基于手背静脉虹膜和指纹融合身份识别算法

针对单模态生物特征识别的局限性,提出融合手背静脉、虹膜和指纹三种生物特征实现身份识别.首先分别对手背静脉图像、虹膜图像和指纹图像进行独立的图像预处理,特征提取和特征匹配,输出各自的匹配分数.分析匹配分数归一化对识别性能的影响,采用Tarh归一化方法对三种生物特征的匹配分数进行归一化处理,最后利用加权求和法则实现匹配分数的融合,利用最小距离分类器实现身份识别.实验结果表明,融合识别算法的等错率为0.009%,当错误接受率接近0时,对应的错误拒绝率仅为0.2%.     

基于kNN-SVM的手背静脉虹膜和指纹融合身份识别

针对识别模式下多生物特征融合识别系统的实现问题,本文基于手背静脉、虹膜和指纹三种生物特征研究了高效的融合识别算法。分别对三种生物特征进行特征提取与匹配,得到独立的匹配分数,基于k近邻(k Nearest Neighbor,kNN)分类器实现手背静脉特征识别,将用户身份范围缩小到k个,实现个人身份的初步识别,利用支持向量机(Support Vector Machine,SVM)算法实现k个样本范围内虹膜和指纹的融合识别,实现最终的个人身份识别。利用构建的三模态生物特征图像数据库进行了实验分析,实验结果表明该系统具有较高的识别性能,具有广阔的     

基于直方图统计特征的虹膜粗分类

为改善大规模虹膜数据库中虹膜匹配算法的性能,本文提出了一种基于灰度统计特征的虹膜类型识别算法.该算法首先将虹膜纹理区域划分为8个子块,然后利用直方图比率提取虹膜类型的直方图统计特征.最后,根据对应子块特征的相似度将虹膜图像识别为五种类型.所提算法在CASIA虹膜库中挑选的500幅虹膜图像样本上进行了测试.仿真实验结果表...     

基于边缘识别的虹膜定位算法

为了提高虹膜定位算法的抗干扰能力,本文提出了一种基于虹膜边缘识别的虹膜定位算法.该算法应用图像几何矩函数提取虹膜内外边缘的特征,通过由支持向量机(SVM)训练的分类器进行虹膜边缘点的识别.最后由Hough变换对识别的结果进行参数求解并实现虹膜的定位.本算法经过了CASIA虹膜图形库的实验验证,仿真实验数据表明所提算法不仅具有较快的定位速度和较高的定位成功率,而且性能稳定.     

基于图像匹配的移动机器人导航研究

针对移动机器人导航过程中基于尺度不变特征变换(SIFT)算法图像匹配速度较慢,提出了基于减法聚类和特征描述符二值化的改进SIFT算法。通过减法聚类消除大量特征点中的冗余特征点,在不影响原SIFT算法稳定性的前提下有效降低了特征点数量,然后将生成的特征描述符进行二值化,依据Hash函数生成索引,以汉明距离作为度量准则。实验结果表明:与原SIFT算法相比,改进的SIFT算法中特征点数量下降30%~40%;匹配对数基本维持不变;匹配率上升6%~12%;匹配时间下降60%~70%。与基于颜色矩的改进SIFT分级图像匹配算法相比,改进的SIFT算法中特征点数量下降15%~25%;匹配对数基本维持不变;匹配率上升5%~10%;匹配时间下降45%~55%。     

基于尺度、方向和距离约束的改进SIFT配准方法

针对SIFT算法在图像配准过程中存在遗漏掉大量的正确匹配对且产生误匹配对等问题,本文提出一种基于尺度、方向和距离约束的改进SIFT配准方法(SODC-SIFT).首先用SIFT算法对图像进行初匹配,利用特征点的尺度和主方向的差异剔除误匹配对;然后用最小二乘法求出两幅图像的几何关系;最后利用距离约束,迭代求解,找出正确匹配对,从而实现图像的精确配准.实验结果表明,本文方法与SIFT算法相比具有较强的鲁棒性,能够提升正确匹配对的数量并提高图像的正确匹配率,增强了算法匹配的精确性.     

基于SIFT的NSCT域抗几何攻击水印算法

目的针对基于尺度不变特征变换(SIFT)的抗几何攻击图像水印算法在图像匹配时容易产生误匹配,影响提取水印的鲁棒性,提出一种改进的SIFT图像水印算法。方法先对载体图像进行两级非下采样Contourlet变换(NSCT),利用中间值量化算法把水印信息嵌入低频系数的方向子带中。图像匹配时利用广义霍夫变换删除误匹配特征点对,提高匹配精度。根据筛选后的特征点匹配对估算几何失真参数,对含水印的载体图像进行几何校正并提取水印,从而实现水印的抗几何攻击。结果实验数据表明对原始特征点匹配对进行筛选后,至少提高了6.8%的匹配精度,提取水印的NC值平均达到0.9以上。结论文中提出的改进算法不仅对几何攻击和常规信号攻击均具有较好的鲁棒性,还能保证水印的不可见性。     

基于不变矩特征模型耦合相似度量规则的图像匹配算法

目的为了解决当前图像匹配算法因主要利用特征点之间的距离来实现特征匹配,从而忽略了特征点的结构特征,导致算法存在较多的漏匹配点以及错误匹配点等不足的问题。方法提出基于不变矩特征模型耦合相似度量规则的图像匹配算法。通过对待检测像素点构造的邻域圆上的点进行分类,制定检测规则,对FAST算子进行改进,利用改进的FAST算子快速、精准地检测图像的特征点。随后,构造不变矩特征模型,取代SIFT算法中获取特征向量的方法,生成低维度的特征描述符。通过Euclidean模型和SSIM建立相似度量规则,对特征点之间的相似度进行度量,完成图像的特征匹配。最后,引入随机抽样一致性(RANSAC)算法剔除错误匹配点,完成图像的匹配。结果仿真结果显示,相较于当前的图像匹配算法,所提算法具有更高的匹配正确度和鲁棒性,其查全率最高可达95%左右,且匹配效率较快,约为3.75 s。结论所提匹配方法具备良好的匹配精度,在图像信息安全、包装条码识别与拼接等领域具有一定的参考价值。     

相似度距离耦合角度径向变换的图像配准算法

目的为了解决当前图像配准算法因利用l1距离或l2距离相似度测量手段来完成图像特征点匹配,使其忽略了相位信息,难以有效消除高斯噪声的影响,使其配准精度与效率不佳不足的问题。方法提出最优相似度距离耦合角度径向变换的抗噪图像配准算法。首先引入角度径向变换,以降低算法复杂度,快速提取图像的特征点。然后联合图像的幅度和相位信息,基于欧式距离测度,定义最优相似度距离测量模型,通过求解其全局最小值,对特征点完成匹配,提高算法的抗噪性能。最后将图像分割为内点与外点,择取6个内点,通过计算其变换矩的几何配准误差,改进随机样本一致策略,对匹配进行提纯,消除误配。结果仿真实验结果显示,与当前基于l1距离或l2距离相似度测量的图像配准技术相比,该算法具有更强的抗高斯噪声性能和更高的匹配精度,且算法时耗最短。结论所提算法能够精确完成图像特征配准。     

基于灰度相关特征点的图像拼接算法

提出了一种基于特征点的图像拼接算法,首先利用Harris角点检测提取两幅图像中的特征点,用特征点邻域灰度相关性将特征点进行匹配,并在此基础上根据变换参数向量的欧式距离对误匹配进行剔除,进而实现图像拼接.实验表明,这种算法能有效的排除误匹配的干扰,降低误匹配率,拼接效果良好.     

一种新颖的虹膜识别方法

提出一种基于多纹理特征融合的新颖虹膜识别方法。该方法对虹膜图像做Gabor小波变换提取不同分辨力不同方向下的纹理特征作为虹膜的全局特征,在滤波后的子窗口图像上运用灰度级共现矩阵(COM)提取虹膜的局部特征。通过加权欧几里德距离和最小距离分别对全局特征和局部特征进行分类识别。设计了FIS(模糊推理系统)特征融合分类方法来提高虹膜识别的鲁棒性。实验结果表明本方法有效可行,可以达到98.5%的识别率,并在保持1.4%较低的FRR(拒绝率)的同时可以使FAR(误识率)减少到0.1%。     

Occlusion invariant face recognition using mean based weight matrix and support vector machine

In this paper, a novel occlusion invariant face recognition algorithm based on Mean based weight matrix (MBWM) technique is proposed. The proposed algorithm is composed of two phases—the occlusion detection phase and the MBWM based face recognition phase. A feature based approach is used to effectively detect partial occlusions for a given input face image. The input face image is first divided into a finite number of disjointed local patches, and features are extracted for each patch, and the occlusion present is detected. Features obtained from the corresponding occlusion-free patches of training images are used for face image recognition. The SVM classifier is used for occlusion detection for each patch. In the recognition phase, the MBWM bases of occlusion-free image patches are used for face recognition. Euclidean nearest neighbour rule is applied for the matching. GTAV face database that includes many occluded face images by sunglasses and hand are used for the experiment. The experimental results demonstrate that the proposed local patch-based occlusion detection technique works well and the MBWM based method shows superior performance to other conventional approaches.     

一种基于核主成分分析和组合分类器的虹膜识别方法

提出了一种新的虹膜特征提取与识别方法,该方法利用核主成分分析(KPCA)在高维空间具有较强的特征选择能力来提取虹膜图像的纹理特征。采用了一种距离度量和支持向量机相结合的两级分类方法,前级采用欧式距离来度量图像间的相似性,若符合条件,给出分类结果,否则拒绝,并转入后一级分类器——支持向量机分类,以减少进入支持向量机的样本数目,该组合分类方法充分利用了支持向量机识别率高和距离度量速度快的优点。实验结果表明,该方法提高了虹膜识别率,是一种有效的虹膜识别方法。     

基于人体手指指节折痕的身份识别方法

基于人体生物特征的认证是鉴别个人身份的有效方法.鉴于人体的手指折痕具有稳定性且对于不同的人具有不相同的特点,本文提出了一种基于手指折痕的身份识别的新方法.该算法系统由三部分组成:图像预处理、特征提取和特征匹配.在预处理阶段,提出了基于中心坐标轴的图像定位和归一化方法,并在手指内侧分割出了用于识别的长方形窗口形状的手指子图(ROI),ROI包含了手指的第一和第二折痕线;在第二阶段,提出了基于Radon变换和奇异值分解的特征提取方法;最后利用基于欧氏距离的最近邻分类器在一个取自61人共488幅手指图像的数据库上进行了匹配试验,结果验证了该方法是可行和有效的(等错误率为2.51%).     

于小波变换的等价图割SAR图像配准方法

为改进SAR图像匹配的稳健性和实时性,提出一种基于小波变换的等价图割SAR图像配准方法.该方法首先利用小波变换对图像进行分解,在低频子图像下构造等价图割,克服相干斑噪声干扰,避免NP困难,解决映射函数选取问题,从图像中分割出精确目标.其次利用尺度不变特征变换（SIFT）方法实现目标的特征匹配,降低搜索空间特征点描述,提高实时性.最后通过匹配关系找到变换参数,实现图像精确配准.实验结果表明,该方法能快速而精确地实现SAR图像配准.     

Statistical feature extraction based iris recognition system

Iris recognition systems have been proposed by numerous researchers using different feature extraction techniques for accurate and reliable biometric authentication. In this paper, a statistical feature extraction technique based on correlation between adjacent pixels has been proposed and implemented. Hamming distance based metric has been used for matching. Performance of the proposed iris recognition system (IRS) has been measured by recording false acceptance rate (FAR) and false rejection rate (FRR) at different thresholds in the distance metric. System performance has been evaluated by computing statistical features along two directions, namely, radial direction of circular iris region and angular direction extending from pupil to sclera. Experiments have also been conducted to study the effect of number of statistical parameters on FAR and FRR. Results obtained from the experiments based on different set of statistical features of iris images show that there is a significant improvement in equal error rate (EER) when number of statistical parameters for feature extraction is increased from three to six. Further, it has also been found that increasing radial/angular resolution, with normalization in place, improves EER for proposed iris recognition system.     

Research on the Pedestrian Re-Identification Method Based on Local Features and Gait Energy Images

The appearance of pedestrians can vary greatly from image to image, and different pedestrians may look similar in a given image. Such similarities and variabilities in the appearance and clothing of individuals make the task of pedestrian re-identification very challenging. Here, a pedestrian re-identification method based on the fusion of local features and gait energy image (GEI) features is proposed. In this method, the human body is divided into four regions according to joint points. The color and texture of each region of the human body are extracted as local features, and GEI features of the pedestrian gait are also obtained. These features are then fused with the local and GEI features of the person. Independent distance measure learning using the cross-view quadratic discriminant analysis (XQDA) method is used to obtain the similarity of the metric function of the image pairs, and the final similarity is acquired by weight matching. Evaluation of experimental results by cumulative matching characteristic (CMC) curves reveals that, after fusion of local and GEI features, the pedestrian reidentification effect is improved compared with existing methods and is notably better than the recognition rate of pedestrian re-identification with a single feature.     

Detecting Iris Liveness with Batch Normalized Convolutional Neural Network

Aim to countermeasure the presentation attack for iris recognition system, an iris liveness detection scheme based on batch normalized convolutional neural network (BNCNN) is proposed to improve the reliability of the iris authentication system. The BNCNN architecture with eighteen layers is constructed to detect the genuine iris and fake iris, including convolutional layer, batch-normalized (BN) layer, Relu layer, pooling layer and full connected layer. The iris image is first preprocessed by iris segmentation and is normalized to 256×256 pixels, and then the iris features are extracted by BNCNN. With these features, the genuine iris and fake iris are determined by the decision-making layer. Batch normalization technique is used in BNCNN to avoid the problem of over fitting and gradient disappearing during training. Extensive experiments are conducted on three classical databases: the CASIA Iris Lamp database, the CASIA Iris Syn database and Ndcontact database. The results show that the proposed method can effectively extract micro texture features of the iris, and achieve higher detection accuracy compared with some typical iris liveness detection methods.