Real-time face tracking with reference images

A digital image acquisition device for detecting faces in an image stream including one or more optics and a sensor for acquiring said image stream, and a processor for being programmed by a processor-readable medium having digital code embedded therein to perform a method of tracking faces in an image stream, wherein the method comprises:

• receiving a new acquired image from a reference image stream including one or more face regions;
• receiving an indication of relative movement of said new acquired image relative to a previously acquired image of said reference image stream, said previously acquired image having an associated set of candidate face regions each having a given size and a respective location;
• and
• applying adjusted face detection to at least a portion of said new acquired image in the vicinity of said candidate face regions as a function of said movement, to provide an updated set of candidate face regions.
• applying meta-data of one or more of the set of candidate face regions to a further action.

A method of detecting faces in a reference image stream using a digital image acquisition device comprising:

• receiving a first acquired image from said reference image stream including one or more face regions;
• sub-sampling said first acquired image at a specified resolution one or more times to provide one or more sub-sampled images;
• identifying one or more regions of said first acquired image including said one or more face regions within said one or more subsampled images of said first acquired image with probabilities each above a predetermined threshold;
• determining a respective size and location of each identified face region within said first acquired image;
• receiving a second acquired image from said reference image stream, and sub-sampling and applying face detection to one or more regions of said subsequent acquired image calculated as probably including one or more face regions corresponding to said one or more face regions identified in said first acquired image;
• acquiring a full resolution main image and applying meta-data of at least one of the one or more face regions to a further action.

A digital image acquisition device for detecting faces in an image stream including one or more optics and a sensor for acquiring said image stream, a processor, and a processor-readable medium having digital code embedded therein for programming the processor to perform a method of detecting faces in the image stream, wherein the method comprises:

• receiving a first acquired image from said reference image stream including one or more face regions;
• sub-sampling said first acquired image at a specified resolution one or more times to provide one or more sub-sampled images;
• identifying one or more regions of said first acquired image including said one or more face regions within said one or more subsampled images of said first acquired image with probabilities each above a predetermined threshold;
• determining a respective size and location of each identified face region within said first acquired image;
• receiving a second acquired image from said reference image stream, and sub-sampling and applying face detection to one or more regions of said subsequent acquired image calculated as probably including one or more face regions corresponding to said one or more face regions identified in said first acquired image;
• acquiring a full resolution main image and applying meta-data of at least one of the one or more face regions to a further action.

One or more processor-readable media having code embedded therein for programming a processor to perform a method of tracking a face in a reference image stream, wherein the method comprises:

• programming a processor-based digital image acquisition device including an imaging optical system, and a processor, for obtaining meta-data to apply to a further action, wherein the method further includes:
• acquiring a full resolution main image and an image stream of relatively low resolution reference images each including one or more face regions;
• identifying one or more face regions within two or more of said reference images;
• determining a relative movement between said two or more reference images;
• determining a size and location of said one or more face regions within each of said two or more reference images;
• applying concentrated face detection to at least a portion of said full resolution main image in a predicted location for candidate face regions having a predicted size as a function of the determined relative movement and the size and location of said one or more face regions within said reference images, to provide a set of candidate face regions for said main image;
• and
• applying meta-data of one or more of the set of candidate face regions to a further action.

One or more processor-readable media having code embedded therein for programming a processor to perform a method of detecting faces in a reference image stream using a digital image acquisition device, wherein the method comprises:

• programming a processor-based digital image acquisition device including an imaging optical system, and a processor, for obtaining meta-data to apply to a further action, wherein the method further includes:
• receiving a first acquired image from said reference image stream including one or more face regions;
• sub-sampling said first acquired image at a specified resolution one or more times to provide one or more sub-sampled images;
• identifying one or more regions of said first acquired image including said one or more face regions within said one or more subsampled images of said first acquired image with probabilities each above a predetermined threshold;
• determining a respective size and location of each identified face region within said first acquired image;
• receiving a second acquired image from said reference image stream, and sub-sampling and applying face detection to one or more regions of said subsequent acquired image calculated as probably including one or more face regions corresponding to said one or more face regions identified in said first acquired image;
• acquiring a full resolution main image and applying meta-data of at least one of the one or more face regions to a further action.