基于数学形态学的脱机手写体汉字识别方法

笔画特征是一种有效的脱机手写体汉字的识别特征,但是笔画细化往往会造成字体的变形,提出一种无需细化预处理的笔画特征提取方法,通过数学形态学中的腐蚀、膨胀等运算,采用不同的、具有自适应性的结构元素对汉字图像进行笔画分解,并利用弹性网格提取其方向特征,最后使用广义K L变换对特征向量的维数进行压缩,去除冗余信息。实验结果验证了本方法的有效性。     

基于笔划特征和MCLRNN模型的联机手写藏文识别

提出了一种新的多层联系子层递归神经网络（MCLRNN）模型并融合藏文字丁的空间结构特征来进行联机手写藏文识别。改进后的网络结构具有多层联系子层来保留若干时刻的网络内部状态,从而可以更好地表征藏文字的各笔划特征以及笔划间的空间结构关系,同时,采用更适用于模式分类的交叉熵准则和改进的梯度下降算法来训练网络,加快了网络的收敛速度并增强其分类能力。仿真实验取得了令人满意的结果。     

On-line handwritten Chinese character recognition via a fuzzy attribute representation

Chinese characters are constructed by strokes according to structural rules. Therefore, the geometric configurations of characters are important features for character recognition. In handwritten characters, stroke shapes and their spatial relations may vary to some extent. The attribute value of a structural identification is then a fuzzy quantity rather than a binary quantity. Recognizing these facts, we propose a fuzzy attribute representation (FAR) to describe the structural features of handwritten Chinese characters for an on-line Chinese character recognition (OLCCR) system. With a FAR. a fuzzy attribute graph for each handwritten character is created, and the character recognition process is thus transformed into a simple graph matching problem. This character representation and our proposed recognition method allow us to relax the constraints on stroke order and stroke connection. The graph model provides a generalized character representation that can easily incorporate newly added characters into an OLCCR system with an automatic learning capability. The fuzzy representation can describe the degree of structural deformation in handwritten characters. The character matching algorithm is designed to tolerate structural deformations to some extent. Therefore, even input characters with deformations can be recognized correctly once the reference dictionary of the recognition system has been trained using a few representative learning samples. Experimental results are provided to show the effectiveness of the proposed method.     

基于贝叶斯网络的脱机手写体汉字智能识别

针对汉字识别的超多类问题,将贝叶斯网络分类器引入小样本字符集脱机手写体汉字识别中．对手写大写数字汉字的小样本字符集构造识别系统,同时与传统的欧氏距离方法进行比较,实验表明该算法将识别率提高到92．4％,在小样本字符集脱机手写体识别中具有较强的实用性和良好的扩展性．     

基于形态学变换的有限集手写体汉字识别

以21个金融汉字为研究对象,提出了一种基于数学形态学和弹性网格技术的特征融合方法.在汉字图像上构造弹性网格,利用形态学变换将汉字分解为4个方向笔画分量,分别提取方向特征和笔画穿透数目特征,然后将这两组特征向量的维数和度量统一后组合成复向量的形式,并采用K-L变换降维,去除冗余信息.该方法无需细化,受笔画不规则变形影响较小.实验证明,是一种有效的特征提取方法.     

基于统计部首模型的联机手写汉字识别方法

利用汉字的部首层次结构有助于减小字符识别器的存储空间和提高泛化性、适应性,但部首分割一直是一个难点.提出一种新的基于部首的联机手写汉字识别方法,该方法把部首形状信息和几何信息集成到识别框架中,在组合搜索过程中利用字符-部首的层次结构字典引导部首的分割与识别,从而提高部首分割的准确率.为克服部首间的连笔,引入角点检测提取子笔划.部首识别采用统计分类器,模型参数通过自学习得到.在字符识别中,采用了2种不同的字典表示以及相应的不同搜索算法.该方法已用于左右与上下结构的字符集,实验结果表明了该方法的有效性.     

Parallel compact integration in handwritten Chinese character recognition

In this paper, a new parallel compact integration scheme based on multi-layer perceptron (MLP) networks is proposed to solve handwritten Chinese character recognition (HCCR) problems. The idea of metasynthesis is applied to HCCR, and compact MLP network classifier is defined. Human intelligence and computer capabilities are combined together effectively through a procedure of two-step supervised learning. Compared with previous integration schemes, this scheme is characterized with parallel compact structure and better performance. It provides a promising way for applying MLP to large vocabulary classification.     

基于弹性笔画长度的汉字笔画平面抽取及识别

针对手写体汉字识别过程中的特征抽取，提出了一种改进的抽取笔画平面的方法。首先，将手写汉字图像进行非线性规一化；然后，利用弹性笔画长度，根据汉字的横竖撇捺四种笔画分别抽取出四种笔画的平面；最后，将四个笔画平面分别均匀划分成S×S个小网格，在每个小格内计算其笔画交叉数目，便得到了一个4S2维的特征向量。实验利用基于最小距离的分类器对含有7600（19类）个汉字的测试集进行了分类，取得了较好的识别效果。     

手写混合字符集识别的多特征多级分类器设计

针对常用的银行汉字和阿拉伯数字混合字符集的识别,提出了依据不同的分类要求，分别选取不同的分类特征，并采用先聚类再用多层感知器(MLP)神经网络分类的多级分类器进行识别的设计方法。实验结果表明，该方法用于手写体混合字符集的识别是行之有效的。     

基于深度学习的异噪声下手写汉字识别的研究

针对手写汉字字符图像识别率受随机噪声影响的问题,提出了一种基于深度学习与抑制噪声相结合的新算法。该算法主要应用于拥有随机噪声的手写汉字字符图片,是其在Python环境下,利用Caffe平台建立抑制噪声与卷积神经网络相结合的模型,通过模型移除噪声并正确识别手写汉字。另外,新算法去除噪声的同时对字符形态没有改变,保留了汉字的原始信息。结果在其两种不同的噪声（高斯噪声和椒盐噪声）下,逐渐提升其噪声强度,进行多次实验,同时与其他方法对比,最终得到其平均识别率为97.05%。实验结果表明,该模型和算法具有效率快、识别能力强的优点。     

基于数学形态学的手写体汉字细化方法研究

提出了一种基于数学形态学的细化方法,该方法使用结构模板的方式对字符图像进行细化,并针对原有细化方法产生的细化不彻底现象,对原结构模板进行了改进。在常用细化结构模板的基础上,新增了几个结构模板,较好地解决了细化不彻底的现象。实验证明,细化后的图像保持了原图像的连通性并达到了很好的细化效果。     

一种用于手写体汉字切分的优化模型

在连通域单元的基础上提出了一种手写体汉字切分的优化模型,该模型可以自适应的确定部件、单个字和粘连字的宽度。另外,对粘连字的切分采用了加权k的均值法。整个切分方法既提高了算法的自适应能力,又提高了切分的正确率。实验表明这种方法具有很好的切分效果。     

A robust method for coarse classifier construction from a large number of basic recognizers for on-line handwritten Chinese/Japanese character recognition

In this paper, a systematic method is described that constructs an efficient and a robust coarse classifier from a large number of basic recognizers obtained by different parameters of feature extraction, different discriminant methods or functions, etc. The architecture of the coarse classification is a sequential cascade of basic recognizers that reduces the candidates after each basic recognizer. A genetic algorithm determines the best cascade with the best speed and highest performance. The method was applied for on-line handwritten Chinese and Japanese character recognitions. We produced hundreds of basic recognizers with different classification costs and different classification accuracies by changing parameters of feature extraction and discriminant functions. From these basic recognizers, we obtained a rather simple two-stage cascade, resulting in the whole recognition time being reduced largely while maintaining classification and recognition rates.     

An irrelevant variability normalization approach to discriminative training of multi-prototype based classifiers and its applications for online handwritten Chinese character recognition

This paper presents an irrelevant variability normalization (IVN) approach to jointly discriminative training of feature transforms and multi-prototype based classifier for recognition of online handwritten Chinese characters. A sample separation margin based minimum classification error criterion is adopted in IVN-based training, while an Rprop algorithm is used for optimizing the objective function. For the IVN approach based on piecewise linear transforms, the corresponding recognizer can be made both compact and efficient by using a two-level fast-match tree whose internal nodes coincide with the labels of feature transforms. Furthermore, the IVN system using weighted sum of linear transforms outperforms that based on piecewise linear transforms. The effectiveness of the proposed approach is first confirmed using an in-house developed online Chinese handwriting corpus with a vocabulary of 9306 characters, and then further verified on a standard benchmark database for an online handwritten character recognition task with a vocabulary of 3755 characters.     

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.     

基于改进inception的脱机手写汉字识别

由于字形的复杂多变,脱机手写汉字的识别一直是模式识别的难题,深度卷积神经网络的发展为其提供了一种直接有效的解决方案。研究基于inceptions 结构神经网络的脱机手写汉字识别,提出了一种inception结构的改进方法,它具有结构更加简单、网络深度扩展更加容易、需要的训练参数量更少的优点。该方法在数据集CISIA-HWDB1.1 上进行了实验验证,采用随机梯度下降优化算法,模型达到了96.95%的平均准确率。实验结果表明,使用改进的inception结构在图像分类上具有更好的鲁棒性,更容易扩展到其他应用领域。     

Model-based stroke extraction and matching for handwritten Chinese character recognition

This paper proposes a model-based structural matching method for handwritten Chinese character recognition (HCCR). This method is able to obtain reliable stroke correspondence and enable structural interpretation. In the model base, the reference character of each category is described in an attributed relational graph (ARG). The input character is described with feature points and line segments. The strokes and inter-stroke relations of input character are not determined until being matched with a reference character. The structural matching is accomplished in two stages: candidate stroke extraction and consistent matching. All candidate input strokes to match the reference strokes are extracted by line following and then the consistent matching is achieved by heuristic search. Some structural post-processing operations are applied to improve the stroke correspondence. Recognition experiments were implemented on an image database collected in KAIST, and promising results have been achieved.     

High accuracy handwritten Chinese character recognition using LDA-based compound distances

To improve the accuracy of handwritten Chinese character recognition (HCCR), we propose linear discriminant analysis (LDA)-based compound distances for discriminating similar characters. The LDA-based method is an extension of previous compound Mahalanobis function (CMF), which calculates a complementary distance on a one-dimensional subspace (discriminant vector) for discriminating two classes and combines this complementary distance with a baseline quadratic classifier. We use LDA to estimate the discriminant vector for better discriminability and show that under restrictive assumptions, the CMF is a special case of our LDA-based method. Further improvements can be obtained when the discriminant vector is estimated from higher-dimensional feature spaces. We evaluated the methods in experiments on the ETL9B and CASIA databases using the modified quadratic discriminant function (MQDF) as baseline classifier. The results demonstrate the superiority of LDA-based method over the CMF and the superiority of discriminant vector learning from high-dimensional feature spaces. Compared to the MQDF, the proposed method reduces the error rates by factors of over 26%.     

An online handwritten music symbol recognition system

The objective of this study is to produce a system that would allow music symbols to be written by hand using a pen-based computer that would simulate the feeling of writing on sheets of paper and that would also accurately recognize the music symbols. To accomplish these objectives, the following methods are proposed: (1) Two features, time-series data and an image of a handwritten stroke, are used to recognize strokes; and (2) The strokes are combined, as efficiently as possible, and outputted automatically as a music symbol. As a result, recognition rates of 97.60 and 98.80% were obtained in tests with strokes and music symbols, respectively.     

基于归一化背景方向特征的脱机手写汉字识别

对4方向背景方向特征进行了改进,提出了8方向背景特征描述方法。与4方向背景方向特征描述方法相比,改进后的特征描述方法可以从0°、45°、90°、135°、180°、225°、270°、315°共8个方向来对汉字图像进行考察,从而进一步提高描述的精度。此外,为了消除笔划粗细的影响,还对背景方向特征进行了归一化处理。实验结果表明改进后的归一化8方向背景方向特征具有更高的识别精度。