Abstract: Disclosed is an unmanned aerial vehicle (UAV) positioning method based on a millimeter-wave radar, including a calibration stage and a positioning stage. The calibration stage includes: acquiring ground coordinates of the unmanned aerial vehicle; and extracting feature points from radar point cloud data and get the ground coordinates of the feature points. The positioning stage includes: acquiring radar point cloud data of a current frame and pre-processing; acquiring UAV motion data and fuse the data with radar point cloud data; extracting characteristic line segment from radar point cloud data; registering the characteristic line segment of the current frame with the characteristic line segment of the previous frame, and finding matching feature points and newly added feature points; and obtaining the ground coordinates of UAV and the ground coordinates of newly added feature points based on the ground coordinates of matched feature points on the map.

Abstract: An optical information recording/reproducing apparatus and an optical information recording/reproducing method that record information using holography, wherein the optical information recording/reproducing apparatus includes a signal generation unit that generates two-dimensional data by a two-dimensional encoding method in which a lower-limit value of a number of continuous ON/OFF pixels in an array in one direction of pixels in a two-dimensional spatial light modulator is K(K?2, K: natural number); and a pickup that records the two-dimensional data, generated by the signal generation unit, on a hologram disc.

Abstract: A data recording apparatus and method using three dimensional (3D) optical memory and an authentication apparatus and method using 3D optical memory are provided. The data recording apparatus includes a recording excitation light splitting unit, a condition storage unit, and a data recording unit. The recording excitation light splitting unit splits recording excitation light into first split light and second split light. The condition storage unit stores recording conditions including information about the waveforms, wavelengths and phases of the split light and information about an arrangement of reflection mirrors configured to reflect the split light. The data recording unit records storage data by making the split light incident on the 3D optical memory through the reflection mirrors under the recording conditions.

Abstract: The invention combines several techniques applying high-resolution photosensitive emulsions for the long-term, archival storage of data, images and text. Data is stored as vertical interference patterns of multiple frequencies in a photographic emulsion. Read-out of the stored data uses a precision mechanism to locate and decode stored data.

Abstract: There is provided an optical information detecting method. The method includes: detecting an image of a source data page coded with balanced codewords by the use of 1:N (where N is greater than 1) excessive detection pixels; determining a distribution pattern of valid detection pixels and invalid detection pixels to be corrected in the detected image by the use of a light intensity distribution of the detected image; and dividing the detected image into balanced codeword detecting areas corresponding to the balanced codewords and sampling data of the balanced codeword detecting areas by the use of the determined distribution pattern and an optical distribution characteristic of the balanced codewords. Accordingly, it is possible to efficiently detect optical information by the use of a 1:N over-sampling method. Specifically, the distribution pattern of valid detection pixels and invalid detection pixels in the detected image of a data page can be properly used to sample a balanced code.

Abstract: Integrated control electronics for a holographic storage system that is adapted for controlling read/write logic in a holographic storage device. The control electronics may control beam steering devices, SLM devices, shutters, optical sensor arrays and lasers.

Abstract: There is provided a hologram recording method, including generating a signal light which is spatially modulated such that digital data is represented by an image of intensity distribution, irradiating the signal light on an optical recording medium after a Fourier transformation of the signal light such that a zero-order component of the signal light comes into focus at a point removed from the optical recording medium, forming a diffraction grating in the optical recording medium by interference between the zero-order component of the signal light and a high-order component thereof, and recording digital data represented by the signal light as a hologram.

Abstract: Data hologram recycling systems, methods and computer program products are configured to arrange data for storage in the intermediate data storage as data segments which are replicas of holographic storage segments for destaging to the holographic data storage, and to determine retrieval for recycling of the destaged holographic storage segments to which aggregated requests for deletion are directed. The retrieval determination may be based on a plurality of policies.

Abstract: Data for storage by holographic data storage is arranged in an intermediate data storage as data segments which are replicas of holographic storage segments. Files of data are aggregated into the data segments, and a destaging control determines the destaging of the data segments to the holographic data storage in accordance with a plurality of policies, such as whether a segment is full, a time threshold has been reached, or whether a threshold number of segments are “open”. The intermediate data storage may be arranged into a number of partitions at least equal to the number of sources having input to the data destaging system, the partitions comprising integral multiples of the data segments.

Abstract: Data for storage by holographic data storage is arranged in an intermediate data storage as data segments which are replicas of holographic storage segments. Files of data are aggregated into the data segments, and a destaging control determines the destaging of the data segments to the holographic data storage in accordance with a plurality of policies, such as whether a segment is full, a time threshold has been reached, or whether a threshold number of segments are “open”. The intermediate data storage may be arranged into a number of partitions at least equal to the number of sources having input to the data destaging system, the partitions comprising integral multiples of the data segments.

Abstract: A reproducing device for performing reproduction regarding a hologram recording medium where a hologram page is recorded in accordance with signal light, by interference between the signal light where bit data is arrayed with the information of light intensity difference in pixel increments, and reference light, includes: a reference light generating unit to generate reference light irradiated when obtaining a reproduced image; a coherent light generating unit to generate coherent light of which the intensity is greater than the absolute value of the minimum amplitude of the reproduced image, with the same phase as the reference phase within the reproduced image; an image sensor to receive an input image in pixel increments; and an optical system to guide the reference light to the hologram recording medium, and also guide the obtained reproduced image according to the irradiation of the reference light, and the coherent light to the image sensor.

Abstract: A method is disclosed to store information in a holographic data storage medium. The method supplies a holographic data storage medium and provides information. The method defines an Active storage portion for the holographic data storage medium and establishes a threshold access interval. The method determines if the information was last accessed within the threshold access interval. If the information was last accessed within said threshold access interval, the method then stores that information as one or more holograms encoded in said Active storage portion of the holographic data storage medium.

Abstract: A method for generating a hologram on a disc surface provides for the use of calibration spots burned onto a disc with an accuracy greater than one half wavelength of light.

Abstract: A holographic storage medium, and a method and an apparatus for recording/reproducing data on/from the holographic storage medium. The method including: dividing a datapage into a plurality of regions; modulating the data into codewords having different on-pixel rates; and arranging the codewords in the plurality of regions, based on the different on-pixel rates.

Abstract: There is provided a hologram recording method, including generating a signal light which is spatially modulated such that digital data is represented by an image of intensity distribution, irradiating the signal light on an optical recording medium after a Fourier transformation of the signal light such that a zero-order component of the signal light comes into focus at a point removed from the optical recording medium, forming a diffraction grating in the optical recording medium by interference between the zero-order component of the signal light and a high-order component thereof, and recording digital data represented by the signal light as a hologram.

Abstract: A hologram information reproducing device is described which can reproduce information from a recording medium on which hologram information is recorded, and which can be downsized. In one aspect, when light from a light source is emitted, the light is converted into parallel reference light, by a lens of an optical system. A mirror changes the orientation of the reference light so that it is oriented obliquely downward towards a recording medium. More specifically, as viewed from the top, the mirror changes a path of the light from the light source unit by approximately 90 degrees. In addition, as viewed from the side, the mirror changes the path of the light from the light source unit downward by approximately 45 degrees. Since an interference pattern recorded on the recording medium is a Bragg grating, when the reference light illuminates a recording area of the recording medium, a reproduction light is obtained by Bragg diffraction.

Abstract: A hologram reconstructing apparatus is disclosed. The apparatus includes: unnecessary light removing means for causing the imaging means to receive necessary light only included in the reconstruction light; driving means for operating the hologram recording medium or a reconstruction light optical system; light detecting means for detecting the state that reconstruction light is projected to the unnecessary light removing means of the light cut by the unnecessary light removing means; and control means for obtaining the displacement of the hologram recording medium based on the information on a specific part of the projection state information detected by the light detecting means and controlling the driving means to cancel the displacement and move the hologram recording medium or the optical system.

Abstract: An apparatus, system, and method are disclosed for calibrating a holographic storage device. A read channel reads a factory-stored hologram from a holographic media. A calculation module calculates a read difference between the read factory-stored hologram and a first holographic pattern that digitally describes the factory-stored hologram. In one embodiment, a calibration module calibrates the read channel with the read difference.

Abstract: Methods and systems are provided for storing data holographically. Multiple distinct data packets are received. The data packets are stored on a temporary data storage. Data that includes the data packets are written holographically during a single write session to a photopolymer storage medium by optically interfering an optical data beam with an optical reference beam. The data are written physically to a data region on the photopolymer storage medium. A bleaching area of the photopolymer storage medium is exposed to a bleaching illumination to optically fix the bleaching area and prevent data from subsequently being written to the bleaching area. The bleaching area includes the data region.

Abstract: A complex objective lens composed of a hologram and an objective lens, capable of realizing stable and high-precision compatible reproducing/recording of a BD with a base thickness of about 0.1 mm for a blue light beam (wavelength ?1) and a DVD with a base thickness of about 0.6 mm for a red light beam (wavelength ?2). In an inner circumferential portion of the hologram, a grating is formed. The hologram transmits a blue light beam as 0th-order diffracted light without diffracting it, and disperses a red light beam passing through an inner circumferential portion as +1st-order diffracted light and allows it to be condensed by an objective lens. Because of this, the focal length of the red light beam becomes longer than that of the blue light beam, whereby a working distance is enlarged.

Abstract: A hologram recording/reproducing device includes a laser light source emitting laser light; a spatial light modulator generating signal light and reference light from the laser light emitted from the laser light source, the signal light and the reference light traveling in a common light path; a first relay lens system including a first shielding plate at a focal position thereof and transmitting the signal light and the reference light generated by the spatial light modulator, the first shielding plate having a pinhole whose size is 1 to 2 times a Nyquist size; a phase modulating element disposed at a conjugate plane of the signal light and the reference light transmitted through the first relay lens system; an objective lens converging the signal light and the reference light transmitted through the phase modulating element on a hologram recording medium; and a light receiving system disposed between the phase modulating element and objective lens and receiving light returning from the hologram recording me

Abstract: An apparatus and method is disclosed wherein, even if the multiplicity in multiplexing of recording data is increased, positioning of data upon reproduction can be performed with a high degree of accuracy without decreasing the recording capacity. Interference fringes generated by interference of a light beam spatially optically modulated by a spatial light modulator on which a marker data page is displayed with reference light are recorded at a recording spot on a hologram recording medium. Similarly, interference fringes corresponding to recording data page are recorded at another recording spot on the hologram recording medium. The multiplicity of such marker data pages upon recording is set to a value with which recognition of markers upon reproduction can be performed with a high degree of accuracy so that, even if the multiplicity of the data pages is raised, positioning information of high accuracy can be obtained.

Abstract: A data writing and reading device is capable of writing and reading data with respect to a holographic storage medium. The data writing and reading device includes a light source which emits a laser beam, a focusing lens unit having a multi-focal lens which splits the laser beam into a reference beam and an object beam and projects the split beams to the storage medium so that an interference pattern between the reference and object beams can be written in the storage medium, and a photo detector for detecting the object beam when the object beam is reproduced in accordance with the holographic data with the incidence of the reference beam to the storage medium. With a simple hardware, data can be written to or read out from the holographic storage medium.

Abstract: Hologram recording devices and techniques can be employed to produce wide-field-of-view holograms. In one embodiment, a specialized lens is used to couple an object beam into a holographic recording material without substantially changing the angle of incidence of the object beam. When displayed, images from holograms recorded using technique can have a field-of-view greater than that of the object beam. In another embodiment, one or more aspheric reflective surfaces are used to couple an object beam into a holographic recording material at relatively steep angles.

Abstract: A complex objective lens composed of a hologram and an objective lens, capable of realizing stable and high-precision compatible reproducing/recording of a BD with a base thickness of about 0.1 mm for a blue light beam (wavelength ?1) and a DVD with a base thickness of about 0.6 mm for a red light beam (wavelength ?2). In an inner circumferential portion of the hologram, a grating is formed. The hologram transmits a blue light beam as 0th-order diffracted light without diffracting it, and disperses a red light beam passing through an inner circumferential portion as +1st-order diffracted light and allows it to be condensed by an objective lens. Because of this, the focal length of the red light beam becomes longer than that of the blue light beam, whereby a working distance is enlarged.

Abstract: In an angle multiplexing holographic storage device, a movable beam splitter is used for splitting a source beam into an object beam and a reference beam. An encoding device is used for encoding the object beam with pixel data. A parabolic reflector differentially reflects the reference beam with the movement of the movable beam splitter. A holographic storage medium is arranged at the focal point of the parabolic reflector and made to lie in the optical path of the encoded object beam so that the differentially reflected reference beams encounter and interfere with the encoded object beam at the same site of the holographic storage medium to form and record various interference patterns.

Abstract: Disclosed is a multiplexing method and apparatus that allows holograms to be spatially multiplexed with partial spatial overlap between neighboring stacks of holograms. Each individual stack can additionally take full advantage of an alternate multiplexing scheme such as angle, wavelength, phase code, peristrophic, or fractal multiplexing, for example. An amount equal to the beam waist of the signal beam writing a hologram separates individual stacks of holograms. Upon reconstruction, a hologram and its neighbors will all be readout simultaneously. An filter is placed at the beam waist of the reconstructed data such that the neighbors that are read out are not transmitted to the camera plane. Alternatively, these unwanted reconstructions can be filtered out with an angular filter at an intermediate plane in the optical system that has a limited angular passband.

Abstract: A holographic data storage medium has a polymer film which is set up as a storage layer whose refractive index can be changed locally by heating. The polymer film is set up for the storage of optical phase information via the local optical path length of the polymer film, which is illuminated in transmission when the information is read out. To the polymer film, there can be assigned an absorber dye, in order to at least partly absorb a write beam to input information and to give up the heat produced in the process at least partly locally to the polymer film. Preferably, a reflective layer is arranged behind the polymer film.

Abstract: Disclosed are optical systems and methods of producing obliquity corrected light beams, for example, holographic recording and retrieval systems that utilize an obliquity corrected reference beam. One method includes directing a light beam reflected from a prism mirror to a reference plane with an angle of incidence to the reference plane, wherein the prism mirror varies the width of the light beam according to the angle of incidence to the reference plane. The optical system may include a holographic data storage system and the reference plane may be associated with a holographic storage medium.

Abstract: A method for generating a hologram on a disc surface provides for the use of calibration spots burned onto a disc with an accuracy greater than one half wavelength of light.

Abstract: Disclosed is a multiplexing method and apparatus that allows holograms to be spatially multiplexed with partial spatial overlap between neighboring stacks of holograms. Each individual stack can additionally take full advantage of an alternate multiplexing scheme such as angle, wavelength, phase code, peristrophic, or fractal multiplexing, for example. An amount equal to the beam waist of the signal beam writing a hologram separates individual stacks of holograms. Upon reconstruction, a hologram and its neighbors will all be readout simultaneously. An filter is placed at the beam waist of the reconstructed data such that the neighbors that are read out are not transmitted to the camera plane. Alternatively, these unwanted reconstructions can be filtered out with an angular filter at an intermediate plane in the optical system that has a limited angular passband.

Abstract: A method for monitoring diffraction while reading a hologram includes: illuminating a holographic medium with a reference beam to generate a data beam for a hologram that has been recorded at a set diffraction efficiency with a first polarization, the reference beam having a second polarization; and measuring an offset component in an output arm of the data beam.

Abstract: The present invention discloses a recording medium comprising an improved doped Stoichiometric Lithium Niobate (SLN) crystal for high-speed holographic data storage. The improved doped SLN has an extremely high optical damage resistance of more than 145 kW/cm2 for power density of an incident laser beam along the c axis. The Recording time using the present improved doped SLN is advantageously very short and is about 1 second for a single hologram with a saturated diffraction efficiency of 28.7% at a recording laser beam density of 70 W/cm2. Reliable retrieval of a signal-image written at as low as 1 milliseconds has been performed in the Z-cut doped SLN. The present recording medium is an improved doped SLN of a Z-cut SLN crystal doped with Iron (Fe) and Terbium (Tb). The Terbium (Tb) content within the fluxed melts for growing the improved doped SLN ranges from 10 ppm to 140 ppm.

Abstract: A hybrid data storage system comprising at least one memory system and at least one holographic drive, data being transmitted between the holographic drive and the memory system. At least one holographic drive writes data to a first holographic recording medium, and reads the written data from said first recording medium and from at least one other holographic recording medium.

Abstract: An optical head comprises an integrated unit for recording and reproducing page data on a reflective recording medium, wherein the integrated unit includes recording and reproducing units each corresponding to a bit of data of the page data, wherein each of the recording and reproducing units has a light emitter for emitting an object beam and a reference beam, an optical switch for transmitting or blocking the object beam, and a detector. Each of the recording and reproducing units records a bit of data corresponding to a state indicating whether or not a hologram has been formed and reproduces a bit of data corresponding to a state indicating whether or not a reference beam has been received by the light receiver when a reference beam is emitted to a recording position. The integrated unit of the optical head records and reproduces page data on a recording medium by recording and reproducing bit data on the recording medium by each of the recording and reproducing units.

Abstract: In a holographic digital data storage system, holographic page data has at least two concentric patterns with the optical information arranged within an outermost pattern of at least two concentric patterns. Since at least two concentric patterns in the holographic page data are deformed into at least two elliptic patterns in the diffracted beam caused by irradiation of the reference beam, at least two elliptic patterns are extracted from the diffracted beam and then at least two elliptic patterns are estimated to generate at least two estimated concentric patterns. A compensated vector between said at least two elliptic patterns and said at least two estimated concentric patterns is used to reconstruct the optical information from the diffracted beam.

Abstract: A system for recording and reading out holograms in a storage medium including a pattern encoder, a first fourier transform lens with a focal length f1, a second fourier transform lens with a focal length f2, a detector array, and a first and second prism. The first prism is located between the pattern encoder and the first fourier transform lens, wherein the optical length between the pattern encoder and the first fourier transform lens through the first prism is equal to a back focal length BFL1. The second prism located between the second fourier transform lens f2 and the detector array, wherein the optical path length between the second fourier transform lens and the detector array through the second prism is equal to a back focal length BFL2.

Abstract: A method of recording holograms includes: generating a first signal-beam from a signal-beam source and a first reference beam from a reference-beam source; recording a first hologram in a holographic medium from an interference between the first signal beam and the first reference beam; shifting the reference-beam source after the act of recording the first hologram; generating a second signal beam from the signal-beam source and a second reference beam from the reference-beam source after the act of shifting the reference-beam source following the recording of the first hologram; and recording a second hologram in the holographic medium from an interference between the second signal beam and the second reference beam.

Abstract: The invention is directed to self-referenced holographic recording techniques that make use of a diffusive element. Self-referenced holography refers to holographic recording techniques in which a reference beam is created from a zero frequency Fourier component of a data encoded object beam. In accordance with the invention, a diffusive element can be positioned in a holographic recording system to create the reference beam from the zero frequency Fourier component of the data encoded object beam. Using a diffusive element to create a reference beam in self-referenced holography can provide advantages to the self-referenced holographic recording system.

Abstract: A plurality of holographic recording media are positioned one above the other on an optical substrate and contain conventional stationary or moving imagery or data sets such as binary data representative of for example written text. A plurality of memory address access media are alternately interleaved between the plurality of holographic recording media. The memory access media causes a pair of optical beams to create an interference pattern at particular hologram recording media layers causing that layer to be read out. The specific memory access media layer is selected by means of scanning the interference pattern spatially within the interrogation beam, or by means of scanning the interrogation beam in wavelength.

Abstract: A method for the generation of volume spatially-resolved holographic data storage within a photosensitive glass sample that incurs changes of optical properties in response to two-photon absorption, the method including directing non-ultraviolet pulsed laser radiation at the photosensitive glass sample to induce changes of optical properties in the glass sample, splitting of the pulsed laser radiation, prior to reaching the glass sample, into an object beam having a direct optical path of a first predetermined length and a reference beam, changing the path of the reference beam to have an indirect optical path of a second pre-determined length, focusing each of the object beam and the reference beam along the respective optical paths, to intersect at a focal volume of the glass sample, and therein to cause the two-photon absorption, providing a variable time delay in the direct path of the object beam so that it reaches the chosen region within the focal volume of glass at the same time as the reference beam,

Abstract: A method of correcting errors arising from interpixel cross talk in the detection of a reconstructed holographic data image includes determining any misregistration between the pixels and the bit images. The measured output signals are then corrected to compensate for signal strength lost to or gained by nearby pixels through interference effects resulting from the misregistration, thereby producing a calculated data image that is substantially corrected for interpixel crosstalk. The relevant algorithms are provided and experimental verification is presented.

Abstract: Techniques for continuously programming a coherent transient spatial-spectral optical signal processor involve the repeated application of two or more spatially distinct optical programming pulses to a non-persistent hole-burning material to write an accumulated, spatial-spectral population grating with low intensity optical pulses as compared to single shot programming. An optical data stream is introduced on a processing beam, resulting in a processor output signal spatially distinct from all the processing pulses. Programming and processing take place simultaneously, asynchronously and continuously. For accumulated gratings, the frequency stability of the optical source is an important consideration.

Abstract: There is provided an apparatus for storing/restoring holographic data and a method for coding/decoding holographic data. In a recording mode, the apparatus divides input data into a plurality of groups, each of which includes two binary digits; and encodes each of the groups into a 2×2 data block wherein a first row of the 2×2 data block has the two binary digits and a second row thereof has another binary digits generated by applying a binary differential calculation on the first row. In a restoring mode, the apparatus divides a signal restored from a storage media into a plurality of 2×2 data blocks; and decodes each of the 2×2 data blocks into two binary digits by comparing values of a first row of the 2×2 data block with those of a second row thereof. In this way, phenomena of isolated “on” or “off” can be avoided.

Abstract: There is provided an apparatus for storing/restoring holographic data and a method for coding/decoding holographic data. In a recording mode, the apparatus divides input data into a plurality of groups, each of which includes two binary digits; and encodes each of the groups into a 2×2 data block wherein a first row of the 2×2 data block has the two binary digits and a second row thereof has another binary digits generated by applying a binary differential calculation on the first row. In a restoring mode, the apparatus divides a signal restored from a storage media into a plurality of 2×2 data blocks; and decodes each of the 2×2 data blocks into two binary digits by comparing values of a first row of the 2×2 data block with those of a second row thereof. In this way, phenomena of isolated “on” or “off” can be avoided.

Abstract: The invention relates to a skip-sorted spatial multiplexing holographic storage technique that addresses the problems of cross-talk, image distortions, and physical change of the medium encountered in current recording processes in which photopolymer media are used. The skip-sorted technique involves storing holograms in layers of arrays, such that a substantially uniform background exposure is provided for subsequent layers.

Abstract: A hybrid data storage system that includes a controller that communicates with an outside source of information, and at least one holographic drive engine that communicates with controller. The information is transmitted between the controller and the outside source of information and between the holographic drive engine and the controller.

Abstract: Scanning sensor scans on a circumference and simultaneously a radiation wave is received by scanning sensor to generate received signal Sm(f). A radiation wave is received by a fixed sensor at a position not changed with respect to the center of a circle with the circumference to generate received signal Sr(f). The received signal Sm(f) is made to interfere with the received signal Sr(f) to acquire an interference signal. The interference signal is detected to obtain measured data E(r,&phgr;) at each point on the circumference. Also, evaluation data V(&phgr;′) is calculated to estimate a direction of the radiation wave based on measured data E(r,&phgr;) at each point. A multi-dimensional hologram data processing apparatus consists of N-dimensional data array memory, N-dimensional flag array memory, N-dimensional array address generating unit, and digital signal processing unit.

Abstract: Digital signal sequences to be recorded in predetermined unitary recording areas are transformed into blocks, a plurality of bit data carrying all digit levels to be read and determined upon reproduction are included in the resultant blocks, and sequences of the data blocks are recorded in the recording medium in the unitary recording areas. Upon reproduction, the blocks of the read signals obtained from a recording medium are recognized, a threshold value is determined for each block on the basis of the values of read signals corresponding to bit data carrying all digit levels to be read and determined, and each digit level of bit data in the read signal are read and determined on the basis of the threshold values.

Abstract: An apparatus for compensating for pixel distortion while reproducing hologram data includes an extraction unit, a determination and calculation unit, a table, and a compensation unit. The extraction unit extracts a reproduced data image from a reproduced image frame including the reproduced data image and borders. The determination and calculation unit determines position values of edges of the extracted reproduced data image, and calculates average magnification error values of pixels within line data from position values of start and end point pixels thereof, which are based on the determined position values of the edges. The table stores misalignment compensation values for the pixels within the line data, wherein the misalignment compensation values correspond to predetermined references for average magnification error values.