A structural health monitoring method includes directly forming an acoustic transducer on a surface of a structure to be monitored; generating, by the acoustic transducer, an acoustic wave to apply stress loading to a region of interest on the structure; and detecting a presence of a defect in the region of interest. Detecting includes a non-contact optical imaging of the region of interest with and without the stress loading and an analysis of imaging data from the non-contact optical imaging.

A displacement measurement device includes: an irradiation unit that irradiates a measurement object with coherent light; a luminance-change coordinate point detection unit that detects a luminance-change coordinate point where a luminance change has occurred, based on light reflected from the measurement object, and outputs data related to the luminance-change coordinate point; and circuitry that calculates an amount of displacement of the measurement object, based on the data related to the luminance-change coordinate point, by performing computations of a first numerical sequence and a second numerical sequence. The first numerical sequence includes a set of first elements each representing a location of the luminance-change coordinate point extracted from the data. The second numerical-sequence includes a set of second elements each representing a location of the luminance-change coordinate point extracted from the data.

Shearography systems provide independent setting of fringe frequency and shear magnitude by situating an interferometer with a tiltable reflector proximate a pupil plane of an imaging optical system. Fringe frequency can be selected based on a modified Savart plate. In other examples, a Wollaston prism or a polarization grating is translated with respect to an image sensor to vary shear magnitude while maintaining a substantially fixed fringe frequency.

A system and a method for sensing an object using two-stage photo-acoustic excitation are provided herein. The method may include: scanning the object at a first resolution by alternately and repeatedly photo-acoustically exciting and sensing each of multiple first regions on the object to yield multiple first outputs; determining, based on the multiple first outputs, at least one first region of the multiple first regions that includes at least one zone and a specific depth of the at least one zone below a surface of the object; scanning the first region that includes the at least one zone at a second resolution by alternately and repeatedly photo-acoustically exciting and sensing each of multiple second regions in the at least one first region thereof to yield multiple second outputs; and determining, based on at least one of the multiple second outputs, specified parameters of the at least one zone.

A defect inspection apparatus generates a surface layer inspection image which is an image representing displacement of an inspection target in a measurement region based on an intensity pattern of interfered laser light. The defect inspection apparatus is configured to generate an appearance inspection image which is an image of an outer surface of the measurement region based on an intensity pattern of incoherent light.

A method and apparatus for performing shearography where the shear length and direction can be set in image processing, thus allowing all shear sizes to be computed and tested from a single data set, which can be collected in a single pass over a test surface or test object. The present process assures that a single data set can be processed with optimal shear length for multiple target types, thus reducing or eliminating the chance of missing a target detection while additionally enhancing target shape analysis by allowing the calculation of target response versus shear length and shear direction.

An example system for in-situ inspection of a composite structure includes a surface-strain imaging apparatus and a controller. The surface-strain imaging apparatus is configured to image an area of an outer surface of the composite structure while a temperature of the composite structure warms to thermal equilibrium with a surrounding environment and a temperature gradient exists within the composite structure. The controller includes a processor and a memory, and is configured to detect, using data received from the surface-strain imaging apparatus, an out-of-plane displacement of the outer surface in the area caused by the temperature gradient. The controller is also configured to determine that the out-of-plane displacement satisfies a threshold condition and, based on determining that the out-of-plane displacement satisfies the threshold condition, flag the area of the outer surface for further inspection.

A method for evaluating a leadframe surface includes positioning a leadframe on a measurement apparatus at a first predetermined distance relative to an end portion of a light source of an optical sensor; irradiating a predetermined area on a surface of the leadframe with light having a single predetermined wavelength from the light source; receiving, with a light receiver of the optical sensor, reflected light from the predetermined area on the surface of the leadframe, and converting the reflected light into an electric signal; determining a reflection intensity value of the predetermined area on the surface of the leadframe based on the electric signal; and calculating a reflection ratio of the predetermined area on the surface of the leadframe based on the reflection intensity value and a predetermined reference reflection intensity value associated with the light source.

The present invention relates to a method of observing a changing surface by means of laser interferometry, in particular by means of laser speckle interferometry, wherein the changing surface is preferably a surface of a tube and the method is used to determine the pressure in the tube. A further aspect of the invention relates to a corresponding apparatus.

[PROBLEM] To provide a defect detection device capable of detecting not only a defect within a visible range but also a defect outside the visible range among the objects to be inspected. [SOLUTION] A defect detection device 10 includes: an excitation source 11 capable of being placed at any position on a surface of an inspection target object S, the excitation source 11 being configured to excite an elastic wave within the inspection target object S, the elastic wave being predominant in one vibration mode and propagating in a predetermined direction; an illumination unit (pulsed laser light source 13, illumination light lens 14) configured to perform stroboscopic illumination on an illumination area of the surface of the inspection target object by using a laser light source; a displacement measurement unit (speckle shearing interferometer 15) configured to collectively measure a displacement of each point in a front-back direction within the illumination area in at least three different phases of the elastic wave, by speckle interferometry or speckle shearing interferometry; and a reflected wave/scattered wave detector 16 configured to detect either one or both of a reflected wave and a scattered wave of the elastic wave, based on the displacement measured by the displacement measurement unit.