Today’s high volume of traffic on our roadways is being more and more assisted by Intelligent Traffic Systems. From identifying traffic violations, object on the highways, traffic monitoring to toll collection, they help to keep our roadways moving and more importantly safe!
Enforcement systems are used over a wide range of speed enforcement, red light enforcement and lane violation detection. The goal of these systems is to change driver behaviors and make roads safer. Cameras for these applications are typically based on high sensitivity sensors starting from 2MP and usually 25fps.
TOLL COLLECTION & ENFORCEMENT
Cameras read licence plates of vehicles passing through toll gates and then electronically deducted from the account associated with each plate. The major advantage of this process is that Electronic Toll Collection can be done with vehicles in motion creating a quick, efficient process. A more common application is toll enforcement where cameras can identify the size of a vehicle so that a different toll rate can be paid or prevent fraud by capturing licence plates of non-paying vehicles.
Cameras help monitor traffic flow, as well as road and weather conditions. The most important application is Automatic Incident Detection, to ensure quick response on accidents and other obstructions, particularly in critical locations like tunnels and bridges. Cameras used in traffic monitoring must handle difficult weather conditions and changing lighting. A retractable IR-cut filter and an automatic iris enable highly flexible adaptation during day and night hours. In combination with a wide dynamic range and high sensitivity these features ensure an excellent image quality under tough environmental conditions. The integrated multi-channel streaming (MJPEG, MPEG4, H.264) allows 24/7 recording while minimising the required bandwidth and storage space.
CAMERA TECHNOLOGIES USED FOR INTELLIGENT TRAFFIC SYSTEMS
Two types of camera can be used – Industrial cameras, such as the HIKrobot CE Series; a housed compact (29x29mm) with many sensor options from VGA to 20MP.
Or the HIKrobot CB USB3.0, a board level camera idea for an OEM integrated solution with excellent price to performance ratio and simply USB3 connectivity.
KEY CAMERA FEATURES FOR INTELLIGENT TRAFFIC SYSTEMS:
Real time capability: Image capture starts immediately after a trigger signal has been sent to the camera. This is especially important in high-speed applications such as speed enforcement and tolling, and for flash synchronisation.
Sequencer acquisition mode: The camera captures a series of images with different settings like AOI or exposure time, in a minimum amount of time. This is useful when the camera should capture a highly reflective car license plate and the driver’s face at the same time and on an appropriate (different) brightness level.
Broad sensor range: The wide variety of ITS applications requires a wide range of sensors offering different price points, resolutions, technologies (CCD/CMOS), and pixel sizes.
High sensitivity: High sensor sensitivity allows for short exposure times to capture clear images of fast-moving objects, (e.g. in speed enforcement).
Multi-streaming: Video streams captured in traffic monitoring applications use a high amount of bandwidth and storage capacity. With multi-streaming, separate video streams with different areas of interest and quality can be set up for different purposes and thus save bandwidth and storage capacity.
Image compression: In multi-camera systems and for longtime storage, image compression helps to save bandwidth and reduces the storage space required. Image compression can also be used in combination with multi-streaming: separate video streams can be encoded using different compression formats.
Auto iris functionality: Lenses with auto iris functionality can automatically adjust the lens iris opening and image settings such as gain and exposure time for different light conditions.
Day/night functionality: Cameras with day/night functionality are equipped with an IR-cut filter that is placed in front of the sensor in good light conditions for good color rendering. In night mode, the IR-cut filter is removed to make use of infrared light for clear black-and-white images in low light.