Abstract: A method of non-destructive testing includes non-destructively testing an object over a range of test levels, directing coherent light onto the object, directly receiving the coherent light substantially as reflected straight from the object, and capturing the reflected coherent light over the range of test levels as a plurality of digital images of the object. The method also includes calculating differences between pixel values of a plurality of pairs of digital images of the plurality of digital images, and adding the pixel value differences of the plurality of pairs of digital images to yield at least one cumulative differential image.

Abstract: Described is an anomaly detector apparatus 10 for detecting an anomaly in a substrate, e.g., a tire comprising: a source of coherent light 20 to shine the light 27 directly onto the tire surface 24 and the light being reflected 32 from the tire; a stressing apparatus 12, which is juxtaposed to the tire and which, can optionally stress the tire; a reflected light receiving apparatus 40 for receiving the light 32 reflected directly from the tire surface 24 whether the tire is in a stressed or unstressed condition; a comparator 44 which views and compares images of reflected light from the reflected light receiving apparatus 40 when the tire is stressed or unstressed thereby ascertaining an anomaly in the tire and generates an output from the comparison; and a display apparatus 46 electronically connected to the comparator for displaying the output from the comparator.

Abstract: Described is an anomaly detector apparatus 10 for detecting an anomaly in a tire comprising: a source of coherent light 18 to shine the light 27 directly onto the tire surface 24 and the light being reflected 32 from the tire; a stressing apparatus 12 which can stress the tire; a reflected light receiving apparatus 40 for receiving the light 32 reflected directly from the tire surface 24 when the tire is in a stressed and unstressed condition; a processor 44 which compares images of reflected light from the reflected light receiving apparatus 40 when the tire is stressed and unstressed thereby ascertaining an anomaly in the tire and generates an output from the comparison; and a display apparatus 46 electronically connected to the processor for displaying the output from the processor.

Abstract: A shearogram representing an object and including a fringe pattern arising from a change in local surface strain brought about by an applied stress during the making of the shearogram is reconstructed by a special viewer. The viewer holds the shearogram transparency adjacent to a focusing lens having an optical axis, and projects off-axis white light through the lens and transparency to a focal plane where the resulting diffraction pattern is viewed directly on a screen or by a video camera and display monitor. By projecting the light from different positions around the axis a first position can be found which tunes the diffraction efficiency to an optimum for the best view of fringe patterns and a second position can be found which eliminates the fringe patterns and shows only a photographic image of the object. The light source is a rotatable disk with two apertures containing light diffusing elements which are illuminated by a lamp. The disk is rotated to change the projection angle.

Abstract: Method and apparatus for analyzing the deformation of an object resulting from the application of stress. A novel optical element is used to perform shearometric analysis upon a test object. The novel optical element has an overall pattern of first and second pluralities of regions having significantly different indices of transmissivity. The pattern of variations causes pairs of light rays which are reflected from two distinct points on the test object at a divergent angle to emerge from the optical element so that they are nearly parallel. The nearly parallel rays are then received upon a photoelectrical sensing means such as a video camera or photoelectric array. Because the rays impinging thereon are nearly parallel, they may be adequately resolved by the photoelectric sensing means, thus enabling shearometric analysis to be performed electronically in a rapid and cost-effective manner.

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.