Given the advances made with regards to video analytics in mainstream applications, it seems strange that ANPR – automatic numberplate recognition – hasn’t been embraced with the same gusto. Ideal for a wide range of vehicle management tasks, ANPR delivers real benefits. For some, issues with image capture have made reliability hard to guarantee. Iluminar claims to have the answer with its LPRS-60-24, a dedicated ANPR image capture camera.
[dropcap]I[/dropcap]n recent years, the use of IVA (intelligent video analytics) has become increasingly common in mainstream applications. Often used as a trigger for alarm events, the move has seen IVA functionality built in to an increasing number of devices and software packages. This reflects how higher resolution digital video can enhance typical system performance through the use of analytics.
The capabilities of such solutions range from basic line-crossing detection through sabotage protection, basic counting and facial detection. However, one form of analytics that hasn’t seen a widespread take-up in the mainstream is ANPR. There are two main reasons for this.
The first has much to do with the way in which ANPR providers positioned themselves. In the past, ANPR was aimed at law enforcement agencies and the larger campus-style sites. The market for smaller scale sites, and tasks such as vehicular access control and traffic management, often weren’t considered as lucrative. With regard to such thinking, things gave started to change.
The second stumbling block was the use of standard cameras for ANPR purposes. Whilst this is possible with careful specification and configuration of devices, results can be erratic, and many installers and integrators consider the technology to be more trouble than it is worth.
Iluminar offers the LPRS-60-24, a dedicated ANPR camera which enhances image capture for numberplate recognition solutions.
Specification
The LPRS-60-24 is a high resolution monochrome composite camera featuring on-board infrared illuminators. The camera utilises a 1/3 inch Sony Exview CCD chipset to deliver a claimed resolution of 580 TV lines.
Much of the camera’s configurations are fixed. This may seem restrictive, but it does ensure optimum performance with regard to ANPR-related image capture. As such, the camera is not suitable for secondary use for general surveillance. It should be used solely for numberplate capture.
The unit features integral infrared 850 nanometre LED illuminators, and the power of these is adjustable via a potentiometer. The specified range for the camera is from 4 to 18 metres; another variant offers ranges of 2 to 10 metres.
Numberplates can be read at speeds of up to 30mph, which is ideal for site entrances, approach roads, etc., where the user has the opportunity to regulate speeds.
The facia of the camera includes an optical filter which reduces visible light falling on the CCD. This helps to eliminate glare from sunlight, headlights, etc., and maximises contrast for numberplates.
The camera features a fixed omni-focus 16mm lens. Shutter speed is fixed at 1/1,000th of a second. Functionality such as Gain is automatic, as are all image manipulation features.
The LPRS-60-24 is supplied in a black coated aluminium housing, which features a cable-managed bracket with three-axis alignment. This makes positioning a simple task. The housing is rated to IP67 making it ideal for outdoor use. Operating temperature range is -10 to 50 degrees C.
Power input is 24V AC. The power connector and BNC output are fitted to a pre-attached flylead. Fixings are included, as is a brief but adequate installation guide.
Performance
Installation of the LPRS-60-24 is very straightforward. It is, however, vital that whoever fits the unit has an understanding of design considerations when siting ANPR capture devices. The connection for power is a via a screw terminal block, and the BNC connection is simple. Both are on a flylead. Once mounted, you’re nearly finished. The one installer adjustment is for infrared intensity. This is adjusted via a potentiometer.
The very first thing you’ll notice is that during daylight hours, the image has a high degree of detail, although in shaded areas it might be a little darker and duller than you’d expect. As light levels fall, so does the degree of detail. Fear not; this is how it should be!
The optical filter reduces the incidence of visible light falling onto the CCD, and the fast shutter speed also has an impact. However, the filter does not affect the transmission of infrared light, and this makes any reflective surface – such as a numberplate – appear with a high degree of contrast.
The impact isn’t as great during the day, although numberplates can be clearly defined within an image. In lower light, gloom and at night, the performance is increased, because the numberplate has a much higher level of contrast.
Fixed lenses can sometimes be a concern if there isn’t an opportunity to adjust focus, but the F2.0 optics on the LPRS-60-24 are very well set-up and, and there’s no sign of softness in the image.
The camera housing is obviously ‘borrowed’ from a different model, because the rear of the includes two potentiometers for zoom and focus. However, these are simply pot covers and there is no functionality to be accessed.
The infrared illuminators are permanently lit. This does eliminate any need for switching or other management of the camera.
Finally, with regard to robustness, the camera doesn’t give any reason for concern. It is well built, sturdy and shouldn’t give any problems even in a typically British winter.
Verdict
The LPRS-60-24 is a product with a very singular focus. It is optimised for ANPR, and should not be used for anything else. Indeed, this is made very clear by Iluminar. To the Benchmark way of thinking, ANPR solutions should use dedicated cameras which are optimised for the purpose. Otherwise, there are simply too many potential issues.
Whilst you may initially think that taking away nearly all control over performance from the installer is a negative, it’s not. The unit is well optimised for its task, and if installed correctly it delivers the type of performance required.
As such, the LPRS-60-24 has to be Recommended for ANPR applications.