一、特有名词
acoustic scale: 通常设置为0.1,意味着声学模型的log概率得到的权重远低于语言模型。在Score的脚本中,经常会看到一系列要搜索的语言模型权重(例如7到15的范围)。 这些可以解释为声acoustic scale的倒数; 这是两者对维特比解码很重要的比例
alignment:表示一句话通过维特比(最佳路径)对齐的HMM状态序列表示,与transtions-id同义。show-alignment显示
likelihood:使用标准的交叉熵训练的神经网络系统,我们通过将对数概率除以上下文相关状态的先验来获得“伪似然性”。
posterior:后验概率,Alignments and lattices can be converted to posteriors over transition-ids (see lattice-to-post.cc), or over lattice arcs (see ali-to-post.cc and lattice-arc-post.cc). Posteriors over transition-ids can be converted to posteriors over pdf-ids or over phones; see the tools ali-to-post.cc, post-to-pdf-post.cc and post-to-phone-post.cc
二、关于lattice的工具
latgen-faster-mapped: 生成lattice
lattice-scale:Apply scaling to lattice weights
lattice-add-penalty: Add word insertion penalty to the lattice
lattice-best-path: Generate 1-best path through lattices; output as transcriptions and alignments
lattice-align-words: Convert lattices so that the arcs in the CompactLattice format correspond with words
lattice-align-phones:Convert lattices so that the arcs in the CompactLattice format correspond with phones