Method for verifying users and updating database, and face verification system using the same
First Claim
1. A method of verifying a face in a face verification system, comprising the steps of:
- (a) separating background and a face from an input face image to detect a face region;
(b) detecting the positions of eyes from the detected face region and shifting the detected positions of eyes in predetermined directions by a predetermined distance, thereby generating new coordinate points of the eyes;
(c) normalizing the face region on the basis of the new coordinate points of the eyes;
(d) extracting recognition features from the normalized face regions and calculating feature values;
(e) teaching a feature classifier using the feature values and storing the feature values in a database;
(f) detecting a face region from another input face image for verification, normalizing the face region, extracting recognition features of a face, and calculating feature values; and
(g) determining whether the input face image is similar to any face image registered in the database based on the feature values.
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Abstract
To reduce degradation of recognition performance due to eye detection errors during face verification and to overcome a problem in that sufficient data to design an optimum feature classifier cannot be obtained during face registration, a method includes shifting the positions of eyes detected during face registration in predetermined directions by a predetermined distance to generate pairs of new coordinate points of the eyes; normalizing a face image on the basis of each pair of new coordinate points of the eyes; using the results of normalization in teaching a feature classifier, thereby coping with eye detection errors. In addition, two threshold values are used to prevent a database from being updated with a face of an unregistered person and to update the database with a normal client'"'"'s face image that has been used during the latest face verification.
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Citations
20 Claims
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1. A method of verifying a face in a face verification system, comprising the steps of:
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(a) separating background and a face from an input face image to detect a face region; (b) detecting the positions of eyes from the detected face region and shifting the detected positions of eyes in predetermined directions by a predetermined distance, thereby generating new coordinate points of the eyes; (c) normalizing the face region on the basis of the new coordinate points of the eyes; (d) extracting recognition features from the normalized face regions and calculating feature values; (e) teaching a feature classifier using the feature values and storing the feature values in a database; (f) detecting a face region from another input face image for verification, normalizing the face region, extracting recognition features of a face, and calculating feature values; and (g) determining whether the input face image is similar to any face image registered in the database based on the feature values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A face verification system comprising:
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a face region detector for separating background and a face from an input face image to detect a face region; an eye-position shift unit for detecting the positions of eyes from the detected face region and shifting the detected positions of eyes in predetermined directions by a predetermined distance, thereby generating new coordinate points of the eyes; a face region normalizer for normalizing the face region on the basis of the new coordinate points of the eyes; a recognition feature extractor for extracting recognition features from the normalized face regions and calculating feature values; a feature classifier teacher for teaching a feature classifier using the calculated feature values; a database for storing the calculated feature values; and a determiner for determining whether another input face image is similar to any face image registered in the database based on the feature values. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification