Patent ID: 6603507
Filing Date: 2003-08-05
Classification: H04N

Abstract:
A method for controlling a light source in a night vision system, which comprises a pulsed light illuminator and a gated light sensor, the method comprising:estimating or measuring a desired observing distance d of an object; setting a shortest distance d1 for back-scattering lights to enter the light sensor; determining a pulse width Tp of a light beam emitted from the pulsed light illuminator, in which Tp=2(dâˆ’d1)/c, where c represents a light speed; determining a duty cycle D for the pulsed light illuminator, wherein D is equal to Tp/(Tp+T2d), where T2d=2d/c; the pulsed active-light illuminator emitting light pulses with the pulse width Tp and an emitting period (Tp+T2d); and the light sensor receiving the light pulses which are reflected by the object, wherein the light sensor has a sensing period identical to the emitting period but with a delay time of T2d.