Global digital image correlation up to very high temperatures with grey level corrections

Abstract

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On accounting for speckle extinction via DIC and PCA

“…Sciuti et al [28] analyzed the effects of brightness and contrast corrections using one Q8 element or the same mesh applied for the kinematics for studying MgO curing inside a climatic chamber. Archer et al [29] accounted for brightness inversion of the pattern at very high temperatures. Hallo et al [30] used low order polynomials for brightness and contrast corrections to detect and quantify damage in optics of a high energy laser facility.…”

On the effect of sintering temperature on the fracture energy of an Alumina-Mullite-Zirconia castable at 600 °C

“…Recently, DIC was successfully used to study crack propagation in refractories [16][17][18][19][20][21][22][23][24][25]. However, when DIC is to be applied at high-temperatures, special care should be taken to handle effects related to heat-haze [26][27][28][29], changing emissivities [30] and black body radiation [31][32][33][34] (when above 800°C), and pattern preparation [26,28,[33][34][35].…”

On the benefits of correcting brightness and contrast in global digital image correlation: Monitoring cracks during curing and drying of a refractory castable

“…Some of them are due to lighting of the experiment [20,21,2,22,23], drifts of electron beams in SEMs [11,24], and variations of the refractive index caused by temperature gradients between the imaging device and the sample [18,25]. The use of lighting with band pass filters [26,27,18] mitigated radiation effects due to high temperatures, or working at shorter wavelengths [14] as suggested by Planck's law [28]. Besides the afore-mentioned hardware solutions, software solutions were also implemented very early on [20,2].…”

“…Some specific cases used the gray level corrections, for example, DIC analyses of infrared pictures [8,9], and distortion corrections of infrared lenses [33]. Tests performed at temperatures up to 1860°C, for which gray level inversions occurred, can also be monitored via global DIC [28]. Such procedures were extended to global stereocorrelation to account for illumination variations [34], in hybrid multiview correlation to register images of different modalities [35].…”