Smart windowing for reducing power consumption of a head-mounted camera used for detecting facial expressions

A method comprising:

• capturing images of a region on a user's face utilizing an inward-facing head-mounted camera comprising a sensor that supports changing of its region of interest (ROI);
• detecting, based on the images, a type of facial expression expressed by the user, which belongs to a group comprising first and second facial expressions;
• responsive to detecting that the user expresses the first facial expression, reading from the camera a first ROI that covers a first subset of facial landmarks relevant to the first facial expression;
• and
• responsive to detecting that the user expresses the second facial expression, reading from the camera a second ROI that covers a second subset of facial landmarks relevant to the second facial expression;
• wherein the first and second ROIs are different.

A non-transitory computer readable medium storing one or more computer programs configured to cause a processor based system to execute steps comprising:

• capturing images of a region on a user's face utilizing an inward-facing head-mounted camera comprising a sensor that supports changing of its region of interest (ROI);
• detecting, based on the images, a type of facial expression expressed by the user, which belongs to a group comprising first and second facial expressions;
• responsive to detecting that the user expresses the first facial expression, reading from the camera a first ROI that covers a first subset of facial landmarks relevant to the first facial expression;
• and
• responsive to detecting that the user expresses the second facial expression, reading from the camera a second ROI that covers a second subset of facial landmarks relevant to the second facial expression;
• wherein the first and second ROIs are different.