Abstract: Systems and methods are described for off-axis illumination direct-to-digital holography.

Abstract: With interferometric test systems, the test object is frequently measured over several sections in order to realize a complete test. If special structural features are found, in particular defects, it is usually difficult to localize the structural features shown on the result images on the object. It is the object of the present method to transfer the interferometrically measured data from the various sections to a joint object coordinate system. To achieve this object, the shape of the object is measured and the spatial coordinates for the deformation data on the object surface are determined from this measured. Thus, a method is realized which permits determining the exact spatial orientation and position of the discovered structural features on the object. On the one hand, the defects on the object can thus be localized precisely while, on the other hand, an exact quantitative evaluation of the results is possible.

Abstract: Surface-enhanced Raman optical data storage (SERODS) systems having increased reading and writing speeds, that is, increased data transfer rates, are disclosed. In the various SERODS read and write systems, the surface-enhanced Raman scattering (SERS) data is written and read using a two-dimensional process called parallel signal transfer (PST). The various embodiments utilize laser light beam excitation of the SERODS medium, optical filtering, beam imaging, and two-dimensional light detection. Two- and three-dimensional SERODS media are utilized. The SERODS write systems employ either a different laser or a different level of laser power.

Abstract: A structure (22) is located relative to a reference surface (26a, 42) using an optical target (28) affixed to the structure (22) and having a reflective angular-reference hologram (30) thereon with an effective angular orientation. An alignment light beam (38) is directed perpendicular to the reference surface (26a, 42) and incident upon the angular-reference hologram (30) on the optical target (28), and a signal return of the alignment light beam (38) is received at a measurement location. The angular orientation of the structure (22) is adjusted to achieve a signal return of the alignment light beam (38) corresponding to an alignment of the alignment light beam (38) to the effective angular orientation of the reflective angular-reference hologram (30). Multiple reflective angular-reference holograms (30) may be spatially superimposed upon each other in the optical target (28) or spatially separated from each other on the optical target (28).

Abstract: A system for performing real time optical comparisons using an optical correlator permits comparing a sampled image to a wide variety of reference images through the utilization of a multiple quantum well spatial light modulator which is utilized to rapidly present a large number of reference images for correlation. The utilization of the multiple quantum well spatial light modulator as the spatial light modulator in a van der Lugt image correlator in combination with a spectrometer permits optical comparisons at 300,000 frames per second versus 10,000 frames per second, the best case for liquid crystal based spatial light modulators.

Abstract: 1. Method and apparatus for testing objects.

Abstract: A three-dimensional particle image velocimetry method is described, in which a stream system containing light-scattering particles is exposed continuously over a certain period or at least two discrete points in time using a laser lightsheet, and a hologram is produced and evaluated. Increased accuracy in determining velocity is achieved by evaluating the hologram with regard to its phase information interferometrically by using a reconstruction wave and superimposing a reference wave.

Abstract: Improvements to the acquisition and replay systems for direct-to-digital holography and holovision are described. A method of recording an off-axis hologram includes: splitting a laser beam into an object beam and a reference beam; reflecting the reference beam from a reference beam mirror; reflecting the object beam from an illumination beamsplitter; passing the object beam through an objective lens; reflecting the object beam from an object; focusing the reference beam and the object beam at a focal plane of a digital recorder to form an off-axis hologram; digitally recording the off-axis hologram; and transforming the off-axis hologram in accordance with a Fourier transform to obtain a set of results. A method of writing an off-axis hologram includes: passing a laser beam through a spatial light modulator; and focusing the laser beam at a focal plane of a photorefractive crystal to impose a holographic diffraction grating pattern on the photorefractive crystal.

Abstract: This invention relates to a method and device for non-destructive inspection by means of holographic interferometry of details, machine units, mechanisms, and various materials, which eliminates the problem of relative displacement of the object with regard to the holographic equipment, especially due to vibratory motion of the object. This is achieved by transporting the reference and object beams between the investigated object, light source, and interferometer in flexible wave guidance cables and that the endpoints of the flexible wave guidance cables are securely attached in a fixed distance from the investigated object, recording medium of the interferometer and light source, respectively. This will also give the benefit of dividing the holographic interferometer into an object part and a registering part which forms the interferograms.

Abstract: Improvements to the acquisition and replay systems for direct-to-digital holography and holovision are described. A method of recording an off-axis hologram includes: splitting a laser beam into an object beam and a reference beam; reflecting the reference beam from a reference beam mirror; reflecting the object beam from an illumination beamsplitter; passing the object beam through an objective lens; reflecting the object beam from an object; focusing the reference beam and the object beam at a focal plane of a digital recorder to form an off-axis hologram; digitally recording the off-axis hologram; and transforming the off-axis hologram in accordance with a Fourier transform to obtain a set of results. A method of writing an off-axis hologram includes: passing a laser beam through a spatial light modulator; and focusing the laser beam at a focal plane of a photorefractive crystal to impose a holographic diffraction grating pattern on the photorefractive crystal.

Abstract: The proposed holographic particle image velocimetry (HPIV) system employs holograms of two time-separated particle fields, illuminated by separate reference beams on a single recording medium. 90-degree scattering is utilized for the object wave, in order to improve Numerical Aperture and resolve the third dimension of the hologram. The proposed HPIV system then uses substantially the same optical geometry for the reconstruction process. A CCD camera is utilized to extract particle subimages, thin slice by thin slice, and a centroid-finding algorithm is applied to extract centroid locations for each volume. The concise cross correlation (CCC) algorithm for extracting velocity vector fields from the centroid data is an important enabling feature of the proposed system. Correlations are calculated between subsets of centroids representing the images or cubes, and velocity vectors are computed from the individual correlations.

Abstract: In one embodiment, an apparatus for measuring pressure is provided including a holographic element containing at least one volume hologram; a reference member; a sensing member coupled to the pressure being measured, and at least one light source; wherein the device operates by passing a reference light beam between the reference member and the holographic element, the reference beam having a constant optical path, and passing a sensing light beam between the sensing member and the holographic element, the sensing beam having optical path that varies as a function of the pressure; the volume hologram converting the reference beam and the sensing beam into an information light beam the intensity of which is a measure of the pressure. Preferably, the reference member and the sensing member are made from the same material.

Abstract: A process for velocimetric measurement of a target including causing interference in a dynamic holographic material of a reference laser beam and a beam diffused by the target, and measuring variations in luminous intensity transmitted by the material with a photoelectric detector, wherein the target vibrates with a displacement greater than the wavelength and with an extension limited around a mean position.

Abstract: A method is for three-dimensionally, optically measuring measuring objects by comparison with a reference object, where image data of the measuring object are acquired and compared to image data of the reference object, and the measuring object is directly or indirectly assessed with regard to deviations from the reference object. A quick and, at the same time, reliable assessment of the measuring object is achieved in that the measuring object and/or the reference object or a holographic recording of the measuring object and/or of the reference object are/is rotated relative to one another about at least one axis, the image data of the measuring object being acquired and the comparison being performed in various, relative rotational positions, in that an evaluation regarding a maximum agreement of the measuring object with the reference object is performed in the different comparisons, and in that the deviation is assessed in the rotational position determined by the maximum agreement.

Abstract: A process for velocimetric measurement of a target including causing interference in a dynamic holographic material of a reference laser beam and a beam diffused by the target, and measuring variations in luminous intensity transmitted by the material with a photoelectric detector, wherein the target vibrates with a displacement greater than the wavelength and with an extension limited around a mean position.

Abstract: Multi-domain, phase-compensated, differential-coherence detection of photonic signals for interferometric processes and devices may be manufactured holographically and developed in situ or with an automatic registration between holograms and photonic sources in a single frame. Photonic or electronic post processing may include outputs from a cycling or rotation between differently phased complementary outputs of constructive and destructive interference. A hyper-selective, direct-conversion, expanded-bandpass filter may rely on an expanded bandpass for ease of filtering, with no dead zones for zero beat frequency cases. A hyper-heterodyning, expanded bandpass system may also provide improved filtering and signal-to-noise ratios. An ultra-high-resolution, broadband spectrum analyzer may operate in multiple domains, including complex “fingerprints” of phase, frequency, and other parameters.

Abstract: Systems and methods for determining the position and classification of an object and which may provide signals that control deployment of an active restraint device, for example. Using a pulsed laser light beam from a laser source that is spread and preferably diffused to avoid ocular damage, an interference pattern is returned to a sensing module through a spectral filter. There it is optionally combined with a reference beam from the laser source, modified to emulate coherence length effects, and incident upon a phase transmission holographic template that may be segmented into regions for example. Each region of the holographic template contains Fourier transform images of occupant types. Behind the holographic template is a detector array that is sensitive to the laser light. An interference pattern derived from the object is convoluted or cross-correlated with the template. When an match occurs, a bright spot appears on the detector array.

Abstract: The invention relates to an apparatus for performing electronic shearography on a test object, especially a tire or retread tire. The apparatus uses a laser light source to illuminate the test object. An optical element through which electromagnetic radiation is reflected from the test object is transmitted and forms a random interference image. The random interference image can be electronically processed to provide a video animation of the effects of stress on the test object.

Abstract: The method and apparatus of the invention pertains to a simultaneously modulated light beam carrying the information of a three-dimensional image is directed to pixels (image points) defining a first light emitting surface, a component of the light beam is emitted from the pixels within a predetermined angle of view (field of view) in the different view directions, with an intensity corresponding to the three-dimensional image, the modulated light beams are directed to the pixels from different entry angles, depending on the emitting angles within the angle of view, wherein the light beams modulated corresponding to the different directions are directed to the pixels of the first light emitting surface from one or more light emitting points of a second light emitting surface, the second light emitting surface being spaced apart with a predetermined distance from the first light emitting surface.

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.

Abstract: A spectrum analyzer for producing a first two-dimensional array of time varying spectral analysis image input signals, a reference image generator for producing a second two-dimensional array of spectral analysis image reference signals, and a time-integrative correlator, which can be non-coherent or coherent, or correlating the two groups of image representitive signals to determine the degree of matching between an input image and a library reference image. The spectrum analyzer can include an interferometer, a tunable optical filter, or a time-wavelength-multiplexing holographic lens for viewing the input image. A monolithic non-holographic version provides a rugged, compact and portable image analyzer for examining many types of images.

Abstract: The present invention relates to multifunctionalized alkoxy, the alkoxy functionality Y being introduced onto a suitable polyhydrooorganosiloxane by a dehydrogenation/condensation reaction from the alcohol from which Y derives and then the functionality W by a hydrosilylation reaction from the olefinic compound from which W derives. The multifunctionalized alkoxy polyorganosiloxanes can be used as antiadhesion modulators in silicone compositions and as silica covering agents in silicone compositions containing fillers.