Patrick Sandoz

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BACKGROUND/AIMS The aim of this paper is to propose an objective procedure for the evaluation of the skin aspect. This work is based on light scattering phenomena and in-vivo measurements of the skin profile and of the skin Bi-directional Reflection Distribution Function (BRDF). METHODS We consider the basic mechanisms of light reflection and scattering(More)
This paper presents a visual measurement method able to sense 1D rigid body displacements with very high resolutions, large ranges and high processing rates. Sub-pixelic resolution is obtained thanks to a structured pattern placed on the target. The pattern is made of twin periodic grids with slightly different periods. The periodic frames are suited for(More)
This article introduces smart sample holders for optical microscopy. Their purpose is to allow the absolute determination of the position of the observed zone with respect to the sample holder itself and with a high accuracy. It becomes then straightforward to find a given zone of interest by positioning coarsely the microscope slide to the same position(More)
High positioning accuracy with micropositioning robots (MPRs) is required to successfully perform many complex tasks, such as microassembly, manipulation, and characterization of biological tissues and minimally invasive inspection and surgery. Despite the widespread use of high-resolution micro- and nanopositioning robots, there is very little knowledge(More)
Accuracy is an important issue for microrobotic applications. High accuracy is usually a necessary condition for reliable system performance. However there are many sources of inaccuracy acting on the microrobotic systems. Characterization and compensation enable reduction of the systematic errors of the micropositioning stages and improve the positioning(More)
We introduced recently phase measurements usually performed in interferometry to the domain of image processing and intelligent vision [IEEE Trans. Instrum. Meas. 49, 867 (2000)]. Our purpose is to sense with a high accuracy the position, orientation, and displacement of two-dimensional (2D) surfaces observed by a static vision system. We report on(More)
This paper presents a visual method for 1D in-plane displacement measurement which combines a resolution of a few nanometers with an unambiguous excursion range of 168μm. Furthermore, position retrieval is only based on elementary phase computations and thus might become compatible with high-rate processing by implementing the processing algorithm on high(More)
We report a simple method for generating microaxicons at the extremity of commercial optical fibers. The proposed solution, based on a polishing technique, can readily produce any desired microaxicon cone angle and is independent of the nature of the fiber. An optical study of microaxicon performance, in terms of confinement ability and length of the(More)