Patent ID: 8035514

Claim:
A motion detection system for detecting a presence of a moving object within a secure area, the system comprising: a first sensor responsive to light in a first range of wavelengths in the secure area, the first sensor generating a first output signal indicative of a first detected parameter of the light in the first range of wavelengths; a second sensor proximate to the first sensor, the second sensor being responsive to light in a second range of wavelengths in the secure area; a logic unit for compensating the first output signal based in part upon a reference signal indicative of a second parameter of the light in the second range of wavelengths; and an alarm generation unit to generate an alarm if the first output signal exceeds a first threshold value, the first threshold value being a function of a baseline of the first output signal, wherein the second parameter comprises an intensity value of the light in the second range of wavelengths, wherein the reference signal is indicative of a differentiation of said intensity value with respect to time, wherein the reference signal is a second signal indicative of the second parameter of the light in the second range of wavelengths detected by the second sensor, wherein the logic unit compensates the first output signal only when the second parameter of the light in the second range of wavelengths exceeds a second preprogrammed threshold value, and wherein the second preprogrammed threshold value is added to an average value over a predetermined time period of the light in the second range of wavelengths detected by the second sensor over said predetermined time period.