Abstract: An apparatus for determining the perimeter of an object being scanned comprises a scanning chamber for receiving therein an object being scanned; a source of laser beam disposed within the scanning chamber for impinging on the object being scanned, the laser beam being adapted to orbit around the object; an array of sensors disposed within the chamber, each of the sensors being adapted to detect light emanating from the surface of the object due to the laser beam exiting from the object; and each of the sensors being disposed such that at least only one of the sensors generates a peak response to light emanating from a point on the surface at a predetermined distance from a reference point, such that at each angular position of the laser beam in the orbit, a specific point at a distance from the reference is determined, thereby to generate a set of points representing the perimeter of the surface after a complete orbit.