Abstract: A mobile platform captures a scene that includes a real world object, wherein the real world object has a non-uniform pattern in a predetermined region. The mobile platform determines an area in an image of the real world object in the scene corresponding to the predetermined region. The mobile platform compares intensity differences between pairs of pixels in the area, with known intensity differences between pairs of pixels in the non-uniform pattern, to identify any portion of the area that differs from a corresponding portion of the predetermined region. The mobile platform then stores in its memory, a value indicative of a location of the any portion relative to the area. The stored value may be used in any application running in the mobile platform.

Abstract: A mobile platform detects and tracks a three-dimensional (3D) object using occlusions of a two-dimensional (2D) surface. To detect and track the 3D object, an image of the 2D surface with the 3D object is captured and displayed and the 2D surface is detected and tracked. Occlusion of a region assigned as an area of interest on the 2D surface is detected. The shape of the 3D object is determined based on a predefined shape or by using the shape of the area of the 2D surface that is occluded along with the position of the camera with respect to the 2D to calculate the shape. Any desired action with respect to the position of the 3D object on the 2D surface may be performed, such as rendering and displaying a graphical object on or near the displayed 3D object.