Sensor Sections
Transport Data Systems uses a variety of sensors in its automatic vehicle classification and license plate capture systems. TDS has worked closely with a number of sensors to develop the specific drivers required to interface to these sensors. TDS has performed a significant amount of development testing with each of these sensors in a live traffic environment.
TDS designs for AVC systems routinely use a Doppler radar to provide velocity data on the target as it passes through the profiling zone. The Doppler radar is produced by Eaton VORAD. It was developed by Eaton to supply the sensor input to a collision avoidance system. It is designed to operate in an external environment in all weather conditions. The EVT300 has been approved by the U.S. Federal Communications Commission for use on the highway. The unit has a serial interface to the user and requires a 7.5 VDC regulated supply to be located within 10 feet of the unit. TDS provides a special adapter for mounting of the unit.
TDS designs for AVC systems routinely use a light curtain to provide profile data on the target as it passes through the profiling zone and to separate vehicles. TDS uses light curtains produced by STI. STI produces a standard range of curtains from 3 to 5 feet in height. STI has developed a custom 10 foot curtain for TDS with 3/4 inch spacing on the bottom 5 feet and 1.5 inch spacing on the top 5 feet. STI produces environmental enclosures for the curtain transmit and receive elements to all for operation in all weather conditions. The light curtains have a serial interface and a separate digitial output which indicates curtain penetration. The curtain processor may be purchased in a case or stand-alone for mounting in a separately provided user case.
TDS designs for AVC systems routinely use an overhead laser scanner to provide profile data on the target as it passes through the profiling zone and to separate vehicles. The Model LMS211 overhead scanner is produced by Sick, Inc of Germany. It has been designed to operate externally in all weather conditions. It provides a serial output to the user. It requires a separate regulated power supply for operation of the unit and for powering the environmental control system built into the unit. TDS is an authorized distributor for the Sick transportation product line. TDS can provide the interface application for interfacing to the scanner from either a Windows or Linux application.
TDS designs for AVC systems use a Sensorline fiber optic treadle to provide axle data on the target as it passes through the profiling zone. These sensors are designed for permanent embedding in the road surface. They are capable of detecting vehicles at high speeds. They feature a lifetime of more than 10,000,000 crossings. Two of these strips (1.7 meter) are used to provide dual tire detection.
TDS has developed a treadle frame and treadle carrier to allow
for quick replacement of the fiber treadle with simple tools. No
concrete work or on site potting required. Just remove the old carrier
and replace it with a new one.
When required, TDS designs for AVC systems use a weigh-in-motion sensor to provide weight and axle data on the target as it passes through the profiling zone. Kistler quartz sensors allow wheel loads to be determined as vehicles drive past. These sensors are modular elements that are assembled into strips and installed into slots that are saw-cut across an asphalt or concrete road. The output from these sensors when coupled with the velocity data from the AVC Doppler radar produce accurate vehicle weights on a tire by tire basis.
TDS has developed a quartz sensor frame and carrier to allow for
quick replacement of the quartz sensor with simple tools. No concrete
work or on site potting required. Just remove the old carrier and
replace it with a new one.
TDS designs for license plate capture systems use area scan digital cameras produced by Point Grey. These include the Scorpion and the Grasshopper. The Scorpion is a 1600 x 1200 pixel digital area scan camera with integrated
remote camera control, digital I/O, RS-232 interface and FireWire interface (IEEE 1394A). The Grasshopper is a 2448 x 2048 pixel digital area scan camera with integrated remote camera control, digital I/O, RS-232 interface and FireWire interface (IEEE 1394B).
Each of these cameras can be set up to operate in the visible or near IR bands. For more information on the cameras, please visit the Point Grey website.
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TDS delivers the cameras with
a Pelco case and one of a variety of Pelco mounts. TDS also manufactures ring shaped
pulsed LED visible and near IR illuminator boards for inclusion inside the Pelco case. These illuminators have sufficient strength to provide the needed coverage at ranges up to 45 feet.