Abstract: A method aims at identifying, starting from objects in a digital image, a virtual raster included in a coding pattern. The objects in the image at least partially reproduce marks on a base, each mark being associated with a respective point of intersection of raster lines belonging to the virtual raster. The method comprises the steps of matching sets of objects against a cell unit, which corresponds to a recurring known basic element of said raster; when a set corresponds with the cell unit, identifying the objects in the set as approved; and reconstructing the virtual raster on the basis of the mutual arrangement of the approved objects. A computer program, a storage medium and a device for position determination are also described.

Abstract: A device, a method and a memory medium on which is stored a computer program for position determination are provided. The device (1) has a sensor (6) for recording an image of a position code (18) on a surface (4, 17), processing means (10) for determining a position on the surface based on the recorded image and at least a first writing means (11) for writing on the surface. The device is arranged to write on the surface by means of the first writing means, depending upon whether the position has been determined or not.