Abstract: A method and apparatus for measuring strains in a test object in any of a plurality of directions. The object is illuminated with coherent light so that light is reflected to a focussing lens and a shearing diffraction grating having lines extending in a plurality of directions. The various diffracted orders interfere at the focal plane of the lens and are recorded on a photographic media. The object is then stressed and a second exposure is made on the same media, resulting in interference between the fringes produced on the two exposures. The media is developed as a transparency and subjected to optical processing to detect strain in any direction.

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: Holder and spreader fixturing for spreading and positioning the bead portions of tire casings to enable unobstructed holographic inspection of the interior of tire casings for manufacturing defects, including holder fixtures comprised of a pair of spreader rings insertable into the rim opening of the tire casing and engaging opposite bead portions of the tire casings. A plurality of U-shaped externally positioned props assembled to each of the spreader rings position the bead portions in the spread-apart position and provide an unobstructed view from the rim opening. Various configurations of the spreader rings include a split one-piece ring; a one-piece ring having trimmed side flanges; and a collapsible hinged spreader ring configuration.

Abstract: A method of and apparatus for processing multispectral data is provided and which permits an operator to make parameter level changes during the processing of the data. The system is directed to production of a color classification map on a video display in which a given color represents a localized region in multispectral feature space. Interactive controls permit an operator to alter the size and change the location of these regions, permitting the classification of such region to be changed from a broad to a narrow classification.

Abstract: To form a hologram of a section of an object surface one end of each of a pair of elongated, flexible, optical fibers is illuminated with a laser beam through an optical mechanism which allows adjustment of the amount of light that falls on each of the fiber ends. The opposite end of one of the fibers is disposed adjacent to the object of which the hologram is to be formed so that the light output of that fiber diffuses and illuminates the relevant surface. A photographic plate is disposed to receive light reflected from the object surface as well as a reference beam radiating from the output end of the other fiber. A photodetector device receives a portion of the reference beam at one input and a portion of the object beam at another input and provides a visual indication of the relative intensity of the beams. The input to the fiber elements is adjusted to achieve the desired beam ratio for forming a hologram.

Abstract: A method of producing single-class and multi-class composite classification maps from multispectral data is provided. The multispectral data is transformed into a binary matrix format which is then encoded on an optical medium such as photographic film. The encoded data is holographically correlated with coded patterns representing selected spectral signatures to produce signal-class classification maps. Several single-class maps are optically superimposed to produce multi-class composite classification maps.