YLAB@RU at Spoken Term Detection Task in NTCIR-9

The information retrieval based on speech recognition is an important technique to easy access to large amount of mul-timedia contents including speech. The development of spoken term detection (STD) techniques, which detect a given word or phrase from spoken documents, is widely conducted. This paper proposes a new method of STD based on the vector quantization (VQ). Spoken documents are represented as sequences of VQ codes, and they are matched with a text query to be detected based on the V-P score which measures the relationship between a VQ code and a phoneme. The representation of VQ codes is an intermediate form between acoustic features such as MFCC parameters and sub-word symbols which are often used in conventional STD methods. The dependency of acoustic features on a speaker is avoided by the speaker-dependent VQ.