Correcting for digital image correlation speckle inversion at high temperature using color cameras.

Digital image correlation (DIC) is a popular, noncontacting technique to measure full-field deformation by using cameras to track the motion of an applied surface pattern. Because it is noncontacting, DIC can be performed for extreme temperature applications (e.g.

High speed ultraviolet digital image correlation (UV-DIC) for dynamic strains at extreme temperatures.

Digital Image Correlation (DIC) is a camera-based method of measuring full-field displacements and strains from the surface of a deforming object. It can be applied at any length scale (determined by the lenses) and any time scale (determined by the camera), and because it is non-contacting, it can also be used at temperatures much higher than can be withstood by bonded strain gauges. At extreme temperatures, materials emit light in the form of blackbody radiation, which can saturate the camera sensor.

A high magnification UV lens for high temperature optical strain measurements.

Digital Image Correlation (DIC) measures full-field strains by tracking displacements of a specimen using images taken before and after deformation. At high temperatures, materials emit light in the form of blackbody radiation, which can interfere with DIC images. To screen out that light, DIC has been recently adapted by using ultraviolet (UV) range cameras, lenses, and filters.

Ultraviolet digital image correlation (UV-DIC) for high temperature applications.

A method is presented for extending two-dimensional digital image correlation (DIC) to a higher range of temperatures by using ultraviolet (UV) lights and UV optics to minimize the light emitted by specimens at those temperatures. The method, which we refer to as UV-DIC, is compared against DIC using unfiltered white light and DIC using filtered blue light which in the past have been used for high temperature applications. It is shown that at low temperatures for which sample glowing is not an issue all three methods produce the same results.