一种基于子波包和中值滤波的图像去噪方法

通过对图像的子波包变换进行阈值操作，可以较好地滤除高斯白噪声，但图像中往往还含有脉冲噪声，运用中值滤波可以有效地滤除脉冲噪声，将子波包变换和中值滤波相结合，可以有效地降低图像噪声，达到比改进的均值滤波算法更理想的效果。     

基于Matlab的Bark子波实现

文章给出了一种用Matlab实现Bark子波的方法．引入子波基函数与实际频率的关系，介绍了Bark子波的定义和数学性质，结合Matlab进行算法实现并进行了仿真实验，结果表明Bark子波对语音信号具有很好的重构性能。     

海上高分辩率采集

海洋石油地震勘探是由陆地地震勘探发展而来,先延展至浅海,最后发展到深海.海上地震数据采集设备,包括震源系统,数据记录系统和导航定位系统.随着海洋石油能源开发的需求,以及科学技术的快速发展,采集设备和方法得到了不断的改进、更新和发展.追求高的分辩率,贯穿于地震勘探的始终.随着我国石油工业的发展,较大的、易于勘探的构造型油田,首先被找到和开发,现在要觅找的石油资源,不是地震勘探难于开展的地区,就是小的油气藏或地质条件十分复杂的区域.我国海上油气层薄,非构造油藏多,没有高分辩率的地震资料,许多油田是难于寻找和开发,以至于高投入低产出,得不偿失.尽管我国开展高分辩率勘探时间不是很长,起步晚,但发展相当快.近二十余年来,我国的高分辩率地震勘探相继在南海渤海显现成效.可以相信,高分辩率地震勘探将促进海洋石油的迅速发展.     

Novel Adaptive Beamforming Algorithm Based on Wavelet Packet Transform

An analysis of the received signal of array antennas shows that the received signal has multi-resolution characteristics, and hence the wavelet packet theory can be used to detect the signal. By emplying wavelet packet theory to adaptive beamforming, a wavelet packet transform-based adaptive beamforming algorithm (WP-ABF) is proposed . This WP-ABF algorithm uses wavelet packet transform as the preprocessing, and the wavelet packet transformed signal uses least mean square algorithm to implement the adaptive beamfonning. White noise can be wiped off under wavelet packet transform according to the different characteristics of signal and white under the wavelet packet transform. Theoretical analysis and simulations demonstrate that the proposed WP-ABF algorithm converges faster than the conventional adaptive beamforming algorithm and the wavelet transform-based beamforming algorithm. Simulation results also reveal that the convergence of the algorithm relates closely to the wavelet base and series; that is, the algorithm convergence gets better with the increasing of series, and for the same series of wavelet base the convergence gets better with the increasing of regularity.     

MA(q)模型参数的估计——一种混合相位子波反演算法

笔者在文中讨论了混合相位子波A的反演问题.利用高阶累积矩获得近似反子波B(0),再通过B(0)与地震记录S褶积生成数据S=B(0)*S,最后对模型S=C(0)*r采用统计递归算法SRA[14]得到介入子波C(0)=(C,C*).真实子波A的估计通过解方程C=B(0)*A得到.如果混合相位子波A的长度有限,我们的算法可获得相当满意的结果.     

利用子波变换实现的雷达目标跟踪滤波器

本提出了利用非降样子波分解实现的雷达目标跟踪滤波器,并对其性能进行了理论上和实验上的分析。分析表明这一滤波器对噪声强度和目标机动的变化比卡尔曼方法具有更好的鲁棒性。     

A Robust Interacting Multisensor State Fusion Based on Adaptive Outlier Controlling Multirate Model

An adaptive outlier controlling multirate model based on Hong’s multirate kinetic model was represented in order to resist the outliers and utilize their useful information. Wavelet transform was introduced to detect and control the outliers. The multirate information extraction and the controlling of outliers were properly integrated to establish an adaptive outlier controlling multirate model. The proposed model was applied to multisensor state fusion with interacting multiple model (IMM), and a robust interacting multisensor state fusion algorithm was established based on adaptive outlier controlling multirate model. The Monte-Carlo simulation shows that it could improve the accuracy of fusion estimation by 70% compared to Hong’s algorithm and at least 14% to Xiao’s algorithm.     

Wavelet De-noising of Speech Using Singular Spectrum Analysis for Decomposition Level Selection

The problem of speech enhancement using threshold de-noising in wavelet domain was considered.The appropriate decomposition level is another key factor pertinent to de-noising performance.This paper proposed a new wavelet-based de-noising scheme that can improve the enhancement performance significantly in the presence of additive white Gaussian noise.The proposed algorithm can adaptively select the optimal decomposition level of wavelet transformation according to the characteristics of noisy speech.The experimental results demonstrate that this proposed algorithm outperforms the classical wavelet-based de-noising method and effectively improves the practicability of this kind of techniques.     

子波变换及其在股市数据分析中的应用

把股票日收益率看作一维时间信号,通过子波变换与多尺度分析,求出了体现股市数据奇性的Lipschitz指数α。α为负表明在奇点比不连续更加奇异,证明了股票价格的变化是分形的。同时,由文中图示可知,在尺度s很大时,子波变换和多尺度分析可以将股市数据中偶然因素造成的涨跌消除,具有突出主要因素和客观突变点的特点,这一点对于从宏观上预测股价的走势有重要意义。