1. A method for constructing a digital representation of a physical plane from a physical scene, the method comprising: determining an orientation and an initial portion of a physical plane in the image of the physical scene in three dimensional space; generating a rectified image, wherein the rectified image contains a fronto-parallel view of at least part of the physical plane; subdividing the rectified image into a plurality of grid cells; for each of the plurality of grid cells, generating an image signature based on at least one image characteristic associated with said grid cell; selecting one or more initial grid cells contiguous to at least part of the obtained initial portion of the physical plane to include as part of the digital representation of the physical plane; comparing the image signature for each neighboring grid cell contiguous to the one or more initial grid cells to the image signature of one or more grid cells currently included in the digital representation of the physical plane; and adding each grid cell that meets a predetermined threshold to the digital representation of the physical plane.