用大模型引导解码,提升自监督语音识别准确率。
Large Language Model Guided Decoding for Self-Supervised Speech Recognition
- 结合大模型生成候选词,用声学模型提供得分。
- 在多个数据集上优于现有大模型解码方法。
- 特别适合处理复杂句、缩写和专业术语。
自监督语音识别(SSL-ASR)利用大量未标注音频预训练声学模型(如wav2vec2.0或HuBERT),再用少量标注数据微调进行语音转录。传统解码使用CTC解码器,并通过外部语言模型(如n-gram或神经LM)引导束搜索生成最终结果。然而,将大语言模型(LLM)作为外部语言模型仍具挑战,因其词概率过于自信。本文提出一种新方法:利用LLM的解码机制生成候选下一词,在每个候选词上由SSL模型对输入声学特征进行对齐并提供声学得分。基于最大后验估计(MAP)分解公式,计算组合声学与LLM得分,保留得分最高的词进入束中,推进到下一步解码。在多个数据集上的实验表明,该方法显著优于当前最先进的基于大模型的解码、后处理及纠错方法,尤其在处理复杂句子、缩写和领域特定词汇时表现突出。
原文摘要 · Abstract (English)
Self-supervised automatic speech recognition (SSL-ASR) is an ASR approach that uses speech encoders pretrained on large amounts of unlabeled audio (e.g., wav2vec2.0 or HuBERT) and then fine-tunes them with limited labeled data to perform transcription. Decoding is usually performed with a CTC decoder, whose hypotheses are scored and refined using an external language model (LM), typically an n-gram or neural LM, which guides beam search to produce the final transcription. Using Large Language Models (LLMs) as external LMs remains a challenge, as their word probabilities are overly confident. The proposed method integrates an LLM with an SSL acoustic model by using the LLM's decoding mechanism to generate a set of candidate next tokens. For each candidate, the SSL model provides an acoustic score by aligning it to the input acoustics of the SSL model. A combined acoustic and LLM score is then calculated based on decomposing the MAP estimator of words given the acoustic signal. The tokens with the highest combined scores are maintained in a beam, which is then used to proceed to the next decoding step. We illustrate the effectiveness of our method through a comprehensive comparison with the current state-of-the-art LLM-based decoding, post-processing, and error-correcting methods across multiple datasets. Our approach proves particularly effective when processing challenging inputs such as complex speech sentences, acronyms, and domain-specific vocabulary.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。