Optical systems

Claim 1

IN AN OPTICAL SYSTEM, THE COMBINATION INDLUDING SOURCE MEANS OF SUBSTANTIALLY MONOCHROMATIC LIGHT, MEANS FOR POSITIONING A PHOTOGRAPH OR THE LIKE TO BE REPRODUCED, LENS MEANS FOR PROJECTING SAID LIGHT ONTO SAID PHOTOGRAPH, THE LIGHT PROJECTED FROM SAID PHOTOGRAPH COMPRISING LIGHT OF VARYING AMPLITUDE PROJECTED FROM A PLURALITY OF POINTS FORMING SPATIAL FREQUENCIES IN THE LIGHT PROJECTED THEREFROM CORRESPONDING TO A PERIODICITY COMPONENT FOR WHICH THE VARIABLE IS THE POSITION OF THE POINT IN THE PLANE OF THE PHOTOGRAPH, SAID PROJECTED LIGHT BEING DIFFRACTED BY SAID PHOTOGRAPH IN ACCORDANCE WITH SPATIAL FREQUENCIES WITH THE ANGLES OF DIFFRACTION BEING PROPORTIONAL TO SAID SPATIAL FREQUENCIES, MEANS FOR PRODUCING AN IMPROVED IMAGE OF SAID PHOTOGRAPH IN AN IMAGE PLANE, SAID MEANS COMPRISING FILTER MEANS HAVING DIFFERENT LIGHT ABSORPTION FACTORS OVER DIFFERENT AREAS THEREOF FOR VARYING THE AMPLITUDE OF SAID DIFFRACTED LIGHT IN PREDETERMINED ZONES CORRESPONDING TO PREDETERMINED ANGLES OF DIFFRACTION, SO THAT THE OPTICAL TRANSMISSIBILITY OF SAID FILTER MEANS IS A PREDETERMINED FUNCTION OF SAID SPATIAL FREQUENCY, AND LENS MEANS FORMING A CORRECTED IMAGE OF SAID PHOTOGRAPH FROM THE LIGHT TRAMSMITTED THROUGH SAID FILTER MEANS.