BTH:an Efficient Parsing Algorithm for Keyword Spotting

In this paper, we propose BTH, a parsing algorithm which is able to efficiently parse keyword lattice that contains large number of false candidates. In BTH, the grammar is written in template form, and then, it is compiled into a hash table. BTH analyzes the lattice without unfolding to keyword sequences, by propagating acceptable templates among the linked keywords and filtering through the hash table in each keywords. It has a time bound proportional to n2 (where n is the number of keywords in the lattice), although the number of false candidates increases exponentially. Simulation results shows that BTH can parse lattice which contains over 100 billion false candidates within 0.35 sec, with grammar which is corresponding to 2 million of templates, on a notebook-PC(PentiumII 266MHz).