0000000001082448
AUTHOR
David Joannic
3D part Inspection with Laser Uncertainties Control
International audience
Systematic Error Correction of a 3D Laser Scanning Measurement Device
International audience; Non-contact measurement techniques using laser scanning have the advantage of fast acquiring large numbers of points. However, compared to their contact-based counterparts, these techniques are known to be less accurate. The work presented in this paper aims at improving the accuracy of these techniques through an error correction procedure based on an experimental process that concerns mechanical parts. The influence of the three parameters defining the relative position and the orientation between the sensor and the surface is studied. The process used to build an experimental global model of error is presented and applied to a typical part composed of planes or sk…
Analyse de la mesure des pièces 3D complexes
International audience
ESTIMATION ET CORRECTION DES ERREURS SYSTEMATIQUES D'UN SYSTEME DE MESURE 3D ASSOCIANT SCANNER NAPPE LASER ET MMT
Les techniques de mesure sans contact par scanning laser permettent d'acquérir un grand nombre de points, à une cadence très rapide. Elles sont de plus en plus utilisées pour des applications industrielles telles que la rétro-conception, le contrôle de forme,... Toutefois, les incertitudes de mesures sont plus importantes que celles obtenues par les techniques classiques de mesure par contact. Nous proposons une procédure de correction des erreurs systématiques basée sur démarche expérimentale et qui concerne la mesure de pièces présentant une surface mate (peu de présence de bruit spéculaire). Les paramètres retenus dans la procédure sont les paramètres de positionnement du capteur par rap…
Comparaison de la mesure des déformations de fantômes de l’aorte à partir d’image obtenues par IRM et stéréovision
International audience; The study of the wall strain distribution could be helpful to improve the decision criterion for surgery of aortic aneurysm. Recently, numerical simulations can complete the data obtained from imaging measurement in order to develop reliable models. However, the used medical imaging tools are not experimentally validated, in metrological point of view. The aim of this study focused on accuracy and reliability of measurement obtained from kinetic MR sequences. The measures of deformations from MRI were compare to those obtained from stereovision system. Cylindrical phantom of silicone material similar to arterial behavior simulated a symmetric aneurysm was designed. A…
Taking digitized points quality into account in geometrical specification measurement by laser sensor
International audience; Today, the new measurement techniques without contact like the laser sensors are used more and more in industrial applications. They allow to obtain many points in a short time. However these techniques have a less good accuracy than the classical process with contact probe for metrology application. The work presented in this paper, is part of a research project on the in-process product inspection. In the case of in-process product inspection, the throughput time must be the shortest with a good dimensional accuracy. So, it is necessary to increase the measurement accuracy of the points cloud for using the laser scanners. For this first approach, we suggest to buil…
Effective orifice area assessment in BI-leaflet mechanical valves by MRI,
International audience; Effective orifice area (EOA) and mean pressure gradientare routine echocardiographic measurements of valvularprosthesis function in both the mitral and aortic position.EOA computation is based on the continuity equationand is used to describe the “effective” orifice formed bythe flow traversing a geometrical orifice. In the case ofbi-leaflet biomechanical valvular prosthesis (BMHV),the orifice of the valve is divided into 3 zones. BMHVperformance assessment by MRI have been described inthe in-vitro setting in [1] using the maximum pressuregradient. Additionally, a method using jet layer has beenused to detect EOA dynamically [2]. 4D-PC flowsequences enable measuremen…
Comparison of the strain field of abdominal aortic aneurysm measured by magnetic resonance imaging and stereovision: a feasibility study for prediction of the risk of rupture of aortic abdominal aneurysm
International audience; The prediction of the risk of rupture of abdominal aortic aneurysm (AAA) is a complex problem. Currently the criteria to predict rupture of abdominal aortic aneurysms are aneurysm diameter and growth rates. It is generally believed that study of the wall strain distribution could be helpful to find a better decision criterion for surgery of aortic aneurysms before their rupture. The wall strain distribution depends on many biological and biomechanical factors such as elastic properties of the aorta, turbulent blood flow, anatomy of the aorta, presence of thrombus or not and so on. Recently, numerical simulations to estimate rupture-potential have received many attent…
Validation of the Strain Assessment of a Phantom of Abdominal Aortic Aneurysm: Comparison of Results Obtained From Magnetic Resonance Imaging and Stereovision Measurements
Predicting aortic aneurysm ruptures is a complex problem that has been investigated by many research teams over several decades. Work on this issue is notably complex and involves both the mechanical behavior of the artery and the blood flow. Magnetic resonance imaging (MRI) can provide measurements concerning the shape of an organ and the blood that flows through it. Measuring local distortion of the artery wall is the first essential factor to evaluate in a ruptured artery. This paper aims to demonstrate the feasibility of this measure using MRI on a phantom of an abdominal aortic aneurysm (AAA) with realistic shape. The aortic geometry is obtained from a series of cine-MR images and reco…
Path Planning in Inspection Process of 3-D Parts Used the Visibility Technique
International audience; In this paper presents a new method for digitalization of parts with non-contact sensor remains nevertheless complex. It is not completely solved today, in particular from a metrological point of view. In this article, we consider the determination of the trajectory planning within the framework of the control of dimensional and geometrical specifications. The sensor used in this application is a laser planner scanner with CCD camera oriented and moved by a CMM. Thus, we seek to determine which are the best possible orientations of the sensor with respect to the geometrical specifications of the measured part, giving the admissible measurement uncertainties. The deve…
3D digitizing path planning for part inspection with laser scanning
If the first work relating to the automation of the digitalization of machine elements goes back to approximately 25 years, the process of digitalization of parts with non-contact sensor remains nevertheless complex. It is not completely solved today, in particular from a metrological point of view. In this article, we consider the determination of the trajectory planning within the framework of the control of dimensional and geometrical specifications. The sensor used in this application is a laser planner scanner with CCD camera oriented and moved by a CMM. For this purpose, we have focused on the methodology used to determine the best possible viewpoints which will satisfy the digitizing…
3D part inspection path planning of a laser scanner with control on the uncertainty
International audience; This article concerns the measurement process of mechanical parts using laser scanners. From the point of view of industrial applications, the objective is to guarantee the measurement accuracy during the scanning with regard to the geometrical product specifications. The proposed method can be summarized as follow: the first step consists of analyzing the interval of tolerance for the different specifications and to attribute to every geometrical entity a maximal uncertainty of measurement. This uncertainty depends on the angle of incidence between the laser plane and the scanned surface. In the second step, an approach based on the concept of visibility is used fro…