Abstract: A coherent imaging system produces coherent flood illumination directed toward a remote object and local oscillator (LO) illumination derived based on a same master oscillator as the flood illumination. A Doppler sensor receives the LO illumination and a return of flood illumination reflected off the object. Doppler shift data from the Doppler sensor, corresponding to a longitudinal velocity of the object relative to the imaging system, is used to produce Doppler-shifted LO illumination received by a low bandwidth, large format focal plane array (FPA), together with the return illumination from the object. Interference between the Doppler-shifted LO illumination and the return illumination facilitates producing an image of the object with the low bandwidth FPA despite the longitudinal velocity. Pixel intensities from the FPA are integrated over a period approaching the maximum interference frequency. The Doppler sensor and FPA may concurrently process return for a high energy laser target spot.

Abstract: The present invention relates to a vibration and noise mapping system and method, which enables to generate the vibration and noise maps of the vibration and noise sources, and to determine areas, the vibration and acoustic performance of which are needed to be improved, and/or the problematic areas quickly.

Abstract: An image display device with an image display element; an optical system; an optical waveguide having a light incident port at a first portion of the optical waveguide and a light outgoing port at a second portion of the optical waveguide, the optical waveguide configured to (a) receive light from the image display element via the optical system and (b) output the light via the light outgoing port; a light shielding element; a first element that deflects light received through the first portion of the optical waveguide; and a second element that deflects light conveyed in the optical waveguide to output the light through the second portion of the optical waveguide, wherein, the first portion and the second portion are at different positions along the optical waveguide, and the first element is between the light incident port of the optical waveguide and the light shielding element.

Abstract: A method and apparatus for inspecting a structure. In one illustrative embodiment, an apparatus comprises a laser system located outside of an area that includes a region of a structure to be inspected, a mobile platform located within the area to be inspected, and a projection system associated with the mobile platform. The laser system is configured to generate a laser beam. The projection system receives the laser beam and projects the laser beam onto a surface of the region of the structure. The laser beam causes a number of ultrasonic waves to form within the structure.

Abstract: A virtual image display device with an optical waveguide to guide, by internal total reflection, parallel pencil groups meeting a condition of internal total reflection, a first reflection volume hologram grating to diffract and reflect the parallel pencil groups incident upon the optical waveguide from outside and traveling in different directions as they are so as to meet the condition of internal total reflection inside the optical waveguide and a second reflection volume hologram grating to project the parallel pencil groups guided by internal total reflection inside the optical waveguide as they are from the optical waveguide by diffraction and reflection thereof so as to depart from the condition of internal total reflection inside the optical waveguide.

Abstract: A virtual image display device with an optical waveguide to guide, by internal total reflection, parallel pencil groups meeting a condition of internal total reflection, a first reflection volume hologram grating to diffract and reflect the parallel pencil groups incident upon the optical waveguide from outside and traveling in different directions as they are so as to meet the condition of internal total reflection inside the optical waveguide and a second reflection volume hologram grating to project the parallel pencil groups guided by internal total reflection inside the optical waveguide as they are from the optical waveguide by diffraction and reflection thereof so as to depart from the condition of internal total reflection inside the optical waveguide.

Abstract: A reader for mechanical actuation of fluids within a test cartridge. The instrument interface including multiple independently-controlled plungers aligned to respective fluidic pouches on a test cartridge that is inserted into a testing apparatus embodying the instrument interface. The plungers include tips for applying mechanical force to the respective fluidic pouches.

Abstract: A liquid delivery apparatus is provided for depositing liquid materials onto prescribed areas. The apparatus includes a sensing and delivery pin and a photo sensor. The apparatus is sized to deliver a droplet of liquid material to the surface of a target area without coming into contact with the target surface. The apparatus is also capable of drawing geometric features, such as lines and grids of liquid material. The photo sensor measures the intensity of light during a processing cycle. Measured reflected-light intensity can be compared in real-time to a reference curve which is based on test process cycles representing the light intensity expected when the process proceeds in the preferred fashion to produce a normal spot having an expected droplet size. The light intensity measurements can also be fitted with a mathematical function such as an asymmetric double sigmoidal curve.

Abstract: A photoacoustic measuring apparatus includes a light source, a movable holding unit which holds an object, a light diffusing unit which fixes the distance between the light diffusing unit and the holding unit and diffuses light incident from the light source, and an acoustic wave obtaining unit which obtains an acoustic wave generated from the object by the light emitted via the holding unit and the light diffusing unit.

Abstract: A sensor arrangement for detecting objects, includes an ultrasonic sensor and an optical sensor integrated into the ultrasonic sensor.

Abstract: A multipoint laser Doppler vibrometer system (1) comprises a laser diode (2), beam expanding lens (3), a holographic optical element (HOE, 4) and a CMOS camera (5) receiving reflected light via optics (6). The HOE (4) is a hologram of a flat diffusely reflecting surface. Some light (8) is diffracted by the recorded hologram in the HOE (4) to provide a reference beam of light that is directed back towards the camera (5). Apart from some absorption the remaining light (9) continues onwards to illuminate the object The light that is reflected and scattered from the object (10) passes efficiently through the HOE (4) and interferes with the reference light (8) that is holographically reconstructed by the HOE (4) and subsequently detected by the camera (5). The beam from the laser diode (2) is divergent, which means that the sensitivity vector varies across the field of view.

Abstract: A method for visualizing objects under light obstructing barriers of a target, the method including emitting an ultrasound wave and a laser wave towards a target, detecting a reflected laser wave is detected by optical means, analyzing the optical signal at the ultrasound frequency with demodulation means, generating ultrasonic image characteristics of the interaction of the ultrasound with the different layers of the target, and generating an optical image of the target obtained using optical imaging, wherein the ultrasonic image is fused with the optical image and the fused image is displayed on a display device.

Abstract: A method of detecting hazardous conditions to aircraft is disclosed. The hazardous conditions produce sound waves in the atmosphere. The method comprises directing a first laser beam from a first laser acoustic sensor to a mating first reflector; directing a second laser beam from a second laser acoustic sensor to a mating second reflector; and directing a third laser beam from a third laser acoustic sensor to a mating third reflector. The method further comprises aligning the first laser acoustic sensor to project a first beam pattern, the second laser acoustic sensor to project a second beam pattern, and the third laser acoustic sensor to project a third beam pattern. The method further comprises measuring an effect of the sound waves on the first beam pattern, the second beam pattern, and the third beam pattern. The effect is an indicator of the hazardous conditions.

Abstract: Formed Laser Sources (FLS) using pulsed laser light for generation of ultrasonic stress waves are combined with air-coupled detection of ultrasound to provide for the hybrid non-contact, dynamic and remote ultrasonic testing of structural materials, especially railroad tracks. Using this hybrid technique, multimode and controlled frequency and wavefront surface acoustic waves, plate waves, guided waves, and bulk waves are generated to propagate on and within the rail tracks. The non-contact, remote nature of this methodology enables high-speed, fill access inspections of rail tracks. The flexibility and remote nature of this methodology makes possible the detection of critical cracks that are not easy, or impossible to detect, with current inspection techniques available to the railroad industry.

Abstract: An ultrasonic probe which does not require electric wiring to a large number of microcomponents and does not induce increase of crosstalk and electric impedance. This ultrasonic probe comprises an optical transmission path array incorporating a plurality of optical transmission paths on which light is incident at first ends thereof; and a plurality of ultrasonic detecting elements which are formed on these optical transmission at the second ends thereof and adapted to reflect the light incident through the respective fibers based on ultrasonic waves applied thereon.

Abstract: At least one parameter of at least one fluid in a pipe 12 is measured using a spatial array of acoustic pressure sensors 14,16,18 placed at predetermined axial locations x1,x2,x3 along the pipe 12. The pressure sensors 14,16,18 provide acoustic pressure signals P1(t), P2(t), P3(t) on lines 20,22,24 which are provided to signal processing logic 60 which determines the speed of sound amix of the fluid (or mixture) in the pipe 12 using acoustic spatial array signal processing techniques with the direction of propagation of the acoustic signals along the longitudinal axis of the pipe 12. Numerous spatial array processing techniques may be employed to determined the speed of sound amix. The speed of sound amix is provided to logic 48 which calculates the percent composition of the mixture, e.g., water fraction, or any other parameter of the mixture or fluid which is related to the sound speed amix. The logic 60 may also determine the Mach number Mx of the fluid.

Abstract: An ultrasonic probe which does not require electric wiring to a large number of microcomponents and does not induce increase of crosstalk and electric impedance. This ultrasonic probe comprises an optical transmission path array incorporating a plurality of optical transmission paths on which light is incident at first ends thereof; and a plurality of ultrasonic detecting elements which are formed on these optical transmission at the second ends thereof and adapted to reflect the light incident through the respective fibers based on ultrasonic waves applied thereon.

Abstract: A frustrated total internal reflection acoustic field sensor which allows the acquisition of the acoustic field over an entire plane, all at once. The sensor finds use in acoustic holography and acoustic diffraction tomography. For example, the sensor may be produced by a transparent plate with transparent support members tall enough to support one or more flexible membranes at an appropriate height for frustrated total internal reflection to occur. An acoustic wave causes the membrane to deflect away from its quiescent position and thus changes the amount of light that tunnels through the gap formed by the support members and into the membrane, and so changes the amount of light reflected by the membrane. The sensor(s) is illuminated by a uniform tight field, and the reflection from the sensor yields acoustic wave amplitude and phase information which can be picked up electronically or otherwise.

Abstract: Faults, dimensions and other characteristics of a material or structure are sensed by a coherent beam's reflection from the material during ultrasonic or very fast vibration. The reflected beam acquires a phase substantially different from its original phase and from the phase of a reference beam split from the common source beam. The reflected beam and the reference beam are superimposed by diffraction in a multiple quantum well adaptive holographic beamsplitter, and the superimposed beams are detected by a photodetector capable of detecting small interference changes from ultrasonic surface displacements or perturbations. An apparatus and method defining an improved homodyne interferometer for performing the method is described.

Abstract: A process is disclosed for determining the vibration characteristics of a body by modal analysis. The body is made to vibrate at different frequencies and optical interference images of the body are recorded for the different frequencies. The interference images are analyzed on the basis of a mathematical/physical model, in view of the vibration characteristics at predetermined points, and the thus obtained information about the vibration characteristics of said points is subjected to a modal analysis.

Abstract: A vibration detection assembly is described which includes an emitter of light which has object and reference beams, the object beam reflected off of a vibrating object of interest; and a photorefractive substance having a given response time and which passes the reflected object beam and the reference beam, the reference beam and the object beam interfering within the photorefractive substance to create a space charge field which develops within the response time of the photorefractive substance.

Abstract: A method and apparatus are provided of optically detecting transient motion from the surface of a workpiece. After directing a laser beam onto a surface of a workpiece the beam is reflected from it and then interferes with a pump beam removed from the laser source, inside a real-time holographic material, so as to form a grating diffracting the pump beam into a reference beam, which interferes at the output of the real-time holographic material with the received light beam, so as to produce a signal representative of the surface transient motion. An electric field is applied to the holographic material of sufficient magnitude to increase substantially the intensity of said reference beam and to give to this beam a phase differing substantially from the phase of said received light beam.

Abstract: A system for non-destructively inspecting or testing for faults or damage in or beneath the surface of structures, such as debonds or delaminations in composite materials, or cracks, broken stringers, delaminations and the like in structures. High energy acoustic impulses are focused onto a sample point or local area for vibrationally exciting the surface of the structure under inspection. A laser Doppler camera system directs a laser beam onto the excited area and derives from reflected light energy information including time domain signals. A Fast Fourier Transform (FFT) is constructed for each sample point and an analysis made to set aside FFTs deviating from a preselected standard which represent damaged or other anomalous areas. The remaining FFTs represent an average or statistical FFT spectrum of the undamaged or fault-free area. The average FFTs and the deviating FFTs are then subtracted to provide a clear and unambiguous signal of the fault and other anomalous areas in the structure under test.

Abstract: An object is typically illuminated by laser light, and reflected light carrying a speckle pattern is amplified by an image intensifier. First and second speckle patterns representing the object before and after its deformation, respectively are written by double writing into a ferroelectric liquid crystal spatial light modulator (FLC-SLM). The double-written image is read out from the FLC-SLM, and converted by a Fourier transform optical system into an output optical image, i.e., Young's fringe. The output optical image is detected by a photoelectric converter, and analyzed by an image processing device to determine a deformation of the object.

Abstract: An object is tested for defects by interferometry, by comparing images of the object taken under stressed and unstressed conditions. The stress is applied by perturbing the object with acoustic waves, produced by a speaker directed towards the object, without any mechanical coupling to the object. The acoustic energy can be of a single frequency, or it can be distributed over a set of random frequencies (i.e. white noise), or it can be in the form of a signal which is "swept" through a range of frequencies. In the latter case, the results can be stored in a video buffer which records the maximum signal obtained, for each pixel, while the signal is swept through the frequency range. Different defects in the object may resonate at varying frequencies within the given range. By exciting the object at each frequency within the range, and superimposing the maximum signals obtained for each pixel, the resulting image is likely to show all the locations on the object which may be defective.

Abstract: An optically phase-locked electronic speckle pattern interferometer mixes a local oscillator beam with a beam reflected from a target surface to create a speckle pattern at each of two separate image planes. The speckle pattern includes speckles whose intensities vary as a result of time-varying Doppler shifting of the reflected beam by movement or deformation of the target surface. The local oscillator beam is phase-locked to the Doppler signature of a lock-point speckle on one image plane. The phase-locking of the local oscillator beam to Doppler information of interest enables the interferometer to coherently detect speckle in the image plane sharing frequency, amplitude, and phase characteristics with the lock-point speckle, which supports the efficient processing of images obtained from the other image plane. The processing produces a contoured image of the target surface, with demarcation between coherently and non-coherently detected speckle.

Abstract: An optical nondestructive testing method of composite materials utilizes optical interferometry to find the resonant vibration from at least one surface of the target part of an object being inspected, and also determines the resonant frequency at that time. Another resonant frequency exhibiting the same resonant vibration is then obtained from the rear surface of the part of the object being inspected and the two resonant frequencies are used to derive the depth of defects in the object.

Abstract: A method of holographic analysis of an article is disclosed. The method involves generating holograms of an article to be analyzed and a reference article over a range of excitation energy levels and comparing the features of the holograms so generated to characterize the material and structural properties of the article.

Abstract: A method and a device for measuring and mapping vibrations wherein one or a number of local sensors and a measuring means can make local registrations and frequency decompositions of the vibrations of an oscillating object. The same sensors and measuring means may be used in combination with an image-forming unit and an associated measuring means for local and image-forming recording of the vibrations of an oscillating object, respectively. By oscillating an excitation source an object can be made to oscillate harmonically. Furthermore, the local and image-forming measurements are collocated with the aid of a means for calculation.

Abstract: Object deformations are analyzed by recording interferometric images using a television camera. The camera's photosensitive recording cathode is successively exposed to interferometric images of the object, respectively before and after a stress is applied to the object, while the camera's scanning beam is blanked out in order to record a composite image having fringe families arrayed as a function of the deformation of the object. Subsequent scanning of the cathode produces video signals representing variations of intensity in the superimposed illumination patterns of the composite image. The video signals may be digitized, analyzed and displayed on a cathode ray tube.

Abstract: In the disclosed method and structure a pulse of a sound filed to be mapped is illuminated at at least two extremes values at different moments with a laser beam of short duration compared to the period of the illuminated sound pulse and interference produced between the resulting reflected beam and a reference beam. A holographic image is formed. The relative phase of the laser pulse and the reference is changed between the individual illuminations by a preselectable amount which deviates from .pi. and which suppresses the optical and/or acoustical noise. Specifically, a time delay initiates the first illumination process when an extreme value is reached at the beginning of the sound pulse to be mapped. A counter is started by this time delay and counts the half and quarter waves of the sound pulse. The counter initiates an additional illumination process after a preselectable odd number has been reached. A phase shifter changes the relative phase between the object beam and the reference beam.

Abstract: A nondestructive testing technique for examining the integrity of a bonded joint consists of forming a time-average hologram of the object while it is being vibrated at a number of frequencies generated at random within a defined bandwidth.

Abstract: A system for determining the spatial structure or composition of complex sound fields within a duct or other structural enclosure that is excited by acoustic energy is disclosed wherein at least two holograms are recorded and analyzed to provide both the amplitude and phase of the various modal components that comprise the sound field. In situations in which the sound field of interest is periodic, the desired amplitude and phase information is determined from a pair of holograms in which each hologram is formed by photographically recording the diffraction pattern resulting when an array of elastomeric regions, positioned on the wall of the acoustically excited structure, is illuminated by two pulses of coherent monochromatic light that are spaced apart in time by nT/2, where T is the period of the dominant acoustic excitation signal and n is an odd integer.

Abstract: Hologram apparatus for testing for defects in welds has a frame with means for supporting the frame. A laser beam is directed towards one end of the frame where it is reflected by a rotatable mirror onto an area of the weld lying in a predetermined direction within an arc of about 90.degree. extending from a point directly below the mirror. A head is mounted for rotation on said one end of the frame coaxially with the mirror. A photosensitive recording medium is mounted on the head for receiving laser light reflected from said weld. A reference beam mirror is mounted on the head for reflecting laser light from the rotatable mirror to the recording medium as a reference beam. The rotatable mirror and the head are interconnected to cause the ratio of the angular movement of the head to the angular movement of the rotatable mirror to be two to one.

Abstract: Apparatus and methods for measuring deflection of rotating fan blades of a gas turbine engine is disclosed. The measurement of bending and torsional deformation in response to integral and to nonintegral vibration as well as to structural loading is developed. Optical measuring techniques including the projection of collimated light beams into the fan section of the engine are employed. A linear readout of angular deflection is displayed on a distant screen for amplification of the actual deflection. The plurality of beams provide a deflection profile covering the full surface of the blade.