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Face tracking

  • US 7,492,924 B2
  • Filed: 07/18/2003
  • Issued: 02/17/2009
  • Est. Priority Date: 07/18/2003
  • Status: Expired due to Fees
First Claim
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1. A computer-implemented method comprising:

  • using a processor to perform the steps of;

    receiving a first digital image in a sequence of digital images and eye and mouth coordinates;

    outputting eye and mouth coordinates on a subsequent digital image in the sequence of digital images; and

    computing transformation parameters that represent a transformation from a base face model for the first digital image to a subsequent deformable model for the subsequent digital image;

    wherein receiving comprises estimating the base face model, denoted Mb, and the base face model'"'"'s transformation parameters, denoted T′

    , by the eye and mouth coordinates;

    wherein outputting comprises;

    calculating an initial model, denoted M, for the subsequent digital image as a transformed base model Mb using the transformation parameters T′

    ,rotating the subsequent image to the first digital image, denoted I(x,y), to generate a normalized model of the initial model M;

    calculating a horizontal and vertical gradient map on the rotated image; and

    estimating new transformation parameters, denoted T*, by minimizing an energy function E(T,I(x,y)) representative of the goodness of fit between the transformed model and the corresponding digital image, and of the optimality of the new transformation parameters, where T* corresponds to the complex argument of the minimum of the energy function, denoted arg min T E(T,I(x,y)).

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