Illumination Invariant Recognition of Three-Dimensional Texture in Color Images

In this paper, illumination-affine invariant methods are presented based on affine moment normalization techniques, Zernike moments, and multiband correlation functions. The methods are suitable for the illumination invariant recognition of 3D color texture. Complex valued moments (i.e., Zernike moments) and affine moment normalization are used in the derivation of illumination affine invariants where the real valued affine moment invariants fail to provide affine invariants that are independent of illumination changes. Three different moment normalization methods have been used, two of which are based on affine moment normalization technique and the third is based on reducing the affine transformation to a Euclidian transform. It is shown that for a change of illumination and orientation, the affinely normalized Zernike moment matrices are related by a linear transform. Experimental results are obtained in two tests: the first is used with textures of outdoor scenes while the second is performed on the well-known CURET texture database. Both tests show high recognition efficiency of the proposed recognition methods.     

基于Tchebichef不变距的图形识别

论文提出一种新的基于Tchebichef不变距的图形识别方法,Tchebichef不变距通过对图像进行大小归一化、平移处理以及旋转处理并结合Tchebichef正交距得到;利用提出的Tchebichef不变距作为特征进行图形的识别,和采用Hu不变距以及Zernike不变矩的识别方法相比,无论是在无噪声还是在有噪声的情况下都有更高的识别精度;仿真试验证实了本方法的可行性。     

A new benchmark on the recognition of handwritten Bangla and Farsi numeral characters

The recognition of Indian and Arabic handwriting is drawing increasing attention in recent years. To test the promise of existing handwritten numeral recognition methods and provide new benchmarks for future research, this paper presents some results of handwritten Bangla and Farsi numeral recognition on binary and gray-scale images. For recognition on gray-scale images, we propose a process with proper image pre-processing and feature extraction. In experiments on three databases, ISI Bangla numerals, CENPARMI Farsi numerals, and IFHCDB Farsi numerals, we have achieved very high accuracies using various recognition methods. The highest test accuracies on the three databases are 99.40%, 99.16%, and 99.73%, respectively. We justified the benefit of recognition on gray-scale images against binary images, compared some implementation choices of gradient direction feature extraction, some advanced normalization and classification methods.     

手写液晶体数字及识别技术

对手写数字的识别是模式识别的一个重要研究方向。通常的手写数字风格多变,无法实现高精度的识别。为此,提出一种新颖的手写数字记录方式,称为“手写液晶体数字”,进而为其设计了一种专门的识别算法。通过多个采样窗口提取图像特征,并与各类数字的标准特征向量进行相似度计算;基于贝叶斯判决原理,依据最大后验概率完成分类;建立专门的数据集并进行测评。实验结果表明,新算法具有极高的识别率,而且识别速度很快。     

基于BP神经网络的手写数字识别算法研究

讨论了一个手写数字识别系统的原理及其实现。特征提取的方法是:计算字体轮廓的曲率特征,并在计算曲率的过程中使用了B样条函数;对曲率进行了大小和平移规整化,这样得到的曲率具有大小和方向的不变性。为了得到更紧凑的特征,采用了小波对其进行降维。采用了BP神经网络作为分类器,实验结果表明,对于字形相似的数字也达到了较高的识别率。还简介了识别系统的模块设计和界面设计。     

Multiresolution recognition of unconstrained handwritten numerals with wavelet transform and multilayer cluster neural network

In this paper, we propose a new scheme for multiresolution recognition of unconstrained handwritten numerals using wavelet transform and a simple multilayer cluster neural network. The proposed scheme consists of two stages: a feature extraction stage for extracting multiresolution features with wavelet transform, and a classification stage for classifying unconstrained handwritten numerals with a simple multilayer cluster neural network. In order to verify the performance of the proposed scheme, experiments with unconstrained handwritten numeral database of Concordia University of Canada, Electro-Technical Laboratory of Japan, and Electronics and Telecommunications Research Institute of Korea were performed. The error rates were 3.20%, 0.83%, and 0.75%, respectively. These results showed that the proposed scheme is very robust in terms of various writing styles and sizes.     

Verification—a method of enhancing the recognizers of isolated and touching handwritten numerals

This paper investigates verification schemes and their applications to the recognition of both isolated and touching handwritten numerals. Definitions and functionality analyses of the verifiers are given. The measurement of precision rate is used to assess the system reliability in a class-specific manner. Verification-enhanced systems are proposed with extensive experiments conducted on both isolated and touching numerals. Two databases for touching numerals are built/organized to serve as standard data sets. Experimental results indicate a substantial improvement in system precision rates by the verification scheme, which proves the effectiveness of the proposed systems and justifies the important role of verifiers in OCR systems.     

基于统计和结构特征的手写数字识别研究

针对目前手写数字识别精度不高的问题,通过对手写数字图像的研究,提出了基于手写数字图像的空间、旋转、层次和结构特性的特征提取方法.该方法把手写数字的统计和结构特征结合起来,以特征提取方法为基础,利用LibSVM算法对手写数字特征进行了训练和识别.通过实验给出了各个参数的推荐值,利用推荐参数值,手写数字MNIST字体库的识别率高达99.3333％.实验结果表明了该算法在识别手写数字上的有效性和准确性.     

一种Pseudo-Zernike矩的改进算法

Pseudo—Zernike矩在模式识别中被广泛采用。但由于Pseudo-Zernike矩的复杂性，相关算法研究尚未得到良好解决。文中对常用算法进行改进，提出了一种直接将矩形图像映射到单位圆内进而求取Pseudo—Zernike矩的算法，并将其应用于识别阿拉伯数字。实验结果表明该算法在计算速度和识别精度上都有明显提高。     

多分类器组合及其应用于手写体数字识别

在许多模式识别的应用中经常遇到这样的问题:组合多个分类器.提出了一种新的组合多个分类器的方法,这个方法由反向传播神经网络来控制,一个无标号的模式输入到每一个单独的分类器,它也同时输入到神经网络中来决定哪两个分类器作为冠军和亚军.让这两个分类器通过一个随机数发生器来决定最终的胜者.并且将这个方法应用到识别手写体数字.实验显示单个分类器的性能能够得到可观的改变.     

Image normalization by complex moments

The role of moments in image normalization and invariant pattern recognition is addressed. The classical idea of the principal axes is analyzed and extended to a more general definition. The relationship between moment-based normalization, moment invariants, and circular harmonics is established. Invariance properties of moments, as opposed to their recognition properties, are identified using a new class of normalization procedures. The application of moment-based normalization in pattern recognition is demonstrated by experiment.     

Translation invariants of Zernike moments

Moment functions defined using a polar coordinate representation of the image space, such as radial moments and Zernike moments, are used in several recognition tasks requiring rotation invariance. However, this coordinate representation does not easily yield translation invariant functions, which are also widely sought after in pattern recognition applications. This paper presents a mathematical framework for the derivation of translation invariants of radial moments defined in polar form. Using a direct application of this framework, translation invariant functions of Zernike moments are derived algebraically from the corresponding central moments. Both derived functions are developed for non-symmetrical as well as symmetrical images. They mitigate the zero-value obtained for odd-order moments of the symmetrical images. Vision applications generally resort to image normalization to achieve translation invariance. The proposed method eliminates this requirement by providing a translation invariance property in a Zernike feature set. The performance of the derived invariant sets is experimentally confirmed using a set of binary Latin and English characters.     

改进的手背静脉识别算法

提出了一种基于不变矩和支持向量机的手背静脉识别算法。算法在采用修正的NiBlack算法从原始图中分割出静脉纹路,然后采用改进的条件细化算法进行细化获得静脉骨架的基础上,提取静脉骨架的7个修正的几何不变矩作为支持向量机分类器的输入进行静脉分类识别,在有500个样本的数据库上进行实验,获得了95.5%的识别率,表明了算法的有效性。     

基于支持向量机的手写体数字识别

提出了一种基于支持向量机的手写体数字识别系统。支持向量机方法，突破了传统模式识别方法的局限，使得基于支持向量机的分类器具有较好的推广能力。文中重点阐述了支持向量机的基本原理和集成在该系统中的重要的处理模块，实验结果表明该系统具有较高的识别率和较强的实用性。     

基于结构矩不变量的形状相似性比较

在传统的几何矩定义的基础上进行扩展，给出了结构矩的定义和计算。其实质是对原有几何矩定义中的密度函数经过变换得到新的密度函数。在此基础上定义的不变矩突出或者扩大了形状之间的差别，因而使形状相似性的比较建立在更为可靠的基础上。基于平方变换的实验表明，与传统的几何矩相比结构矩方法具有更好的效果。     

Moment invariants for the analysis of 2D flow fields

We present a novel approach for analyzing two-dimensional (2D) flow field data based on the idea of invariant moments. Moment invariants have traditionally been used in computer vision applications, and we have adapted them for the purpose of interactive exploration of flow field data. The new class of moment invariants we have developed allows us to extract and visualize 2D flow patterns, invariant under translation, scaling, and rotation. With our approach one can study arbitrary flow patterns by searching a given 2D flow data set for any type of pattern as specified by a user. Further, our approach supports the computation of moments at multiple scales, facilitating fast pattern extraction and recognition. This can be done for critical point classification, but also for patterns with greater complexity. This multi-scale moment representation is also valuable for the comparative visualization of flow field data. The specific novel contributions of the work presented are the mathematical derivation of the new class of moment invariants, their analysis regarding critical point features, the efficient computation of a novel feature space representation, and based upon this the development of a fast pattern recognition algorithm for complex flow structures.     

一种基于骨架特征顺序编码的脱机手写体数字识别方法

本文提出了并实现了一种基于数字骨架顺序编码的脱机手写体识别方法,该方法利用绑架化等预处理操作得到手写体数字的骨架,然后对数字骨架进行跟踪,按顺序得到一系列曲线段,并以12种线型对这些曲线段进行拟合,从而得到一组数字骨架的顺序编码,最终利用这组顺序编码和样本训练生成的识别字典完成对数字的识别,本方法具有较高的识别可靠率,已在成绩单自动录入和识别系统中得到了成功的应用。