Using several different techniques, one can compensate for the distortion introduced when the viewer is not at the same depth with respect to the hologram as the camera.Īn anamorphic physical camera can be created with a standard spherical-surfaced lens coupled with a cylindrical lens, or alternately two crossed cylindrical lenses can be used. This is an undesirable constraint on the viewability of holographic stereograms. In general for HPO holographic stereograms, the best viewer location where a viewer of a holographic stereogram can see an undistorted image is at the plane where the camera (or the camera model in the case of computer graphics images) captured the scene. Halle in The Generalized Holographic Stereogram, Master's Thesis, Massachusetts Institute of Technology, February 1991, which is hereby incorporated by reference herein in its entirety. This object beam typically passes through optics (not shown) so that when the object beam reaches tile 110, it can be used in conjunction with a reference beam to form an interference pattern which is recorded as hogel 120.ĭistortion associated with the generation of hogels for horizontal-parallax-only (HPO) holographic stereograms is analyzed Michael W. An object beam (not shown) passes through spatial light modulator 130, which modifies the intensity of the object beam according to values of the various pixels 140. Spatial light modulator (SLM) 130 includes a number of pixels 140 upon which a computer graphics image can be displayed. Similarly, two elements of a hologram production system 100 are shown in FIG. As illustrated by arrows 150 and 160, the relative position of each pixel 140 with respect to hogel 120 can be used to define directions in which a three-dimensional (3D) computer graphics scene can be viewed and/or rendered. Each of the pixels 140 can define a directional image sample through the hologram. The computer graphics image 130 is made up of a number of pixels 140 each of which can have data values depending on, for example, color and intensity. 1 illustrates the relationship between a hogel 120 and the computer graphics image 130 used to create the hogel (this relationship is similar to the relationship among hologram printer components such as a spatial light modulator and holographic recording material, as discussed below). Two-step holograms are created using indirect or transfer methods, that require recording a transfer hologram before printing the master hologram.įIG. 17, 1998, which is hereby incorporated by reference herein in its entirety. patent application entitled “Method and Apparatus for Recording One-Step, Full-Color, Full-Parallax, Holographic Stereograms,” Ser. Examples of techniques for one-step hologram production can be found in the U.S.
A number of hogels recorded together on the same piece of holographic recording material is often referred to as a tile. To record each hogel on holographic recording material, an object beam is conditioned through the rendered image and interfered with by a reference beam. In some one-step systems, computer processed images of objects or computer models of objects allow the respective system to build a hologram from a number of contiguous, small, elemental pieces known as hologram elements or hogels. Both computer image holograms and non-computer image holograms may be produced by such one-step technology. One-step hologram (including holographic stereogram) production technology has been used to satisfactorily record holograms in holographic recording materials without the traditional step of creating preliminary holograms.
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