US 12,405,239 B2
Photothermal analysis of a part of solid material
Camille Trottier, Arpajon (FR)
Assigned to OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AÉROSPATIALES, Palaiseau (FR)
Appl. No. 17/774,066
Filed by OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AÉROSPATIALES, Palaiseau (FR)
PCT Filed Oct. 28, 2020, PCT No. PCT/EP2020/080306
§ 371(c)(1), (2) Date May 3, 2022,
PCT Pub. No. WO2021/089383, PCT Pub. Date May 14, 2021.
Claims priority of application No. 1912330 (FR), filed on Nov. 4, 2019.
Prior Publication US 2022/0381717 A1, Dec. 1, 2022
Int. Cl. G01N 25/72 (2006.01); G01J 5/00 (2022.01); G06T 7/00 (2017.01)
CPC G01N 25/72 (2013.01) [G01J 5/0003 (2013.01); G06T 7/0004 (2013.01); G01J 2005/0077 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of photothermal analysis of a piece which is composed of at least one solid material, the method being intended to reveal whether at least one defect is present in a surface portion of the piece, and comprising the following steps:
/1/ injecting heat into a first region of the surface portion of the piece, called heating region, then, after a period during which some of the injected heat has diffused into another region of the surface of the piece, which is called detection region and which is distinct from the heating region, capturing at least one thermal image, called analysis image, of the detection region; and
/2/ subtracting a reference image from the analysis image, at least for a portion of said analysis image which corresponds to the detection region, in order to obtain a revealing image which shows whether at least one defect is present in said detection region,
wherein, for each analysis image captured, the reference image which is subtracted from said analysis image corresponds to a thermal emission distribution in the detection region, as caused by at least some of the heat injected into the surface portion of the piece, for a case where said surface portion of the piece is without defects in the detection region,
and wherein the reference image which is subtracted from the analysis image results from a search for best match between said analysis image and a configured model of thermal emission distribution which is used to define the case where the surface portion of the piece is without defects in the detection region.