141 results about "Computer-generated holography" patented technology

A method of computing a hologram by determining the wavefronts at the approximate observer eye position that would be generated by a real version of an object to be reconstructed. In normal computer generated holograms, one determines the wavefronts needed to reconstruct an object; this is not done directly in the present invention. Instead, one determines the wavefronts at an observer window that would be generated by a real object located at the same position of the reconstructed object. One can then back-transforms these wavefronts to the hologram to determine how the hologram needs to be encoded to generate these wavefronts. A suitably encoded hologram can then generate a reconstruction of the three-dimensional scene that can be observed by placing one's eyes at the plane of the observer window and looking through the observer window.

A high power light source is provided. The light source includes one or more diodes that may produce relatively coherent light of a desired intensity. The diodes may be pulsed to provide light as desired. The light projected by the diodes passes through a combiner, which combines the light from the different diodes and passes the combined light to an incoherence apparatus. The incoherence apparatus may include a rotating surface relief phase device such as an optical hologram, a computer generated hologram, or a diffractive optical element with random phase modulation. The incoherence apparatus may include a rotating fiber conduit comprising a plurality of multifiber cores. The incoherence apparatus renders the combined light incoherent and passes it to an illuminator apparatus that focuses the incoherent combined light onto an image plane.

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 4pi 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.

A thin and flexible radio frequency (RF) antenna tag or label is disclosed which contains an RF circuit connected to an antenna which is created by demetallizing the area around the antenna pattern on a thin, metallized substrate such as a film or paper web. Antenna(s) may be formed on one or both sides of the substrate and can contain printed, holographic, optical variable device, diffractive, dot matrix, computer-generated holograms or computer-generated optical images. The demetallized RF antenna on the substrate can optionally further be transferred to a second substrate or web by means of a cold foil stamping process. The tag or label is thin and flexible, enabling a wide range of applications including RF tagging of anti-theft devices, product packaging of all types, credit cards, passports, admission tickets, stamps, vehicles, badges, fare cards, roadway tolls, customs and immigration checkpoints identification, and animal identification / tracking devices.

An optical, wavelet-based fractal modulation of ultra-short light pulses is used as part of a high-bandwidth communications system. The preferred embodiment utilizes the scheme as part of a hybrid wireless optical and RF transmission system for broadband communications among fixed and / or mobile platforms. An ultra-short pulse laser, high-power WDM-ARRAY laser or high-power incoherent light sources may be used. Computer-generated hologram techniques are employed in designing the optical transceiver subsystems for spectral encoding and decoding of wavelet patterns. Part of the design goal is to select a diversity receiver Field-of-View (FOV) in a way that the effects of scintillation are reduced by as much as possible. Compared to existing optical wireless systems, the invention offers a much higher average transmission bit rate and a much smaller bit error rate outage value, thus enabling highly available FSO links. Wireless transceiver will be capable of communications with nearly line-of-sight FSO links and will be more tolerant to shadowing. Also, the optical medium is designed to be more secure than counterparts against any intrusion.

Novel methods are disclosed for designing and constructing miniature optical systems and devices employing light diffractive optical elements (DOEs) for modifying the size and shape of laser beams produced from a commercial-grade laser diodes, over an extended range hitherto unachievable using conventional techniques. The systems and devices of the present invention have uses in a wide range of applications, including laser scanning, optical-based information storage, medical and analytical instrumentation, and the like. In the illustrative embodiments, various techniques are disclosed for implementing the DOEs as holographic optical elements (HOEs), computer-generated holograms (CGHs), as well as other diffractive optical elements.

A display device for computer generated holography can time sequentially re-encode a hologram on the hologram-bearing medium for the left and then the right eye of an observer. Conventional holograms do not have to time multiplex for the left and then the right eye because, at any one time, the view seen by the left eye differs from the right eye anyway.

A method of computing a hologram by determining the wavefronts at the approximate observer eye position that would be generated by a real version of an object to be reconstructed. In normal computer generated holograms, one determines the wavefronts needed to reconstruct an object; this is not done directly in the present invention. Instead, one determines the wavefronts at an observer window that would be generated by a real object located at the same position of the reconstructed object. One can then back-transform these wavefronts to the hologram to determine how the hologram needs to be encoded to generate these wavefronts. A suitably encoded hologram can then generate a reconstruction of the three-dimensional scene that can be observed by placing one's eyes at the plane of the observer window and looking through the observer window.

A display device includes: a light source; an illumination optical system; a diffraction pattern generation unit; a spatial modulation element that generates diffracted light; and a shielding unit that selectively enters a first state where a first and second partial areas are a transmitting and shielding areas, respectively, and a second state where the first and second partial areas are the shielding and transmitting areas, respectively. The spatial modulation element displays the fictive image on a first and second display areas corresponding to the first and second partial areas when the shielding unit is in the first and second states, respectively. The diffraction pattern generation unit generates a first and second portion diffraction patterns from an image in an area corresponding to the first and second display areas out of the original image when the shielding unit is in the first and second states, respectively.

The invention relates to a transformation domain printing-scanning resistant digital watermarking method based on computer-generated holography. The method integrates QR two-dimension codes, double random phase modulation encryption technique, a conjugate symmetry prolongation Fourier computer-generated holography technique and a wavelet transform technique, adopts the QR two-dimension codes as original watermarking information, preprocessed QR two-dimension code information is used for two-value watermarking so as to perform double random phase modulation encryption, finally the conjugate symmetry prolongation Fourier computer-generated holography technique is utilized to calculate amplitudes and phase information of complex images so as to obtain a watermarking hologram after holography technique records are encrypted. An image obtained by performing holographic decryption and double random phase modulation decryption on the hologram generated in the mode is free of noise, and the robustness of a watermarking algorithm is improved. The safety of the watermarking algorithm is improved by using the double random phase modulation encryption technique. The QR two-dimension codes form a two-value image and can carry copyright information and enable accurate copyright owner or group positioning to be possible.

The invention belongs to the field of computer-generated holography and three-dimensional display, and particularly relates to a time-division multiplexing-based color holographic three-dimensional display method and system. By the display system, a multi-view two-dimensional image of a color target object is obtained by a method of CCD camera or computer graphics; a group of target images suitable for phase-type hologram calculation are generated after a preprocessing transformation process; a corresponding phase-type hologram is calculated by an iterative Fourier transform algorithm and is loaded to a spatial light modulator in a time-division manner; a synchronization control circuit controls red, green and blue three-color light sources to synchronously display in sequence; and three monochromatic holographic reconstructed images are generated on a reconstruction plane in a time-division manner, and corresponding reconstructed image pixels are directionally diffracted to the position at which a pixel-type nano grating is fixed to form different viewpoints, thereby obtaining multi-view color reconstructed images and achieving true color three-dimensional display. The hologram is quickly refreshed and loaded by combining the spatial light modulator, so that the multi-view real color full-parallax dynamic holographic three-dimensional reconstruction of the target object is achieved.

The invention discloses a head-mounted augmented reality three-dimensional display apparatus. By use of a nanometer grating structure capable of realizing a gathering light field visual angle magnification function, i.e., a nanometer lens function, visual angle magnification of three-dimensional virtual information is realized, projection is performed in front of human eyes, perfect integration of virtual objects and real scenes is realized through a transparent light field lens, since a visual angle is magnified, the human eyes, when observing scenes integrated with the virtual objects and the real scenes, cannot find that the scenes are integrated scenes, experience is enabled to be more real, at the same time, based on a holographic principle, computer-generated holography can be conveniently combined with a nanometer structure function light field lens, accordingly, a visual-fatigue-free and high-brightness head-mounted 3D augmented reality display scheme and apparatus are realized, and dynamic focusing supporting 3D display images can also be conveniently realized.

The invention belongs to the technical field of computer-generated holography and three-dimensional display, and particularly relates to a phase modulation full-parallax holographic stereogram implementation method. A target object, a CCD camera, a computer, holographic units, a holographic stereogram, a laser light source, a collimation system and a space optical modulator are included. A multi-angle anaglyph of the target object is obtained according to the method of the CCD camera or the computer graphics, and the frequency spectrums of the holographic units are extracted through the Fourier transform relation between the holographic units and a reappearance plane. The calibrated holographic unit frequency spectrum serves as a reappearance target image, all phase modulation holographic units are obtained through the iteration Fourier algorithm, and the holographic stereogram is generated. The holographic stereogram is loaded to the space optical modulator, and full-parallax multi-view reappearance of the target object is achieved by irradiating the holographic stereogram through the laser light source. By means of the holographic stereogram implementation method, multi-view reappearance of the three-dimensional object can be achieved, interference caused by conjugate images in an existing holographic stereogram is eliminated, the bandwidth of the space light modulator is fully used, the diffraction efficiency of the holographic stereogram is effectively improved, and the full-parallax holographic stereogram is displayed through the phase modulation space optical modulator.

In order to meet the legal requirements regarding color of light from a headlight, especially at the light-dark boundary and how much scattered light can occur in the dark region, a lens (5) is provided, which has a diffractive structure on at least one of its surfaces (8). This lens (5) is built into a headlight with a diaphragm (4) arranged between the lens (5) and a light source (3) so that the diffractive structure is arranged substantially only in a region of the lens surface that is not masked by the diaphragm. In various embodiments a computer-generated hologram (17a-17e) can be arranged in the other region of the lens surface that is masked by the diaphragm, so that the lighting apparatus can perform other functions, such as improving driver visibility, displaying an image, measuring the distance to an object or detecting rain or snow.

Silicate glasses for storing holographic data and for producing computer-generated holograms, including photo-darkenable-refractive (PDR) and photo-bleachable-refractive (PBR) glasses. In one embodiment, a PBR glass plate contains a photosensitive glass layer of a silver ion-exchanged holographic recording (SIHR) glass, with a base glass composition that has been ion-exchanged in an aqueous ion-exchange solution containing silver ions. The SIHR glass is uniformly darkened with darkening-light radiation, causing a refractive index change in the photosensitive glass layer upon exposure to bleaching-light radiation without any post-exposure steps. In another embodiment, an optical information recording medium includes a PDR glass plate containing SIHR glass optimized for multiplex recording and for reproducing information, which utilizes holography with darkening-light radiation as recording beams. In still another embodiment, an optical information recording medium includes a PBR glass plate containing SIHR glass optimized for multiplex recording and for reproducing information, which utilizes holography with bleaching-light radiation as recording beams.

In order to meet the legal requirements regarding color of light from a headlight, especially at the light-dark boundary and how much scattered light can occur in the dark region, a lens (5) is provided, which has a diffractive structure on at least one of its surfaces (8). This lens (5) is built into a headlight with a diaphragm (4) arranged between the lens (5) and a light source (3) so that the diffractive structure is arranged substantially only in a region of the lens surface that is not masked by the diaphragm. In various embodiments a computer-generated hologram (17a-17e) can be arranged in the other region of the lens surface that is masked by the diaphragm, so that the lighting apparatus can perform other functions, such as improving driver visibility, displaying an image, measuring the distance to an object or detecting rain or snow.

Provided is an optical encryption method based on chaos and computer-generated holography. By means of the method, a chaos sequence is successfully used for forming a random phase array to carry out modulation coding on object light waves, the boqi coding method which revises off-axis reference light is used, and optical encryption and decryption are achieved on the basis of computer-generated holography. The invention belongs to the technical field of information security. In the decryption process, by means of the method, as long as correct chaos sequence initial values are obtained, the random phase array can be obtained, and therefore clear initial images can be rebuilt combining correct system architecture parameters. Compared with a conventional random phase encryption method, the chaos sequence initial values are used as secret keys, and therefore difficulty of phase array storage and transmission does not exist any longer, data bulk of the secret keys is greatly compressed, and meanwhile, digitization of computer-generated holography technology encryption information is more beneficial for storage and transmission of information.

Methods of making volume phase holograms and / or making computer-generated holograms using silver ion-exchanged silicate glass articles that include a photo-darkenable-refractive (PDR) glass plate and / or a photo-bleachable-refractive (PBR) glass plate. In one embodiment, a method of forming a volume phase hologram includes the steps of making a PBR glass plate that has at least one photosensitive glass layer of a silver ion-exchanged holographic recording (SIHR) glass, and of exposing the photosensitive glass layer to the bleaching-light radiation of laser write beams, causing the volume phase hologram to form in the photosensitive glass layer of the PBR glass plate. The base glass composition of the SIHR glass has been ion-exchanged in an aqueous ion-exchange solution containing silver ions. The SIHR glass is then uniformly darkened with darkening-light radiation. This process causes the photosensitive glass layer of the PBR glass plate to show a change in refractive index upon exposure to the bleaching-light radiation without any post-exposure treatment.

The present invention provides liquid crystal devices comprised of a composite of an internal polymer network localized on the substrate surfaces and short-pitch dual-frequency switchable cholesteric liquid crystal that operate in two different modes including in-plane switching (amplitude modulation) and out-of-plane switching (phase modulation). The invention further provides a method of making a liquid crystal device demonstrating uniform lying helical axis where the device comprises a composite of an internal spatially ordered polymer network localized by in-situ photo-polymerization at the surface of the substrate. The invention can be used for flat panel displays, as well as spatial light modulators for applications such as optical waveguides, optical beam scanners, computer-generated holograms, and adaptive optics.

A computer-generated hologram comprising a plurality of cells. The hologram has information recorded therein, the information operable to recreate a stereoscopic image of an object. At least one of said plurality of cells Pj has information related to a luminance TWLci (θXY, θYZ) of a virtual point light source Qi from a plurality of virtual point light sources. The luminance corresponds to a point S on the object. The point S is on a straight line between said one of the plurality of cells Pi and the virtual point light source Qi.

A method of enlarging an observation window from which the reconstruction from a Computer Generated Hologram (CGH) may be viewed, including reproducing a CGH, and shifting a location of an exit pupil or observation window of an optical system reproducing the CGH. A method of increasing a viewing angle from which the reconstruction from a Computer Generated Hologram (CGH) may be seen, including producing a plurality of instances of a CGH, projecting each one of the instances in a different direction so that a first exit pupil of a first instance is close to a second exit pupil of a second instance. An optical system including a plurality of exit pupils associated with a plurality of optical components, further including a light deflector for jittering a location of a first exit pupil so as to increase an overlap of the first exit pupil with a second exit pupil. Related apparatus and methods are also described.

The invention discloses a holography-based great-visual angle three-dimensional image display method and a holography-based great-visual angle three-dimensional image display system. In the method and the system, a non-coaxial three-lens light path is disclosed and designed, and in combination with computer generated holography, small-visual angle three-dimensional images of target images in different observation azimuth angles are generated through the variations of lens positions in the three-lens light path; and based on volume holographic storage technology, the small-visual angle three-dimensional images in the different observation azimuth angles are stored into a volume recording medium with the same reference light to realize the display of great-visual angle three-dimensional images. When a three-lens-non-coaxial optical system is adopted to perform computer generated holographic encoding, the small-visual angle three-dimensional images in the different observation azimuth angles have a common sampling lattice, which can simplify the mathematical model processing of the target images and improve the efficiency of a computer generated holographic algorithm; and the storage and display of a plurality of great-visual angle three-dimensional images can be further realized through the variations of incident angles of the reference light by adopting volume holography and making full use of the characteristic of the high storage capacity of the volume holography, which is favorable for the practicability of three-dimensional image display technology.

A main object of the present invention is to provide a transparent card with a hologram having the excellent design property and a high security property. The present invention achieves the object by providing a transparent card with a hologram, characterized by comprising a configuration with a transparent card substrate made of a resin transparent with respect to a visible light, and a hologram layer having a computer generated hologram part to function as a transmission type Fourier transform lens laminated.

The present invention provides liquid crystal devices comprised of a composite of an internal polymer network localized on the substrate surfaces and short-pitch dual-frequency switchable cholesteric liquid crystal that operate in two different modes including in-plane switching (amplitude modulation) and out-of-plane switching (phase modulation). The invention further provides a method of making a liquid crystal device demonstrating uniform lying helical axis where the device comprises a composite of an internal spatially ordered polymer network localized by in-situ photo-polymerization at the surface of the substrate. The invention can be used for flat panel displays, as well as spatial light modulators for applications such as optical waveguides, optical beam scanners, computer-generated holograms, and adaptive optics.

The present invention provides a computer generated hologram which forms a light intensity distribution on a predetermined plane by giving a phase distribution to a wavefront of incident light, comprising an anisotropic layer whose refractive index with respect to linearly polarized light in a first direction is different from a refractive index of the anisotropic layer with respect to linearly polarized light in a second direction perpendicular to the linearly polarized light in the first direction, and an isotropic layer whose refractive index with respect to the linearly polarized light in the first direction is equal to a refractive index of the isotropic layer with respect to the linearly polarized light in the second direction.

A convolution integrator that can be used favorably to prepare, at high speed, a computer generated hologram that can reproduce a reproduction image formed by reproduction points at various distances and differing in initial phase is provided. A plurality of element processors PE are practically cascade-connected. Each element processor PE includes: a constant generator 91A, outputting a propagation function value that is generated based on a coordinate value Z and an initial phase value P; a multiplier 92, multiplying the propagation function value and a luminance value I and outputting the product value; an adder / subtractor 93, performing addition / subtraction on the product value and a hologram time series signal PDin and outputting the sum / difference value; and a register 94, receiving, holding, and then outputting the sum / difference value as a hologram time series signal PDout. The hologram time series signal PDout, output from a register 94 of an element processor of a preceding stage that is cascade-connected, is input as the hologram time series signal PDin into an adder / subtractor 93 of an element processor of a subsequent stage.

The present invention makes it possible to reliably hold a computer-generated hologram 17 and a sample surface 18a in ideal design positions and to perform interference measurements on the surface shape of the sample surface 18a by holding the computer-generated hologram 17 in a predetermined attitude by using a retaining member, and interposing a spacer 45 between this retaining member and the object so that relative positioning of both the computer-generated hologram 17 and the sample surface 18a is performed. Light transmission type targets used for alignment are respectively disposed on the four corners of the frame body of the CGH 17 and the four corners of the measurement mirror 18, and the system is devised so that images of these targets can be obtained by an image focusing lens 43 and CCD camera 44, thus making it possible to check the adjustment of the alignment of the CGH 17 and sample surface 18a.