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Time lapse recording apparatus having abnormal detecting function

  • US 6,600,872 B1
  • Filed: 06/21/1999
  • Issued: 07/29/2003
  • Est. Priority Date: 06/19/1998
  • Status: Expired due to Fees
First Claim
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1. A time lapse recorder comprising:

  • a dividing means for dividing an input picture signal into signals corresponding to small area blocks each consisting of a plurality of pixels;

    a motion estimate means for retrieving motion vectors of blocks most similar to each other in picture frames of different times;

    a motion compensating means for obtaining a difference between a coding subject frame and a motion vector computation frame for each of the blocks on the basis of the motion vectors;

    an orthogonal transform means for executing orthogonal transform of the blocks;

    a quantizing means for quantizing transform coefficient values as the output of the orthogonal transform means;

    a code quality control means for controlling picture quality and quantity of codes generated per frame in accordance with the complexity of the input picture;

    a variable length coding means for variable length coding quantized coefficient data outputted from the quantizing means;

    an abnormality detecting means for detecting abnormality of input picture;

    a recording interval control means for changing recording frame number at a constant interval in the normal state and in unit times in the abnormality detection state; and

    a recording means for recording the variable length coded data in a recording medium under control of the recording interval control means, wherein the abnormality detecting means computes the coding bit number of the variable length coding means for each frame, compares the difference of this coding bit number from the coding bit number of the immediately preceding frame having the same predicted structure and executes abnormal detection when the compared difference is above a predetermined threshold value, and wherein the recording interval control means adaptively controls the recording frame number according to a multiple-valued output of the abnormality detecting means.

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