REPORT lehtonen-2005/IDIAP Hierarchical approach for spotting keywords Lehtonen, Mikko acoustic stream hierarchical processing EXTERNAL http://publications.idiap.ch/attachments/reports/2005/rr05-41.pdf PUBLIC Idiap-RR-41-2005 2005 IDIAP The paper presents a new approach to spotting a particular sound (keyword) in an acoustic stream. The approach is based on hierarchical processing where equally-sampled posterior probabilities of phoneme classes are estimated first, followed by matched filtering that yields non-equally spaced values, one for each phoneme, indicating confidences of underlying phoneme being present. The target keyword is indicated by a particular sequence of high-confidence phonemes.