VEHICLE DETECTOR MEASUREMENT APPARATUS AND METHOD USING FRAME SEGMENTATION

摘要

A vehicle detector includes one or more inductive sensors 12 connected to an oscillator circuit 16. A timing circuit 34 defines a plurality of sequential measurement frame segments. The oscillator circuit 16 is coupled to an inductive sensor 14 during each of the measurement frame segments. The time duration of each of the plurality of measurement frame segments is measured. After the completion of each frame segment for a particular inductive sensor, a total measurement frame time duration for that sensor is calculated based upon durations of a predetermined number of measurement frame segments for that sensor 20, 36, 38. The total measurement frame time duration and a reference time duration are compared and a difference is determined. If the difference between the total measurement frame time duration and the reference time duration exceeds a threshold value, an output signal indicative of the presence of a vehicle in the vicinity of the inductive sensor is generated.