Normalized image feature processing
First Claim
1. A method of processing an image represented by an array of digital signals, said method comprising the steps offlocating within the image array of digital signals the position of at least one predetermined feature;
- extracting image data from said image array of digital signals representing each said feature;
generating for each feature a feature vector digital signal representing the position of the image data of the feature in an N-dimensional space, N being an integer and said space being defined by a plurality of reference vector signals each of which is an eigenvector of a training set of images of like features; and
modifying the digital signal image data of each feature to normalize the shape of each feature thereby to reduce its deviation from a predetermined standard shape of said feature, which step is carried out before generating the feature vector signal for each feature.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of processing an image including the steps of: locating within the image the position of at least one predetermined feature; extracting from the image data representing each feature; and calculating for each feature a feature vector representing the position of the image data of the feature in an N-dimensional space, such space being defined by a plurality of reference vectors each of which is an eigenvector of a training set of like features in which the image data of each feature is modified to normalize the shape of each feature thereby to reduce its deviation from a predetermined standard shape of the feature, which step is carried out before calculating the corresponding feature vector.
262 Citations
11 Claims
-
1. A method of processing an image represented by an array of digital signals, said method comprising the steps off
locating within the image array of digital signals the position of at least one predetermined feature; -
extracting image data from said image array of digital signals representing each said feature; generating for each feature a feature vector digital signal representing the position of the image data of the feature in an N-dimensional space, N being an integer and said space being defined by a plurality of reference vector signals each of which is an eigenvector of a training set of images of like features; and modifying the digital signal image data of each feature to normalize the shape of each feature thereby to reduce its deviation from a predetermined standard shape of said feature, which step is carried out before generating the feature vector signal for each feature. - View Dependent Claims (5, 6, 7, 8)
-
-
2. A method of processing an image represented by an array of digital signals, said method comprising the steps of:
-
locating within the image array of digital signals the position of at least one predetermined feature; extracting image data from said image array of digital signals representing each said feature; generating for each feature a feature vector digital signal representing the position of the image data of the feature in an N-dimensional space, N being an integer and said space being defined by a plurality of reference vector signals each of which is an eigenvector of a training set of images of like features; and modifying the digital signal image data of each feature to normalize the shape of each feature thereby to reduce its deviation from a predetermined standard shape of said feature, which step is carried out before generating the feature vector signal for each feature, wherein the step of modifying the digital signal image data of each feature uses a deformable template.
-
-
3. A method of processing an image represented by an array of digital signals, said method comprising the steps of:
-
locating within the image array of digital signals the position of at least one predetermined feature; extracting image data from said image array of digital signals representing each said feature; generating for each feature a feature vector digital signal representing the position of the image data of the feature in an N-dimensional space, N being an integer and said space being defined by a plurality of reference vector signals each of which is an eigenvector of a training set of images of like features; and modifying the digital signal image data of each feature to normalize the shape of each feature thereby to reduce its deviation from a predetermined standard shape of said feature, which step is carried out before generating the feature vector signal for each feature, wherein the step of locating within the digital signal image the position of at least one predetermined feature employs; a first technique to provide a coarse estimation of position, and a second, different, technique to improve upon the coarse estimation. - View Dependent Claims (4)
-
-
9. A method of verifying the identity of the user of a data carrier, said method comprising the steps of:
-
generating a digital signal facial image of the user; receiving the data carrier and reading therefrom identification data signals; performing on the digital signal facial image the steps of; (i) locating within the digital signal image the position of at least one predetermined feature; (ii) extracting digital signal image data from said image representing each said feature; (iii) generating for each feature a feature vector signal representing the position of the image data of the feature in an N-dimensional space, N being an integer and said space being defined by a plurality of reference vectors signals each of which is an eigenvector of a training set of images of like features; and (iv) modifying the digital signal image data of each feature to normalize the shape of each feature thereby to reduce its deviation from a predetermined standard shape of said feature, which step is carried out before generating the feature vector for each feature; comparing data signals representing each feature vector with the identification data signals; and generating a verification signal in dependence upon the comparison.
-
-
10. Apparatus for verifying the identity of the user of a data carrier comprising:
-
means for generating a digital signal facial image of the user; means for receiving the data carrier and reading therefrom identification data signals; means for performing on the digital signal facial image the steps of; (i) locating within the digital signal image and position of at least one predetermined feature; (ii) extracting digital signal image data from said image representing each said feature; (iii) generating for each feature a feature vector signal representing the position of the image data of the feature in an N-dimensional space, N being an integer and said space being defined by a plurality of reference vector signals each of which is an eigenvector of a training set of images of like features; and (iv) modifying the digital signal image data of each feature to normalize the shape of each feature thereby to reduce its deviation from a predetermined standard shape of said feature, which step is carried out before calculating the feature vector for each feature; and means for comparing data signals representing each feature vector with the identification data signals and generating a verification signal in dependence upon the comparison. - View Dependent Claims (11)
-
Specification