A system for automatically obtaining I/V spectra from a LEED experiment, using a video camera, monitor and computer was developed. This was used to obtain data for clean Cu(001) and Cu(001) ( 2× 2)R45° oxygen adsorbed surfaces. Structural details were determined by analyzing these data using the Patterson function. The limitations of this function and the effect of various parameters are discussed. The analysis provided sensible answers for the clean surface and results for the oxygen adsorbed surface pointed to the model in which oxygen atoms are incorporated between the top and first layers of copper atoms.