Jean-José Orteu

• Professor
• Managing Director at IMT Mines Albi

In this work, we are focused on conformity control of complex aeronautical mechanical assemblies,typically an aircraft engine, at the end or in the middle of the assembly process. A 3D scannercarried by a robot arm provides acquisitions of 3D point clouds which are further processed by deepclassification neural networks. The Computer-Aided Design (...

This paper shows the application of several learning-based image classification techniques to conformity check, which is a common problem in industrial visual inspection. The approaches are based on processing 2D images. First, a classification pipeline has been developed. An effort has been invested into choosing an appropriate classifier. First e...

We present a method to train a deep-network-based feature descriptor to calculate discriminative local descriptions from renders and corresponding real images with similar geometry. We are interested in using such descriptors for automatic industrial visual inspection whereby the inspection camera has been coarsely localized with respect to a relat...

In the aviation industry, automated inspection is essential for ensuring quality of production. It allows acceleration of procedures for quality control of parts or mechanical assemblies. As a result, the demand of intelligent visual inspection systems aimed at ensuring high quality in production lines is increasing. In this work, we address a very...

Three-dimensional surface defect inspection remains a challenging task. This paper describes a novel automatic vision-based inspection system that is capable of detecting and characterizing defects on an airplane exterior surface. By analyzing 3D data collected with a 3D scanner, our method aims to identify and extract the information about the und...

This article describes the complete dimensioning of a method and apparatus dedicated to the automatic detection of defects on optical mirror-like components called optical solar reflector (OSR), which are used to ensure the thermal control of satellites. Firstly, the requirements of the method are defined according to the properties of the optical...

We have developed a software for the detection and characterisation of defects based on the analysis of 3D point clouds provided by a scanner. This software has been developed within an industrial application dealing with the control of an aircraft fuselage surface. It could be also used for other applications like the detection of defects on a car...

In this paper, we propose a new approach to detect and inspect airplane tires. We use normalized correlation based template matching to detect tires and GrabCut segmentation method to extract them from the background. We inspect the tires condition by investigating the tire treads. Ridge based intensity profiling gives satisfying inspection results...

We focus on quality control of mechanical parts in aeronautical context using a single pan-tilt-zoom (PTZ) camera and a computer-aided design (CAD) model of the mechanical part. We use the CAD model to create a theoretical image of the element to be checked, which is further matched with the sensed image of the element to be inspected, using a grap...

This paper deals with an automated preflight aircraft inspection using a pan-tilt-zoom camera mounted on a mobile robot moving autonomously around the aircraft. The general topic is image processing framework for detection and exterior inspection of different types of items, such as closed or unlatched door, mechanical defect on the engine, the int...

In high-speed machining, it is of key importance to avoid any collision between the machine tool and the machining set-up. If the machining set-up has not been assembled correctly by the operator and does not conform to the 3D CAD model used to compute the 3D trajectory sent to the machining unit, such collisions may occur. This paper presents a ne...

This paper focuses on quality control of mechanical parts in aeronautical context by using a single PTZ camera and the CAD model of the mechanical part. In our approach two attributed graphs are matched using a similarity function. The similarity scores are injected in the edges of a bipartite graph. A best-match-search procedure in bipartite graph...

This paper deals with the inspection of an airplane using a Pan-Tilt-Zoom camera mounted on a mobile robot moving around the airplane. We present image processing methods for detection and inspection of four different types of items on the airplane exterior. Our detection approach is focused on the regular shapes such as rounded corner rectangles a...

Digital 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 si...

The fundamental matrix can be estimated from point matches. The current gold standard is to bootstrap the eight-point algorithm and two-view projective bundle adjustment. The eight-point algorithm first computes a simple linear least squares solution by minimizing an algebraic cost and then projects the result to the closest rank-deficient matrix....

Digital 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 si...

We report on the main results of a collaborative work devoted to the study of the uncertainties associated with Digital image correlation techniques (DIC). More specifically, the dependence of displacement measurement uncertainties with both image characteristics and DIC parameters is emphasised. A previous work [Bornert et al. (2009) Assessment of...

The wood plastic composites studied in this work are composed of high-density polyethylene matrix and Pinus pinaster wood fibers. Despite some interesting intrinsic properties, this wood plastic composite has limited mechanical properties because of the incompatibility between the polar hydrophilic fibers and the non-polar hydrophobic matrix. In th...

Structured light methods achieve 3D modelling by observing with a camera system, a known pattern projected on the scene. The main drawback of single projection structured light methods is that moving the projector changes significatively the appearance of the scene at every acquisition time. Classical multi-view stereovision approaches based on the...

The goal of this study is to examine the perturbation induced by the convective effect (or mirage effect) on shape measurement and to give an estimation of the error induced. This work explores the mirage effect in different spectral bands and single wavelengths. A numerical approach is adopted and an original setup has been developed in order to i...

Cet article propose une méthodologie d'inspection automatisée d'assemblages mécaniques basée sur l'utilisation d'un bras manipulateur, équipé en tête d'effecteur d'un capteur de vision artificielle. La méthodologie d'inspection proposée dans cet article se base sur le couplage d'informations 2D et 3D, pour tirer profit de la rapidité de l'analyse e...

Background Surface and Volume Digital Image Correlation Errors and Uncertainties Stereo-Correlation or 3D-DIC Conclusions Bibliography

Digital image correlation (DIC) is a classic pattern recognition technique that is widely used for experimental measurements, mainly for: (1) surface displacement analysis in solid mechanics, and (2) particle image velocimetry (PIV) in fluid mechanics. DIC is based on using a correlation function to locate the best matching position of two images t...

The tensile behavior of wood–plastic composite (WPC) with or without additive is studied using full-field strain measurements by 3D digital image correlation. It is shown that macroscopic values of the longitudinal strain are close to those measured by mechanical extensometer using standard mechanical tests. The modulus of elasticity provided by a...

We describe a new hand-held 3D modelling device using vision and inertial measurements. Our system allows fast and accurate acquisition of the geometry and appearance information of any 3D object. We focused our work towards an easy manipulation and operating condition.Our methods allow automatic registration with no preparation of the scene (i.e....

A novel non-intrusive technique (stereo-correlation) was used to determine the apparent volume of a banana in convective drying condition. The volume was calculated using the 3D Digital Image Correlation method (3D-DIC), which provides the 3D shape of the banana during drying. The combination of this technique and mass measurement allows the calcul...

Accurate, 3D full-field measurements at the micron-level are of interest in a wide range of applications, including both facilitation of mechanical experiments at reduced length scales and accurate profiling of specimen surfaces. Scanning electron microscope systems (SEMs) are a natural platform for acquiring high magnification images for stereo-re...

Résumé Nous présentons dans cette communication une amélioration d'une méthode présentée dans [6]. Notre objectif est d'obtenir les contours dans une image à partir de la binarisation des modules des gradients. Ces contours sont obtenus à partir d'un seuil calculé automatiquement sur l'histogramme du module des gradients. La méthode doit être simpl...

A multiple-camera system (more than two cameras) has been developed to measure the shape variations and the 3D displacement field of a sheet metal part during a Single Point Incremental Forming (SPIF) operation. The modeling of the multiple-camera system and the calibration procedure to determine its parameters are described. The sequence of images...

This paper presents a method for precise registration of 3D images acquired from a new sensor for 3D digitization moved manually by an operator around an object. The system is equipped with visual and inertial devices and with a speckle pattern projector. The presented method has been developed to address the problem that a moving speckle pattern d...

In this study, the mechanical properties and microstructure of HDPE/wood fibre composites are investigated. The four-point bending and tensile behaviour of Wood Plastic Composite (WPC) with or without additive are studied by using full-field strain measurements by 3-D Digital Image Correlation (3-D DIC). A non-linear behaviour is shown. The modulus...

L'article expose l'application d'une méthode d'optimisation globale au problème de la rectification projectives d'images non calibrées. La plupart des méthodes disponibles dans la littérature utilisent une méthode d'optimisation locale lors de l'étape de minimisation des distorsions projectives. L'application d'une méthode d'optimisation globale po...

Optical methods that give displacement or strain fields are now widely used in experimental mechanics. Some of the methods can only measure in-plane displacements/strains on planar specimens and some of them can give both in-plane and out-of-plane displacement/strain fields on any kind of specimen (planar or not). In the present paper, the stereovi...

Figure 2.1 shows a simple optical system that consists of a single, ideal lens, i.e. a thin lens. Such lenses are good approximations when (a) the angles and diameters of the focused, light rays are sufficiently small so that the Gauss approximation is appropriate and (b) geometrical aberrations and other optical defects can be neglected [107]. Nex...

A camera is typically an opto-electronic device consisting of several sub-systems. First is the optics, consisting of elements such as a series of lenses, optical filters and shuttering elements that collect light from the object and focus the image onto the sensor plane. Second is the camera hardware. For example, when using a charge coupled devic...

Image matching is a discipline of computer vision that is of central importance to a large number of practical applications. To name just a few, image matching is used to solve problems in industrial process control, automatic license plate recognition in parking garages, biological growth phenomena, geological mapping, stereo vision, video compres...

Two-dimensional deformation and motion measurements were the foundation of the early applications in digital image correlation for solid mechanics measurements. In all cases, a nominally flat specimen (with or without a geometric discontinuity) was imaged while being subjected to nominally tensile loading. Throughout the loading process, it was ass...

Two-dimensional (2D) and three-dimensional (3D) computer vision employ the pinhole camera model, distortion models and general optimization procedures described in Chapter 3. For two-dimensional computer vision, it is assumed that the motions of a planar object occur within the object plane. In most 2D cases, the object plane is nominally parallel...

As shown in the several 2D examples in Chapter 6, the 3D examples in Chapter 7 and the volumetric imaging study in Chapter 8, digital image correlation has been used to make accurate measurements in a wide range of physically relevant experiments, ranging from the micro-scale to structural scale. As with any measurement method, effective use in lab...

There are several initial considerations for a typical stereo-vision system, such as shown schematically in Fig. 4.3 or Fig. I.1. These include (a) anticipated object motion with corresponding (a-1) field of view on object, (a-2) system depth of field and (a-3) spatial resolution of camera; (b) surface lighting; (c) camera exposure time and (d) sur...

Error estimation in stereo-vision systems has been an area of research for many years [14, 59, 75, 81, 104, 124, 183, 228, 335]. The enclosed developments, based on the fundamental equations given in Chapters 3 and 4, are meant to provide an introduction to their application for estimation of both 3D position bias and variability. Consider a two-ca...

In all of the previous sections, images of an object surface that are acquired by a sensor array are combined with a calibrated imaging model to convert the image sensor information into 2D or 3D surface position data. Typically, the imaging model is a form of perspective transformation, with functions defined to correct the model predictions. In r...

Résumé Nous évoquons dans cet article, la problématique de la mo-délisation 3D d'un objet par un capteur visuel déplacé ma-nuellement par un opérateur. L'objet est posé sur un plan : l'opérateur déplace le capteur sur une demi-sphère cen-trée sur l'objet. Plusieurs fonctions doivent être dévelop-pées pour construire un modèle par ce procédé : acqui...

Image Correlation for Shape, Motion and Deformation Measurements provides a comprehensive overview of data extraction through image analysis. Readers will find and in-depth look into various single- and multi-camera models (2D-DIC and 3D-DIC), two- and three-dimensional computer vision, and volumetric digital image correlation (VDIC). Fundamentals...

As used in this article, the term "digital image correlation" refers to the class of non-contacting methods that acquire images of an object, store images in digital form and perform image analysis to extract full-field shape, deformation and/or motion measurements. Digital image registration (i.e. matching) has been performed with many types of ob...

The effect of out-of-plane motion (including out-of-plane translation and rotation) on two-dimensional (2D) and three-dimensional (3D) digital image correlation measurements is demonstrated using basic theoretical pinhole image equations and experimentally through synchronized, multi-system measurements. Full-field results obtained during rigid bod...

Optical full-field measurement methods such as Digital Image Correlation (DIC) are increasingly used in the field of experimental mechanics, but they still suffer from a lack of information about their metrological performances. To assess the performance of DIC techniques and give some practical rules for users, a collaborative work has been carrie...

An innovative technique for measuring both the shape, the displacement, the strain and the temperature fields at the surface of an object using a single stereovision sensor is proposed. The sensor is based on two off-the-shelf low-cost high-resolution uncooled CCD cameras. To allow both dimensional and thermal measurements, the sensor operates in t...

The Ecole des Mines d'Albi and the LAAS-CNRS initiated in 2006 a collaboration with AIRBUS Toulouse for the development of a computer-vision-based system for the inspection of aeronautics parts (fuselage parts, metallic or composite aeronautical panels, etc.) in order to detect shape defects (shape deviation with regard to the desired overall shape...

Refractory castables exhibit very low fracture strain levels when subjected to tension or bending. The main objective of this work is to show that 3-D digital image correlation (3-D DIC) allows such low strain levels to be measured. Compared to mechanical extensometer measurements, 3-D DIC makes it possible to reach similar strain resolution levels...

A combination of drift distortion removal and spatial distortion removal are performed to correct Scanning Electron Microscope (SEM) images at both ×200 and ×10,000 magnification. Using multiple, time-spaced images and in-plane rigid body motions to extract the relative displacement field throughout the imaging process, results from numerical simul...

Nous proposons un nouveau système permettant de détecter un feu dans le proche infrarouge à l’aide d’une caméra CCD bas-coût. Après la présentation de notre problématique, nous décrivons le dispositif expérimental, puis nous expliquons la méthode de détection mise au point en insistant sur la nécessité d’utiliser une approche « multicritères ».

Optical methods that yield displacement or strain fields are now emerging significantly in the mechanical sciences. At the Research Center on Tools, Materials and Forming Processes (CROMeP) at École des Mines d'Albi, a binocular stereovision system has been developed that can be used to measure: (a) the three-dimensional (3D) shape of a static obje...

In this paper, we present a new system based on a low-cost CCD camera to detect a fire in the near infrared spectral band. After a brief description of the main features of the camera used in the study and the characteristics related to hot spots detection, we point out the interest of this imaging technique compared to classical thermal sensors us...

This paper presents a contribution to the joint in-situ measurement of strain and temperature by using Fiber Bragg Gratings (FBG) sensor. FBG’s are particularly suited to measuring strain and temperature in smart structures, e.g. for composite laminate materials in-situ measurements [Botsis, J., Humbert, L., Colpo, F. and Giaccari, P., Opt. Las. En...

We propose a framework for obtaining synthetic speckle-pattern images based on successive transformations of Perlin's coherent noise function. In addition we show how a given displacement function can be used to produce deformed images, making this framework suitable for performance analysis of speckle-based displacement/strain measurement techniqu...

A novel approach for correcting both spatial and drift distortions that are present in scanning electron microscope (SEM) images is described. Spatial distortion removal is performed using a methodology that employs a series of in-plane rigid body motions and a generated warping function. Drift distortion removal is performed using multiple, time-s...

We introduce a new approach to aircraft cargo compartment surveillance. The originality of the approach is in the use of a single sensor type, a CCD camera, to detect fire events and freight movement in aircraft cargo holds (multiphenomenon/monosensor approach). The CCD camera evaluation and the radiometric and geometric models are provided in (Sen...

Optical methods that give displacement or strain fields are now emerging significantly in the mechanical sciences. Much work has been done on two-dimensional (2D) displacement/strain measurement from a single camera but the proposed methods give only in-plane strains. A binocular correlation-based stereovision technique has been developed:(a)to mea...

We present a new video sensor for multimeasurements in an aircraft cargo compartment called a video sensor unit (VSU). This sensor, based on CCD technology, operates in the near IR (NIR) spectral band to measure temperatures due to overheating and fire events. After a characterization of the measurement chain, a radiometric model is applied to the...

A heat treatment vacuum furnace equipped with a CCD camera is used to follow the shape evolution of two axisymmetric steel samples during gas cooling. The experimental results are compared with numerical simulations performed with the finite element technique. A good agreement is obtained between the theoretical predictions and experiments. The sha...

The paper presents a video surveillance system which is able to measure the load displacements in an aircraft cargo area as well as the appearance of fires (hot surfaces, flame and smoke). To benefit from both measurements and cost savings, the system is based on an uncooled CCD camera operating in a near infrared (NIR) spectral band. In this artic...

An important task in most 3D vision systems is camera calibration. Many camera models, numerical methods and experimental set-ups have been proposed in the literature to solve the calibration problem. We have analysed and tried many methods, and we conclude that the main problems lie in the choice of the numerical methods and on the calibration obj...

We present in this paper a stereovision system that has been developed in Ecole des Mines d'Albi Material Research Center laboratory for the automatic measurement of 3D deformed surfaces, in collaboration with the LAAS-CNRS laboratory. This method uses off-the-shelf lenses, CCD cameras and frame grabber, and requires that a predefined pattern be ap...

UNION MINIERE (UM) is a Belgian firm with an international coverage. It is one of the leading companies in the field of non-ferrous metals. With subsidiaries in several European countries, mainly in Belgium and in France but also in the US, the UM group deals with every step in the production process: mining, smelting, refining, transforming, recyc...

Automation of mining operations involves the use of sensing, remote monitoring and control systems in order to confront a variety of situations and environmental conditions. The need of profitability of a mine sometimes requires that selective cutting be performed in order to separate rich ore from waste at the cutting stage. Basically, the problem...