Abstract: A method of determining linear position by means of lenticular screens in a direction perpendicular to the axes of the lenticules and in the planes of the screens is disclosed comprising the steps of:a) directing a collimated beam of radiation perpendicularly into a first sheet of lenticular material;b) allowing the beam transmitted by the first sheet to enter a second sheet of similar pitch, oriented parallel to the first sheet, and with the axes of the lenticules parallel to the axes of the first sheet, and spaced so as to recollimate the radiation beam upon exit from the second sheet;c) placing a radiation detector array situated to receive the collimated beam exiting from the second lenticular sheet and subtending the field-of-view of the lenticules;d) sensing the position of the collimated beam within the field-of-view of the lenticules, and keeping account of the number of transits and fractions thereof of the beam across the center of the field-of-view of the lenticules with the detector array, due to