Vocal Interface for a Man-Machine Dialog

VOCAL INTEILFACE FOR A MAN-MACHINE DIALOG Dominique BEROULE LIMSI (CNRS), B.P. 30, 91406 ORSAY CEDEX, FRANCE ABSTRACT We describe a dialogue-handling module used as an interface between a vocal terminal and a task- oriented device (for instance : a robot manipula- ting blocks). This module has been specially desi- gned to be implanted on a single board using micro- processor, and inserted into the vocal terminal which already comprises a speech recognition board and a synthesis board. The entire vocal system is at present capable of conducting a real time spo- ken dialogue with its user. I INTRODUCTION A great deal of interest is actually being shown in providing computer interfaces through dia- log processing systems using speech input and out- put (Levinson and Shipley, 1979). In the same time, the amelioration of the microprocessor technology has allowed the implantation of word recognition and text-to-speech synthesis systems on single boards (Li~nard and Mariani, 1982 ; Gauvain, 1983 ; Asta and Li~nard, 1979) ; in our laboratory, such modules have been integrated into a compact unit that forms an autonomous vocal processor which has applications in a number of varied domains : vocal command of cars, of planes, office automation and computer-aided learning (N~el et al., 1982). Whereas most of the present language under- standing systems require large computational re- sources, our goal has been to implement a dialog- handling board in the LIMSI's Vocal Terminal. The use of micro-systems introduces memory si- ze and real-time constraints which have incited us to limit ourselves in the use of presently availa- ble computational linguistic techniques. Therefore, we have taken inspiration from a simple model of semantic network ; for the same reasons, the ini- tial parser based on an Augmented Transition Net- work (Woods, 1970) and implemented on an IBM 370 (Memmi and Mariani, 1982) was replaced by another less time- and memory-consuming one. The work presented herein extends possible application fields by allowing an interactive vocal relation between the machine and its user for the execution of a specific task : the application that we have chosen is a man-machine communication with a robot manipulating blocks and using a Plan Gene- rating System. SPEECH I RECOGNIZER SEMANTIC [ SYNTACTIC PROCESSING ANALYSIS SEMANTIC ] TREATMENT I 8"ANC"INO.,I \ 'I o .t.E I .AsE QOEST,ON i i i l I I B ASSERT~N ANSWER t i /./f I SENTENCE I !' PRODUCTION ( t ( SPEECH J SYNTHESIZER Figure I. Block diagram of ~he system II SYNTACTIC PROCESSING A. Prediction Device Once the acoustic processing of the speech si- gnal is performed by the 250 word-based recognition board, syntactic analysis is carried out. It may be noted that response time and word confusions increase with the vocabulary size of word recognition systems. To limit the degradation of performance, syntactic information is used : words that can possibly follow a given word may be predicted at each step of the recognition process with the intention of reducing vocabulary. 43 B. Parameters Transfer In order …

Content truncated to 500 words