Face searching and detection in a digital image acquisition device

A non-transitory computer-readable storage medium, storing one or more instructions which, when executed by one or more processors, cause the one or more processors to perform:

• acquiring data of a digital image which depicts one or more objects;
• determining a first size of a first detection window and an initial location of the first detection window in the digital image;
• wherein the first detection window encompasses a first portion of the digital image;
• determining, for the first detection window, first detection window data that represents the first detection window at a first image resolution level;
• determining a first set of face detection tests that are to be applied to the first detection window data;
• applying the first set of face detection tests to the first detection window data to determine a first confidence level value that indicates a likelihood that a particular object, of the one or more objects, is included in the first detection window;
• in response to determining that the first confidence level value is not greater than a first threshold value:
• determining a second size that is greater than the first size;
• determining a second detection window that has the second size;
• wherein the second detection window encompasses a second portion of the digital image;
• determining, for the second detection window, second detection window data that represents the second detection window at a second image resolution level;
• determining a second set of face detection tests that are to be applied to the second detection window data;
• and
• applying the second set of face detection tests to the second detection window data to determine a second confidence level value that indicates a likelihood that the particular object, of the one or more objects, is included in the second detection window.

A device, comprising:

• an image acquiring unit communicatively coupled to a memory unit, and configured to acquire data of a digital image that depicts one or more objects;
• and
• a face detection unit configured to:
• determine a first size of a first detection window and an initial location of the first detection window in the digital image;
• wherein the first detection window encompasses a first portion of the digital image;
• determine, for the first detection window, first detection window data that represents the first detection window at a first image resolution level;
• determine a first set of face detection tests that are to be applied to the first detection window data;
• apply the first set of face detection tests to the first detection window data to determine a first confidence level value that indicates a likelihood that a particular object, of the one or more objects, is included in the first detection window;
• in response to determining that the first confidence level value is not greater than a first threshold value:
• determine a second size that is greater than the first size;
• determine a second detection window that has the second size;
• wherein the second detection window encompasses a second portion of the digital image;
• determine, for the second detection window, second detection window data that represents the second detection window at a second image resolution level;
• determine a second set of face detection tests that are to be applied to the second detection window data;
• and
• apply the second set of face detection tests to the second detection window data to determine a second confidence level value that indicates a likelihood that the particular object, of the one or more objects, is included in the second detection window.