Keyword spotting enhancement for video soundtrack indexing

Multimedia databases contain an increasing number of videos that are not easily semantically accessed. Among the useful indices that can be extracted from the soundtrack, the presence of a keyword at some place plays a prominent role. This paper deals with the specificities of such a keyword spotter and the enhancements brought to our previous technique (1996) based on frame labeling. To be useful, such a keyword spotter has to be speaker-independent. Moreover, it has to be able to detect any word from an open vocabulary. This directly implies the use of a phonemic representation of the word. These constraints usually lead to an excessively time-consuming tool. The division of the indexing process into two parts-the first one off-line, the second one at query time-allows a faster response.