Speaker independent recognition of spontaneously spoken connected digits

Abstract

An important area of speech recognition is automatic recognition of connected digit strings (i.e., sequences composed of the digits zero through nine, and oh). Applications of this technology include credit card authorization, catalog ordering, dialing of telephone numbers, and data entry. For the past two years AT&T has experimented with a system for automatic recognition of 10 digit merchant identification codes, and 15 digit customer credit card numbers, for the purpose of authorizing purchases charged to a credit card. Our evaluation used data collected from about 1000 customers who provided 2000 connected digit strings over 800-based dialed up telephone connections. The recognizer correctly recognized 97% of the digit strings with no rejections using constraints on the validity of both merchant identifications and credit card numbers. Several schemes for applying these task constraints in a practical implementation are discussed in this paper. Also, recognition of the dollar amounts of the transaction are presented with some preliminary results.