OPTICAL REPRODUCTION SYSTEMS FOR HIGH-RESOLUTION SONAR OR RADAR CHARTS

摘要

1405440 Optical apparatus SIEMENS AG 28 Dec 1972 [30 March 1972] 59837/72 Heading G2J In an optical reproduction system for sonar or radar charts, a series of unidimensional holograms I produced by a pulsed sonar or radar system and recorded as a function of the reception time is reconstructed by illuminating the holograms 1 by a convergent laser beam 2 and reproduced by means of a lens 4 having a short focal length F4 and arranged on the optical axis at a distance from the focus of the laser beam corresponding to its focal length. At the same time the range co-ordinate p is reproduced in magnified form by a cylindrical lens 3 and the lens 4 upon a cylindrical lens 6 arranged at an angle to the optical axis. The reconstruction plane 5 of the reduced azimuthal co-ordinate x is at an angle # relative to a plane perpendicular to the optical axis. By means of the cylindrical lens 6, which is at an angle of 90-0 degrees relative to the optical axis, the reconstruction plane of the azimuthal coordinate x is reproduced at infinity. The image planes of the azimuthal and range co-ordinates of the object are superimposed by means of a lens 7 and a cylindrical lens 9, the focal lengths of these lenses being so chosen that the magnifications of both co-ordinates are the same. By using the tilted cylindrical lens 6, the image magnification is made independent of the object range, and therefore it is possible in this fashion to produce undistorted sonar or radar charts 10.