Single Lane Post Classification AVC System

The TDS classification systems combine Doppler radar and a overhead mounted laser scanner profiler to automatically classify vehicles into user defined categories (autos, trucks, buses, motorcycles, etc.). The TDS laser scanner based automatic vehicle profiling system also utilizes pattern recognition for class differentiation.

Data from the overhead scanner(s) is used to form a matrix depiction of the vehicle as seen from the overhead position of the laser(s). The vehicle detection process is initiated when careful examination of the laser scanner output indicates the presence of a vehicle. During periods when no vehicle is being detected by the laser scanner, the processor periodically polls the laser scanner looking for any indication of a vehicle presence. When the curtain is penetrated, the processor uses velocity information from the Doppler radar to determine the position of the vehicle relative to the initial location point set by the curtain. Based upon this position, the laser scanner is polled at regular predefined distance intervals (as opposed to time). A complete set of data points is transmitted from the laser scanner to the signal/data processor at each sample distance. From this information a vehicle profile is generated. This process continues until the laser scanner no longer contains any indications of a vehicle. At that point the vehicle profile is terminated.

The real time flow of data from a treadle or a side mounted laser scanner provides for the determination of axle distances from the front edge of the vehicle. The length of the vehicle is determined from the number of individual data sets that are recorded. A treadle based dual tire detector can also be added to the system in the event that dual tires play a role in the classification scheme.

Actual Profile - Single Lane Laser Automatic Vehicle Classifier System

The functional capabilities of the various models are shown in the following table. All systems include the Doppler radar and use one or more overhead laser(s) for separation and width detection. Axle detection is provided by a fiber treadle or a side mounted laser scanner.

Model Number Overhead Lasers Length Width Profile Height Profile Axle Detection Dual Tire Detect
210 1 Yes Limited Yes Treadle No
220 1 Yes Limited Yes Treadle Yes
230 1 Yes Limited Yes No No
240 2 Yes Full Yes Treadle No
241 2 Yes Full Yes Treadle Yes
242 2 Yes Full Yes No No
250 2 Yes Full Yes Laser No