Automatic and semi-automatic collection of registration plates is an attractive prospect particularly when flow rates and hostile site conditions preclude the economic use of more traditional techniques. Collection of registration plates by voice onto audio tape is a well established technique and with the reduction in price of equipment, video recording is also becoming popular. However, manual transcription of the captured data is a time consuming, error prone and costly exercise. It would obviously be advantageous if transcription could be performed automatically by speech recognition or image processing respectively. In this paper, field trials designed to test the collection of registration plate data using audio tape and video tape are described and comparative results for automatic transcription of both are presented. Initial results suggest that, using currently available equipment in field conditions, automatically transcribed audio tape is more accurate than automatically transcribed video tape, but is still inferior to manual transcription. The nature of the errors encountered and ways in which they might be reduced are also discussed.
Samenvatting