To obtain the video image detector that surely catches various motions of an intruder and can detect both a fast motion and a slow motion of the intruder.
A video signal integration circuit 5 integrates a lightness of an input video signal and provides an output of the integrated value to a microcomputer 6. The microcomputer 6 receives a lightness level of the video signal stored in a storage circuit 7, compares it with a lightness level of the video signal received and provides an output of a detection output when the difference is larger than a prescribed value. The microcomputer 6 replaces the lightness level stored in the storage circuit 7 with the lightness level of the video signal newly entered. Similarly, the microcomputer 6 compares the lightness level of the video signal stored in storage circuit 8 with a lightness level of the video signal newly received. In this case, a timing for the detection is set longer than the case with the storage circuit 7. Thus, the detection by the former copes with a fast motion of an intruder and the detection by the latter copes with a slow motion of the intruder.
YAMAZOE YASUO
SATO YUJI
HITACHI VIDEO & INF SYST
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