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1.
直升机声信号谐波集及小波子空间能量特征提取与识别   总被引:4,自引:1,他引:3  
对目标识别中的特征提取技术进行了研究,介绍了两种用于被动声信号特征提取的方法.分别将谐波集(HS)频率和不同尺度小波子空间能量作为特征矢量,给出相应的算法;并利用实测信号将这些技术运用到直升机目标的识别问题中,利用kNN分类器对直升机目标和非直升机目标进行分类。结果表明这两种方法都能达到较高的正确识别率。  相似文献   

2.
金属与非金属部件粘接质量声诊断的神经网络方法   总被引:1,自引:0,他引:1  
本文基于神经网络对目标的识别与分类能力,用简单的敲击法获取了某压力容器的声响应信号,通过对声信号的频域特征提取,应用前馈多层神经网络对压力容器的金属与非金属部件之间的粘接质量进行了诊断,实验表明所给出的特征提取方法和神经网络模型是解决金属与非金属粘接质量诊断的一条较为有效的途径。  相似文献   

3.
基于神经网络的战场被动声/地震动目标识别方法   总被引:4,自引:0,他引:4  
目的在于研究人工神经网络在战场声/地震动目标识别应中的有效算法。通过建立战场目标声/地震动特性探测与分析系统,在总结目标特性规律,分析传统BP算法固有缺陷的基础上,采用改进的算法对分类器进行训练,典型战场目标信号样本检验表明,该方法具有良好的识别分类效果,利用基于神经网络的分类来实现对战场声/地震目标的识别分类是可行的。  相似文献   

4.
双谱估计在直升机声信号特征提取中的应用   总被引:7,自引:2,他引:5  
根据直升机信号在更多情况下表现为非高斯的随机过程,提出采用高阶统计量对直升机声信号进行建模与特征提取,导出基于三阶累积量的直升机声信号非高斯参数双谱模型,讨论了双频域内直升机声信号特征提取的方法,并结合实例给出说明,最后指出将高阶统计量分析方法用于直升机声目标识别具有十分有意义的应用前景。  相似文献   

5.
针对直升机声信号中混有与信号不相关的随机噪声,提出了一种将对称相关函数法和MUSIC算法相结合的直升机声目标特征提取新方法。采用MUSIC算法提取直升机声信号的对称相关函数的谐波频率,从而可以得到直升机声信号的谐波频率,将其作为目标特征。计算机仿真结果表明:与传统方法相比,该方法可以抑制噪声,突出谱峰位置,准确地体现直升机声信号的谐波特性。  相似文献   

6.
基于小波包变换的复合材料分层缺陷信号特征分析   总被引:2,自引:0,他引:2  
张冬雨  刘小方  杨剑  成坤 《兵工自动化》2009,28(11):56-58,68
通过自行设计的超声波检测系统对模拟分层试样进行实验,提取出缺陷信号,并对缺陷信号进行频域分析,在此基础上进行了基于小波包乏换的缺陷信号特征提取和BP神经网络识别。通过“能量-缺陷”的信号特征提取方法,比较不同分层位置之间的信号特征,得到一些有用的数据和信息,为复合材料的质量评估提供了重要的参考依据。  相似文献   

7.
基于BP神经网络,建立了多源毁伤信息特征层融合系统,对多源桥梁毁伤信息进行BP网络特征层融合,首先对多源图像信息采用轮廓分析的目标毁伤特征提取算法,进行边缘及直线特征提取,其次进行毁伤区域不变矩特征关联,最后利用BP神经网络进行训练并测试,最终融合得到准确而清晰的桥梁毁伤信息,能够为导弹打击效果的毁伤评估提供准确的信息支撑。  相似文献   

8.
基于倒谱特征和小波包特征熵的直升机声目标识别   总被引:2,自引:0,他引:2  
黄博  高勇 《探测与控制学报》2007,29(6):15-18,23
提出了一种将倒谱特征和小波包特征熵相结合的直升机声目标识别新算法,首先分析了直升机声信号的特点,计算了声信号的MFCC(MEL频率倒谱系数)、差分MFCC(差分MEL频率倒谱系数)和小波包分解后各个频带内的小波包特征熵组成的特征向量,并以此向量输入反向误差传播(Back Propagation,BP)神经网络进行训练,再用训练好的神经网络进行不同直升机型号的识别,最后给出了统计结果。结果表明:该算法对直升机机型的识别有较好的效果。  相似文献   

9.
针对多项式拟合和插值法解算空空导弹攻击区所存在的问题,提出了采用纯BP神经网络和BP网络-插值方法计算空空导弹攻击区。仿真获得纯BP神经网络和BP网络-插值法的界外发射概率、失去发射机会概率,结果表明这两种方法都有较高的拟合精度和速度。最后,分析了两种方法的优缺点,提出了根据作战需求和火控系统的配置情况确定选用何种方法的原则。  相似文献   

10.
针对工频水下磁目标信号特征提取难、目标数据样本少、识别精度低等问题,提出一种基于深度卷积生成对抗网络(DCGAN)与优化卷积神经网络(CNN)相结合的水下工频磁目标识别方法。该方法通过滑动时间窗将信号由一维时序空间映射到二维灰度值图像,将实测水下磁异常信号利用DCGAN进行数据增强,之后构建卷积神经网络并引入DY-ReLU动态激活函数对CNN网络结构进行优化,以达到对目标信号的分类识别的目的。实验结果表明,经由数据增强的网络模型识别率提高了10%;相较于其他常用的静态激活函数,优化的CNN识别率分别提高了4.5%、4%、3%和2.5%,识别精度达到92.5%。验证了该方法的有效性,为水下磁异常检测提供一种新思路。  相似文献   

11.
Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.  相似文献   

12.
The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS (geographical information system) data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.  相似文献   

13.
By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.  相似文献   

14.
Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.  相似文献   

15.
The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.  相似文献   

16.
By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux (kernel version 2.6.11 ) is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.  相似文献   

17.
An expression for estimating the aeroheating on a warhead nose at different supersonic speeds is proposed by incorporating CFD (computational fluid dynamics) and the least-square method. Compared with the traditional estimation formula, the expression is more accurate, convenient and can be used in the optimized design of warheads. The error from the result obtained in the test of a ball cartridge flight is less than 3 %. It satisfies the engineering requirements.  相似文献   

18.
The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent "explosion of terms". Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.  相似文献   

19.
For measuring velocity and impacting position of single fragment of warhead, a non-contact measuring method is proposed, in which a six-light-screen array, a position indicator, a multi-channel chronograph and a computer are used.The principle of measurement is described. The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters. When the fragment flies through the light screen array, the time of passing through each of the screens is recorded by the multi-channel chronograph. According to the time data and the geometrical parameters of the array, the velocity vector and the location of the fragment can be calculated immediately. The presented method can be used to locate the fragment and to measure the real velocity on its flying direction. It can also be used to measure the velocity of a fragment swarm after the system is engineered further.  相似文献   

20.
Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.  相似文献   

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