Abstract: Embodiments of the present invention provide a novel solution that enables mobile devices to continuously track interesting subjects by creating dynamic visual models that can be used to detect and track subjects in-real time through total occlusion or even if a subject temporarily leaves the mobile device's field of view. Additionally, embodiments of the present invention use an online learning scheme that dynamically adjusts tracking procedures responsive to any appearance and/or environmental changes associated with an interesting subject that may occur over a period of time. In this manner, embodiments of the present invention can determine a more optimal focus position that allows movement by either the mobile device or the subject during the performance of auto-focusing procedures and also enables other camera parameters to properly calibrate (meter) themselves based on the focus position determined.