A method for measuring the distance of an object from a measuring device is disclosed, said method comprising the following steps: a) emitting a signal; b) directing the signal towards an object; c) detecting the signal diffused by the object; d) comparing the detected signal with the emitted signal so as to obtain a comparison signal representing the distance travelled by the emitted signal and the object diffused signal. The method of the invention is characterized in that it comprises the steps of: e) carrying out before step a) a measuring device calibration step so as to associate a prefixed comparison signal value to a prefixed distance value; f) identifying the distance value associated, in the previous calibration step, to the value of said comparison signal obtained in step d); g) associating the distance value identified in step f) to the comparison signal obtained in step d). In the calibration step, the luminous image diffused by a surface of known reflectance placed at a prefixed distance is detected to obtain a numerical value for at least a sample x.sub.j, the prefixed distance value at which the surface of known reflectance has been placed is associated to said numerical value so obtained, and the previous steps are iteratively repeated for a prefixed number of times, each time moving the surface of known reflectance by a prefixed distance interval.
An automated package dimensioning subsystem comprising a Laser Detecting and Ranging (LADAR-based) scanning apparatus for capturing two-dimensional range data maps of the space above a conveyor structure, along which packages are transported, and an image contour tracing apparatus for extracting package dimension data from the two-dimensional range data maps.
