1. An information processing apparatus comprising: an image acquisition unit configured to acquire an input image and, for each pixel of the input image, positional information in a space including a predetermined surface as part of a background; and an extraction unit configured to extract from the acquired input image, in an area corresponding to a part of the space including the surface in the background, an object area corresponding to an object existing in the foreground with respect to the surface, based on positional information of the object in the acquired input image, positional information of the surface, and a first reference, and to extract from the acquired input image, in an area corresponding to a part of the space not including the surface in the background, an object area corresponding to the object existing in the foreground with respect to the surface, based on the positional information of the object in the acquired input image, and a second reference different from the first reference.