Kar-Gor. Inc. - Video Detection Overview

Principle

A video camera is installed at a certain height for monitoring the traffic.
Its video signal is used as input for the detection unit.
In a typical Traficon installation, a detection unit consists of a number of VIP (Video Image Processor) boards integrated into a standard 19" rack together with 1 communication board.
During set-up of a VIP, detection lines/zones are superposed on to the appropriate position in the video image.
As a vehicle crosses these detection lines thus activating them, the vehicle is being detected.
Application specific algorithms provide different types of traffic information (See Type of data).
The communication board handles the compression of images and transmission of data, alarms or images.
The Traficon® TMS PC software monitors the video detection system in the traffic control center.

Type of data

Traffic detection systems based on video provide 3 types of data :

Traffic data for statistical processing
Incident related data
Presence data

The traffic data for statistical processing include:

Volume (the total number of detected vehicles)
Speed
Speed discrimination (acceleration or deceleration of the traffic flow)
Density
Occupancy
Concentration
Classification of vehicles (based upon the length of the vehicles)

The incident related data include:

High speed, density or occupancy
Queue or inverse direction detection
Stopped or very slow moving vehicles
Strange objects on the road

Using this incident related data, the detector can generate an alarm to notify the traffic control center.

The presence data include:

Presence of vehicles approaching or waiting at an intersection
Count of vehicles passing over the detection zones
Queue length measurement

The combination of presence information, counts and queue length measurement delivers to the traffic light controller all information needed for an optimal traffic flow control.

Benefits of video detection

The combination of both numerical data and visual image control sets video detection apart from all other detection systems.

The immediate visual feedback received from video detection systems ensures its proper functioning : On a monitor, the operator at the traffic control center can check whether the detector is working correctly or not.

The combination data & images is an enormous advantage in the field of automatic incident detection (AID). Automatically generated alarms warn the operators as soon as an incident takes place and a maximum of information is given:

type
severity
location
relevant traffic data

When an incident occurs, the operator can see what has happened, how many vehicles are involved, what are the casualties, how is the general traffic situation at that point, etc. This combination of data and images facilitates verification of alarms and the swift detection leads to fast intervention of rescue teams. As a result, avoiding secondary accidents and the subsequent closure of lanes lie well within reach.

Cost effectiveness is demonstrated in:

Low installation and infrastructure cost compared to other systems : Above ground installation implies that there is no need for road closures in order to install detectors into the road surface. Detection zones can easily be moved or adapted to a change traffic situation.
Single camera plus VIP service multiple lanes.
Low maintenance cost of cameras : Cleaning the cameras is the major item.
Long life-time of cameras and electronics

Technical efficiency and reliability are clearly indicated by:

a high detection rate (DR)
a low false alarm rate (FAR)
a low mean time to detect (MTTD)
a high mean time between failures (MTBF)
a modular concept with integration of both numerical data presentation and visual image control