Abstract: Apparatus is disclosed for de-emphasizing low spatial frequencies in a two-dimensional optical imaging system.

Abstract: Apparatus for image subtraction in order to extract non-common information from two light images comprises a TV camera tube including a photosensitive coating on its inner face and a grating on its outer face spaced from the photosensitive coating by the thickness of the tube; projectors for projecting the two light images simultaneously, from slightly different angles, onto the photosensitive coating via the grating such that the shadow of the grating interlaces the two light images on the photosensitive coating; and a scanner for electronically scanning the interlaced images on the photosensitive coating to produce a video output, and for processing same to select only the image information which is non-common to the two optical images.

Abstract: Apparatus is disclosed for digitizing an applied analog signal. A plurality of closely-spaced parallel optical waveguide pairs are disposed in an electro-optic crystal substrate. A laser source applies light energy simultaneously to one waveguide of each waveguide pair. Electrical conductors disposed on the substrate and connected to a source of an analog signal apply signals therefrom across a coupling region of each of the plurality of waveguide pairs so as to induce coupling of the laser energy between one waveguide and the other waveguide of each of the pairs. The coupling regions are of different lengths for each of the waveguide pairs, the lengths of the coupling regions being related in a predetermined manner. The coupling is proportional to the applied analog signal and to the lengths of the coupling regions. A comparator is disposed so as to compare the output of both waveguides of each of the waveguide pairs and provide a digitized signal therefrom.

Abstract: Apparatus is provided comprising a laser source, collimating optics for collimating light provided by the laser source, focusing optics for focusing the collimated light provided by the collimating optics, and a detector array disposed at the focal plane of the focusing optics. Two surface acoustic wave transducers are disposed adjacent to one another and adjacent to an optical path between the collimating and focusing optics. The surface acoustic wave transducers are individually connected to antennas which are oriented substantially parallel to one another. The surface acoustic wave transducers launch surface acoustic waves which interact with the laser light and cause the light to be deflected in proportion to the amplitude and frequency of signals applied to the surface acoustic wave transducers by the antennas. The beams deflected by the two surface acoustic waves result in an interference pattern created at the detector array.

Abstract: Apparatus is provided comprising two antennas generally oriented in non-parallel directions such that their effective apertures are different relative to received radiation, each antenna being individually connected to two integrated optica spectrum analyzers. Switching means is provided which alternately switches signals provided by the two antennas between the two integrated optic spectrum analyzers. A microcomputer is connected to the outputs of the two integrated optic spectrum analyzers for comparing the relative intensities of signals received therefrom and provide a signal indicative of the direction of arrival of radiation received by the two antennas.

Abstract: Two multimode optical fibers connected mutually at several locations along their lengths can act as an encoding or decoding structure depending on which terminals are used for the input/output of the data. Two multicoupled lines have one input which acts as the matched filter for another input, thus enabling easy correlation of data. The performance of such a structure was simulated and the results are discussed.

Abstract: There is disclosed a system capable of subtracting in real time the intensities of two incoherently illuminated scenes and providing the sign of the subtracted information. The system utilizes two birefringent devices such as liquid crystal light valves, onto which the two images to be subtracted are projected. One valve is analyzed in between crossed polarizers, or equivalent, while the other one is in between parallel polarizers or equivalent. Both polarizer arrangements, for example, may be implemented with a polarizing beam splitter and a quarter wave plate. The common output image plane, onto which both images are superposed, displays an intensity proportional to the difference between the two inputs. This intensity "rides" on a constant background intensity thus displaying the difference signal as well as its polarity. The read-in and read-out beams could be coherent as well as incoherent, the latter being more desirable due to its speckle-free image.