Safe Speed Forums

Red Light & Speed Enforcement

Technical Sheet No.12

The Idris® patented Technology is so versatile it can be implemented into a variety of applications from a single function system to multi tolling applications. The Idris speed detection system is a single function speed solution. It’s capable of obtaining highly accurate speed data from standard loop sensors installed under the carriageway on a short base line. Idris Technology is an ideal and lane specific detection or trigger method for generic 35mm or digital camera enforcement systems. Specifically where expensive above ground Radar or problematic ‘inroad’ multi Piezo sensor sites have been the only available technology. The system can also be adapted to any loop only traffic environment where high accuracy speed data, length and axle classification are of paramount importance.

As an example, to enable the loop sensor array to be installed between, or around the white “stop” line/bar for Speed on Green Enforcement at a Red Light controlled intersection, 1m loops with a separation of 1m would be typically installed resulting in a 3m loop array with the specified +2kph/+ 2% on Speed accuracy. The Idris ‘loop only’ speed detection system has been developed, proven and validated for loop only speed accuracies of better than +/-2 kph at speed ranges from 5 to 100kph, + 2% above 100 kph, for all vehicle types. Requirements for higher accuracy can be met using detection 2m loops. Using modified Idris vehicle classification algorithms, the developed Idris system is also able to ascertain when an erroneous speed has been detected and positively prevent incorrect image triggers. This creates a secure evidential detection method for enforcement camera systems, .i.e. used in traffic signal controlled junctions, at unmanned rail crossings, on urban or rural highways and at road irregularities where traditional detection methods are unsuitable (such as bends or brows of hills).

A range of tests using commercial vehicles, cars and motorcycles have been conducted; these include close following vehicles, vehicles reversing over the site and high speed vehicles passing within the sensor array. In addition, stationary and low speed vehicles have been tested with parked vehicles on or near to the sensor array together with vehicles performing lane changes over the detection point.

Case 13: Enhanced PIPS' SpikeHD camera
Application: Enhanced PIPS' SpikeHD camera
Idris Technology Partner (ITP): PIPS Technology

Background: Becoming an Idris Technology Partner recently enabled PIPS to develop a new Idris-enhanced camera destined for the ITS market. The Idris software will reside on board the PIPS’ SpikeHD camera.

Product detail: PIPS SpikeHD Camera optimised by Idris on one platform offers a unique and enhanced suite of applications:
individual slow vehicle
Instantaneous/differential/enforceable speed
Access control & classification,
White listed registration plate recognition,
Profile based classification,
Bus lane enforcement & detection,
All combined in ONE box!

The product incorporates the highly accurate automatic license plate recognition (ALPR) capabilities from PIPS with the loop based detection and classification accuracy of Idris software. The compact design specification focuses use of the product on sites where large infrastructure cannot be supported. Both the camera and the recogniser processor are housed within a single IP68 sealed enclosure. It is designed for use in the highest performance applications where it is necessary to provide the ALPR function across a full 4 metre carriageway (3.5m with 0.5m overlap/ 11.48ft with 1.64ft overlap/137.8in with 19.69in overlap).

Marrying the Idris data with the ALPR data generates information such as:
Average speed
Vehicle length
Class and headway.

The unit comprises a high resolution monochrome CCD camera with high sensitivity in the infra-red (IR), surrounded by two banks of IR LEDs. Patented filter / flash technique gives suppression of headlights and bright sunlight. Field-by-field control of camera parameters allows the use of the patented ‘triple flash’ technique to reduce problems of plate-to-plate variability.The 264 wide-angle LED's allow illumination of up to 4 metres (13.12ft) of road and allows the camera to read multiple number plates in a single field of view.

How it works:
Idris smart loops register a vehicle travelling over the loop site and track it for the duration of its time within the site. All the data from the loop signature is collected by Idris and processed to provide a Per Vehicle Record (PVR). At the same time as Idris is collecting the data to create each vehicle's PVR, it is registering each ALPR read that occurs, noting the lane and time of each read. As a vehicle's PVR is being created, Idris analyses the position of ALL vehicles over the site with respect to all ALPR reads which might be associated with the vehicle of interest. It then uses all the spatial information available to match the vehicle it is processing to the correct ALPR record, associating the corresponding number plate to this vehicle. If no acceptable ALPR record is found for a vehicle, a trigger is sent to the camera to take an overview picture of the vehicle for enforcement purposes.

In addition to associating each license plate to a vehicle, Idris notes the location of the read with respect to the site and summarises the read location information for diagnostic purposes. This enables early detection of bad camera adjustment or impending failure indicated by a changed read location or high spread in the locations.

The Vehicle Enforcement System (VES) application software offers socket based transfer of Summary and Evidential Records via either push or pull protocols with full key handling, authentication, encryption and local storage of up to 60,000 events. Pre and post event contextual images showing the direction of travel may also optionally be captured along with the direction of travel.

The camera has four or more powerful processors but, with 50ftps (frames taken per second) plate-finder there is little additional processing required for larger images, so the majority of this is available for improved processing. Real-time JPEG hardware compression is provided for both IR and colour images and can be used to provide a real-time IP video stream of the traffic. This can be used to record the image stream for ground-truthing.

The power requirements and communication structure remain the same with GSM, GPRS, WiFi and Ethernet as standard. Both the SpikeHD and Idris run on embedded Linux operating systems offering standard Linux connectivity and encrypted links. The product offers a pluggable terminal-strip rear connection for rapid cable termination in the field, whilst maintaining a hermetically sealed, purged camera. The standard metal gland cable seals have greater robustness and allow up to 3 separate cable entries for connection to DSRC or other equipment.

Outcome: This innovative and cost effective product will serve the needs of a variety of applications such as road user charging, tunnel safety, enhanced incident detection and lighter open road tolling applications. This product combines two of the most well established and proven technologies available for road user charging and congestion mitigation available today.

Further information contact: Teri England of Idris Technology: teri@diamond.demon.co.uk +44 (0)1296 747667