TY - JOUR
T1 - Improving spatio-temporal resolution of infrared images to detect thermal activity of defect at the surface of inorganic glass
AU - Corvec, Guillaume
AU - Robin, Eric
AU - Le Cam, Jean Benoît
AU - Sangleboeuf, Jean Christophe
AU - Lucas, Pierre
N1 - Funding Information:
Mission of Resources and Skills Technology (MRCT) Grant from French National Center for Scientific Research (2012).
Funding Information:
Mission for Interdisciplinary (MI) Grant from French National Center for Scientific Research (2013).
Publisher Copyright:
© 2016 Elsevier B.V. All rights reserved.
PY - 2016/7/1
Y1 - 2016/7/1
N2 - This paper proposes a noise suppression methodology to improve the spatio-temporal resolution of infrared images. The methodology is divided in two steps. The first one consists in removing the noise from the temporal signal at each pixel. Three basic temporal filters are considered for this purpose: average filter, cost function minimization (FIT) and short time Fast Fourier Transform approach (STFFT). But while this step effectively reduces the temporal signal noise at each pixel, the infrared images may still appear noisy. This is due to a random distribution of a residual offset value of pixels signal. Hence in the second step, the residual offset is identified by considering thermal images for which no mechanical loading is applied. In this case, the temperature variation field is homogeneous and the value of temperature variation at each pixel is theoretically equal to zero. The method is first tested on synthetic images built from infrared computer-generated images combined with experimental noise. The results demonstrate that this approach permits to keep the spatial resolution of infrared images equal to 1 pixel. The methodology is then applied to characterize thermal activity of a defect at the surface of inorganic glass submitted to cyclic mechanical loading. The three basic temporal filters are quantitatively compared and contrasted. Results obtained demonstrate that, contrarily to a basic spatio-temporal approach, the denoising method proposed is suitable to characterize low thermal activity combined to strong spatial gradients induced by cyclic heterogeneous deformations.
AB - This paper proposes a noise suppression methodology to improve the spatio-temporal resolution of infrared images. The methodology is divided in two steps. The first one consists in removing the noise from the temporal signal at each pixel. Three basic temporal filters are considered for this purpose: average filter, cost function minimization (FIT) and short time Fast Fourier Transform approach (STFFT). But while this step effectively reduces the temporal signal noise at each pixel, the infrared images may still appear noisy. This is due to a random distribution of a residual offset value of pixels signal. Hence in the second step, the residual offset is identified by considering thermal images for which no mechanical loading is applied. In this case, the temperature variation field is homogeneous and the value of temperature variation at each pixel is theoretically equal to zero. The method is first tested on synthetic images built from infrared computer-generated images combined with experimental noise. The results demonstrate that this approach permits to keep the spatial resolution of infrared images equal to 1 pixel. The methodology is then applied to characterize thermal activity of a defect at the surface of inorganic glass submitted to cyclic mechanical loading. The three basic temporal filters are quantitatively compared and contrasted. Results obtained demonstrate that, contrarily to a basic spatio-temporal approach, the denoising method proposed is suitable to characterize low thermal activity combined to strong spatial gradients induced by cyclic heterogeneous deformations.
KW - Denoising
KW - Experimental mechanics
KW - Indentation
KW - Infrared thermography
KW - Sodalime glass
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U2 - 10.1016/j.infrared.2016.05.026
DO - 10.1016/j.infrared.2016.05.026
M3 - Article
AN - SCOPUS:84974603379
VL - 77
SP - 193
EP - 202
JO - Infrared Physics and Technology
JF - Infrared Physics and Technology
SN - 1350-4495
ER -