Quantitative temperature field measurements on a non-gray multi-materials scene by thermoreflectometry

Gilblas, Rémi; Sentenac, Thierry; Hernández, Daniel; Maoult, Yannick Le

doi:10.1016/j.infrared.2014.05.014

Cited by 8 publications

(10 citation statements)

References 22 publications

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“…1c), is composed of Zirconia stabilized with yttria, which is doped with Erbium oxide ions on its left side, and with Dysprosium oxide ions on its right. These two parts, called YSZ:Er 3þ and YSZ:Dy 3þ respectively, have very different emissivity values and spectral variations, as determined in the paper [7]. This sample is heated uniformly on the rear side, so the surface temperature on the front side should be relatively homogeneous.…”

Section: Calculation Of the Error On The "Two-emissivity Sample"mentioning

confidence: 97%

“…A shift is then recorded from one wavelength to the other of three pixels. Knowing the value and the shift of radiance temperatures and the value of the emissivity ratio ε r (u,v) measured by thermoreflectometry in a previous work (see article [7]), ε r ¼ 0.56 of part YSZ:Er 3þ (and respectively ε r ¼ 1.2 of YSZ:Dy 3þ ), the colour temperature T C (u,v) is calculated according to Eq. (1) and drawn in Fig.…”

Section: Calculation Of the Error On The "Two-emissivity Sample"mentioning

confidence: 99%

“…The calculation of the colour temperature T C is therefore efficient (since the temperature is higher). The remaining difference between the two parts comes from the thermal conductivity differences (see [7]) between each part, i.e. the thermodynamic surface temperature is not exactly the same.…”

Section: Calculation Of the Error On The "Two-emissivity Sample"mentioning

confidence: 99%

“…Active bichromatic thermography [2] adds equations to take into account strong parasite reflections on a specular metallic surface. Bichromatic thermoreflectometry [7] evaluates the emissivity ratio at two wavelengths by a reflectometry measurement.…”

Section: Introductionmentioning

confidence: 99%

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Effect and correction of the shift in spectral images for polychromatic thermography

Gilblas

Sentenac

2016

International Journal of Thermal Sciences

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This articles investigates the temperature errors due to chromatic aberration in multiwavelength thermography methods. The Chromatic aberration leads to a shift in the perspective projection of a point in the 3D space on the image formed at different wavelengths. This shift causes an error in the temperature field calculated by polychromatic methods, from the fusion for each pixel of radiance temperature images at different wavelengths. The temperature error can reach 40% on a sample with high spatial nonuniformities, due to wide variations of emissivity. This paper suggests an approach to correcting the chromatic aberration that is based not on equipment but on software, coupled with a calibration, using Digital Image Correlation (DIC). This experimental technique is a 2D optical method used in mechanical engineering, for inferring a deformation of a plane structure's surface from a displacement field calculated by correlation between pixels of two successive images. This paper applies the technique to achieve the field displacement induced between two images at two wavelengths by chromatic aberration. After applying this correcting displacement field, the temperature error decreases from 40% to 1% for the pixels located at the boundary of two areas with different emissivities.

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Section: Calculation Of the Error On The "Two-emissivity Sample"mentioning

confidence: 97%

Section: Calculation Of the Error On The "Two-emissivity Sample"mentioning

confidence: 99%

Section: Calculation Of the Error On The "Two-emissivity Sample"mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect and correction of the shift in spectral images for polychromatic thermography

Gilblas

Sentenac

2016

International Journal of Thermal Sciences

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“…The ideal architecture is then only based on infrared cameras for a direct D 3 thermal reconstruction. Assuming that thermal methods already described in [14][15][16] are not in the scope of this paper, the challenge is then to provide a dense image-based D 3 reconstruction [17,18] with infrared cameras.…”

Section: Introductionmentioning

confidence: 99%

Automated thermal 3D reconstruction based on a robot equipped with uncalibrated infrared stereovision cameras

Sentenac

Bugarin

Ducarouge

et al. 2018

Advanced Engineering Informatics

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In many industrial sectors, Non Destructive Testing (NDT) methods are used for the thermomechanical analysis of parts in assemblies of engines or reactors or for the control of metal forming processes. This article suggests an automated multi-view approach for the thermal D 3 reconstruction required in order to compute D 3 surface temperature models. This approach is based only on infrared cameras mounted on a Cartesian robot. The low resolution of these cameras associated to a lack of texture to infrared images require to use a global approach based first on an uncalibrated rectification and then on the simultaneous execution, in a single step, of the dense D 3 reconstruction and of an extended self-calibration. The uncalibrated rectification is based on an optimization process under constraints which calculates the homographies without prior calculation of the Fundamental Matrix and which minimizes the projective deformations between the initial images and the rectified ones. The extended self-calibration estimates both the parameters of virtual cameras that could provide the rectified images directly, and the parameters of the robot. It is based on two criteria evaluated according to the noise level of the infrared images. This global approach is validated through the reconstruction of a hot object against a reference reconstruction acquired by a D 3 scanner.

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Trichromatic thermoreflectometry for an improved accuracy of true temperature field measurement on a multi-material part

Sentenac

Gilblas

Bugarin

2019

International Journal of Thermal Sciences

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Quantitative temperature field measurements on a non-gray multi-materials scene by thermoreflectometry

Cited by 8 publications

References 22 publications

Effect and correction of the shift in spectral images for polychromatic thermography

Effect and correction of the shift in spectral images for polychromatic thermography

Automated thermal 3D reconstruction based on a robot equipped with uncalibrated infrared stereovision cameras

Trichromatic thermoreflectometry for an improved accuracy of true temperature field measurement on a multi-material part

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