The dimensions of a countersunk hole, or of a fastener head, are determined accurately and rapidly by a nondestructive measurement system. At least one laser projects spots of light onto the surface being analyzed. From knowledge of the projection angle, and of the lateral displacement of the spots of light caused by variations in the depth of the surface, one can calculate an actual depth of each point on the surface. A set of parameters defining a mathematical model of the hole or fastener head are fitted to a set of measured coordinates of points on the surface being analyzed, using conventional numerical techniques. The optimized parameters define the dimensions of the countersunk hole or fastener head. The present invention operates independently of the coordinate system used to perform the measurements, so the invention eliminates errors caused by misalignment of optical components. The invention can also provide automatic warnings when the dimensions of a particular countersunk hole or fastener heads exceed predetermined tolerances.
The invention is a non contact laser inspection self centering device to inspect the counter sink portion of a counter sunk fastener hole on a surface. In detail, the self centering and seating device includes a combination laser transmitter and receiver for transmitting a laser bean across a surface and for receiving the return signal from the surface. A self centering device is attached to the combination laser transmitter and receiver for aligning the laser transmitter with the fastener hole such that the transmitted and received laser beam passes across the center of the counter sink portion of the fastener hole. A computer system is connected to the combination laser transmitter and receiver for analyzing the transmitted and returned laser signal from the surface and determining if the counter sink portion of the hole is within tolerance.
A three-dimensional shape measuring apparatus is provided with: an illuminator for illuminating a measurement object by two luminous fluxes in different directions, the two luminous fluxes intersecting each other at a specified position; a light receiver including a plurality of photoelectric conversion elements for receiving light to generate an electric signal in accordance with an intensity of received light; and an objective optical system for transmitting light reflected from the measurement object to the light receiver.
An interferometric measuring device includes a reference arm having a reference surface and a measuring arm having lighting optics for deflecting measuring light onto a measuring surface of an object to be measured, and having an image recorder connected to an analyzing device. A rapid, simple measurement with a rugged design of the measuring device may be achieved by configuring the lighting optics as a light guide body insertable into a cavity in the object to be measured, having a peripheral, radially symmetrical effective reflex surface directed radially or obliquely outward, and also including at least one deflector surface deflecting the measuring light onto same.
An apparatus including: (i) an interferometer positioned to derive measurement and reference wavefronts from a source of electromagnetic radiation, wherein the interferometer is configured to direct the measurement wavefront to reflect from a measurement surface and the reference wavefront to reflect from a reference surface, and further directs reflected measurement and reflected reference wavefronts to overlap with one another and to form an interference pattern; (ii) an auxiliary optic having a curved reflective surface positioned to redirect the measurement wavefront between the interferometer and the measurement surface; and (iii) a translation stage, wherein paths for the measurement and reference wavefronts define an optical measurement surface corresponding to a theoretical test surface that would reflect the measurement wavefront to produce a zero optical path length difference between the measurement and reference wavefronts, and wherein the translation stage is configured to scan the optical measurement surface over the measurement surface.
