基于Word Lattice结构的语音识别置信度算法

Confidence Measures Based on Word Lattice for Speech Recognition

wordlattice是与词图(wordgraph)结构类似但是结构没有词图致密的在小任务语音识别的情况下较为常见的一种中间输出结构,给出了在wordlattice结构上的语音识别置信度估计的一种算法。以lattice结构中的连接弧作为计算单元,给出了利用前后向算法高效计算lattice中每个弧的词后验概率及以其为基础计算每个词的置信度的算法。

Word lattice is an intermediate output form similar to,but less compact than word graph under small task speech recognition.This paper presents an algorithm of confidence measure for speech recognition over word lattice.With lattice arc as computing unit,this paper gives high efficient algorithms of using forward-backward approach to compute word posterior probability for each arc in lattice,and confidence values of words are then computed based on word posterior probabilities of arcs.