Sylvain Karpf
Laboratoire d'Informatique Fondamentale de Lille
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Sylvain Karpf.
CVRMed-MRCAS '97 Proceedings of the First Joint Conference on Computer Vision, Virtual Reality and Robotics in Medicine and Medial Robotics and Computer-Assisted Surgery | 1997
Anne-Claire Jambon; Patrick Dubois; Sylvain Karpf
Laparoscopic surgery consists in operating without opening the abdominal wall, by introducing a video camera and several instruments through small incisions. In this field, simulators can be a good alternative to classical ’in vivo’ training. We present in this paper a low-cost laparoscopic simulator and a training protocol specifically designed for training and evaluating beginner residents in gynecology, more specifically for teaching them the basic gestures of this operating technique. The simulator consists in a box fitted with dummy instruments and tracking sensors, connected via an interface card to a PC with a 3D graphics board. The training protocol is split into four main steps with increasing difficulty, and teaches the residents how to manipulate the camera, then one instrument, then both, and at last the camera and two instruments. Each step is composed of a training part and an evaluation part. The exercises can be modified by the experts. A VCR-like utility allows the students to record and replay their sessions. Moreover, they can train as often as they want, even if their professor is not present.
IEEE Transactions on Biomedical Engineering | 1995
Patrick Dubois; Jean Francois Rouland; Philippe Meseure; Sylvain Karpf; Christophe Chaillou
The practice of laser photocoagulation plays a major role in ocular therapy, but the persistence of many postoperative complications denotes genuine difficulty in mastering the technique. The authors present a device which, thanks to the use of simulation, enables actual practice to be dissociated from apprenticeship. While complying with the constraints of realism with regard to habitual conditions of laser use, the device offers access to a wide variety of clinical situations. The apparatus is built around the traditional instrument. A virtual image of the fundus is produced in real time from the sensors which detect the actual gestures used. The calculations make use of textured geometrical models. Digitized color photographs are organized to form a database which reflects the diversity of pigmentations and pathologies. A software interface has been developed to facilitate the use of the device. The prototype is operated using a PC-compatible computer; it displays the images at the rate of at least seven per second on a miniature CGA screen incorporated in the slit-lamp. It is currently being validated for clinical applications. Above and beyond apprenticeship in laser photocoagulation, its potential applications extend to the entire field of ophthalmological symptomatology and, more broadly, to the simulation of any examination conducted with the help of binocular or endoscopic optics.<<ETX>>
Journal Francais D Ophtalmologie | 2007
N. Santerre; F. Blondel; F. Racoussot; G. Laverdure; Sylvain Karpf; Patrick Dubois; Jean Francois Rouland
Introduction Improvements in computer technology have made it possible to design a cataract surgery teaching simulator in real time. Material and methods A computed representation of the lens was made with a mechanical model simulating the behavior of the lens, to which we added texture. The different models use mesh to make a section, which allowed us to make a section in real time using element removal or separation. Different models were used: a mass-spring mesh, a rigid model and a deformable model created using the finite element method. The contact with the lens is simulated by a collision sphere, which provides the interaction between the surgical instruments and the virtual environment. The surgical instruments viewed on the screen are controlled by a stylus with 6 degrees of freedom. Discussion We obtained the first step of phacoemulsification in real time with a good visual aspect. The surgeon views the procedure and can modify his movements instantaneously. This simulator provides the opportunity for students to safely learn phacoemulsification and improve their technique with an infinite number of procedures. Conclusion The realism offered by this tool provides a rigorous teaching tool that might reduce the learning curve for phacoemulsification.
international conference on computer vision | 1995
Philippe Meseure; Jean-Francois Rouland; Patrick Dubois; Sylvain Karpf; Christophe Chaillou
Retinal laser photocoagulation has been used for a decade, but no real improvement in results has been observed.The simulator described in this paper, by separating actual practice from apprenticeship, allows one both to learn how to manipulate the equipment and to train oneself for making a diagnosis and operating. It has been designed as close as possible to the actual operation conditions and gives the opportunity to deal with a large library of current or rare cases. An actual slit-lamp is supplied with sensors measuring all the degrees of freedom of the system. The images are calculated by a PC computer and are displayed on a miniature screen placed inside the binocular. A user interface is provided through a Computer Assisted Training software, which allows users to manage the pigmentations and pathologies data base, to follow the students skill level and to prepare critical operations.
acm symposium on solid modeling and applications | 1991
Sylvain Karpf; Christophe Chaillou; Eric Nyiri; Michel Meriaux
Many papers have been published for the definition of fast display machines using massive parallelism and VLSI components. Our goal is to design a real time object oriented graphics system. To guarantee realtime, we choose to design an object machine without frame buffer. Each object processor handles one 3D object. All the processors are synchronous and work simultaneously on the same pixel. A pipelined tree achieves inter objects processing (at least hidden part elimination) and feeds a shading post processor. We have built an Elementary Processor computing the expression: Z=aX2+bY2+cXY+dX+ eY+F for each pixel (X,Y). As we cannot define true quadric surfaces with such expressions, we had to look for accorate approximations (we have approximated spheres and cylinders with Phong’s shading). To overcome this limitation, we have defined a true Quadratic Elementary Processor which can solve in real-time the general quadric equation: aX2+bY2+cZ2+dXY+eXZ+ fYZ+gX+hY+iZ+j = O (this requires a real time square root extractor). Such processors allow us to define a Quadric Object Processor that can display true quadric surfaces in real time.
eurographics | 1990
Christophe Chaillou; Michel Meriaux; Sylvain Karpf
Current graphics processors are very slow for displaying shaded 3D objects. A lot of work is being done in order to define faster display processors by using massive parallelism and VLSI components. Our proposal goes along this line with the supplementary aim of displaying images in real time, i.e., 25 or 30 times per second. We choose to design a graphics module without any working memory and thus without frame buffer. A massive parallelism over objects, and thus a pixel pipe-line, are used. Each Object Processor handles one 3D object; all the processors work in a synchronous way, processing the same pixel simultaneously at pixel rate. These processors are built from very simple Elementary Processors (2 adders, 2 registers and 6 memory words) computing linear or quadratic expressions V(x,y), where (x,y) are the coordinates of a pixel. A pipelined tree made of basic operators (min, max, or, and, ... ) gathers the results given by the Object Processors and makes inter-objects operations, at least hidden part elimination. Such a choice of course involves a high hardware complexity when displaying rather simple scenes. However, we feel that it is the price to pay for building graphics processors allowing real-time interactive animation (e.g., the graphics unit of a driving simulator).
eurographics conference on graphics hardware | 1992
Sylvain Karpf; Christophe Chaillou
We present in this paper the IMOGENE II system, a massively parallel Multi-SIMD graphics system. This architecture uses a new rasterization scheme combining Object Parallelism and Parallel Virtual Buffers. This scheme leads to a better efficiency than other massively parallel SIMD systems, and allows a cost-effective, powerful and easily expandable system to be designed. The system consists of several SIMD Scan-Conversion Pipelines each connected to a Multi-Level Virtual Buffer, a Shading Unit computing true Phong Shading, a Virtual Accumulation Frame Buffer for anti-aliasing, and a classical Frame Buffer.
eurographics | 1991
Vincent Lefévère; Sylvain Karpf; Christophe Chaillou; Michel Meriaux
The goal of the I.M.O.G.E.N.E. project is to define a real time graphics system. We focus on true real time display, images being computed at frame rate, i.e 50 (or 60) times a second. The I.M.O.G.E.N.E. machine uses no frame buffer. We use a massive object parallelism; the graphics module is made of a large number of object-processors, each one handling one graphics primitive at pixel rate in rasterscan order. Shading computations are made in a deferred shading processor using Phongs method. After a brief presentation of Object-Oriented Architectures, we present new details about the hardware implementation of our Object Processors, and describe for the first time the shading processor.
Journal Francais D Ophtalmologie | 1995
Jean Francois Rouland; Patrick Dubois; Chaillou C; Meseuree P; Sylvain Karpf; Godin S; Duquenoy F
Archive | 1995
Christophe Chaillou; Patrick Dubois; Sylvain Karpf; Philippe Meseure; Jean-Francois Rouland