鉴别性最大后验概率声学模型自适应

为了更加准确地估计最小音素错误最大后验概率(MPE-MAP)自适应算法中的先验分布中心,使自适应后的声学模型参数更为准确,从而提高系统的识别性能,分别采用最大互信息最大后验概率(MMI-MAP)自适应和基于最大互信息准则与最大似然准则相结合的H-criterion最大后验概率(H-MAP)自适应估计先验分布中心,提出了基于最大互信息最大后验概率先验的最小音素错误最大后验概率(MPE-MMI-MAP)和基于H-criterion最大后验概率先验的最小音素错误最大后验概率(MPE-H-MAP)算法。任务自适应实验结果表明,MPE-MMI-MAP和MPE-H-MAP算法的自适应性能均优于MPE-MAP、MMI-MAP和最大后验概率(MAP)自适应方法,分别比MPE-MAP相对提高3.4%和2.7%。

Discriminative maximum a posteriori for acoustic model adaptation

For Minimum Phone Error based Maximum A Posteriori (MPE-MAP) adaptation, in order to accurately estimate the center of prior distribution and to improve the recognition performance, the Maximum Mutual Information based MAP (MMI-MAP) adaptation and H-criterion, which was the interpolation of MMI and Maximum Likelihood (ML) criterion, based on MAP (H-MAP) adaptation were used for the estimation of the center of prior distribution, which led to MMI-MAP prior based MPE-MAP (MPE-MMI-MAP) and H-MAP prior based MPE-MAP (MPE-H-MAP). The experimental results of task adaptation show that the two proposed methods both can obtain better recognition performance than MPE-MAP, MMI-MAP and MAP adaptation. MPE-MMI-MAP and MPE-H-MAP can obtain 3.4% and 2.7% relative improvement over MPE-MAP respectively.