California Institute of Technology

The United States of America As Represented by the Administrator of the

United States of America As Represented by the Administrator of Nasa

Tien-Hsin Chao

Hua-Kuang Liu

Li-Jen Cheng Cheng

Frederick W Mintz

Hanying Zhou

Jeffrey W Yu

Peter Tsou

Jay C Hanan

George F Reyes

Demetri Psaltis

James L Lambert

Taher Daud

Tsuen-Hsi Liu

Li J Cheng

Keith E Wilson

Anikumar Thakoor

Hanying Znod

Nevin A Bryant

Keith Coste

Nevin Bryant

A method, systems, apparatus and device enable high bandwidth satellite communications. An onboard tracking detector, installed in a low-earth orbit satellite, detects a position of an incoming optical beam received/transmitted from a first ground station of one or more ground stations. Tracker electronics determine orientation information of the incoming optical beam based on the position. Control electronics receive the orientation information from the tracker electronics, and control a waveguide drive electronics. The waveguide drive electronics control a voltage that is provided to an electro-optic waveguide beam steering device. The electro-optic waveguide beam steering device steers an outgoing optical beam to one of the one or more ground stations based on the voltage.

High bandwidth optical links for micro-satellite support

A holographic memory system and apparatus, and a method provide the ability to store multibit holograms in a photorefractive crystal. A single laser diode is configured to emit a collimated laser beam to both write a page of multibit data to and read the page of multibit data from the photorefractive crystal. A multilevel spatial light modulator (DMDSLM) is configured to encode the page of multibit data on an input beam split from the collimated laser beam. A first imaging relay lens pair is positioned between the multilevel spatial light modulator and the photorefractive crystal to image a multibit spatial light modulator image on a plane behind the photorefractive crystal. One or more mirrors are configured to steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal to read or write a page of the multi-bit data.

High density, high bandwidth multilevel holographic memory

An Electro-Optic Imaging Fourier Transform Spectrometer (EOIFTS) for Hyperspectral Imaging is described. The EOIFTS includes an input polarizer, an output polarizer, and a plurality of birefringent phase elements. The relative orientations of the polarizers and birefringent phase elements can be changed mechanically or via a controller, using ferroelectric liquid crystals, to substantially measure the spectral Fourier components of light propagating through the EIOFTS. When achromatic switches are used as an integral part of the birefringent phase elements, the EIOFTS becomes suitable for broadband applications, with over 1 micron infrared bandwidth.

Electro-optic imaging Fourier transform spectrometer

The present invention relates to a three-dimensional (3D) hologram display system. The 3D hologram display system includes a projector device for projecting an image upon a display medium to form a 3D hologram. The 3D hologram is formed such that a viewer can view the holographic image from multiple angles up to 360 degrees. Multiple display media are described, namely a spinning diffusive screen, a circular diffuser screen, and an aerogel. The spinning diffusive screen utilizes spatial light modulators to control the image such that the 3D image is displayed on the rotating screen in a time-multiplexing manner. The circular diffuser screen includes multiple, simultaneously-operated projectors to project the image onto the circular diffuser screen from a plurality of locations, thereby forming the 3D image. The aerogel can use the projection device described as applicable to either the spinning diffusive screen or the circular diffuser screen.

Three-dimensional hologram display system

A method, apparatus, and system provide the ability for storing holograms at high speed. A single laser diode emits a collimated laser beam to both write to and read from a photorefractice crystal. One or more liquid crystal beam steering spatial light modulators (BSSLMs) steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal.

Holographic memory using beam steering

A method, apparatus, and system provide the ability for storing holograms at high speed. A single laser diode emits a collimated laser beam to both write to and read from a photorefractice crystal. One or more liquid crystal beam steering spatial light modulators (BSSLMs) or Micro-Electro-Mechanical Systems (MEMS) mirrors steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal.

A Hybrid Optoelectronic Neural Object Recognition System (HONORS), is disclosed, comprising two major building blocks: (1) an advanced grayscale optical correlator (OC) and (2) a massively parallel three-dimensional neural-processor. The optical correlator, with its inherent advantages in parallel processing and shift invariance, is used for target of interest (TOI) detection and segmentation. The three-dimensional neural-processor, with its robust neural learning capability, is used for target classification and identification. The hybrid optoelectronic neural object recognition system, with its powerful combination of optical processing and neural networks, enables real-time, large frame, automatic target recognition (ATR).

Advanced miniature processing handware for ATR applications

A real-time, dynamic, free space-virtual reality, 3-D image display system which is enabled by using a unique form of Aerogel as the primary display media. A preferred embodiment of this system comprises a 3-D mosaic topographic map which is displayed by fusing four projected hologram images. In this embodiment, 4 holographic images are projected from 4 separate holograms. Each holographic image subtends a quadrant of the 4&pgr; solid angle. By fusing these four holographic images, a static 3-D image such as a featured terrain map would be visible for 360 degrees in the horizontal plane and 180 degrees in the vertical plane. An input, either acquired by 3-D image sensor or generated by computer animation, is first converted into a 2-D computer generated hologram (CGH). This CGH is then downloaded into large liquid crystal (LC) panel. A laser projector illuminates the CGH-filled LC panel and generates and displays a real 3-D image in the Aerogel matrix.

High-resolution large-field-of-view three-dimensional hologram display system and method thereof

A new type of optical correlator performs motion detection or background clutter suppression and correlation simultaneously in a single photorefractive crystal, and is useful for moving target identification and tracking and for stationary clutter rejection. The correlation is of the VanderLugt type and the motion detection or background clutter suppression is based on the erasing property of photorefractive crystals.

Motion-sensitive optical correlator using a VanderLugt Correlator

The opto-electronic morphological processor of the present invention is capable of receiving optical inputs and emitting optical outputs. The use of optics allows implementation of parallel input/output, thereby overcoming a major bottleneck in prior art image processing systems. The processor consists of three components, namely, detectors, morphological operators and modulators. The detectors and operators are fabricated on a silicon VLSI chip and implement the optical input and morphological operations. A layer of ferro-electric liquid crystals is integrated with a silicon chip to provide the optical modulation. The implementation of the image processing operators in electronics leads to a wide range of applications and the use of optical connections allows cascadability of these parallel opto-electronic image processing components and high speed operation. Such an opto-electronic morphological processor may be used as the pre-processing stage in an image recognition system. In one example disclosed herein, the optical input/optical output morphological processor of the invention is interfaced with a binary phase-only correlator to produce an image recognition system.

Opto-electronic morphological processor

An associative optical memory including an input SLM in the form of an edge enhanced LCLV and a pair of memory SLMs in the form of LCTVs forms a matrix array of an input image which is cross correlated with a matrix array of stored images. The correlation product is detected and non-linearly amplified to illuminate a replica of the stored image array to select the stored image correlating with the input image. The LCLV is edge enhanced by reducing the bias frequency and voltage and rotating its orientation. The edge enhancement and non-linearity of the photodetection improves the orthogonality of the stored images. The illumination of the replicate stored image provides a clean stored image, uncontaminated by the image comparison process.

Optoelectronic associative memory

An improved AOTF-based imaging spectrometer that has ability to electronically set the bandpass wavelength of an AOTF to any desired value in its wide tuning range, provides significant observational flexibility. This allows observations to be tailored in real-time and enables the spectrometer to address a wide range of objectives and permits real-time modification of the observational parameters, such as in flight or in other situations in which only remote control is possible. Various improvements in optical architecture provide simplified magnification variability, improved image resolution and light throughput efficiency and reduced sensitivity to ambient light. A preferred embodiment employs a camera zoom lens as the input lens. A TeO.sub.2 AOTF and a relay lens are placed at selected distances behind the back focal plane of the input lens, respectively. A charge coupled device (CCD) camera, which comprises a camera, camera zoom lens and a CCD detector is placed at a selected distance behind the relay lens. An RF signal generator is used to drive the AOTF. Two embodiments of the invention are disclosed herein. One operates in the visible/near-infrared domain, in the wavelength range of 0.48 to 0.76 microns. The other operates in the infrared wavelength range of 1.2 to 2.5 microns.

Real-time imaging spectrometer

An optical system for auto-associative and hetero-associative recall utilizing Hamming distance as the similarity measure between a binary input image vector V.sup.(k) and a binary image vector V.sup.(m) in a first memory array using an optical Exclusive-OR gate for multiplication of each of a plurality of different binary image vectors in memory by the input image vector. After integrating the light of each product V.sup.(k) .times.V.sup.(m), a shortest Hamming distance detection electronics module determines which product has the lowest light intensity and emits a signal that activates a light emitting diode to illuminate a corresponding image vector in a second memory array for display. That corresponding image vector is identical to the memory image vector V.sup.(m) in the first memory array for auto-associative recall or related to it, such as by name, for hetero-associative recall.

Auto and hetero-associative memory using a 2-D optical logic gate

A method and apparatus are disclosed for real-time optical broadband pseudocolor encoding of an image. A light polarization spatial modulator is utilized to density encode an incident beam of plane-polarized light; the beam is dispersed into its primary colors; the polarizations of the dispersed beams are analyzed to produce positive, negative, and bidirectionally modualated images which are each separately encoded with a primary color; and the primary-color encoded beams are combined to produce a pseudocolored image. In a preferred embodiment the pseudocolor encoding apparatus comprises a compact white-light projection system and a liquid-crystal television spatial light polarization modulator. The invention makes possible the large-screen display of broadband pseudocolor images from real-world input scenes from a television camera.

Real-time pseudocolor density encoding of an image

System for optically recognizing and tracking a plurality of objects within a field of vision. Laser (46) produces a coherent beam (48). Beam splitter (24) splits the beam into object (26) and reference (28) beams. Beam expanders (50) and collimators (52) transform the beams (26, 28) into coherent collimated light beams (26', 28'). A two-dimensional SLM (54), disposed in the object beam (26'), modulates the object beam with optical information as a function of signals from a first camera (16) which develops X and Y signals reflecting the contents of its field of vision. A hololens (38), positioned in the object beam (26') subsequent to the modulator (54), focuses the object beam at a plurality of focal points (42). A planar transparency-forming film (32), disposed with the focal points on an exposable surface, forms a multiple position interference filter (62) upon exposure of the surface and development processing of the film (32). A reflector (53) directing the reference beam (28') onto the film (32), exposes the surface, with images focused by the hololens (38), to form interference patterns on the surface. There is apparatus (16', 64) for sensing and indicating light passage through respective ones of the positions of the filter (62), whereby recognition of objects corresponding to respective ones of the positions of the filter (62) is affected. For tracking, apparatus (64) focuses light passing through the filter (62) onto a matrix of CCD's in a second camera (16') to form a two-dimensional display of the recognized objects.

Growing community of inventors

Valencia, CA, United States of America

Tien-Hsin Chao