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提出了利用一种新方法获取合适的环形对称Gabor核函数窗口提取人脸图像的纹理信息,并结合改进的PCA进行人脸识别的方法.首先将人脸与环形Gabor小波函数卷积得到图像在5个尺度上的变换,该过程采用一种新方法获取合适的Ga-bor核函数窗口,以保证与人脸图像卷积后得到更为合理的人脸特征,同时利用一种新的分块PCA方法,将环形Gabor滤波后的子图像分组,对分组后的图像平均分块再进行降维,在空间位置上提取出Gabor人脸细节的主要特征,有效降低了人脸特征冗余.通过实验验证该方法在3.5m内对人脸识别率达到95%,单个人脸识别时间小于0.22 s. 相似文献
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提出了利用一种新方法获取合适的环形对称Gabor核函数窗口提取人脸图像的纹理信息,并结合改进的PCA进行人脸识别的方法。首先将人脸与环形Gabor小波函数卷积得到图像在5个尺度上的变换,该过程采用一种新方法获取合适的Gabor核函数窗口,以保证与人脸图像卷积后得到更为合理的人脸特征,同时利用一种新的分块PCA方法,将环形Gabor滤波后的子图像分组,对分组后的图像平均分块再进行降维,在空间位置上提取出Gabor人脸细节的主要特征,有效降低了人脸特征冗余。通过实验验证该方法在3.5 m内对人脸识别率达到95%,单个人脸识别时间小于0.22 s。 相似文献
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该文提出了一种基于Gabor滤波器和Three-Patch Local Binary Patterns(TPLBP)局部纹理特征提取的合成孔径雷达(Synthetic Aperture Rader, SAR)图像目标识别算法。首先, 利用Gabor滤波器对SAR图像在不同方向上进行滤波, 增强SAR图像中目标及其阴影的关键特征;然后, 利用TPLBP算法对Gabor滤波之后的图像进行局部纹理特征提取, 该算法克服了Local Binary Patterns(LBP)算法无法描述大范围领域纹理特征的缺陷, 并且保持了LBP旋转不变的特性, 减少了SAR图像目标方位变化对识别效果的影响;最后利用极限学习机(Extreme Learning Machine, ELM)分类器实现目标识别。该文通过MSTAR数据库中的3类SAR目标识别实验验证了该算法的有效性。 相似文献
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基于Gabor小波变换和两次DCT的人脸表情识别 总被引:2,自引:1,他引:1
提出了一种基于Gabor小波变换和两次离散余弦变换(DCT)相结合的人脸表情特征提取方法,在保留有效的纹理信息基础上降低了表情特征的维数.首先对人脸表情图像进行第一次DCT压缩图像,然后对处理过的图像执行Gabor变换,提取表情特征,进而对得到的不同尺度和方向的特征图像进行第二次DCT,得到包含大量表情信息的低维特征向量,最后用BP神经网络对特征向量分类.实验结果显示该方法识别率较高. 相似文献
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伊力哈木·亚尔买买提 《电子器件》2019,42(1)
针对人脸在非均匀光照下识别率的降低,提出了拉普拉斯滤波和离散余弦变换(DCT)融合梯度方向直方图(HOG)人脸识别算法。首先通过拉普拉斯滤波对人脸图像进行处理,突出其纹理特征,其次进行离散余弦变换(DCT),有效滤除高频分量,然后利用离散余弦逆变换(IDCT)重建人脸图像,降低其维数,最后通过梯度方向直方图(HOG)算子提取人脸图像固有特征,并利用最近邻方法进行分类识别。实验结果表明,该算法在不同特征维数下的Yale B人脸数据库中识别率高达95%以及课题组自建的维吾尔族人脸数据库中其识别率高达98.5%,优于其他传统算法?具有很强的鲁棒性和实时性。 相似文献
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提出一种基于二维Gabor过滤器对人体血液细胞图像中粘连的红细胞和白细胞进行分割的方法.通过分析、简化、分解Gabor函数,设计了Gabor的多个参数,包括中心频率(ρ),滤波方向θ,以及沿着z轴和y轴Gaussian包络的空间常量σ.在算法的过程中,使用一组包括多个方向和多个频率组合的Gabor过滤器对血液图像进行滤波,提取出图像的纹理特征,然后按照一定的规则对特征图像进行合并,最后再用聚类算法进行分割.实验结果表明该方法具有很好的效果. 相似文献
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聚对苯撑苯并双(口恶)唑发光及其器件制备 总被引:2,自引:0,他引:2
采用光谱技术,研究了聚对苯撑苯并双(口恶)唑(PBO)溶液的光敏发光特性,并用相对法估算出溶液发光效率在50%范围.结合光谱技术、半导体电学和电化学等研究手段,具体研究了以PBO为发光层的单层电致发光器件,研究结果显示,电致发光与薄膜的光致发光有具有相同的发光中心,峰值位于510 nm左右.同时发现,由于存制备过程中不同处理条件使得不同厚度薄膜残留的掺杂物质浓度不同,从而引起薄膜的导电性的不同.使得器件的阈值场强随PBO厚度的减小而逐渐增加. 相似文献
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在高密度小尺寸的系统级封装(SiP)中,对供电系统的完整性要求越来越高,多芯片共用一个电源网路所产生的电压抖动除了会影响到芯片的正常工作,还会通过供电网路干扰到临近电路和其他敏感电路,导致芯片误动作,以及信号完整性和其他电磁干扰问题.这种电压抖动所占频带相当宽,几百MHz到几个GHz的中频电源噪声普通方法很难去除.结合埋入式电容和电源分割方法的特点,提出一种新型高性能埋入式电源低通滤波结构直接替代电源/地平面.研究表明,在0.65~4GHz的频带内隔离深度可达-40~75 dB,电源阻抗均在0.25ohm以下,实现了宽频高隔离度的高性能滤波作用.分别用电磁场和广义传输线两种仿真器模拟,高频等效电路模型分析这种低通滤波器的工作原理以及结构对隔离性能的影响,并进行了实验验证. 相似文献
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Aluminium was a primary material for interconnection in integrated circuits (ICs) since their inception. Later, copper was introduced as interconnect material which has better metallic conductivity and resistance to electromigration. As the aggressive technology scaling continues, the copper resistivity increased because of size effects, which causes increase in delay, power dissipation and electromigration. The need to reduce the resistor-capacitor??????? delay, dynamic power utilisation and the crosstalk commotion is as of now the fundamental main impetus behind the presentation of new materials. The purpose of this paper is to do a survey of interconnect material used in IC from introduction of ICs to till date. This paper studies and reviews new materials available for interconnect application which are optical interconnects, carbon nanotube (CNT), graphene nanoribbons (GNRs) and silicon nanowires which are alternatives to copper. While doing a survey of interconnect material, it is found that multiwalled CNTs, multilayer GNR and mixed CNT bundles are promising candidates and are ultimate choice that can strongly address the problems faced by copper but on integration basis copper would last for coming years. 相似文献
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C. Fulk R. Sporken J. Dumont D. Zavitz M. Trenary B. Gupta G. Brill J. Dinan S. Sivananthan 《Journal of Electronic Materials》2005,34(6):846-850
We investigate the properties of arsenic (As) covered Si(211) and Si(311) surfaces by analyzing data from x-ray photoelectron
spectroscopy (XPS) and low-energy electron diffraction (LEED) images. We then create a model using total surface energy calculations.
It was found that both Si(211) and Si(311) had 0.68±0.08 surface As coverage. Si(211) had 0.28±0.04 Te coverage and Si(311)
had 0.24±0.04 Te coverage. The Si(211) surface replaces the terrace and trench Si atoms with As for a lower surface energy,
while the Si edge atoms form dimers. The Si(311) surface replaces all terrace atoms and adsorbs an As dimer every other edge
site. These configurations imply an improvement in the mean migration path from the bare silicon surface by allowing the impinging
atoms for the next epitaxial layer, tellurium (Te), to bind at every other pair of edge atoms, and not the step terrace sites.
This would ensure a nonpolar, B-face growth. 相似文献
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光子晶体微腔发光二极管 总被引:1,自引:0,他引:1
光子晶体微腔因其具有增强自发辐射、定向输出和单模工作的能力而受到广泛关注。介绍了光子晶体微腔发光二极管的基本原理、设计、特性、制作及其典型器件。 相似文献
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The power generation demand is increasing day-by-day throughout the world, therefore, the use of hybrid systems becomes a significant solution. The hybrid renewable energy system (HRES) is used for delivering power in various regions in order to overcome intermittence of wind and solar resources. Because of increasing environmental problems, for example, greenhouse gas emission and energy cost have interested novel research into substitute methods in favour of electrical power generation. Maximum Power Point Tracking (MPPT) control method is a vast deal of novel research used for enhancing the efficiency of HRES. The authors have revealed that the hybrid techniques i.e. Global MPPT, fuzzy-neuro systems, Adaptive Neuro-Fuzzy Inference System (ANFIS), Perturbed and Observe (P&O) + Adaptive Neural Network (ANN) etc. can provide best results as compared to other MPPT control methods. This paper offering a state of art review of MPPT control techniques for HRES. 相似文献
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Fangqiu Wang Chenghua Wang Shengkui Zhou 《International Journal of Electronics》2013,100(10):1765-1788
Impulse radio ultra-wideband (IR-UWB) ranging and positioning require accurate estimation of time-of-arrival (TOA) and direction-of-arrival (DOA). With receiver of two antennas, both of the TOA and DOA parameters can be estimated via two-dimensional (2D) propagator method (PM), in which the 2D spectral peak searching, however, renders much higher computational complexity. This paper proposes a successive PM algorithm for joint TOA and DOA estimation in IR-UWB system to avoid 2D spectral peak searching. The proposed algorithm firstly gets the initial TOA estimates in the two antennas from the propagation matrix, then utilises successively one-dimensional (1D) local searches to achieve the estimation of TOAs in the two antennas, and finally obtains the DOA estimates via the difference in the TOAs between the two antennas. The proposed algorithm, which only requires 1D local searches, can avoid the high computational cost in 2D-PM algorithm. Furthermore, the proposed algorithm can obtain automatically paired parameters and has better joint TOA and DOA estimation performance than conventional PM algorithm, estimation of signal parameters via rotational invariance techniques algorithm and matrix pencil algorithm. Meanwhile, it has very close parameter estimation to that of 2D-PM algorithm. We have also derived the mean square error of TOA and DOA estimation of the proposed algorithm and the Cramer-Rao bound of TOA and DOA estimation in this paper. The simulation results verify the usefulness of the proposed algorithm. 相似文献
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超宽带脉冲信号的光学生成方法研究 总被引:1,自引:0,他引:1
近年来超宽带(UWB)通信技术迅猛发展,在测量、雷达技术、民用和军事无线通信中有着重要的应用,UWB-over-fiber技术已经成为目前研究的热点,其中就包括UWB脉冲信号的产生方法。区别于传统的电子学方法,光子学产生方法不受电子瓶颈制约,可以实现很高的带宽,并且具有抗电磁干扰、重量轻、结构紧凑的优点。通过对比国内外本领域研究成果,讨论及总结了以下三种原理的UWB脉冲信号的光学生成方法:1)相位调制-强度调制转换(PM-IM);2)半导体光放大器(SOA)的非线性效应;3)频谱塑形和色散所致频域-时域映射,然后对各种方案进行了对比分析。 相似文献
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多孔硅发光机制的分析 总被引:4,自引:0,他引:4
从量子力学的基本理论出发讨论了量子限制效应,推导出多孔硅有效禁带宽度增量并用量子限制效应和表面态及其物质在发光中作用的理论解释了PS光致发光的实验现象。 相似文献