Section: Software

ANTS

contact : Dominique Fohr (fohr@loria.fr).

The aim of the Automatic News Transcription System (ANTS) is to transcribe radio broadcast news. ANTS is composed of five stages: broad-band/narrow-band speech segmentation, speech/music classification, speaker segmentation and clustering, detection of silences/breathing segments and large vocabulary speech recognition. The three first stages split the audio stream into homogeneous segments with a manageable size and allow the use of specific algorithms or models according to the nature of the segment.

Speech recognition is based on the Julius engine and operates in two passes: in the first pass, a frame-synchronous beam search algorithm is applied on a tree-structured lexicon assigned with bigram language model probabilities. The output of this pass is a word-lattice. In the second pass, a stack decoding algorithm using a trigram language model gives the N-best recognition sentences.

A real time version of ANTS has been developped. The transcription is done in real time on a quad-core PC.