Patent ID: 7274387

Claim:
A method of detecting intrusion in an area by analysis of a plurality of time-sequential image frames from at least one image sensor, comprising the steps of: a) taking a current image frame; b) dividing the current image frame into a plurality of cell images, each cell image being a portion of the current image comprising a plurality of adjacent pixels; c) blurring the cell image; d) storing a value representing the blurred cell image in a stack of a plurality of time-sequential cell values, incrementing the stack such that an oldest cell value is lost when the value is added to the stack; e) computing a sliding average of the plurality of cell values in the stack; f) computing a difference between the cell value from the current image and the sliding average; g) reporting a detection if the difference exceeds a defined lower threshold or a defined upper threshold; g1) starting a count when a detection is first reported in step (g); g2) incrementing the count each time another image is processed and the detection remains reported; g3) confirming the detection and setting a cell active condition when the count exceeds a count threshold; and h) repeating the method from step (a); wherein steps (g1), (g2), and (g3) are sequential after step (g).