A basic law of light is that the angle of incidence equals the angle of reflection. However, number plates in the UK and most other countries have a special characteristic, namely they are retro-reflective. The surface is covered in hundreds of tiny hemispheres which cause light to be reflected back to the source. This is the same technology used in safety clothing and signs. No matter from which direction the light is directed, it is reflected back, making the object very visible.
If a standard colour or monochrome camera was employed to read number plates it would have to contend with a huge variety of lighting conditions, daytime, night-time, sunlight, backlight and headlights, and would not function correctly. For continuous number plate capture it is necessary to employ a specialised camera together with a constant level and direction of illumination.
The camera must be sensitive in the infrared part of the spectrum (see ) and fitted with a filter to remove the visible part of the spectrum. The lens would normally have a manual iris set fully open and a high shutter speed (1/1000th second). An infrared illumination source must be fitted adjacent to the camera. Taking advantage of the retro-reflective characteristics of number plates, the infrared light from the illuminator will be reflected directly back to the camera. Because of the filter the camera will respond only to infrared light and produce a monochrome image with no detail except for the number plate.
REG Overview
REG is a complete system for consistent, reliable number plate capture. The unit combines the latest camera, optics, illuminator and filter technology to provide clear images of number plates both day and night. REG overcomes all issues related to vehicle speed, daytime highlights, reflectivity of number plates, accurate focus during the night and the day and vehicle headlights.
REG covers all distances up to 50m. No other number plate capture system covers such a dynamic range of distances
High resolution, high sensitivity
Long lifetime with high reliability. The system is specifically designed to provide an average bulb life of up to 10 years
REG can capture the number plates of vehicles travelling at more than 100 miles per hour
Viewing angle of up to 140 degrees horizontally and 40 degrees vertically
No focus shift between daytime and nighttime operation
Large depth of field
Pole, wall and tripod mounting available for maximum flexibility
PSU supplied
Pre-focused, pre-aligned. No adjustment required
Cable managed bracket armoured conduit for maximum security
Weather resistant
Overcomes all problems associated with vehicle headlights and daytime peaks
Designed specifically to cope with high reflectivity number plates
All units pre-tested before delivery
The REG family is available in a variety of formats:
REG Standard - As above - for distances up to 50m (164ft)
REG Dual As above but also includes an overview camera - for distances up to 18m (60ft)
REG Wedge REG in a wedge housing designed for underground car parks - for distances up to 25m (82ft)
REG-L1 featuring DHC-Imaging Technology - for distances up to 25m (82ft) and vehicle speeds up to 160kph (100mph)
REG-D1 featuring DHC-Imaging Technology and including an overview camera - for distances up to 25m (82ft) and vehicle speeds up to 160kph (100mph)
REG-M1 a mobile number plate capture system featuring DHC-Imaging Technology - for distances up to 25m (82ft) and vehicle speeds up to 160kph (100mph)
