Pulsing technology for ANPR / LPR illumination

Pulsing is a crucial element of any lighting system for ITS automatic number plate recognition applications as it not only fundamentally determines the effectiveness of synchronisation between camera and light, but also the light intensities available at the point where images are taken (through LED overdriving), and the flexibility in system design for taking multi-images from one scene (with Multiple pulse imaging) - both functions are explained below.

The ability to very rapidly pulse (also known as 'flashing' or 'strobing') has several advantages. It is more energy-efficient and so reduces cost, and also prolongs LED component life by comparison with an 'always on' state. There are also health considerations and benefits, especially where the use of infra-red light is concerned. Infra-red lights, if left on continuously, carry the risk of reaching irradiance levels which exceed prescribed safety standards.