摘要:
A lattice (10)includes a transmit bus (14) formed of a single mode optical fiber and a return bus (16) formed of a multimode optical fiber. An optical transmitter (12) applies input signals to the transmit bus (14), and an optical receiver (20) receives the signals guided by the return bus (16). The return fiber bus (16) is looped around the couplers (18A, 18B, etc.) so that the signal output from each segment of the lattice (10) passes through all the preceding segment sbefore reaching the receiver (20). The optical couplers (18A, 18B, etc.) have asymmetric coupling efficiencies so that recirculating light is attenuated.
摘要:
A method and apparatus for performing optical processing on optical information corresponding to a subject (66) combines known optical processing techniques with holography. A reverse ray-trace holographic system is provided so that the image reconstruction beam (90) passes through the optical system in a direction exactly opposite to that travelled by the subject beam (50) during recording of the hologram (88). Aberrations introduced by the system optics are then completely compensated for, allowing use of lower aquality optical components. A single large-aperture lens (68) is used to define a Fourier transform of the optical subject information as the hologram (88) is recorded or the image reconstructed, and the subject information is manipulated within the Fourier transform plane (91).
摘要:
A two dimensional electro-optic modulator (12) comprises an electro-optic element and a two dimensional planar array of individually addressable electrodes (17a-17i, 18a-18i, 19a-19l) for spatially modulating a light beam (32) along a plurality of transverse axes or for imparting a geometric phase front to the light beam. Such a modulator may be used, for example, (1) in a real time or in a time delay and integration mode as a multigate light valve for (a) electro-optic line printing or (b) optical displays, or (2) in a real time mode as (a) a beam focussing and tracking device for optical memories or (b) an arcal input device, a Fourier plane filter, or an image plane correlation mask for optical processing.
摘要:
L'invention concerne un dispositif optique transformateur de Fourier, et un corrélateur optique mettant en oeuvre ce dispositif optique transformateur de Fourier, fournissant la fonction de corrélation de deux motifs d'un objet éclairés en lumière cohérente, en utilisant le principe de la double diffraction. Le système transformateur de Fourier selon l'invention se caractérise essentiellement en ce qu'il génère une onde complexe conjuguée d'une onde modulée par l'objet, se propageant en sens inverse de celle-ci. Cette onde conjuguée étant crée par double diffraction dans un mileu d'interaction (2) pour compenser ainsi les distorsions induites par les composants optiques du système. Le système corrélateur optique mettant en oeuvre ce système transformateur de Fourier se caractérise essentiellement en ce qu'il utilise comme milieu d'enregistrement un matériau recyclable (10). Un faisceau de lecture (F R ) subissant un balayage angulaire permet d'optimiser le rendement de diffraction de ce milieu. Le faisceau modulé par l'objet et le faisceau de lecture sont défléchis de matière synchrone pour améliorer le rapport signal/bruit dans le plan de sortie (7). Application à la poursuite des cibles et à la robotique.
摘要:
A fiber optic lattice filter having a transfer function wherein the poles and zeros are adjustable independently of each other. The filter comprises a cascaded configuration of recursive (100) and non-recursive (102) fiber optic lattice filters. In one preferred embodiment, an all-pass fiber optic filter is formed by cascading all-pole and all-zero lattice filters, and by processing the resulting filtered output signal in a subtractive detection system (104). This detection system produces a signal which represents the difference between two signal outputs provided by the all-zero filter section, and which is adjustable in magnitude, thereby providing an overall filtering function which is capable of handling both positive and negative valued input signals.
摘要:
Pour re-localiser un mobile (11) de direction de déplacement connue (10) sur une carte, on établit une carte en deux parties complémentaires dont les transparences en chaque point i et 1 sont, l'une, fonction croissante de la valeur du paramètre représenté par la carte, l'autre, fonction décroissante. On mémorise les valeurs successives du paramètre, mesurées à partir du mobile sur un segment; on détermine les flux lumineux qui traversent les bandes de la carte parallèles à la trajectoire théorique lorsqu' on dirige à travers la carte des flux dont l'un, i', est fonction croissante du paramètre mémorisé et dont l'autre i', est fonction décroissante; et on détermine l'emplacement transversal et longitudinal du segment pour lequel on a la meilleure corrélation.
摘要:
Signal processing, particularly correlation and auto-correlation, is effected using a "light panel". The light panel consists of (a) an array of two-terminal light-emitting or light-modulating elements (10), the optical state of each element being changed from a first state to a second state when a voltage difference is applied across its terminals, and (b) a complementary array of photo-diodes (12), each arranged to receive light from a respective element of the array of light-emitting or light-modulation elements (10). The interconnection between the two arrays may be simply an optical lens (11). For auto-correlation, each array may be a linear array, with the signal from a single signal source applied to the terminals of each element (10) both instantaneously and after a predetermined time delay. For cross-correlation, each element (10) will be located at a cross-over point of an m x n matrix of conductors (insulated from each other) with its terminals connected to respective conductors at the cross-over point. When the light panel is used for correlation, the photodiodes act as charge integrators. Uses of the apparatus and method include image processing, image analysis and speckle interferometry.
摘要:
An optical system for generating the ambiguity function for two signals uses one-dimensional spatial light modulators (34, 35; 39, 40) to code the signals into a beam of substantially coherent light. After the light has been coded with the first one-dimensional signal a Fourier Transform is performed by lens means (36). A linear phase shifter (37) is placed in the Fourier Transform plane (U). This has the effect of creating a linear dependence along a second dimension when a second Fourier Transform is performed by second Fourier Transform lens means (41) and produces the ambiguity function at the ambiguity plane (U 3 ).