Système d'acquisition 3D pour le pied humain

Abstract : This project was done with the laboratory IRCOM-SIC of Poitiers and the company GABILLY located in Limoges. This company manufactures orthopedic shoes thanks to foot measurements hand-made by a podo-orthesist. The precision is about +/- 4 mm. This company wishes to develop a system of foot metrology in order to obtain an accuracy of 1 mm. The information provided by the system must also give indications of foot pressure. This system depends on the constraints imposed by the measurement, by the dif-ficulty in scanning and modelling the object and by the choice of the acquisition system and modelling. The system developed must be as simple as possible, automatic, the least expensive and must be managed by a standard PC computer. It must provide a cloud of points which is a representation of the human foot. The project was done in a vision axis using color cameras. A specific technique of calibration with a simple plane pattern was done in order to facilitate the use of the system. The detection of the pattern is obtained by the Hough transform. The acquisition system for the human foot is a based on a passive vision technique. The methods developed must work for any type of skin, color, geometry or texture. First, a study on the human skin was done with the view to choose a color space representation and a particular color for the system background. The foot images are segmented by a specific method in order to eliminate all the pixels which do not belong to the foot representation. The segmentation is done in the Hue-Saturation-Intensity color space and thanks to an operation of geodesic dilatation. The points of pressure are obtained by a specific treatment of the image histogram of the segmented Hue. Then, several methods of 3D reconstruction were developed in order to extract a cloud of points. The first one is a technique of reconstruction by projection and the second one is based on the stereovision where the points matching is made by correlation. The modelling or surface reconstruction of the cloud of points obtained is not the first objective but it allows to validate the methods of extraction of clouds of points, several methods of surfaces reconstruction were experimented on organized and non organized cloud of points. Finally, two acquisition systems were developed : 2D and 3D. The 2D system is included in the 3D system and it allows the make the orthopedic soles which represent fifty of the encountered cases. Extracted information is the contour of the foot bottom, the metrology and the points of pressure.
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Signal and Image processing. Université de Poitiers, 2003. French


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Submitted on : Thursday, May 12, 2005 - 4:00:19 PM
Last modification on : Thursday, May 12, 2005 - 4:00:19 PM

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  • HAL Id : tel-00009251, version 1

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Cédric Marchessoux. Système d'acquisition 3D pour le pied humain. Signal and Image processing. Université de Poitiers, 2003. French. <tel-00009251>

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