联机手写笔画特征抽取的逼近-合并算法

为了对联机手写字符识别的笔画进行精确描述,提出了一种基于字符笔画特征抽取的＂逼近-合并＂算法.该算法分析了字符笔画的多边形逼近,求出偏离度最小的多边形逼近,并对该多边形的边进行合并,抽取出笔画方向码,实现了联机手写字符笔画的更有效合并.该方法应用在联机手写体字符识别实验系统中,其识别率为99.13%.     

基于多重规则和路径评价的在线中英文手写识别方法

手写文本识别方法主要应用于文本输入技术,对人机交互领域的发展起关键作用。针对多数在线输入法无法识别中英文混合手写识别的问题,提出一种在线中英文混合手写文本识别方法。通过对文本笔画进行基于水平相对位置、垂直重叠率、面积重叠率规则的整合以及连笔切分,得到一系列字符片段,同时利用笔画个数、宽高比、中心偏离、平滑度等几何特征和识别置信度,对字符片段进行中英文分类。在此基础上,根据分类结果并结合自然语言模型的路径评价及动态规划搜索算法,分别对候选的中、英文字符片段进行合并处理,得到待识别的中、英文字符序列,并将其分别送入卷积神经网络的中、英文识别模型中,得到手写文本识别结果。实验结果表明,在线手写中英文混合文本识别正确率达93.67%,不仅能切分在线手写中文文本行,而且对包含字符连笔的在线手写中英文文本行也有较好的切分效果。     

基于支持向量机的联机手写维吾尔字符识别

提出一种基于结构特征的手写维吾尔字符识别算法,首先根据字符的笔画数目将待识别字符划分为五个子集,然后再根据"附加笔画位置"等特征对字符集再进行划分。根据每个子集中的字符分布情况,提取不同长度的特征向量,然后利用SVM为每个字符集构造一个分类器,进行训练和识别。     

基于主曲线算法的手写字符特征分析与提取

模式特征的提取与选择是提高手写体字符识别率的关键因素。主曲线是主成分分析的非线性推广,它是通过数据分布“中间”并满足“自相合”的光滑曲线,能够很好地描述数据分布的结构特征。利用软K段主曲线算法提取训练数据的特征,在分析手写体字符结构特点的基础上,选出手写体字符识别所使用的粗分类与细分类特征,利用这些分类特征对手写字符进行识别。该方法在CEDAR手写体数字和字符数据库上的实验表明：选取的分类特征能够有效区分相似的手写体字符,提高手写字符的识别率,为脱机手写字符识别研究提供了一种新的方法。     

基于主分量分析的手写数字字符识别

针对手写数字字符识别中由于书写习惯和风格的不同，造成字符模式不稳定的问题，提出了一种图像预处理方法．首先采用数学形态学通过细化和膨胀，统一字符笔画的粗细，并使字符的局部特征得到改善；然后利用主分量分析法(PCA)抽取字符特征，估计字符的重建模型，并通过对重建模型的误差分析进行字符识别；最后通过对美国国家邮政局USPS字库中全部数字字符完整的识别实验，证实了算法的鲁棒性和准确性．     

一种基于模糊规则的手写体粘连数字串分割

手写数字串切分是手写数字OCR系统中必不可少的组成部分.实际应用中一般用框格对数字的书写范围进行约束,切分过程比较容易,如果没有框格约束,手写数字串的切分就成为一个难题.针对无约束的手写数字串切分的难点,提出了一种新的粘连数字串切分方法.该方法先使用主曲线实现字符模板的笔画抽取,然后依据字符笔画的模糊特征处理笔画,最后以字符识别器提供的置信度为依据完成切分过程.为验证该新切分方法的效果.对从银行实地采集的3 000份真实支票进行了切分实验,其中363张支票存在粘连现象,切分正确率为89.68%.实验结果表明,该算法能够有效地切分多字粘连的手写体数字串.     

手写字符识别的非线性主动判别函数

提出了用于手写字符识别的非线性主动判别函数,是线性主动判别函数在手写字符非线性变化情况下的推广。该方法利用Kernel PCA分析捕捉和表示这种非线性变化。将输入空间非线性映射为特征空间,在特征空间的主子空间中生成最优主动原型模板,其与字符特征向量在特征空间主子空间的投影之间的距离即为非线性主动判别函数;同时,基于最小分类错误准则对该函数进行了优化。实验结果表明,非线性主动判别函数获得了比线性主动判别函数更高的识别率。     

形态学处理在光学字符识别中的应用研究

讨论了形态学处理在字符识别中的应用研究,用开运算和闭运算等形态学处理知识对图像进行增强处理,目的是消除字符间断裂、粘连等问题.实验结果表明,用形态学处理进行图像预处理能有效消除笔画断裂、粘连等问题,进一步增强目标字符特征,提高字符识别正确率.     

哈萨克文脱机手写字符识别系统的研究与实现

由于手写哈萨克字符结构的特殊性,仅提取几种单一的字符特征进行识别时正确率较低,识别效果较差。由此采用改进的PCA方法定位单词基线位置,对每个字符提取包括笔画密度特征、投影特征、轮廓特征等在内的36种特征,使用K-W检验对各特征的分类能力进行比较,并采用线性判别函数进行分类,取得了较高的识别精度。实验结果表明,该系统针对脱机字符识别率达到94％以上。     

形态学运算在字符识别中的应用

字符识别作为基本的图像识别技术,在计算机输入、交通和安防等领域都获得了广泛的应用。在进行字符识别前,需要先对图像进行灰度拉伸和阈值分割等一系列预处理以获得有效的目标字符特征。这些处理虽然可以增强目标字符的特征并滤除部分噪声,但同时也经常会造成目标字符的笔画发生断裂。由于待识别字符的笔画为较细的线性结构,采用常规的形态学开运算与闭运算对图像进行处理非但不能连接断裂的笔画,字符笔画还有可能因为细小而被抹去,使图像中的目标字符产生更严重的笔画断裂甚至缺失。讨论了数学形态学运算在字符识别技术中的应用,利用形态学闭     

A novel stroke-based feature extraction for handwritten Chinese character recognition

A stroke-based approach to extract skeletons and structural features for handwritten Chinese character recognition is proposed. We first determine stroke directions based on the directional run-length information of binary character patterns. According to the stroke directions and their adjacent relationships, we split strokes into stroke and fork segments, and then extract the skeletons of the stroke segments called skeleton segments. After all skeleton segments are extracted, fork segments are processed to find the fork points and fork degrees. Skeleton segments that touch a fork segment are connected at the fork point, and all connected skeleton segments form the character skeleton. According to the extracted skeletons and fork points, we can extract primitive strokes and stroke direction maps for recognition. A simple classifier based on the stroke direction map is presented to recognize regular and rotated characters to verify the ability of the proposed feature extraction for handwritten Chinese character recognition. Several experiments are carried out, and the experimental results show that the proposed approach can easily and effectively extract skeletons and structural features, and works well for handwritten Chinese character recognition.     

一种连续手写中文的演化分割方法

在连续手写中文中,有偏旁部首离得较远的单字,单字之间可能会存在粘连、重叠。针对这种情况给出了一种基于识别得分提取单字的演化方法。对行笔划序列进行二进制编码,采用改进的遗传算法实现演化过程。染色体中连续0或1对应的笔划组成候选单字。用汉王手写单字识别器获取它们的识别得分,以单字个数较少和总的识别得分较大为优化目标。遗传算法中的变异概率和交叉概率自适应生成。测试结果表明该方法对连续手写中文具有较好的分割效果。     

完全基于结构知识的汉字笔画抽取方法

从汉字结构知识出发,提出了一种从汉字图像直接抽取笔画的算法,给出了抽取横、竖、撇、捺４种笔画的完全量化的昨去除不同字体的笔画修饰噪声的规则,该方法较好地解决了各笔画的相交、相连及噪声排队等总理２,综在汉字识别及字体自动生成等汉字信息处理方面有重要作用。     

汉字笔段形成规律及其提取方法

该文从点阵图像行(列)连通像素段出发，研究汉字图像的笔段构成，发现汉字点阵图像仅由阶梯型笔段和平行长笔段两种类型的笔段构成，并归纳出阶梯型笔段和平行长笔段的形成规律．以笔段形成规律为基础提出了汉字笔段的提取方法，该方法将像素级汉字图像转变为以笔段为单位的图像，有利于汉字识别、汉字细化及汉字字体的自动生成．最后该文给出了印刷体和手写体汉字笔段提取的实验结果．     

On-line recognition of Korean characters using ART neural network and hidden Markov model

This paper proposes an efficient method for on-line recognition of cursive Korean characters. The recognition of cursive strokes and the representation of a large character set are important determinants in the recognition rate of Korean characters. To deal with cursive strokes, we classify them automatically by using an ART-2 neural network. This neural network has the advantage of assembling similar patterns together to form classes in a self-organized manner. To deal with the large character set, we construct a character recognition model by using the hidden Markov model (HMM), which has the advantages of providing an explicit representation of time-varying vector sequence and probabilistic interpretation. Probabilistic parameters of the HMM are initialized using the combination rule for Korean characters and a set of primitive strokes that are classified by the ART stroke classifier, and trained with sample data. This is an efficient means of representing all the 11,172 possible Korean characters. We tested the model on 7500 on-line cursive Korean characters and it proved to perform well in recognition rate and speed.     

Off-line handwritten Korean character recognition based on stroke extraction and representation

In this paper, we propose an off-line recognition method for handwritten Korean characters based on stroke extraction and representation. To recognize handwritten Korean characters, it is required to extract strokes and stroke sequence to describe an input of two-dimensional character as one-dimensional representation. We define 28 primitive strokes to represent characters and introduce 300 stroke separation rules to extract proper strokes from Korean characters. To find a stroke sequence, we use stroke code and stroke relationship between consecutive strokes. The input characters are recognized by using character recognition trees. The proposed method has been tested for the most frequently used 1000 characters by 400 different writers and showed recognition rate of 94.3%.     

基于基本笔画起收笔和笔压特征的手写汉字的计算机笔迹鉴定

以手写汉字的基本笔画为研究对象,提取笔画的起笔、收笔和笔压作为特征量,进行笔迹鉴定的研究.研究采用了10位书写者,每位书写者各书写70个汉字作为样本,提取4种基本笔画,进行笔迹鉴定的实验,实验取得了较为满意的鉴定率.本研究克服了以往笔迹鉴定中结体依存的不足,适用于所有的汉字.     

Fuzzy state machines to recognize totally unconstructed handwritten strokes

An automatic off-line character recognition system for totally unconstrained handwritten strokes is presented. A stroke representation is developed and described using five types of feature. Fuzzy state machines are defined to work as recognizers of strokes. An algorithm to obtain a deterministic fuzzy state machine from a stroke representation, that is capable of recognizing that stroke and its variants is presented. An algorithm is developed to merge two fuzzy state machines into one machine. The use of fuzzy machines to recognize strokes is clarified through a recognition algorithm. The learning algorithm is a complex of the previous algorithms. A set of 20 stroke classes was used in the learning and recognition stages. The system was trained on 5890 unnormalized strokes written by five writers. The learning stage produced a fuzzy state machine of 2705 states and 8640 arcs. A total of 6865 unnormalized strokes, written freely by five writers other than the writers of the learning stage, was used in testing. The recognition, rejection and error rates were 94.8%, 1.2% and 4.0%, respectively. The system can be more developed to deal with cursive handwriting.     

维吾尔文手写体联机识别中延迟笔画处理方法

延迟笔画处理是维吾尔文联机手写体单词识别中的难点,样本数据格式为一串具有时序性的序列,造成字母主笔画和延迟笔画在序列位置上多半不连续,很大程度上增加了延迟笔画处理和单词识别的难度。为此,提出一种维吾尔文延迟笔画处理方法,其中包括延迟笔画查找与投影,实验结果证明该方法具有良好的效果,单词识别准确率达到93.71%。