Real-Time Face Tracking in a Digital Image Acquisition Device

• US 20080037839A1
• Filed: 06/19/2007
• Published: 02/14/2008
• Est. Priority Date: 08/11/2006
• Status: Active Grant

• Current Assignee: FotoNation Limited (Adeia Inc.)
• Original Assignee: FotoNation Vision Limited (Adeia Inc.)
• Inventors: Steinberg, Eran, Petrescu, Stefan, Nanu, Florin, Drimbarean, Alexandru, Bigioi, Petronel, Corcoran, Peter, Pososin, Alexei
• Granted Patent: US 7,460,694 B2
• Time in Patent Office: Days
• US Class Current: 382/118
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06F 18/2148 characterised by the process organisation or structure, e.g. boosting cascade
• CPC Class Codes: G06V 30/19147 Obtaining sets of training patterns; Bootstrap methods, e.g. bagging or boosting
• CPC Class Codes: G06V 30/2504 Coarse or fine approaches, e.g. resolution of ambiguities or multiscale approaches
• CPC Class Codes: G06V 40/162 using pixel segmentation or colour matching
• CPC Class Codes: G06V 40/165 using facial parts and geometric relationships
• CPC Class Codes: G06V 40/167 using comparisons between temporally consecutive images
• CPC Class Codes: G06V 40/171 Local features and components; Facial parts eye characteristics G06V40/18; Occluding parts, e.g. glasses; Geometrical relationships
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 1/32112 in a separate computer file, document page or paper sheet, e.g. a fax cover sheet H04N1/32122 takes precedence
• CPC Class Codes: H04N 1/32128 attached to the image data, e.g. file header, transmitted message header, information on the same page or in the same computer file as the image for information embedded in the image H04N1/32144
• CPC Class Codes: H04N 2101/00 Still video cameras
• CPC Class Codes: H04N 2201/0084 Digital still camera
• CPC Class Codes: H04N 2201/3205 of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 23/61 based on recognised objects
• CPC Class Codes: H04N 23/611 where the recognised objects include parts of the human body
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/695 Control of camera direction for changing a field of view, e.g. pan, tilt or based on tracking of objects

Abstract

An image processing apparatus for tracking faces in an image stream iteratively receives a new acquired image from the image stream, the image potentially including one or more face regions. The acquired image is sub-sampled (112) at a specified resolution to provide a sub-sampled image. An integral image is then calculated for a least a portion of the sub-sampled image. Fixed size face detection (20) is applied to at least a portion of the integral image to provide a set of candidate face regions. Responsive to the set of candidate face regions produced and any previously detected candidate face regions, the resolution at which a next acquired image is sub-sampled is adjusted.

Claims

1. A method of detecting faces in an image stream using a digital image acquisition device, comprising:

a. determining an orientation of a digital image acquisition device for at least one image of an image stream;

b. acquiring the image, which includes one or more face regions, from said image stream; and

c. applying face detection to at least a portion of said acquired image to provide a set of one or more candidate face regions according to said determined orientation, each candidate face region having a given size and a respective location.

2. A method according to claim 1, wherein said face detection selectively employs a sequence of classifiers from an available plurality of classifier sequences, each classifier sequence being at a given orientation.

3. A method according to claim 1, further comprising:

selectively applying face recognition with said database to at least one candidate face region;

providing an identifier for each face recognized in a candidate face region; and

storing the identifier for each recognized face in association with at least one image of said image stream.

4. An image processing apparatus including one or more processors and one or more digital storage media having digitally-encoded instructions embedded therein for programming the one or more processors to perform an iterative method of detecting faces in an image stream, the method comprising:

a. determining an orientation of said acquisition device for at least one image of said image stream;

b. acquiring an image from said image stream including one or more face regions; and

c. applying face detection to at least a portion of said acquired image to provide a set of one or more candidate face regions according to said determined orientation, each candidate face region having a given size and a respective location.

5. An image processing apparatus according to claim 4, further comprising a hardware orientation sensor for indicating the orientation of said apparatus.

6. An image processing apparatus according to claim 4, wherein the method further comprises analyzing content in one or more images of said image stream to determine the orientation of said apparatus.

7. A method according to claim 4, further comprising:

selectively applying face recognition with said database to at least one candidate face region;

providing an identifier for each face recognized in a candidate face region; and

storing the identifier for each recognized face in association with at least one image of said image stream.

8. A method as claimed in claim 7, wherein said shifting of said face regions is based on face region size and said movement.