Patent ID: 7277209

Claim:
A method for producing a hologram from a virtual object ( 6 ) defined in a three-dimensional geometrical space said method comprising the steps of: computing (E 1 -E 4 ) a set of two-dimensional images ( 80 nm ) representing the object as seen from respective different viewpoints in the three-dimensional geometrical space, each of said two-dimensional images ( 80 nm ) representing the object as seen from one of said different viewpoints, computing (E 5 -E 6 ) a set of elementary holograms ( 90 nm ), each of said elementary holograms corresponding to one of said two-dimensional images, and combining (E 7 ) said elementary holograms ( 90 nm ) in a combined digital image to form a hologram ( 9 ) of the object ( 6 ), wherein each of said two-dimensional images ( 80 nm ) comprises coordinates (Y,Z) and is defined by an intensity distribution (f nm (Y,Z)) over said coordinates, and wherein said step (E 5 -E 6 ) of computing the elementary holograms for a given two-dimensional image ( 80 nm ) comprises the following steps: converting (E 50 , E 51 ) the two-dimensional image defined by the corresponding real function into a complex image defined by a complex function, oversampling (E 52 ) the complex image ( 82 nm ), simulating illumination of the oversampled complex image by an optical wave (DIF) to obtain a diffracted image ( 84 nm ), adding (E 54 ) a complex field representing a reference optical wave (REF) to the resulting diffracted image ( 84 nm ) to produce an interference field, and extracting (E 6 ) amplitude values of the sum of said complex field and the resulting diffracted image ( 84 nm ) to produce the hologram ( 90 nm ) associated with said given two-dimensional image ( 80 nm ), wherein said step of computing the set of two-dimensional images includes the following steps: defining a first geometrical plane ( 7 ) in the three-dimensional geometrical space, said first geometrical plane being separate from said object, defining (E 1 -E 2 ) a matrix of points ( 70 nm ) in said first geometrical plane ( 7 ), each of said points corresponding to one of said different viewpoints, defining a second geometrical plane ( 8 ), said second geometrical plane ( 8 ) being parallel to said first geometrical plane and preferably located between the object ( 6 ) and the first geometrical plane ( 7 ), and projecting (E 3 -E 4 ) images of the object as respectively seen from said points ( 70 nm ) of said matrix onto said second geometrical plane ( 8 ), wherein the projected image constitute said two-dimensional images ( 80 nm ).