Automatic Number Plate Recognition – Evidence Retrieval and Control Computers

Institutions such as police forces, local councils and highways authorities are driving initiatives to make roads safer for the public using Automatic Number Plate Recognition (ANPR) technologies.

The concept is centered on multiple cameras that read license plates, log the readings against police and DVLA databases, and then assess them for potential criminal interest or activity.

The same method has been deployed for average speed detection and enforcement. Commonly seen on motorways, the cameras register the median speed of drivers between specific stretches of road. The cameras are intended to encourage motorists to keep their speed down, with any cars that exceed the law-given threshold incurring a record being created, violation images taken, and data being logged. The platforms supporting this aspect of the application are known as Evidence Retrieval and Control computers.

Traditionally, Evidence Retrieval and Control computers have been large 4U rackmount PCs. However lately, there has been an urgency to reduce the depth of the computers, while still maintaining full functionality. This directive is aimed at saving valuable space, creating increased capacity to connect additional ANPR cameras, therefore enhancing accuracy and generating more revenue.

Due to Home Office restrictions, the visual data collected by ANPR computer platforms cannot be transferred electronically, it must be physically retrieved. Owing to the reduced depth of the chassis, having large amounts of data that cannot be electronically stored presents a significant challenge. However, with the application of expert engineering, a possibility is to integrate a total of four DVD-R drive bays onto the chassis to create the necessary storage capacity, and meet the requirements of the Evidence Retrieval and Control application.

An additional issue created by the transition to a smaller chassis, is that any heat emitted by the components housed in the enclosure will have less room to circulate, amounting to excess heat and strain. To avoid overheating and the inevitable downtime caused as a result, the platforms must have sufficient cooling to secure reliable operation and negate the risk of failure. Configuring the platforms strategically, with three fans and an adequate power supply unit, will certify that components receive sufficient cooling and a healthy, continual and reliable provision of energy.

The Home Office also stipulates that systems performing ANPR roles should be subject to EMC compliance testing. This is to ensure safe functioning and minimal interference with systems working in conjunction with the application.  Testing platforms in-house prior to verification is a time and cost efficient method of ensuring operation within the requisite parameters, alleviating the pressures of the testing process and securing the safety of the Evidence Retrieval and Control Units.

Tagged in: Anpr, Evidence Retrieval and Control, Transport

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