共查询到20条相似文献，搜索用时 250 毫秒
1.
随着汽车流动量的增大,运用汽车管理系统来进行车型识别、自动收费以及交通事故认定工作愈来愈重要。单纯的视频识别受环境因素影响较大,雨雾等天气状况都会严重影响识别结果。采用针对发动机声音的识别方法,可以有效降低环境因素的影响,完成汽车类型的识别。采用MP稀疏分解方法,用Gabor原子进行信号的分解及重构,重构后的信号能较好反映原信号的特征。发动机声音信号相对平稳,信号分解后频域相对稳定,采用单帧进行识别,可满足实时性要求。识别采用BP神经网络作为识别机,效果较好,对于交通系统中的车辆类型识别具有较高的参考价值。 相似文献
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图像融合是进行目标检测和识别的重要技术之一,广泛应用于军事、计算机视觉、医学以及其他领域.文章探讨基于多分辨率分解的像素级图像融合方法的设计,重点研究基于小波变换的融合算法的实现,经仿真取得较好的效果. 相似文献
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为了更好地识别强干扰下的地震信号,介绍了一种改进的小波阈值去噪法对天然地震信号和人工爆破信号去噪.去噪后的信号经过经验模态分解之后,取第一个IMF分量.经过希尔伯特黄变换之后提取HHT谱幅比特征和自相关函数的均值特征,利用支持向量机建立天然地震和人工爆破的模型.在利用建立的模型识别已知的震源类型,判断改进的去噪法对震源类型识别的效果.实验结果表明:去噪法改进之后,对天然地震和人工爆破的识别率有显著的提高. 相似文献
4.
张继才 《数理天地(高中版)》2002,(6)
力的分解是依据力的作用效果进行的,同理,运动的分解也是依照运动效果进行的.也就是说,将实际运动按照一定的效果进行分解。分解成几个效果运动的过程即为运动的分解.运动的分解如同力的分解,遵循平行四边形法则.下面就依据运动的分解法则浅析四种运动的分解方法. 相似文献
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心理学研究结果表明语义透明度会影响学习者对整词词义的识别,但大部分研究主要针对母语者,我们以泰国学生为实验对象,研究其在汉语词汇整词识别过程中语义透明度是否存在影响,实验研究表明语义透明度对初级水平泰国学生学习汉语词汇影响较小,中级水平泰国学生的词素分解意识泛化则导致了不透明词的高错误率.我们认为被试母语的构词方式决定了被试是否具有词素分解意识,这种意识又决定了语义透明度的影响程度. 相似文献
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为解决传统可见光成像在步态信息检测与身份识别中存在的诸多问题,提出了利用人体红外辐射成像及身份认证的新方法。首先将人体自身辐射的红外光转换为红外热图像,然后分割人体目标并将目标轮廓归一化,同时将轮廓序列叠加以获取红外信息能量图,再对其进行小波分解;提取红外信息能量图分解后的边界矩参数及骨架特征参数,以此作为特征参量输入支持向量机进行身份识别,正确识别率（PCR）为78%～91%,且识别效果不受人体携带外物（如背包、抱球）的影响,仅受衣着的影响较大。研究表明：基于人体红外辐射的身份识别有利于人体目标检测与精确描述。 相似文献
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分析了变量的自相似是LRC算法中线性回归模型中的不利因素,提出了改进的LRC算法.该算法利用奇异值分解降低变量间的自相似程度,同时减少了变量的个数,提高了识别过程的速度.在UMIST人脸数据库中的实验显示了算法的有效性. 相似文献
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解决物理问题,既要能熟练应用常规方法,又要能突破常规灵活求解.如分解一个矢量时,没有必要一定采用常规的分解方法（如分解力时常用的正交分解法）,也可以采用非常规的分解方法.因为没有特殊限制的话,一个矢量可以分解为无数对大小、方向不同的分矢量,这些分矢量共同作用的效果,都与那一个矢量单独作用的效果相同,所以,分解矢量完全可以打破常规采用其他的方法.如对中学物理中出现的小船渡河、力的分解、平抛运动、斜上抛运动等问题来说,如果善于打破常规采用非常规分解方法,会有简捷快速的效果,也会对活学物理有一定的启发.本文对所举例题的常规分解方法将不做赘述. 相似文献
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目的：齿轮箱的振动信号频谱结构比较复杂,难以提取其故障特征频率。傅里叶分解方法可以将振动信号分解为多个单分量信号,利用共振频率筛选出最优分量并进行包络解调,识别特征频率以实现故障诊断。创新点：1.为了求解共振频率,提出一种基于短时向量的最大奇异值比方法;2.将傅里叶分解方法引入到齿轮箱故障诊断中,并利用共振频率选择最优分量进行包络解调以提取故障特征频率。方法：1.分析奇异值比与冲击信号的关系,提出求解共振频率的最大奇异值比方法;2.对比最大奇异值比方法与谱峭度方法在求解共振频率方面的表现,从而验证最大奇异值比方法的有效性;3.对比分析所提方法与传统的总体经验模态分解（EEMD）和变分模态分解（VMD）方法在信号分解与故障特征提取方面的效果,并通过仿真和实验进行验证。结论：1.最大奇异值比方法能够准确计算出共振频率,比谱峭度方法求解的频率值更加精确;2.基于傅里叶分解方法和最大奇异值比的共振解调方法能够有效提取故障特征频率,其在故障诊断方面的表现优于EEMD和VMD方法。 相似文献
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虹膜识别技术是一种非侵犯性的身份鉴别技术.文中探讨了虹膜识别系统,该系统分为虹膜图像的捕获、图像的预处理、特征提取和匹配几大部分;并在此基础上提出了自动虹膜识别算法和虹膜图像的校准技术,最后用基于相位匹配和二维傅里叶变换的幅值差方法来确定虹膜图像的匹配结果.实验证明,该方法运算速度较快,识别效果良好. 相似文献
12.
乔静 《西安文理学院学报》2009,12(4):45-47
采用粗定位和精定位相结合的方法进行虹膜定位.首先,利用虹膜为环形的特点,采用几何算法粗略得出虹膜外边界的圆心和半径.然后利用瞳孔区域的灰度值较小的特点对虹膜的内边界进行粗定位.最后根据粗定位的结果采用一定的算子对虹膜的内、外边界精确定位.实验结果表明,定位的精度较高,且速度较快. 相似文献
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在虹膜识别系统中，虹膜图像的质量是影响识别效果的一个重要因素，在对现有虹膜图像质量评价算法分析的基础上，针对引起“注册失败”的最主要的几个因素，建立了一种综合的虹膜质量评价模块。实验表明，该方法的虹膜质量综合评价因子对虹膜图像的质量评价结果符合主观评价方法的评价结果。 相似文献
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根据虹膜的环状结构特性以及眼部图像的灰度分布特点,提出了基于梯度方向信息的虹膜定位方法.实验证明,该算法能提高虹膜定位的速度和精度. 相似文献
16.
YUAN Xiao-yan ZHOU Hao SHI Peng-fei 《浙江大学学报(A卷英文版)》2007,8(8):1227-1231
Iris recognition,as a biometric method,outperforms others because of its high accuracy. Iris is the visible internal organ of human,so it is stable and very difficult to be altered. But if an eye surgery must be made to some individuals,it may be rejected by iris recognition system as imposters after the surgery,because the iris pattern was altered or damaged somewhat during surgery and cannot match the iris template stored before the surgery. In this paper,we originally discuss whether refractive surgery for vision correction(LASIK surgery) would influence the performance of iris recognition. And experiments are designed and tested on iris images captured especially for this research from patients before and after refractive surgery. Experiments showed that refractive surgery has little influence on iris recognition. 相似文献
17.
MOTIVATION Iris recognition, widely accepted as one of the best biometrics recognition methods in the world because of its stability, uniqueness and noninvasive-ness (Adler, 1965; Daugman, 1993; Ma et al., 2002; Wildes, 1997), has the potential of applications in very wide areas. As a kind of pattern recognition to classify the iris correctly by comparing the similarity between irises, two major works are: (1) to find the appropriate features to represent iris properly; and (2) to classi… 相似文献
18.
郭曙光 《南宁职业技术学院学报》2010,15(5):93-96
虹膜识别的网络身份认证系统包含虹膜注册、识别模块、网络传输模块及数据加密等三大模块。用统计学原理统计不同阈值下的FAR、FRR,选择合理阈值,提高了系统识别率。结合网络传输及DES数据加密算法,实现了基于虹膜识别的网络身份认证系统。 相似文献
19.
Prevalence of combined reading and arithmetic disabilities 总被引：1，自引：0，他引：1
Dirks E Spyer G van Lieshout EC de Sonneville L 《Journal of learning disabilities》2008,41(5):460-473
This study assesses the prevalence of combined reading and arithmetic disabilities in 799 Dutch schoolchildren using st dardized school achievement tests. Scores of arithmetic, word recognition, reading comprehension, and spelling of child in fourth and fifth grade were used. The main interest involved the co-occurrence of word recognition and arithmetic d abilities because of their possible relationship. The authors find a percentage of 7.6 for combined reading and arithme disabilities. Reading disabilities and arithmetic disabilities co-occurred more often than expected based on rates of the s arate conditions. Children with combined reading and arithmetic disabilities seem to have more generalized achievem difficulties than single-deficit groups. Different operationalizations for reading disabilities (spelling and reading comp hension measures instead of word recognition) led, in part, to selection of other children. This might imply that differ processes underlie the relationship between arithmetic and word recognition disabilities compared to the relationship arithmetic disabilities with difficulties in spelling and reading comprehension. 相似文献
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Accuracy and fastness of iris localization are very important in automatic iris recognition. A new fast iris localization algorithm based on improved generalized symmetry transform (GST) was proposed by utilizing iris symmetry. GST was improved in three aspects: 1 ) A new distance weight function is defined. The new weight function, which is effective in iris localization, utilized the characteristic of irises that the iris is a circular object and it has one inner boundary and one outer boundary. 2) Each calculation of the symmetry measurement of a pair of symmetry points was performed by taking one point of a pair as the starting point of the transformation. This is the most important reason for fast iris localization, due to which, repetitious computation was largely excluded. 3) A new phase weight function was proposed to adjust GST to locate circle target much better because the inner part of iris is darker than the outer part. The edge map of iris image was acquired and GST was only implemented on the edge point, which decreased computation without loss of accuracy. The modification of distance weight function and phase weight function leads to the accuracy of localization, and other ideass peed up the localization. Experiments show that the average speed of new algorithm is about 7.0-8.5 times as high as traditional ones including integro-differential operator and Hough transform method. 相似文献