Method and apparatus for face tracking utilizing integral gradient projections
First Claim
1. A method comprising:
- determining at least one transfer function relating integral projection curves of a face region in a first frame, wherein the face region has a predefined position and a predetermined size, and of a first window in a second frame, wherein the first window is co-located in size and position with the face region;
determining a scaling factor based upon the at least one transfer function;
determining integral gradient projections for the face region in the first frame and for a second window in the second frame with the second window having a size that is based upon a size of the first window modified by the scaling factor;
determining a distance between the integral gradient projections of the face region in the first frame and of the second window in the second frame; and
determining whether the scaling factor is verified based on a relationship between the distance and a predefined threshold.
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Accused Products
Abstract
A method, apparatus and computer program product are provided for estimating and verifying translation motion and/or a scaling factor between face regions in respective frames during face tracking. A method determines translation motion between face regions in two successive frames based upon integral gradient projections of a face region in a first frame and a corresponding window in a second frame. The method also verifies the translation motion between the first and second frames utilizing integral gradient projections. A method also determines a transfer function relating integral projection curves of a face region in a first frame that has a predefined position and a predetermined size and a co-located window of same size in a second frame, determines a scaling factor based upon the transfer function and then verifies the scaling factor utilizing integral gradient projections.
19 Citations
21 Claims
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1. A method comprising:
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determining at least one transfer function relating integral projection curves of a face region in a first frame, wherein the face region has a predefined position and a predetermined size, and of a first window in a second frame, wherein the first window is co-located in size and position with the face region; determining a scaling factor based upon the at least one transfer function; determining integral gradient projections for the face region in the first frame and for a second window in the second frame with the second window having a size that is based upon a size of the first window modified by the scaling factor; determining a distance between the integral gradient projections of the face region in the first frame and of the second window in the second frame; and determining whether the scaling factor is verified based on a relationship between the distance and a predefined threshold. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus comprising:
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at least one processor; and at least one memory including computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following; determine at least one transfer function relating integral projection curves of a face region in a first frame, wherein the face region has a predefined position and a predetermined size, and of a first window in a second frame, wherein the first window is co-located in size and position with the face region; determine a scaling factor based upon the at least one transfer function; determine integral gradient projections for the face region in first frame and for a second window in the second frame with the second window having a size that is based upon a size of the first window modified by the scaling factor; determine a distance between the integral gradient projections of the face region in the first frame and of the second window in the second frame; and determine whether the scaling factor is verified based on a relationship between the distance and a predefined threshold. - View Dependent Claims (7, 8, 9, 10)
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11. A computer program product comprising at least one non-transitory tangible computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:
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program code instructions configured to determine at least one transfer function relating integral projection curves of a face region in a first frame, wherein the face region has a predefined position and a predetermined size, and of a first window in a second frame, wherein the first window is co-located in size and position with the face region; program code instructions configured to determine a scaling factor based upon the at least one transfer function; program code instructions configured to determine integral gradient projections for the face region in the first frame and for a second window in the second frame with the second window having a size that is based upon a size of the first window modified by the scaling factor; program code instructions configured to determine a distance between the integral gradient projections of the face region in the first frame and of the second window in the second frame; and program code instructions configured to determine whether the scaling factor is verified based on a relationship between the distance and a predefined threshold. - View Dependent Claims (12, 13, 14, 15)
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16. An apparatus comprising:
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at least one processor; and at least one memory including computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following; determine a translation motion between first and second frames based upon integral projections of a face region in the first frame, wherein the face region has a predefined position and a predetermined size, and of a first window in the second frame, wherein the first window is co-located in size and position with the face region; and verify the translation motion between the first and second frames, wherein the at least one memory including the computer program code is configured to, with the at least one processor, cause the apparatus to verify the translation motion by; determining integral gradient projections for a second window in the second frame, wherein the second window is based on movement of the first window translated by the translation motion; determining integral gradient projections for the face region in the first frame; determining a distance between the integral gradient projections of the second window and of the face region; and determining whether the translation motion is verified based on a relationship between the distance and a predefined threshold. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification