Abstract: An apparatus and a method for detecting surface motion of an object subject to ultrasound are disclosed. The method comprises generating a laser beam, dividing the laser beam into a reference beam and an object beam to be directed onto the surface, thereby producing a scattered object beam, introducing a small-amplitude modulation in the optical path difference between the reference beam and the scattered object beam, detecting the interference between the scattered object beam and the phase modulated reference beam using a plurality of detecting elements to generate a plurality of electrical interference signals, wherein the electrical interference signals each comprise a wanted signal component indicative of the surface motion and a noise signal component, and processing the electrical interference signals to determine the surface motion of the object.

Abstract: An apparatus and a method for detecting surface motion of an object subject to ultrasound are disclosed. The method comprises generating a laser beam, dividing the laser beam into a reference beam and an object beam to be directed onto the surface, thereby producing a scattered object beam, introducing a small-amplitude modulation in the optical path difference between the reference beam and the scattered object beam, detecting the interference between the scattered object beam and the phase modulated reference beam using a plurality of detecting elements to generate a plurality of electrical interference signals, wherein the electrical interference signals each comprise a wanted signal component indicative of the surface motion and a noise signal component, and processing the electrical interference signals to determine the surface motion of the object.

Abstract: Methods and apparatus to determine the orientation of randomly arranged birefringent fibers are disclosed. One method comprises emitting light, creating Ni polarization states of the emitted light, illuminating the birefringent fibers with the emitted light so polarized, thereby generating IRi internal reflection components of the light in the birefringent fibers, observing the light from the illuminated birefringent fibers, creating Oi polarization states of the observed light, forming Ii images of the observed polarized light, each image comprising an information (Ni, Oi, IRi), wherein i=1, 2, . . . , n and n?3, separating the i-th internal reflection component from the i-th image, and calculating an angle of a neutral axis of the birefringent fibers using the IRi internal reflection components.

Abstract: A multi-channel laser interferometric method and apparatus are provided for optically measuring transient motion from a surface (17). A laser beam (11) is generated and then divided into first and second beams having respective intensities representing minor and major fraction of the predetermined laser intensity. The reference beam (18) illuminates the surface (17) at which deformation is expected. The light back-scattered by the surface is collected by a single aperture lens (15) and then made to interfere with the probe beam (67) which has been expanded (32), onto a two-dimensional array of detectors (71). Each signal (83) corresponding to each detector of the array is converted individually to an electrical signal, each electrical signal is amplified and processed (84), and the plurality of processed signals (85) is then averaged in an electrical summing means (45).

Abstract: Methods and apparatus to measure visual appearance of birefringent fibers are disclosed. One method comprises emitting light, creating Ni polarization states of the emitted light, illuminating the birefringent fibers with the emitted light so polarized, thereby generating IRi internal reflection components, ERi external reflection components, and Di diffusion components of the light in the birefringent fibers, observing the light from the illuminated birefringent fibers, creating Oi polarization states of the observed light, forming Xi images of the observed polarized light, each image comprising an information (Ni, Oi, IRi, ERi, Di), wherein i=1, 2, . . . n and n?4, measuring the intensity Ii in each pixel in the Xi images, and separating the i-th internal reflection component, the i-th external reflection component, and the i-th diffusion component from the i-th image for the Xi images.

Abstract: Methods and apparatus to measure visual appearance of randomly arranged birefringent fibers are disclosed. One method comprises emitting light, creating Ni polarization states of the emitted light, illuminating the birefringent fibers with the emitted light so polarized, thereby generating IRi internal reflection components, ERi external reflection components, and Di diffusion components of the light in the birefringent fibers, observing the light from the illuminated birefringent fibers, creating Oi polarization states of the observed light, forming Xi images of the observed polarized light, each image comprising an information (Ni, Oi, IRi, ERi, Di), wherein i=1, 2, . . . n and n?4, measuring the intensity Ii in each pixel in the X, images, and separating the i-th internal reflection component, the i-th external reflection component, and the i-th diffusion component from the i-th image for the Xi images.

Abstract: Methods and apparatus to determine the orientation of randomly arranged birefringent fibers are disclosed. One method comprises emitting light, creating Ni polarization states of the emitted light, illuminating the birefringent fibers with the emitted light so polarized, thereby generating IRi internal reflection components of the light in the birefringent fibers, observing the light from the illuminated birefringent fibers, creating Oi polarization states of the observed light, forming Ii images of the observed polarized light, each image comprising an information (Ni, Oi, IRi), wherein i=1, 2, . . . , n and n?3, separating the i-th internal reflection component from the i-th image, and calculating an angle of a neutral axis of the birefringent fibers using the IRi internal reflection components.

Abstract: An apparatus and a method for detecting surface motion of an object subject to ultrasound are disclosed. The method comprises generating a laser beam, dividing the laser beam into a reference beam and an object beam to be directed onto the surface, thereby producing a scattered object beam, introducing a frequency shift between the reference beam and the scattered object beam, wherein the frequency shift is smaller than the ultrasonic frequency, detecting the interference between the scattered object beam and the frequency shifted reference beam using a plurality of detecting elements to generate a plurality of electrical interference signals, wherein the electrical interference signals each comprise a wanted signal component indicative of the surface motion and a noise signal component, and processing the electrical interference signals to determine the surface motion of the object.

Abstract: A laser interferometric apparatus for measuring a displacement of an object is disclosed, the apparatus comprising a laser source for producing a laser beam having a given intensity, a beam splitter for dividing the laser beam into a reference beam and an object beam to be directed to the object, thereby producing a scattered object beam being modulated according to the displacement of the object, interference means adapted to provide at least two electrical interference signals from the scattered object beam and the reference beam, the at least two electrical interference signals each comprising a wanted signal component indicative of the object displacement and an intensity noise component, and processing means for subtracting the at least two electrical interference signals, thereby generating an output signal, the output signal comprising substantially the wanted signal component alone, wherein the intensity noise is substantially rejected.

Abstract: A multi-channel laser interferometric method and apparatus are provided for optically measuring transient motion from a surface (17). A laser beam (11) is generated and then divided into first and second beams having respective intensities representing minor and major fraction of the predetermined laser intensity. The reference beam (18) illuminates the surface (17) at which deformation is expected. The light back-scattered by the surface is collected by a single aperture lens (15) and then made to interfere with the probe beam (67) which has been expanded (32), onto a two-dimensional array of detectors (71). Each signal (83) corresponding to each detector of the array is converted individually to an electrical signal, each electrical signal is amplified and processed (84), and the plurality of processed signals (85) is then averaged in an electrical summing means (45).

Abstract: A laser interferometric apparatus for measuring a displacement of an object is disclosed, the apparatus comprising a laser source for producing a laser beam having a given intensity, a beam splitter for dividing the laser beam into a reference beam and an object beam to be directed to the object, thereby producing a scattered object beam being modulated according to the displacement of the object, interference means adapted to provide at least two electrical interference signals from the scattered object beam and the reference beam, the at least two electrical interference signals each comprising a wanted signal component indicative of the object displacement and an intensity noise component, and processing means for subtracting the at least two electrical interference signals, thereby generating an output signal, the output signal comprising substantially the wanted signal component alone, wherein the intensity noise is substantially rejected.