The invention relates to a holographic display for storing and reducing a spatial structure, having a holographic screen forming the master hologram, and having a projection device which illuminates the holographic screen in order to reproduce the spatial structure. The invention, for the holographic display to be constructed from a plurality of holographic screens which are respectively assigned to a dedicated projection device.

A portable holographic information retrieval system is described in which individual holograms each of which contains the alphanumeric information from an individual page of a book, are reconstructed on a rear-illuminated viewing screen. The individual holograms are contained on a permanent transparency as a matrix, the holograms of successive pages of a book being arranged in a sequential manner. The entire matrix of individual page holograms is contained on a transparency which is approximately equal in size to a standard 35 millimeter photographic slide. The reconstruction apparatus has the rear-illuminated viewing screen collapsibly mounted to a system housing. The housing includes a small source of a collimated beam of light for illuminating a selected "page" in the transparency. The transparency is mounted on a carriage which is capable of being traversed relative to the illuminating collimated beam of light so that an individual page hologram may be reconstructed by having a real image formed on the viewing screen. When collapsed for storage, the portable retrieval system is approximately the size of a standard volume.

A landing signal officer trainer having a cylindrically rolled holographic ilm with stored attitude data of yaw and pitch rotatably and slidably mounted in conjunction and relation to a laser beam source to vary yaw and pitch image attitude of a plane, a pechan prism rotatable to vary roll of the plane image, a zoom lens system to vary range of the plane image, enlarging lens apparatus to present an adequate image to a landing signal officer (LSO) observing the image, and a control panel operable by an instructor to vary the plane attitude and range position in accordance to the signals given by the trainee and thus provide unprogrammed training in guiding landing aircraft without use of actual equipment and in a manner in which the trainee participates. The invention further contemplates the provision of a ship holographic image variable in pitch and control apparatus for selectively coordinating plane range and ship pitch to produce land or abort conditions.

A holographic apparatus uses electronically processed three-dimensional information about an object to produce a three-dimensional display of that object and its movement. A holographic screen has a plurality of angularly multiplexed holographic images which are selectively illuminated by a modulator and light source to produce the three-dimensional surface outline of the object to be seen. Color encoding and rapid sequential presentation of images gives the effect of a full-color, three-dimensional "television" in which movement of the object and both horizontal and vertical parallax can be provided.