Real-time face tracking in a digital image acquisition device

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;
• calculating a corresponding integral image for at least one of said skin tone regions of said sub-sampled acquired 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;
• and
• responsive to failing to detect at least one face region for said image, enhancing the contrast of the luminance characteristics for at least a region corresponding to one of said skin tone regions in a subsequently acquired image.

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, at least one of said filters including a restrictive skin filter and at least one of said filters including a relaxed skin filter;
• calculating a corresponding integral image for at least one of said skin tone regions of said sub-sampled acquired 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;
• and
• responsive to failing to detect at least one face region for said image, enhancing the contrast of the luminance characteristics for at least a region corresponding to one of said skin tone regions in a subsequently acquired image.