20 research outputs found

    Détection et caractérisation de défauts par analyse des nuages de points 3D fournis par un scanner

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    National audienceNous avons développé un logiciel qui permet de détecter et caractériser des défauts par analyse des nuages de points 3D fournis par un scanner. Ce logiciel a été développé dans le cadre du contrôle de l'état de surface d'un fuselage avion. Il pourrait être utilisé pour d'autres applications comme par exemple la détection de défauts à la surface d'une carrosserie automobile

    Shape Measurement Using a New Multi-step Stereo-DIC Algorithm That Preserves Sharp Edges

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    International audienceDigital Image Correlation is widely used for shape, motion and deformation measurements. Basically, the main steps of 3D-DIC for shape measurement applications are: off-line camera calibration, image matching and triangulation. The matching of each pixel of an image to a pixel in another image uses a so-called subset (correlation window). Subset size selection is a tricky issue and is a trade-off between a good spatial resolution, achieved with small subsets that preserve image details, and a low displacement uncertainty achieved with large subsets that can smooth image details.In this paper, we present a new multi-step DIC algorithm specially designed for measuring the 3D shape of objects with sharp edges. With this new algorithm an accurate 3D reconstruction of the whole object, including sharp edges that are preserved, can be achieved

    Strepsiptera brasileiros. IV: revisão e redescrição do gênero Brasixenos Kogan & Oliveira, 1966 (Stylopidae)

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    Brasixenos Kogan & Oliveira, 1966 (Strepsiptera, Stylopidae) é revisto; sete espécies são redescritas e é descrita como nova B. myrapetrus (localidade-tipo: Brasil, São Paulo, em Polybia (Myrapetra) paulista - Vespidae).<br>Brasixenos Kogan & Oliveira, 1966 (Strepsiptera, Stylopidae) is revised; seven species are redescribed, and one, B. myrapetrus, is proposed as new (type-locality): Brazil, São Paulo, in Polybia (Myrapetra) paulista - Vespidae)
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