| 摘要 |
The present invention comprises a method and apparatus for detection motion in video in which frames from an incoming video stream are digitized. The pixels of each incoming digitized frame are compared to the corresponding pixels of a reference frame, and differences between incoming pixels and reference pixels are determined. If the pixel difference for a pixel exceeds an applicable pixel difference threshold, the pixel is considered to be "different". If the number of "different" pixels for a frame exceeds an applicable frame difference threshold, motion is considered to have occurred, and a motion detection signal is emitted. In one or more other embodiments, the applicable frame difference threshold is adjusted depending upon the current average motion being exhibited by the most recent frames, thereby taking into account "ambient" motion and minimizing the effects of phase lag. In one or more embodiments, different pixel difference thresholds may be assigned to different pixels or groups of pixels, thereby making certain regions of a camera's field of view more or less sensitive to motion. In one or more embodiments of the invention, a new reference frame is selected when the first frame that exhibits no motion occurs after one or more frames that exhibit motion.
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