Real-time face tracking in a digital image acquisition device
View Patent ↗An image processing apparatus for tracking faces in an image stream iteratively receives an acquired image from the image stream including one or more face regions. The acquired image is sub-sampled 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 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 is adjusted for sub-sampling a subsequent acquired image.
1. A method of detecting faces in an image stream, the method comprising:
receiving an acquired image from said image stream including one or more face regions;
sub-sampling said acquired image at a specified resolution to provide a sub-sampled image;
identifying one or more regions of said acquired image predominantly including skin tones by applying one of a number of filters to define said one or more regions of said acquired image predominantly including skin tones;
calculating a corresponding integral image for at least one of said one or more regions of said sub-sampled image;
applying face detection to at least a portion of said integral image to provide a set of one or more candidate face regions each having a given size and a respective location
adjusting focus distance incrementally for each of multiple new acquired images at least until at least one candidate face region is detected;
providing a quality measure for one of a candidate region of an image or said acquired image; and
responsive to said quality measure, applying a relaxed skin filter to a subsequently acquired image.
2. A method as claimed in claim 1 , wherein applying the face detection comprises applying relaxed face detection parameters.
3. A method as claimed in claim 1 , wherein responsive to failing to detect at least one face region for said image, the method further comprises enhancing a contrast of luminance characteristics for at least a region corresponding to one of said one or more regions in a second subsequently acquired image.
4. A method as claimed in claim 1 , further comprising auto-focusing an image capture device on a detected face region.
5. A method as claimed in claim 1 , further comprising adjusting an image capture setting for optimal representation of a detected face region in a second acquired image.
6. A method as claimed in claim 1 , further comprising superimposing a bounding box over a detected face region.
7. A method as claimed in claim 6 , wherein the superimposing of the bounding box indicates automatic tracking of the detected face region within the image stream.
8. A method as claimed in claim 1 , wherein at least one of said filters includes said relaxed skin filter.
9. A method as claimed in claim 1 , wherein at least one of said filters includes a restrictive skin filter.
10. A method as claimed in claim 9 , wherein at least one of said filters includes said relaxed skin filter.
11. One or more non-transitory processor-readable digital storage media having digitally-encoded instructions embedded therein for programming one or more processors to perform an iterative method of detecting faces in an image stream, the method comprising:
receiving an acquired image from said image stream including one or more face regions;
sub-sampling said acquired image at a specified resolution to provide a sub-sampled image;
identifying one or more regions of said acquired image predominantly including skin tones by applying one of a number of filters to define said one or more regions of said acquired image predominantly including skin tones;
calculating a corresponding integral image for at least one of said one or more regions of said sub-sampled image;
applying face detection to at least a portion of said integral image to provide a set of one or more candidate face regions each having a given size and a respective location;
adjusting focus distance incrementally for each of multiple new acquired images at least until at least one candidate face region is detected;
providing a quality measure for one of a candidate region of an image or said acquired image; and
responsive to said quality measure, applying a relaxed skin filter to a subsequently acquired image.
12. One or more non-transitory processor-readable digital storage media as claimed in claim 11 , wherein applying the face detection comprises applying relaxed face detection parameters.
13. One or more non-transitory processor-readable digital storage media as claimed in claim 11 , wherein responsive to failing to detect at least one face region for said image, the method further comprises enhancing a contrast of luminance characteristics for at least a region corresponding to one of said one or more regions in a second subsequently acquired image.
14. One or more non-transitory processor-readable digital storage media as claimed in claim 11 , wherein the method further comprises auto-focusing an image capture device on a detected face region.
15. One or more non-transitory processor-readable digital storage media as claimed in claim 11 , wherein the method further comprises adjusting an image capture setting for optimal representation of a detected face region in a second acquired image.
16. One or more non-transitory processor-readable digital storage media as claimed in claim 11 , wherein the method further comprises superimposing a bounding box over a detected face region.
17. One or more non-transitory processor-readable digital storage media as claimed in claim 16 , wherein the superimposing of the bounding box indicates automatic tracking of the detected face region within the image stream.
18. One or more non-transitory processor-readable digital storage media as claimed in claim 11 , wherein at least one of said filters includes said relaxed skin filter.
19. One or more non-transitory processor-readable digital storage media as claimed in claim 11 , wherein at least one of said filters includes a restrictive skin filter.
20. One or more non-transitory processor-readable digital storage media as claimed in claim 19 , wherein at least one of said filters includes said relaxed skin filter.
21. 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:
receiving an acquired image from said image stream including one or more face regions;
sub-sampling said acquired image at a specified resolution to provide a sub-sampled image;
identifying one or more regions of said acquired image predominantly including skin tones by applying one of a number of filters to define said one or more regions of said acquired image predominantly including skin tones;
calculating a corresponding integral image for at least one of said one or more regions of said sub-sampled image;
applying face detection to at least a portion of said integral image to provide a set of one or more candidate face regions each having a given size and a respective location;
adjusting focus distance incrementally for each of multiple new acquired images at least until at least one candidate face region is detected;
providing a quality measure for one of a candidate region of an image or said acquired image; and
responsive to said quality measure, applying a relaxed skin filter to a subsequently acquired image.
22. An apparatus as claimed in claim 21 , wherein applying the face detection comprises applying relaxed face detection parameters.
23. An apparatus as claimed in claim 21 , wherein responsive to failing to detect at least one face region for said image, the method further comprises enhancing a contrast of luminance characteristics for at least a region corresponding to one of said one or more regions in a second subsequently acquired image.
24. An apparatus as claimed in claim 21 , wherein the method further comprises auto-focusing an image capture device on a detected face region.
25. An apparatus as claimed in claim 21 , wherein the method further comprises adjusting an image capture setting for optimal representation of a detected face region in a second acquired image.
26. An apparatus as claimed in claim 21 , wherein the method further comprises superimposing a bounding box over a detected face region.
27. An apparatus as claimed in claim 26 , wherein the superimposing of the bounding box indicates automatic tracking of the detected face region within the image stream.
28. An apparatus as claimed in claim 21 , wherein at least one of said filters includes said relaxed skin filter.
29. An apparatus as claimed in claim 21 , wherein at least one of said filters includes a restrictive skin filter.
30. An apparatus as claimed in claim 29 , wherein at least one of said filters includes said relaxed skin filter.