Finally, an example is given to verify the effectiveness and correctness of this optimization model.