Locking and unlocking a mobile device using facial recognition

A method for automatically unlocking a mobile device having a camera, comprising:

• capturing an initial image using the camera while the device is locked;
• detecting movement of the device while the device is locked;
• in response to detecting movement of the device, capturing a new image using the camera;
• determining that the device moved to a use position by comparing the new image with the initial image, wherein the use position indicates that a user is likely to want to use the device;
• in response to determining that the device is in the use position, capturing subsequent images using the camera;
• analyzing the subsequent images to detect a user's face;
• and
• in response to detecting the user's face, unlocking the device.

A mobile device, comprising:

• a camera to capture images of a scene;
• and
• a processor configured to
• cause the camera to capture images while the device is unlocked,
• analyze the images to determine whether a user's face is present in the images, and
• lock the device in response to determining that a user's face is not present in the images captured over a predetermined amount of time.

A mobile device, comprising:

• a camera to capture images of a scene;
• an inertial sensor to detect movement of the device;
• and
• a processor configured to
• cause the camera to capture an initial image while the device is locked,
• cause the camera to capture a new image in response to the inertial sensor detecting movement of the device while the device is locked,
• determine that the device moved to a use position by comparing the new image with the initial image, wherein the use position indicates that a user is likely to want to use the device,
• cause the camera to capture subsequent images in response to determining that the device is in the use position,
• analyze the subsequent images to detect a user's face, and
• unlock the device in response to detecting the user's face.