Continuous Autofocus Based on Face Detection and Tracking

One or more processor readable media having code embodied therein for programming a processor to perform an autofocus method for a digital image acquisition device based on face detection, wherein the device has a processor and uses a lens and image sensor to acquire a digital image of a scene that includes one or more out of focus faces or partial faces or both, wherein the method comprises:

• detecting the one or more out of focus faces or partial faces or both within the digital image by applying one or more sets of classifiers trained on faces that are out of focus;
• determining one or more sizes of the one of more respective out of focus faces or partial faces or both within the digital image
• determining one or more respective depths to the one or more out of focus faces or partial faces or both based on the one or more sizes of the one of more faces or partial faces or both within the digital image;
• adjusting one or more respective focus positions of the lens to focus approximately at the determined one or more respective depths;
• and
• acquiring one or more further images of scenes that include at least one of the one or more faces or partial faces or both with the lens focused at the one or more respectively adjusted focus positions.

A digital image acquisition device including a lens, an image sensor, a processor and a memory having code embedded therein for programming the processor to perform an autofocus method based on face detection, wherein the method comprises:

• acquiring a digital image of a scene that includes one or more out of focus faces or partial faces or both;
• detecting the one or more out of focus faces or partial faces or both within the digital image by applying one or more sets of classifiers trained on faces that are out of focus;
• determining one or more sizes of the one of more respective out of focus faces or partial faces or both within the digital image
• determining one or more respective depths to the one or more out of focus faces or partial faces or both based on the one or more sizes of the one of more faces or partial faces or both within the digital image;
• adjusting one or more respective focus positions of the lens to focus approximately at the determined one or more respective depths;
• and
• acquiring one or more further images of scenes that include at least one of the one or more faces or partial faces or both with the lens focused at the one or more respectively adjusted focus positions.