Patent ID: 8471910

Claim:
A method of providing fault tolerance in a security system, the method comprising: providing for at least a plurality of different areas to be monitored, at least one first type camera device for each of the different areas in said plurality; operating at least one first type camera device, during a normal mode of operation, to perform a target detection operation to detect the presence of a moving target in the area being monitored by the particular first type camera device, said normal mode of operation being a mode of operation in which confirmation of detection of a target by another camera device is performed prior to a guard interface unit being notified of a target detection by an individual camera device; using a second type camera device during said normal mode of operation to verify detection of a target by one of said first type camera devices prior to said guard interface unit being notified of the detection of said target by one of said first type camera devices; monitoring the condition of said first type camera devices to determine proper camera device operation; and upon detecting a fault condition in a first type camera device, initiating a fault mode of operation including: changing criteria required to generate an alarm and forward video to said guard interface unit so that an alarm is generated and video is forwarded to the guard interface unit during said fault mode of operation based on detection of a target by a single camera device without confirmation of detection of the target by another camera device; and controlling said second type camera device to monitor the area which was being monitored by said first type camera device corresponding to the detected fault condition.