一种利用Gabor小波特征的目标跟踪方法

小波特征跟踪是一种新的目标跟踪方法。这种方法利用Gabor小波提取目标的边界特征来组成特征模板,并由小波滤波器系数组成特征向量。在跟踪过程中不断优化特征模板的旋转、尺度及平移等几何变形参数,使得小波特征向量值在最小平方和的意义上与初始值相匹配,从而实现目标旋转、尺度及平移等几何变形时的自动跟踪。实验表明,该方法能够有效地跟踪飞机、车辆等目标,并且能够抵抗全局亮度的变化和局部遮挡的干扰。     

基于Gabor小波纹理特征的目标识别新方法

给出了一种基于Gabor小波纹理特征的目标识别新方法．主要是利用Gabor小波设计了一种多通道小波滤波器。对图像目标直接进行小波变换，用Gabor小波变换系数的模的平均值和其标准方差来表示抽取的图像目标的特征，把获得的小波特征归一化后输入到改进的BP神经网络分类器进行分类识别．最后。进行了一系列的仿真实验，结果表明，这种特征提取方法能有效提取图像目标纹理特征，并且对噪音和形状的变化具有鲁棒性．在应用于目标识别时，神经网络的训练时间减少到lOmin，识别率达到94％．     

基于多通道Gabor滤波器的高鲁棒灰度图像目标识别新方法

提出了一种针对低质量的灰度图像的基于多通道Gabor小波滤波器的高鲁棒目标识别新方法。主要是利用Gabor小波设计了滤波器,滤波器的中心频率是一个从低到高的范围。滤波器采用不同方向、不同尺度,从而组成多通道滤波器。对灰度图像直接进行小波变换,用Gabor小波变换系数的模的平均值和其标准方差来表示抽取的灰度图像目标的特征,并对获得的小波特征归一化后输入到改进的BP神经网络分类器中进行分类识别。对四种不同的飞机灰度图像目标进行了分类识别仿真实验。结果表明,这种特征提取方法能有效地提取灰度图像目标纹理特征,并且对噪音和形状的变化具有强鲁棒性。在应用灰度图像对目标进行识别时,神经网络的训练时间减少到10min,识别率达到94%。     

基于Gabor小波变换的ICA火灾图像纹理识别算法

针对火灾图像纹理识别问题,提出了基于Gabor小波变换的ICA火灾图像纹理识别算法,并根据火灾图像纹理识别特点进行了优化。首先用不同尺度和方向的Gabor滤波器对待识别图像滤波,得到其特征图像,然后将特征图像转化成特征向量作为ICA的输入,得到基矢量子空间,再将测试图像经过Gabor滤波器的特征向量投影到ICA子空间中得到系数向量作为目标识别特征,最后用支持向量机进行识别。通过与Gabor滤波器法和ICA方法的对比实验,表明该算法可以在火灾纹理图像的识别率上比传统方法提高5%以上,为火灾图像识别提供了一种新思路。     

菲涅耳数字全息图的Gabor小波变换再现法

提出了一种基于Gabor小波变换的菲涅耳全息图的数值再现方法,实现无需空间滤波处理,即可对物光波进行数值再现.给出Gabor小波变换以及小波变换脊的定义,并从理论上证明通过对全息图进行Gabor小波变换,提取小波变换脊对应的小波变换系数,包括幅值与相位信息,即可直接获得与+1级频谱相对应的被测物光在全息面上的强度与相位分布,并同时直接消除零级衍射像以及孪生像的影响.通过计算机模拟再现光波经全息图衍射后的传播规律实现数值再现,得到清晰的再现像.通过计算机模拟一相位型物体以及实验证明该方法的有效性.     

基于跟踪度的Gabor小波特征跟踪方法的研究

图像的边缘包含了目标的大量特征信息。利用Gabor小波可以从目标图像中提取具有特征位置、角度和尺度的参数。利用这些参数可以重建除均值以外的所有图像信息。图像边缘与均值无关。根据重建图像边缘线段的长度和边缘拟和度以及特征点的个数,提出了跟踪度的概念,分析了跟踪度的性质,并在跟踪度准则指导下确定了跟踪的特征点个数。仿真实验证明,跟踪度反映了目标特征跟踪的可靠程度,提供了跟踪精度的客观标准,为选择特征点个数、平衡计算复杂度和跟踪精度提供了客观的依据。通过对目标进行姿态变换和大面积遮挡的跟踪实验证明,当跟踪度达到0 95以上时就可以稳定地跟踪目标。     

新生儿疼痛面部表情识别方法的研究

针对新生儿的疼痛与非疼痛面部表情识别,提出将Gabor变换和支持向量机(SVM)相结合的分类识别方法.对归一化后的大小为112 pixel×92 pixel的新生儿面部图像进行二维Gabor小波变换,提取出412160维Gabor特征;针对Gabor特征向量维数高、冗余大的特点,采用Adaboost算法作为特征选择工具,去除冗余的Gabor特征,从412160维特征中选取出900维Gabor特征;对选取出的Gabor特征用SVM进行疼痛表情的分类识别.该方法综合运用Gabor特征对于面部表情的良好表征能力、AdaBoost算法的特征选择能力以及SVM在处理少样本、高维数问题中的优势.对510幅新生儿的表情图像进行测试的结果表明,疼痛与非疼痛表情的分类识别率达到85.29%,疼痛与安静表情的分类识别率达到94.24%,疼痛与哭表情的分类识别率达到78.24%.     

一种新的红外成像末制导目标跟踪方法

为了稳定跟踪导弹末制导阶段的红外目标,提出了一种基于尺度不变特征变换的红外目标跟踪算法.尺度不变性特征变换所提取的图像纹理特征具有尺度和旋转不变性,跟踪算法分别提取目标模板和待跟踪图像的尺度不变特征变换特征.根据最小欧氏距离准则提取目标模板与待跟踪图像间相匹配的尺度不变特征变换特征点对,利用该特征点对拟合反映两图像间映射关系的仿射模型,并据此估计目标中心位置及调整目标模板尺寸.仿真结果表明,跟踪算法能够较好地实现在导弹末制导阶段对红外地面杂波背景下目标的稳定跟踪,其跟踪准确度和稳定度优于传统方法.
关键词:末制导跟踪|尺度不变性特征变换|特征匹配|仿射模型     

一种自适应的Gabor图像特征抽取和权重选择的人脸识别方法

为了克服光照、表情变化等因素对人脸识别的影响,本文提出了一种自适应的Gabor图像特征抽取和权重选择的人脸识别方法.该方法首先把每幅人脸图像经过Gabor小波变换后得到的40个不同尺度和方向下的图像都看作是独立的样本,再把不同人脸中的同一尺度和方向的变换结果进行特征重组,得到40个独立地新特征矩阵.为了增强对光照、表情...     

利用黑洞原理改进稀疏外观模型跟踪算法

为了解决跟踪漂移问题,提出了一种利用黑洞原理改进的稀疏外观模型目标跟踪算法,用来提高目标跟踪的鲁棒性。利用黑洞原理从目标模板中搜索聚类中心来降低目标模板数量。通过学习分类器用于构造目标特征;用黑洞原理获取模板字典表示目标;采用高斯分布运动模型获取目标样本,在贝叶斯框架下根据观测模型获取最优目标位置实现跟踪。不同视频序列被用于改进的稀疏外观模型跟踪算法和其他先进目标跟踪算法进行仿真实验。实验结果表明,实现了目标跟踪的目的,有效地降低了目标局部遮挡问题的影响,提高了目标跟踪精度。     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.