Patent ID: 7016518

Claim:
A license plate reader system for all ambient light conditions, comprising a high power infrared illuminator for night and a monochrome camera that: a) is enhanced for infrared sensitivity and resolution; b) has shutter speeds set up to capture clear license plate pictures on vehicles moving at any speed up to a predicted speed limit for the vehicles, even with their headlights on; c) has optical filtering of light wavelengths outside the range of light wavelength emitted by the high power infrared illuminator, in order to avoid sensor overload from headlights and reflected glare from sunlight; d) has high resolution and low inter-pixel leakage; e) has a lens set up with a small aperture formed by an iris to avoid sensor overload, to increase depth of field for focused images of license plates on moving vehicles, and to avoid vertical smearing of images; in which the high power infrared illuminator provides illumination of over a distance of at least 35 meters from the camera at an intensity to capture clear license plate pictures even with fast moving vehicles and even with their headlights on.