基于Contourlet区域对比度的遥感图像融合算法

为综合利用多传感器遥感图像之间的信息，提出了一种基于contourlet变换的遥感图像融合算法。Contourlet是近年发展起来的一种多尺度几何分析工具，比小波变换更适合对图像等二维信号进行处理。算法的思想是将源图像分别进行contourlet变换，在contourlet域完成图像信息的融合，最后通过逆变换得到融合结果。根据分解系数特性，首次提出了contourlet域的区域对比度作为高频子带的融合规则，系数选择更符合人类视觉系统的要求，使得融合图像更有意义。低频子带采用基于区域能量的加权平均作为系数融合规则，在充分保留图像主要信息的前提下进一步增强了算法的稳定性。实验结果表明该算法在性能上明显优于PCA及小波图像融合等传统算法，且能够有效增强源图像的对比度和细节信息。     

基于非等间距采样输出的旋转矢量姿态算法

基于实际系统中陀螺的输出为非等间隔的角增量信号，重点研究了采样时刻的变化对捷联姿态算法的影响，并推导出旋转矢量三子样算法和二子样算法的通用表达式及其误差方程。传统的Miller算法已被证明是本算法的特例。研究发现，算法误差与由采样时刻构成的误差系数阵密切相关，Miller算法中的等间距采样使得该矩阵奇异，而改变采样间距可使其满秩，从而降低算法误差。然而对角增量输出的二子样算法而言，等间隔采样比非等间距采样具有更小的箕法漂移。仿真及试验结果证明了本文的观点。     

应用联合变换相关器的成像制导系统

提出了一种光电混合的成像制导系统，它采用光学联合变换相关器作为其主要的图像识别单元，利用计算机对识别结果进行判决和显示，并发出跟踪信号给导引头，从而实现制导。联合变换相关器是对光学图像信号进行并行处理的器件，实时识别性能强，精度高。此成像制导系统克服了传统的红外制导系统易受外界因素影响，实时处理能力差，误判率较高的缺点，具有并行处理速度快、信息吞吐量大、体积小等优点，应用前景广阔。     

基于AT89C52的离散信号测量电路设计

介绍了离散信号测量与控制在反舰导弹雷达导引头自动测控系统中的重要性 ,给出了基于AT89C5 2单片机控制的离散信号测量电路的具体构成和工作原理     

二维小波变换及其在医学图像处理中的应用

介绍了二维离散小波变换的一般形式，在图像分解的基础上．分析了二维小波变换在医学图像消噪和图像增强中的应用，同时给出应用实例。结果表明，应用小波分析进行医学图像处理，能够有效地改善图像质量，有利于医生对病情的诊断和治疗。     

用最大熵谱法估计大气湍流谱

最大熵谱分析方法是一种非线性的新的谱分析方法。其基本原理可浅近地解释为:对一个所考虑的时间系列,它的前 m 个自相关系数已知,要求构造其后的自相关系数,但不损失系列的熵即不损失其信息。实际的处理过程是:用自回归方法在最小二乘原则下对系列作最佳拟合,然后求拟合系列的理论谱。最大熵谱法不要求对原始系列的滤波和对粗谱的平滑整理。本文从实际应用的角度,简述了该方法的过程,介绍了编程计算的方法和步骤,并结合实例计算了几组大气湍流谱。文章认为最大熵谱分析方法是一种值得推广应用的优秀的谱分析方法。     

用Radon变换迭代法重建含有遮挡物的三维折射率场

本文通过计算机模拟研究，结合气体折射率场的光验知识．考查了将Ｒａｄｏｎ变换迭代法用于光学干涉层析计量含有遮挡物的三维折射率场的重建精度。作为一个应用实例，测量和计算了某一截面的气体温度分布，并与热电偶测量的值进行了比较。     

Hybrid integration method for highly maneuvering radar target detection based on a Markov motion model

To detect highly maneuvering radar targets in low signal-to-noise ratio conditions, a hybrid long-time integration method is proposed, which combines Radon-Fourier Transform (RFT), Dynamic Programming (DP), and Binary Integration (BI), named RFT-DP-BI. A Markov model with unified range-velocity quantification is formulated to describe the maneuvering target’s motion. Based on this model, long-time hybrid integration is performed. Firstly, the whole integration time is divided into multiple time segments and coherent integration is performed in each segment via RFT. Secondly, non-coherent integration is performed in all segments via DP. Thirdly, 2/4 binary integration is performed to further improve the detection performance. Finally, the detection results are exported together with target range and velocity trajectories. The proposed method can perform the long-time integration of highly maneuvering targets with arbitrary forms of motion. Additionally, it has a low computational cost that is linear to the integration time. Both simulated and real radar data demonstrate that it offers good detection and estimation performances.     

Multi-state autonomous drilling for lunar exploration

Due to the lack of information of subsurface lunar regolith stratification which varies along depth, the drilling device may encounter lunar soil and lunar rock randomly in the drilling process. To meet the load safety requirements of unmanned sampling mission under limited orbital resources, the control strategy of autonomous drilling should adapt to the indeterminable lunar environments. Based on the analysis of two types of typical drilling media (i.e., lunar soil and lunar rock), this paper proposes a multi-state control strategy for autonomous lunar drilling. To represent the working circumstances in the lunar subsurface and reduce the complexity of the control algo-rithm, lunar drilling process was categorized into three drilling states:the interface detection, initi-ation of drilling parameters for recognition and drilling medium recognition. Support vector machine (SVM) and continuous wavelet transform were employed for the online recognition of dril-ling media and interface, respectively. Finite state machine was utilized to control the transition among different drilling states. To verify the effectiveness of the multi-state control strategy, drilling experiments were implemented with multi-layered drilling media constructed by lunar soil simulant and lunar rock simulant. The results reveal that the multi-state control method is capable of detect-ing drilling state variation and adjusting drilling parameters timely under vibration interferences. The multi-state control method provides a feasible reference for the control of extraterrestrial autonomous drilling.     

Numerical investigation on flow nonuniformity-induced hysteresis in scramjet isolator

Numerical simulation and theoretical analysis were conducted to study the hysteresis inside scramjet isolator during the reciprocating process of back pressure variation. It is revealed that only a regular reflection is theoretically possible for two leading shocks when the inflow Mach number is greater than 2.0, and no hysteresis can occur in the transition between shock reflection types. Nevertheless, wall suction, gas injection, and background waves cause non-uniformity of the incoming flow and would make hysteresis possible. Besides the classical hysteresis in the transition between shock reflection, new kinds of hysteresis were found in both the deflection angle of separated boundary layer and the location of the shock train. Moreover, the occurrence of hysteresis in the deflection angle of the separated boundary layer is accompanied with the shock reflection hysteresis. In the case with background waves or gas injection, hysteresis in the starting position of leading shock was observed too. As back pressure decreases, the leading shock does not follow the same path as that as the back pressure increases, and it is anchored at the location where the background shock or the injection interacts with the leading shock. It is inferred that, if two strong adverse pressure gradient regions move towards and interact with each other, hysteresis will take place when they start to separate.