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Method and device to estimate motion in a sequence of moving pictures

  • US 4,853,775 A
  • Filed: 03/22/1988
  • Issued: 08/01/1989
  • Est. Priority Date: 03/23/1987
  • Status: Expired due to Term
First Claim
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1. A method to estimate motion in a sequence of television type moving pictures, where each picture is formed by a determined number of light spots located at intersections of lines and columns, said method of the type where motion is estimated by performing a gradient algorithm which minimizes a mean square deviation between local variations in luminance of a current pel of the picture and those of a pel in a similar position to the current pel in the prior image, said method comprising the steps of:

  • initializing an algorithm by displacement values estimated according to several directions within a close causal neighborhood of the current pel and of the propagation of each estimate in a scanning direction of picture lines,choosing a propagating direction for the algorithm depending on a position, in the picture, of a line to which the current pel belongs,calculating a modulus of a gradient of the current pel and comparing the result with a pre-determined threshold value,choosing a displacement for the present pel in the causal neighborhood of this pel when the modulus of the gradient obtained is below the pre-determined threshold value, andchoosing the displacement that gives the smallest displaced frame difference, or estimating a new displacement when the gradient modulus obtained is above the predetermined threshold.

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