Abstract: A tire quality control arrangement for nondestructive material testing of vehicle tires, aircraft tires, and the like by way of holographic interferometry. A conical mirror arranged in the path of the object beam to examine a tire positioned in concentric relation with the conical mirror; a projecting device includes an objective positioned at the observation point for providing the interference pattern of at least one "meridian" portion of the inner surface of the tire to be examined on a screen; a light intensity measuring device ascertains the brightness distribution of the interference pattern or figure along a "meridian" cutting line of the tire being examined and an extreme value detector ascertains the position of the brightness extremes of the interference pattern succeeded by a device for determining the density or distribution of extremes along the "meridian" line.

Abstract: An apparatus for a laser interferometric tire checking in which a thermoplastic film serves as light sensitive layer, and in which optical members are provided in the path of the object beam diffusely reflected by the inner surface of the tire. By means of these optical members the spreading angle of the beam cone inciding upon the light sensitive layer is limited to less than 40.degree..According to a specific embodiment of the invention, within the region of the radial central plane of the tire to be checked there is provided a mirror which is inclined relative to the last mentioned plane and is located in the path of the object beam which illuminates the inner surface of the tire to be checked and is reflected by this tire inner surface. According to a particularly advantageous embodiment of the invention, the tire and the mirror are turnable relative to each other parallel to the central tire plane.

Abstract: A checking device for tires of land and air vehicles which includes a coherent light source, a photo shutter as well as an optical circuit which divides a beam emitted by the light source into an object beam and into a reference beam, and which deflects these beams. The device comprises a conical mirror coaxial with the tire to be checked and located in the path of the object beam. A registering layer is located in the beam cone of the object beam reflected in a diffuse manner by the tire surface to be checked through the intervention of the conical mirror. In the beam path of the reference beam there is located a registering layer which is adapted to be observed by means of an observing system. Means are provided for subjecting the tire to be checked to a pressure drop relative to the atmosphere surrounding the tire to be checked.

Abstract: The specification describes a method for the optical determination of departures in shape, changes in shape, and changes in position. In the method by means of light rays patterns are produced on the object and the patterns are represented by a photoelectronic device. Light rays originating from a coherent light source are projected by lenses or mirrors or holographically as a line or lines and/or point arrangements on an object, which are represented by means of an objective on an optoelectronic receiving device. In it they are converted into electric pulses, which after analog-digital conversion in an electronic computing unit are stored and are digitally coordinated with spatial coordinates. The data so obtained are compared with the data, obtained in the same manner, of the same object before its change in shape or position or with the data of an ideal or real object determining its ideal shape.

Abstract: A method and apparatus for nondestructive testing of articles by holography in which light beams from a virtual point source of laser light and from an observation point are reflected by a reflector toward the same point on the object being checked. The light beams when extended beyond the reflector intersect on an ellipsoid having the point source and the observation point as foci. A plate having a hologram of the article is interposed between the observation point and the reflector and flaws in the object being tested show up on the plate as interference lines when the object is modified in shape by a mass influence such as a temperature change, or a change in pressure thereon, or by vibrations.