GB730912A - Improvements relating to motion picture projection systems - Google Patents

Abstract

730,912. Kinematograph apparatus. BRITISH THOMSON-HOUSTON CO., Ltd. Jan. 20, 1954 [Jan. 30, 1953], No. 2729/53. Class 97 (1). [Also in Group XXXVIII] The angular movements of a kinematograph camera in azimuth and/or elevation, to follow a centre of interest of a scene being photographed, are recorded synchronously with the images recorded on the film. The same film or a separate magnetic tape or tapes may be used for recording the camera movements, and during subsequent projection of the film, the projected beam is angularly moved so that the image appears at different positions on the screen, in accordance with the recorded camera movements. These movements may be recorded subsequently to the filming. Also, further angular movements, additional to those of the camera, may be applied to the projected beam, these movements being added to the panning record, e.g. when the film is edited. The projected beam may be angularly moved by rotating the whole projector, or by other means such as prisms or mirrors in the light beam or by movement of the projection lens relative to the film. Loud-speakers arranged behind the screen may be selected according to the rotational position of the projected beam. The projecting system may be used with an illuminated or coloured surround, such as described in Specifications 514,673 or 727,696. In the case of stereoscopic projection both beams are controlled together. Recording, Fig. 2. Wipers 21, 22, are moved over associated potentiometers, in accordance with the movements of the camera 20 in azimuth and elevation, respectively, and apply voltages corresponding to these movements to modulator amplifiers 24, 25 in each of which a separate carrier is frequency or amplitude-modulated in accordance with the input signal, and recorded on a tape 26 running synchronously with the film. Projection, Fig. 1. The azimuth and elevation signals recorded on the tape, which is driven synchronously with the projector 2, are applied by pick-offs 3, 4 to demodulator amplifiers 5, 6 respectively. The output signals therefrom are compared in servo-amplifiers 7, 8 respectively, with azimuth and elevation projector position voltages derived, e.g. from potentiometers 11, 12. Servomotors 9, 10 are driven in accordance with the difference voltages to align the projector in azimuth and elevation respectively with the angular position indicated by the record.