Patent GB-1300578-A (GB)
Title: Apparatus for acquiring and displaying real time 3-d information
IPC: G03B35/00
Filed: 1969-09-19
Abstract: 1300578 Optical apparatus OPTICS TECHNOLOGY INC 19 Sept 1969 [19 Sept 1968] 46359/69 Heading G2J [Also in Division H4] Apparatus for displaying a 3D image of a target O (Fig. 1) comprises a wave energy source e.g. a laser 12 whose output is optically focused on the target, and the reflected energy is optically imaged on an electronic shuttering device 18 admitting the image to a recorder 20 operative to receive either momentarily or permanently the gated image; and which may be a lens system transferring image to a display 21, or a storage device e.g. magnetic tape, magnetic core assembly or the like. A range gate generator 22 is triggered by pulser 24 to generate gate pulses at predetermined variable delay intervals from each trigger pulse which successively open shutter device 18 for a time interval short compared with that required for an energy pulse from 12, to advance a given distance along target O. Source 12 is also triggered from pulser 24. The output pulses from 24, 26a to 26d &c. (Fig.2); initiate gate pulses 28a to 28d.....28' delayed in time T, T+t, T+2t, T+3t, ....T+nt &c. which successively open the shuttering device 18 to form images at the recorder; 30a, 30b, 30c, 30d....30n; representing images of the target in discrete Z planes corresponding to different depth dimensions. A fibre optic bundle 32 (Fig.3) couples the shuttering device 18 and the recorder to a 3D display 21, wherein the images are lens focused on a disc 36 rotated by motor 42. Plural fibre - optic bodies 48 each corresponding to one image are mounted circumferentially in apertures of the disc and the faces thereof are successively spaced at graduated distances from a viewing station 44, while the disc rotation and the gate generator are synchronised over link 50 comprising e.g. a peripheral iron element 54 in the disc co-operating with an electromagnetic pick-up head 52 producing one pulse per revolution. Disc rotation at e.g. 20 r.p.s. produces a 3D image of the target, and the respective lengths of the fibre-optic bodies may have nonlinear relationships to the positions of the Z planes to magnify selectively a given region and avoid depth distortion. Alternatively, the fibre optic bodies may be formed so that the fibres diverge from a smaller input face to a larger output face. The disc may comprise Fig.4 (not shown) a single optical fibre body which is circumferentially wedge shaped to define a helical viewing face, or Fig. 5 (not shown) two transparent elements of differing refractive indices shaped in opposition to define a helical interface. The display may comprise Fig. 6 (not shown) a frosted screen mounted for oscillatory movement to and from a viewing station, and a lens similarly mounted for synchronous oscillatory movement with the screen and focusing the images therein; one excursion corresponding to one resolution of disc 36 (Fig.1) to produce a similar image sequence. The display may also comprise (Fig. 7) an electronic image intensifier 75 transmitting images over lens 73 and rotary mirror 74 to frustroconical reflector 84 and corresponding reflector 86 between which reflectors are circularly positioned along a locus of parallel optical paths about the rotary mirror axis, a number of plural fibre-optic bodies of graduated lengths corresponding to the positions of the several images, and rotary mirror 88 is rotated with mirror 74 and produces the appropriate 3D image; the image intensifier being synchronised with gating generator 22 to gate successive images. In Fig. 8 the sequential images over fibre optic bundle 32 are focused on image splitter reflector 100 and auxiliary reflector 106 producing identical images at inputs of electronic image intensifier 102, 104; whose outputs are viewed binocularly and stereoscopically. The electron beams of the intensifiers are deflectable laterally by coils 108a, 108b and 110a, 110b, energized by a programmed signal source 112 feedback linked at 50 to gate generator 22, to position the images so that they appear visually at successive distances corresponding to the several images of the target 30a to 30n in discrete Z planes corresponding to different depth dimensions. The intensifiers are replaceable by galvanometers deflecting reactors 100, 106 in accordance with coil energization. The image information can be stored on tape or magnetic core assembly for subsequent display, or derived from computed information. The wave energy transmitted may be radar or sonar waves.