On the use of lattices of time-synchronous cross-decoder phone co-occurrences in a SVM-phonotactic language recognition system
Amparo Varona, Mikel Peñagarikano, Luis Javier Rodríguez-Fuentes, Germán Bordel · 2011
This paper presents a simple approach to phonotactic language recognition which uses Lattices of Time-Synchronous Cross-Decoder Phone Co-occurrences at the frame level. In previ-ous works we have successfully applied cross-decoder infor-mation, but using statistics of n-grams extracted from 1-best phone strings. In this work, the method to build and properly use lattices of cross-decoder phone co-occurrences is fully ex-plained and developed. For evaluating the approach, a choice of open software (Brno University of Technology phone de-coders, HTK, SRILM, LIBLINEAR and FoCal) was used, and experiments were carried out on the 2007 NIST LRE database. The proposed approach outperformed the baseline phonotactic systems both considering n-grams up to n=3 (yielding around 13 % relative improvement) and up to n=4 (yielding around 7 % relative improvement). In both cases, best results were obtained by considering the m=400 most likely cross-decoder coocurrences: 1.29 % EER and CLLR = 0.203. The fu-sion of the baseline system with the proposed approach yielded 1.22 % EER and CLLR = 0.203 (meaning 18 % and 15 % rela-tive improvements, respectively) for n=3, and 1.17 % EER and CLLR = 0.197 (meaning 15 % and 10 % relative improvements, respectively) for n=4, outperforming state-of-the-art phonotac-tic systems on the same task.