Fast Context-Biasing for CTC and Transducer ASR models with CTC-based Word Spotter
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Abstract (arXiv)
Accurate recognition of rare and new words remains a pressing problem for contextualized Automatic Speech Recognition (ASR) systems. Most context-biasing methods involve modification of the ASR model or the beam-search decoding algorithm, complicating model reuse and slowing down inference. This work presents a new approach to fast context-biasing with CTC-based Word Spotter (CTC-WS) for CTC and Transducer (RNN-T) ASR models. The proposed method matches CTC log-probabilities against a compact context graph to detect potential context-biasing candidates. The valid candidates then replace their greedy recognition counterparts in corresponding frame intervals. A Hybrid Transducer-CTC model enables the CTC-WS application for the Transducer model. The results demonstrate a significant acceleration of the context-biasing recognition with a simultaneous improvement in F-score and WER compared to baseline methods. The proposed method is publicly available in the NVIDIA NeMo toolkit.
Key facts. Cited by 7 papers in the map (data through 7 Oct 2026). Builds on 18 of its 27 references that are in the map. First posted on arXiv 11 Jun 2024.
Builds on
18 of 27 references.
References · 18
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6 more
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Built on by
Citing papers per year: 2025: 3; 2026: 4.
7 papers.
- 2025NGPU-LM: GPU-Accelerated N-Gram Language Model for Context-Biasing in Greedy ASR Decodingcited by 7
- 2025Pushing the Limits of Beam Search Decoding for Transducer-based ASR modelscited by 4
- 2025TurboBias: Universal ASR Context-Biasing powered by GPU-accelerated Phrase-Boosting Treecited by 4
- 2026Contextual Earnings-22: A Speech Recognition Benchmark with Custom Vocabulary in the Wildcited by 2
- 2026TurboBias 2.0: Streaming Context-Biasing for Production-Efficient ASR Systemscited by 0
- 2026PTC-Bias: Phoneme-Level Temporal Competition for Bias Retrieval and Post-Decoding Correction in Speech LLMscited by 0
- 2026BaLEEN: Biasing with Latent Encoded Entities for Context-Aware ASRcited by 0
- 2026BaLEEN: Biasing with Latent Encoded Entities for Context-Aware ASR29 Sep 2026
- 2026PTC-Bias: Phoneme-Level Temporal Competition for Bias Retrieval and Post-Decoding Correction in Speech LLMs23 Sep 2026
- 2026TurboBias 2.0: Streaming Context-Biasing for Production-Efficient ASR Systems21 Aug 2026
- 2026Contextual Earnings-22: A Speech Recognition Benchmark with Custom Vocabulary in the Wild28 Mar 2026
- 2025TurboBias: Universal ASR Context-Biasing powered by GPU-accelerated Phrase-Boosting Tree9 Aug 2025
- 2025Pushing the Limits of Beam Search Decoding for Transducer-based ASR models30 May 2025
- 2025NGPU-LM: GPU-Accelerated N-Gram Language Model for Context-Biasing in Greedy ASR Decoding28 May 2025