Applied Evaluation of Speech Recognisers with Respect to Tape Recorded Data.

In several transport planning and maintenance survey applications data can be efficiently captured by audio tape-recording. Such recording is useful in situations where the rapidity of events; or the need for the operator to keep his eyes on the objects being recorded; make it difficult to use other recording methods such as paper and pencil; or keyboards. Examples of the sort of situations considered in this report are car registration plate surveys (moving and parked vehicles) ; and street furniture inventory surveys.

The transcription of such tape recorded data has; up until now; been a time consuming and labour intensive process; and it was therefore decided to investigate the possibility of using a speech recogniser to automatically transcribe the data. Whilst laboratory studies of the efficacy of the speech recognition process have of course been carried out; there have been very few field trials to evaluate the technology in specific application areas. This paper describes such an evaluation; for the case in which the speech recogniser is used for transcribing data recorded on an audio cassette. Different types of recogniser were tested on data recorded under both laboratory and field conditions. The suitability of associated equipment; (microphones and tape recorders); is also assessed for use with speech recognisers; and the recommended models are described. A training programme is suggested for new users and the results of the equipment trials and training program are presented. Camparisons are also made with other more traditional methods of data collection and transcription.