0000000000135889
AUTHOR
Hugues Favreliere
showing 6 related works from this author
HD-RTI: an adaptive multi-light imaging approach for the quality assessment of manufactured surfaces
2021
International audience; Reflectance Transformation Imaging (RTI) is a technique for estimating surface local angular reflectance from a set of stereo-photometric images captured with variable lighting directions. The digitization of this information fully fits into the industry 4.0 approach and makes it possible to characterize the visual properties of a surface. The proposed method, namely HD-RTI, is based on the coupling of RTI and HDR imaging techniques. This coupling is carried out adaptively according to the response at each angle of illumination. The proposed method is applied to five industrial samples which have high local variations of reflectivity because of their heterogeneity of…
Flatness calibration of XY translation stages through modal parameterization
2011
International audience; The issue of this document is to improve the metrological performances of XY translation stages of an optical profilometer Altisurf©. We propose a calibration protocol to correct the systematic geometrical errors, for example pitch and roll, related to geometrical errors of guiding system. It consists in measuring a flat glass with λ/10 (flatness ≈ 60 nm) and a very high precision optical sensor (u=0.06 μm). The correction surface is then parameterized by an original method of parameterization: the modal parameterization, to differentiate the systematic and random geometrical errors. The modal parameterization of a surface results from the Discrete Modal Decompositio…
PTMs developments for the appearance control on high-added value surfaces
2011
International audience; In many areas of activity, the value of a product depends greatly on the perceived quality, including visual one. This work aims to better control sensory perception of products with high added value, especially on the first step of the visual control: the detection, or localization of anomalies in appearance to the surfaces. Companies have controllers, specially trained to locate and evaluate anomalies. These specialists have a higher sensitivity for the detection and evaluation of defects as a potential buyer for example, and this higher acuity is generally completed by a weighting of the intensity of defects according to their location. However, there is still gre…
Reflectance-based surface saliency
2017
In this paper, we propose an original methodology allowing the computation of the saliency maps for high dimensional RTI data (Reflectance Transformation Imaging). Unlike most of the classical methods, our approach aims at devising an intrinsic visual saliency of the surface, independent of the sensor (image) and the geometry of the scene (light-object-camera). From RTI data, we use the DMD (Discrete Modal Decomposition) technique for the angular reflectance reconstruction, which we extend by a new transformation on the modal basis enabling a rotation-invariant representation of reconstructed reflectances. This orientation-invariance of the resulting reflectance shapes fosters a robust esti…
Vers une automatisation du contrôle visuel des produits
2015
International audience; La "qualité esthétique" des produits occupe aujourd'hui une place de plus en plus importante dans la maîtrise de la qualité. Elle se pose en tout cas parfois comme un objectif supplémentaire à atteindre par l'entreprise pour améliorer et pérenniser les relations que celle-ci établit avec ses clients. Le contrôle qualité à mettre en place doit réduire autant que possible la subjectivité dans l'évaluation de ce type de qualité, cette subjectivité pouvant être à l'origine de désaccords entre l'entreprise et ses clients sur le niveau de qualité à obtenir. Nos précédents travaux ont jusqu'à présent visé à mieux formaliser les différentes étapes d'un contrôle visuel des pr…
Multi-scale analysis of surface topographies by modal filtering
2012
International audience; This work introduces an innovative method for the multi-scale analysis of surface topographies, which consists of applying a method based on a new parameterization. This kind of surface parameterization refers to natural modes of vibration, and is therefore named modal parameterization. It allows us to characterize the form, waviness and roughness defects of a surface. This parameterization opens up new fields of analysis, such as the appearance quality of surfaces. It is thereby possible to decompose a measured surface in a vector basis, of which vectors are represented by plane natural eigenmodes sorted by frequency and complexity. Different filtering operations ca…