That the machine vision industry is taking traffic installations seriously is evident by the amount of hardware and software products tailor-made for ITS applications that are now available on the market. A good example comes from US-based GRIDSMART Technologies which has developed a single wire fisheye camera that provides a horizon to horizon view for use at intersections. Not only does the single camera replace four or more in a ‘traditional’ configuration, it also covers the centre of the intersection where the traffic flows intersect.
Beyond the standard traffic management and incident detection, the horizon to horizon view gives users additional data collection capabilities as it tracks objects through the intersection and the system reports in which direction vehicles and cyclist head. The company’s vision processing algorithm automatically counts vehicles and measures intersection performance 24/7. According to the company, such long-term counts provide a more accurate understanding of the intersection and how it is affected by seasonal variation, weather and other factors that will not be apparent in the traditional 24-48 hour studies.
Another example is the Axis P3905-RE network camera range which is designed for onboard video surveillance in or on buses, trams, subway, emergency vehicles, cars and other vehicles. In addition to the network connectivity, the camera has edge storage capabilities and an active tampering alarm function for the detection of tampering attempts such as blocking or spray-painting.
The standard 6mm lens provides a 55° horizontal field of view, while fitting the 3.6mm version widens this to 87°.
Another US company, Eutecus, that provides video analytics solutions for applications including intelligent lighting and advanced driver assistance technology, was approached by a user wanting more cost-effective red light violation detection with significantly improved performance. The unnamed user operates red light violation and speeding detection systems, traffic surveillance and other video- and radar-based solutions for municipalities across the U.S.
Video content for typical red light violation detection systems is transmitted from the intersection to a centralised facility for time-consuming manual review by operators to distinguish violators from the innocent.
Eutecus used a Camera Link version of Teledyne DALSA’s Genie TS cameras with its own Bi-i Smart Cube platform to enable it to run its Multi-core Video Analytics Engine (MVE) on the video stream. The Genie cameras offer high-quality resolution, high frame rate, large pixels and in this case the required Camera Link interface. While the camera continuously acquires frames, the data is analysed in real-time in order that only the violations are captured and images in which no violation occurs are discarded.
In this application, the camera provides the primary video analytics source, monitoring both the traffic light and the traffic itself.
Andrew Herson, senior manager at Eutecus says: “The Genie camera essentially ‘maps’ distinct images of the traffic light as well as images of the vehicle in relation to the intersection stop line. This scene analysis is combined with data from radar, and a second, low-resolution video camera provides documentation that can be used for verification in the event a driver disputes a ticket.”
According to Euctecus, the system only sends pictures to the operator if the images of the traffic light and vehicle/stop line don’t align as they should – thereby indicating a violation. The operator then confirms the violation and generates a ticket without the need for a lengthy or exhaustive video review.
It says the automated nature of the solution eliminates the potential for human error and increases overall system reliability, and adds that it can capture and process multiple simultaneous events, such as two cars running a red light at the same time.
As the system’s ‘intelligence’ is embedded with the camera, the entire solution can be installed above ground which Herson says provides municipalities with a streamlined and far less costly solution than traditional traffic monitoring applications. Beyond red light violation, the system is said to be suitable for applications including toll enforcement, speeding detection, wrong-way driver detection, stopped-vehicle detection and as a traffic light sensor.
Beyond capturing offences, the radar part of the system can gather blind data including counting vehicles, cyclists and pedestrians and classifying vehicle type into car, van and truck.
While machine vision helps reduce the amount of data being transferred over the network, the ever-growing number of installations means capacity limitation remains a concern.
However, the latest CoaXPress standard for HD-SDI, USB, GigE or Camera Link, defines a high-speed interface between a camera and a processing device, such as a frame grabber, and offers better performance than traditional analogue.
In its simplest form, a single coaxial cable is sufficient to transmit data at up to 625 megabytes per second, to simultaneously transmit control data and triggers, and to provide at least 13W of power to the camera. Where even higher data transmission rates are required, four parallel cables can be used to provide rates of up to 2,500 megabytes per second.
According to Jean-Bernard De Bal, vice president of business development at image acquisition and software supplier Euresys, this meets the needs of bandwidth-hungry applications. These include high speed traffic cameras shooting 560 frames per second (fps) in real-time with 4 Mega pixel (MP) resolution or ultrahigh definition 26MP cameras shooting at 80fps where the sharper images will enhance license plate recognition accuracy. Such specifications are far better than traditional full HD 1080p cameras, which shoot 2MP at 60fps.
Signal latency is another critical consideration for vehicle tracking and highway control applications and here again the CoaXPress standard can be useful as it allows the transfer of uncompressed video so zero latency is possible. High frequency real-time triggering and exposure time adjustment can also be accommodated.
CoaXPress connections can be made using the same heavy-duty coaxial cables used for analogue and HD-SDI cameras allowing analogue cameras to be replaced with high resolution digital units using the same cable network, making upgrades cheaper and easier. And as the thick copper cable inside coaxial cables is protected from electromagnetic interferences by a Faraday cage, they perform in the harshest environments and are able to withstand shocks and vibrations.