Face recognition with combined PCA-based datasets

• US 8,050,466 B2
• Filed: 04/06/2009
• Issued: 11/01/2011
• Est. Priority Date: 08/02/2006
• Status: Active Grant

• Current Assignee: FotoNation Limited (Adeia Inc.), National University of Ireland Galway
• Original Assignee: DigitalOptics Corporation Europe Limited (Adeia Inc.), National University of Ireland Galway
• Inventors: Costache, Gabriel N., Corcoran, Peter
• Primary Examiner(s): STREGE, JOHN B
• Application Number:
  US12/418,987
• Publication Number:
  US 20090238410A1
• Time in Patent Office: 939 Days
• Field of Search: 382/118, 382/224
• US Class Current: 382/118
• CPC Class Codes: G06F 18/2135 based on approximation criteria, e.g. principal component analysis
• CPC Class Codes: G06F 18/253 of extracted features
• CPC Class Codes: G06V 10/7715 Feature extraction, e.g. by transforming the feature space, e.g. multi-dimensional scaling [MDS]; Mappings, e.g. subspace methods
• CPC Class Codes: G06V 10/806 of extracted features
• CPC Class Codes: G06V 40/169 Holistic features and representations, i.e. based on the facial image taken as a whole

Abstract

A face recognition method for working with two or more collections of facial images is provided. A representation framework is determined for a first collection of facial images including at least principle component analysis (PCA) features. A representation of said first collection is stored using the representation framework. A modified representation framework is determined based on statistical properties of original facial image samples of a second collection of facial images and the stored representation of the first collection. The first and second collections are combined without using original facial image samples. A representation of the combined image collection (super-collection) is stored using the modified representation framework. A representation of a current facial image, determined in terms of the modified representation framework, is compared with one or more representations of facial images of the combined collection. Based on the comparing, it is determined which, if any, of the facial images within the combined collection matches the current facial image.

Claims

1. A consumer digital camera including a processor programmed by digital code to perform a face tracking and recognition method for working with two or more collections of facial images, the method comprising:

(a) in-camera tracking of a detected face in a series of acquired digital images;

(b) determining a first representation framework for a first collection of facial images;

(c) storing a representation of said first collection using said first representation framework;

(d) determining a modified representation framework based on statistical properties of original facial image samples of a second collection of facial images and the stored representation of the first collection;

(e) combining the stored representation of the first collection and the second collection without using original facial image samples, including back-projecting the second collection into the first representation framework, combining the back-projected representation of the second collection and the stored representation of the first collection into a combined image collection (super-collection), and forward projecting the combined collection into the second representation framework;

(f) storing a representation of the combined image collection (super-collection) using said modified representation framework;

(g) comparing a representation of a current facial image, determined in terms of said modified representation framework, with one or more representations of facial images of the combined collection; and

(h) based on the comparing, determining whether one or more of the facial images within the combined collection matches the current facial image.

2. The consumer digital camera of claim 1, the method further comprising, prior to (b), updating said first collection by combining the first collection with a third collection.

3. The consumer digital camera of claim 2, wherein the updating comprises adding one or more new data samples to the first collection.

4. The consumer digital camera of claim 1, the method further comprising re-projecting data samples of the first collection into a new eigenspace without using original facial images of the first collection.

5. The consumer digital camera of claim 4, wherein the re-projecting uses existing PCA features.

6. The consumer digital camera of claim 1, the method further comprising combining training data from said first and second collections.

7. A consumer digital camera according to claim 1 which does not use original data samples of the first collection.

8. The consumer digital camera of claim 1, wherein the first and second collections contain samples of different dimension, and the method further comprises:

(i) choosing a standard size of face region for the new collection, and

(ii) re-sizing eigenvectors using interpolation to the standard size.

9. The consumer digital camera of claim 8, wherein said samples of different dimension were analyzed using different standard sizes of face region.

10. The consumer digital camera of claim 1, the method further comprising generating the modified representation framework according to the following:

12. The consumer digital camera of claim 1 the method further comprising updating the PCA features based on first eigenvectors and first sets of eigenvalues for each of the first and second sets of facial regions.

13. The consumer digital camera of claim 12, wherein the updating comprises calculating a new set of eigenvectors from the previously calculated first eigenvectors of the first and second sets of facial regions.

14. A consumer digital camera according to claim 1 which does not use original data samples of the first and second sets of facial regions.

11. A consumer digital camera including a processor programmed by digital code to perform a face tracking and recognition method operable on two or more collections of images, one or more of said images containing one or more facial regions, comprising:

(a) in-camera tracking of a detected face in a series of acquired digital images;

(b) determining distinct representation frameworks for first and second sets of facial regions extracted from corresponding image collections each framework;

(c) storing representations of said first and second sets of facial regions using their respective representation frameworks;

(d) determining a third, distinct representation framework based on the representations of the first and second sets of facial regions;

(e) combining the stored representation of the first and the second sets of facial regions without using original facial image samples including back-projecting the sets of facial regions into their respective representation frameworks, combining the two back-projected representations of these sets of facial regions into a combined dataset, and forward projecting the combined dataset into the third representation framework;

(f) storing a representation of the combined dataset using said third representation framework;

(g) comparing a representation of a current facial region, determined in terms of said third representation framework, with one or more representations of facial images of the combined dataset; and

(h) based on the comparing, determining whether one or more of the facial images within the combined dataset matches the current facial image.

15. The consumer digital camera of claim 11, wherein the first and second sets of facial regions contain samples of different dimension, and the method further comprises:

(i) choosing a standard size of face region, and

(ii) re-sizing eigenvectors using interpolation to the standard size.

16. The consumer digital camera of claim 15, wherein said samples of different dimension were analyzed using different standard sizes of face region.

17. The consumer digital camera of claim 11, the method further comprising generating the third representation framework according to the following: