CAMERA SUPERVISORY SYSTEM

PROBLEM TO BE SOLVED: To provide a camera supervisory system adopting a background distinction system that can discriminate by comparatively simple processing whether the presence of abnormality is due to an environmental change or to a true fault occurrence. SOLUTION: An analog/digital converter section 2 converts an analog video signal from a camera 1 into a digital video signal and a background image memory section 3a and on input image memory section 3b of an image memory 3 store the digital video signal. An image processing section 4 extracts an area where a difference of a received image with respect to a background image exceeds a prescribed threshold on the basis of the stored data in the image memory 3 and stores a temporal change in the area to a system memory 5. A decision section 6 devices the presence of the fault on the basis of the data in the image processing section 4 and the system memory 5. The decision section 6 discriminates an environmental change such as lighting, an intruder or the like, disturbance on the camera, or interruption of a video input on the basis of the size of the area in excess of the prescribed threshold value and its temporal change or the like and raises an alarm on occurrence of a true fault.