Method and apparatus for tracking a moving object
First Claim
1. A method of tracking the movement of a three dimensional object in a scene over a series of two dimensional picture frames, the method comprising the steps ofa) forming an initial template in an initial frame of the series, said initial template including the moving object to be tracked;
- b) dividing said initial template into a plurality of sub-templates which are not associated with specific features of said object;
c) searching a subsequent frame of said series to locate a first region of said subsequent frame which matches said initial template and determining a first displacement in position between said initial template and said first region of said subsequent frame;
d) searching said subsequent frame of said series to locate respective sub-regions of said subsequent frame of said series which match respective sub-templates of the initial template and determining respective additional displacements in position between each sub-template and its respective matched sub-region of said subsequent frame;
e) determining from the first displacement and the additional displacements, a relative displacement in position between said first region of said subsequent frame and said respective sub-regions of said subsequent frame;
f) using said relative displacement to determine coefficients for a bivariate transform capable of mapping said first and additional displacements in position; and
g) performing said bivariate transform to produce an updated initial template.
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Accused Products
Abstract
A method of tracking a moving object in a scene, for example the face of a person in videophone applications, comprises forming an initial template of the face, extracting a mask outlining the face, dividing the template into a plurality (for example sixteen) sub-templates, searching the next frame to find a match with the template, searching the next frame to find a match with each of the sub-templates, determining the displacements of each of the sub-templates with respect to the template, using the displacements to determine affine transform coefficients and performing an affine transform to produce an updated template and updated mask.
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Citations
13 Claims
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1. A method of tracking the movement of a three dimensional object in a scene over a series of two dimensional picture frames, the method comprising the steps of
a) forming an initial template in an initial frame of the series, said initial template including the moving object to be tracked; -
b) dividing said initial template into a plurality of sub-templates which are not associated with specific features of said object; c) searching a subsequent frame of said series to locate a first region of said subsequent frame which matches said initial template and determining a first displacement in position between said initial template and said first region of said subsequent frame; d) searching said subsequent frame of said series to locate respective sub-regions of said subsequent frame of said series which match respective sub-templates of the initial template and determining respective additional displacements in position between each sub-template and its respective matched sub-region of said subsequent frame; e) determining from the first displacement and the additional displacements, a relative displacement in position between said first region of said subsequent frame and said respective sub-regions of said subsequent frame; f) using said relative displacement to determine coefficients for a bivariate transform capable of mapping said first and additional displacements in position; and g) performing said bivariate transform to produce an updated initial template. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for tracking the movement of a three dimensional object in a scene over a series of two dimensional picture frames, said apparatus comprising in combination:
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a) means for forming an initial template in an initial frame of the series, said initial template including the moving object to be tracked; b) means for dividing said initial template into a plurality of sub-templates which are not associated with specific features of said object; c) means for searching a subsequent frame of said series to locate a first region of said subsequent frame which matches said initial template and determining a first displacement in position between said initial template and said first region of said subsequent frame; d) means for searching said subsequent frame of said series to locate respective sub-regions of said subsequent frame of said series which match respective sub-templates of the initial template and determining respective additional displacements in position between each sub-template and its respective matched sub-regions of said subsequent frame; e) means for determining from the first displacement and the additional displacements, a relative displacement in position between said first region of said subsequent frame and said respective sub-regions of said subsequent frame; f) means for determining coefficients for a bivariate transform capable of mapping said first and additional displacements in position using said relative displacement; and g) means for performing said bivariate transform to produce an updated initial template. - View Dependent Claims (11, 12, 13)
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Specification