基于HMM的汉语文本识别后处理研究

本文用HMM(Hidden Markov Model)描述汉语文本识别后处理,将汉语语言和单字识别这两个概率模型结合起来,以充分利用单字识别器提供的信息。语言模型的参数由语料库统计得到;单字识别模型的参数为条件概率,经理论分析,它可转化为后验概率来求解。在分析训练样本集单字识别结果的基础上,提出一种统计方法估计候选字的后验概率。HMM在脱机手写体汉语文本识别中的实验表明,后处理性能除取决于语言模型外,还取决于后验概率的精确估计。

Post-processing Study of Chinese Document Recognition Based on HMM

In this paper , a post-processing method using HMM(Hidden Markov Model) for Chinese document recognition is proposed. HMM combines language model with single character recognition(SCR) model to make the best of SCR output . The parameters of language model are derived from corpus , while the parameters of SCR model are conditional probabilities that can be converted into posterior probabilities by theoretic analysis. On the basis of SCR output analysis , posterior probabilities of candidates are obtained by statistical method. Experiments in off - line Chinese document recognition show that post - processing performance depends on efficient evaluation of posterior probability , besides proper language model.