Detection and characterization of web vibrations by artificial vision

In this paper, we address the problem of the detection of transverse web vibrations by means of a digital camera and a laser dots pattern device. For this purpose, we briefly present some video processings which yield an accurate location of the projection of laser dots in the image. However, the main contribution of this work is in the new approach developed for estimating, on-line, transverse web vibration frequencies with a geometrical method and without contact. To do so, some techniques commonly used in the computer vision field are extended to some classes of non-rigid objects suitable to account for a part of an elastic web. Finally, we compare the estimated frequencies with those provided by a simple vibrating elastic string model, in motion

Helicobacter pullorum cytolethal distending toxin targets vinculin and cortactin and triggers formation of lamellipodia in intestinal epithelial cells

Helicobacter pullorum, a bacterium initially isolated from poultry, has been associated with human digestive disorders. However, the factor responsible for its cytopathogenic effects on epithelial cells has not been formally identified. The cytopathogenic alterations induced by several human and avian H. pullorum strains were investigated on human intestinal epithelial cell lines. Moreover, the effects of the cytolethal distending toxin (CDT) were evaluated first by using a wild-type strain and its corresponding cdtB isogenic mutant and second by delivering the active CdtB subunit of the CDT directly into the cells. All of the H. pullorum strains induced cellular distending phenotype, actin cytoskeleton remodeling, and G2/M cell cycle arrest. These effects were dependent on the CDT, as they were (1) not observed in response to a cdtB isogenic mutant strain and (2) present in cells expressing CdtB. CdtB also induced an atypical delocalization of vinculin from focal adhesions to the perinuclear region, formation of cortical actin-rich large lamellipodia with an upregulation of cortactin, and decreased cellular adherence. In conclusion, the CDT of H. pullorum is responsible for major cytopathogenic effects in vitro, confirming its role as a main virulence factor of this emerging human pathogen.This work was supported by the Institut national de la santé et de la recherche médicale, the University Bordeaux Segalen, the Conseil Régional d’Aquitaine (grants 20030304002FA and 20040305003 FA), the Société Nationale Française de Gastroentérologie, the European Union (FEDER no. 2003227

Systems and technologies for objective evaluation of technical skills in laparoscopic surgery

Minimally invasive surgery is a highly demanding surgical approach regarding technical requirements for the surgeon, who must be trained in order to perform a safe surgical intervention. Traditional surgical education in minimally invasive surgery is commonly based on subjective criteria to quantify and evaluate surgical abilities, which could be potentially unsafe for the patient. Authors, surgeons and associations are increasingly demanding the development of more objective assessment tools that can accredit surgeons as technically competent. This paper describes the state of the art in objective assessment methods of surgical skills. It gives an overview on assessment systems based on structured checklists and rating scales, surgical simulators, and instrument motion analysis. As a future work, an objective and automatic assessment method of surgical skills should be standardized as a means towards proficiency-based curricula for training in laparoscopic surgery and its certification

InfoSyll: A Syllabary Providing Statistical Information on Phonological and Orthographic Syllables

here is now a growing body of evidence in various languages supporting the claim that syllables are functional units of visual word processing. In the perspective of modeling the processing of polysyllabic words and the activation of syllables, current studies investigate syllabic effects with subtle manipulations. We present here a syllabary of the French language aiming at answering new constraints when designing experiments on the syllable issue. The InfoSyll syllabary provides exhaustive characteristics and statistical information for each phonological syllable (e.g. /fi/) and for its corresponding orthographic syllables (e.g. fi, phi, phy, fee, fix, fis). Variables such as the type and token positional frequencies, the number and frequencies of the correspondences between orthographic and phonological syllables are provided. As discussed, such computations should allow precise controls, manipulations and quantitative descriptions of syllabic variables in the field of psycholinguistic research.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Model-based 3-D Pose Estimation and Feature Tracking for Robot Assisted Surgery with Medical Imaging

Abstract — In this paper we address the problem of the pose estimation based on multiple geometrical features for monocular endoscopic vision with laparoscopes and for stereotaxy with CT scanners. Partial and full pose estimation (6 dofs) are considered with applications to minimally invasive surgery. At the University of Strasbourg, we have been developing a set of techniques for assisting surgeons in navigating and manipulating the three-dimensional space within the human body. In order to develop such systems, a variety of challenging visual tracking and registration problems with pre-operative and/or intra-operative images must be solved. This paper integrates several issues where computational vision can play a role. Depth recovery (from the tip of a surgical instrument w.r.t. living tissue), the Plücker coordinates (4 dofs) of a markerless cylindrical instrument, the 6 dofs of a needle-holder with an heterogeneous set of features and stereotaxy are the examples we describe. Projective invariants with perspective projection, quadrics of revolution and stereotactic markers are features which are useful to achieve the registration with uncalibrated or calibrated devices. Visual servoing-based tracking methods have been developed for image-guided robotic systems, for assisting surgeons in laparoscopic surgery and in interventional radiology. Real-time endoscopic vision and single-slice stereotactic registration has been proposed to retrieve the out-of-field of view instruments, to position a needle and to compensate small displacements like those due to patient breathing or any small disturbances which may occur during an image-guided surgical procedure. I