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基于到达时差(Time Difference of Arrival,TDOA)的多声源定位中,由于麦克风阵列对测量的TDOA值无法与目标声源进行关联,声源定位过程会产生关联模糊,从而影响多声源定位结果的精度。针对这一问题,提出基于阵列重构的多声源关联模糊消除方法。通过广义互相关(Generialized Cross⁃Correlation,GCC)算法估计麦克风阵列的TDOA值,再利用排序算法获得定位麦克风阵列所有可能的TDOAs序列,并基于Chan算法估计所有可能的声源。通过轮换定位麦克风阵列的参考麦克风,构造多组校验子阵列,利用真实声源与阵列麦克风的相对位置关系来滤除虚假声源。对于不同校验子阵列筛选出的所有声源位置,以出现频数最大化原则再次进行冗余校验,从而提升最终筛选真实声源的准确性。仿真及实验结果表明,该方法能够以最少数量常规麦克风有效消除多声源定位中的虚假声源。在同等麦克风数量的情况下,该方法的定位精度及定位鲁棒性高于对比方法。 相似文献
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鲁棒语音识别技术在人机交互、智能家居、语音翻译系统等方面有重要应用。为了提高在噪声和语音干扰等复杂声学环境下的语音识别性能,基于人耳听觉系统的掩蔽效应和鸡尾酒效应,利用不同声源的空间方位,提出了基于双耳声源分离和丢失数据技术的鲁棒语音识别算法。该算法首先根据目标语音的空间方位信息,在双耳声信号的等效矩形带宽(Equivalent Rectangular Bandwidth,ERB)子带内进行混合语音信号的分离,从而得到目标语音的数据流。针对分离后目标语音在频域存在频谱数据丢失的问题,利用丢失数据技术修正基于隐马尔科夫模型的概率计算,再进行语音识别。仿真实验表明,由于双耳声源分离方法得到的目标语音数据去除了噪声和干扰的影响,所提出的算法显著提高了复杂声学环境下的语音识别性能。 相似文献
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对大型轴承表面损伤进行定位,有助于及时发现故障,加快修复速度。提出了一种使用单个声发射传感器对大型轴承表面损伤进行定位的方法。针对轴承环形结构,利用Lamb波频散特性,估计不同频段信号的可能模式和传播速度,使用Akaike信息准则(AIC)确定不同频段信号到达传感器的时间差。根据不同频带到达传感器的时间差估计不同模式下声发射源位置。针对传播模式不确定和仅利用一个时间差的镜像位置问题,改变传感器位置后对同一声发射源进行第二次定位,剔除不合理的传播模式,从而得到声发射源的唯一确定位置。通过在圆柱滚子推力轴承上进行的断铅试验,验证了该方法的有效性。 相似文献
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提出多模式贝叶斯准则下的概率数据关联滤波新概念,并将该方法与基于匹配场-长项积分混合处理相结合,建立了基于Bayes框架的检测跟踪一体化算法,较好地实现了对机动目标的被动定位和跟踪. 相似文献
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S. H. Lo 《International journal for numerical methods in engineering》1989,28(11):2695-2707
This paper investigates the possibility of integrating the two currently most popular mesh generation techniques, namely the method of advancing front and the Delaunay triangulation algorithm. The merits of the resulting scheme are its simplicity, efficiency and versatility. With the introduction of ‘non-Delaunay’ line segments, the concept of using Delaunay triangulation as a means of mesh generation is clarified. An efficient algorithm is proposed for the construction of Delaunay triangulations over non-convex planar domains. Interior nodes are first generated within the planar domain. These interior nodes and the boundary nodes are then linked up together to produce a valid triangulation. In the mesh generation process, the Delaunay property of each triangle is ensured by selecting a node having the smallest associated circumcircle. In contrast to convex domains, intersection between the proposed triangle and the domain boundary has to be checked; this can be simply done by considering only the ‘non-Delaunay’ segments on the generation front. Through the study of numerous examples of various characteristics, it is found that high-quality triangular element meshes are obtained by the proposed algorithm, and the mesh generation time bears a linear relationship with the number of elements/nodes of the triangulation. 相似文献
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Zhang Dailin Chen Youping Kong Ching Tom Ai Wu Zhou Zude 《IEEE transactions on magnetics》2007,43(10):3868-3871
The position angle is very important in the current control of permanent-magnet linear motors (PMLMs), and its error affects the control precision of currents. However, the position angle is often not accurately detected because of faults in motor making, pulse loss of linear encoders, and so on. In order to precisely control the currents of PMLMs, a compensation scheme of position angle errors is proposed based on the mathematical relation between position angle errors and currents. In the scheme, a position angle error compensator is designed to compensate the position angles detected by linear encoders. Furthermore, a filter and a class of iteration learning algorithm are proposed to avoid the errors produced by detected phase currents and phase voltages. Simulation results show that position angle errors of PMLMs are fully compensated. Using the designed position angle error compensator, currents can be controlled in a more precise manner. 相似文献
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A dynamic geometry model was built to describe the Doppler-broadening characteristics of the first-order Bragg lines for bistatic shipborne surface wave radar. They are time-varying because the Doppler frequency shifts of sea echoes are simultaneously modulated by the velocity components projected from the unavoidably different motions of both platforms, which is more complex than its counterpart in the monostatic mode. The geometrical relation is used to obtain the received signal model: strong first-order sea clutter interferences and submerged ship targets with constant and non-constant speeds are considered as mixed-order multicomponent polynomial-phase signals (mc-PPSs) and both second-order sea clutter continuum and atmospheric noise as additive noise. Then, a scheme based on the product high-order ambiguity function is proposed to extract the targets; it is a recursive procedure in which the first-order sea clutter is removed by an existing time-space cascaded filtering method. Monte Carlo simulations show the validity and efficiency of the proposed scheme. 相似文献
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大视场线结构光视觉传感器的现场标定 总被引:2,自引:0,他引:2
针对大视场线结构光视觉传感器的现场标定,提出了一种基于自由组合一维靶标的标定方法。自由组合多个一维靶标并固定,其中每个一维靶标至少包含3个共线特征点。靶标在传感器测量空间内自由摆放至少两次。以一维靶标两两之间夹角恒定为约束求解摄像机内部参数;由一维靶标消影点性质和特征点之间距离约束,求解各特征点在摄像机坐标系下的空间坐标;根据交比不变计算光平面与各一维靶标交点的摄像机坐标,拟合出光平面方程。实验表明,该方法可获得与平面靶标相当的标定精度,具有靶标加工容易、精度高、摆放次数少的特点,适合大视场线结构光视觉传感器的现场标定。 相似文献
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The purpose of this paper is to propose an effective solution scheme of simultaneous optimization design of layup configuration and fiber distribution for maximum stiffness design of laminated plates. Firstly, a numerical analysis of the lamination parameters feasible region for a laminated plate consisting of various given number of ply groups (each ply group may have different thickness and all the fibers in one ply group are orientated in an identical direction) is carried out, and it is found that the feasible region based on only a few ply groups is very close to the overall one determined by infinite plies. Therefore, it is suggested that the feasible region of lamination parameters of a laminated plate could be approximately determined by the layup configuration of least ply groups. Secondly, a two-step simultaneous optimization scheme of layup configuration and fiber distribution for maximum stiffness design of laminated plates is proposed. Accordingly, by using ply thickness, fiber orientation angle and fiber volume fraction in a laminated plate of least ply groups as design variables, the optimal lamination parameters for maximum stiffness is obtained. Then, taking the optimal lamination parameters as the design objective, a detailed layup design optimization is implemented by considering some limitations on manufacturing, such as preset ply thickness, and specific fiber orientation angle and a limited maximum number of consecutive plies in the same fiber orientation. Numerical examples are also presented to validate the proposed two-step optimization scheme. 相似文献
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采用多源图像分形特征的多目标检测方法 总被引:1,自引:1,他引:0
针对多目标的检测,本文提出一种采用多源图像分形特征的特征级融合检测方法.首先对多目标检测的特点进行了分析,对分形理论进行了介绍,然后详细介绍了该融合检测算法的思路和原理.该算法首先由红外图像阈值分割出部分目标;然后利用分维数图的统计特征可以增强分形维数的奇异性,在可见光图像的分维数图中搜索与已检测出的目标区域具有相近分形统计特征的区域,进行标记;再根据"距离相似度准则"进行目标的聚类识别,排除背景干扰,最终检测出全部目标.实验结果表明该融合检测算法能有效地进行多目标的检测与识别. 相似文献