The Influence of Word Detection Variability on IR Performance in Automatic Audio Indexing of Course Lectures

This paper presents a study of the influence of acoustic variability on topic spotting performance in an applica-tion involving automatic indexing of course lectures. The application involves users formulating keyword que-ries to an indexing system which includes phone lattice based acoustic representations of audio material, a mechanism for keyword searching of a phone lattice, and a measure for evaluating the relevance of short segments of the audio files with respect to the query. The paper describes the results of a study where keyword detection performance for query terms provided by domain experts is related to the information retrieval (IR) performance obtained using a novel information retrieval measure. IR performance obtained from text transcriptions of the audio recordings and from the audio recordings them-selves are presented