Abstract: The method consists of computing (E1-E4) a set of two-dimensional images in a three-dimensional geometrical space representing a virtual object from respective different viewpoints. The virtual object is represented by digital data stored in a computer. Holograms are computed (E5-E6) for the respective two-dimensional images using a fast complex transform, such as a Fourier transform. The holograms are then juxtaposed (E7) to form a digital hologram of the object which is physically reproduced (E8) by a spatial light modulator. A three-dimensional image of the object is obtained by illuminating the spatial light modulator with a coherent source.

Abstract: A three-dimensional image is stored (E0) in a computer memory in the form of digital data and defined in a three-dimensional geometrical space. Two-dimensional images are calculated (E1) by determining, in the three-dimensional geometrical space, the intersections between the three-dimensional image and a plurality of parallel section planes. Respective holograms are calculated (E2) for the two-dimensional images, and are then reproduced (E3) sequentially on a spatial light modulator illuminated by a coherent light source. A transparent three-dimensional image is thus reproduced.

Abstract: The method consists of transforming a digital two-dimensional image defined by a real function into a complex two-dimensional image defined by a complex function, oversampling the complex image, simulating the production of a diffracted image resulting from the diffraction of an optical wave by the oversampled complex image, and adding a complex field representing a reference optical wave to the resulting diffracted image to produce a hologram. The hologram produced in this way can be used to produce images in three dimensions or in telecommunications.

Abstract: The invention relates to an ultrarapid camera for visualizing the intensity profile of a laser pulse. This camera comprises in vacuum housing a photocathode, an extraction grid, focalization electrodes, deflection plates and a visualization screen. According to the invention, the electron emitting photocathode is constituted by at least one metal tip (3, 12) and means (9, 10) are provided to send said laser pulse (13) into a zone situated in front of said tip.

Abstract: The invention relates to a method for the photographic recording and the visual restitution of a tridimensional scene by means of a coherent light source (1). According to the invention, in view of the photographic recording, a coherent light beam is projected onto said scene such that it illuminates only a small portion of the surface of the scene (3) and a photosensitive recording plate (4) is disposed in such a way that it receives diffuse light coming from said scene; in view of the visual restitution, a first face of said plate is illuminated by a coherent light beam while the second face of said plate is observed.