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Facial expression recognition is necessary for designing any realistic human-machine interfaces. Previous published facial expression recognition systems achieve good recognition rates, but most of them perform well only when the user faces the camera and does not change his 3D head pose. We propose a new method for robust, view-independent recognition of facial expressions that does not make this assumption. The system uses a novel 3D model-based tracker to extract simultaneously and robustly the pose and shape of the face at every frame of a monocular video sequence. There are two main contributions. First, we demonstrate that the 3D information extracted through 3D tracking enables robust facial expression recognition in spite of large rotational and translational head movements (up to 90 degrees in head rotation). Second, we show that the Support Vector Machine is a suitable engine for robust classification. Recognition rates as high as 91 percent are achieved at classifying 5 distinct dynamic facial motions (neutral, opening/closing mouth, smile, raising eyebrow).

The cross-correlation relaxation rate constant between dipolar interaction and chemical shift anisotropy (interference term) is of considerable interest for structural and dynamical determinations. The present study focuses on methods related to its impact on longitudinal nuclear relaxation, and especially to a procedure based on the applications of a train of π pulses applied to both nuclei involved in such a process (Levitt MH, Di Bari L. Bull. Magn. Reson. 1994; 16: 94–114). The resulting steady state leads, in principle, to a straightforward determination of the relevant interference term. Simulations taking into account inhomogeneity of the radio-frequency (RF) field show that artifacts are responsible for instabilities which in practice preclude such a determination. An alternative method making use of a very limited number of RF pulses, combined with an appropriate filter, proves to be rather robust in view of achieving a proper measurement of the required interference term. Copyright © 2003 John Wiley & Sons, Ltd.

A simple and inexpensive approach for extracting the three-dimensional shape of objects is presented. It is based on 'weak structured lighting'; it differs from other conventional structured lighting approaches in that it requires very little hardware besides the camera: a desk-lamp, a pencil and a checker-board. The camera faces the object, which is illuminated by the desk-lamp. The user moves a pencil in front of the light source casting a moving shadow on the object. The 3D shape of the object is extracted from the spatial and temporal location of the observed shadow. Experimental results are presented on three different scenes demonstrating that the error in reconstructing the surface is less than 1%.

This paper describes a two-stage system for 3D tracking of pose and deformation of the human face in monocular image sequences without the use of special markers. The first stage of the system learns the space of all possible facial deformations by applying principal component analysis on real stereo tracking data. The resulting model approximates any generic shape as a linear combination of shape basis vectors. The second stage of the system uses this low-complexity deformable model for simultaneous tracking of pose and deformation of the face from a single image sequence. This stage is known as model-based monocular tracking. There are three main contributions of this paper. First we demonstrate that a data-driven approach for model construction is suitable for tracking non rigid objects and offers an elegant and practical alternative to the task of manual construction of models using 3D scanners or CAD modelers. Second, we show that such a method exhibits good tracking accuracy (errors less than 5 mm) and robustness characteristics. Third, we demonstrate that our system exhibits very promising generalization properties in enabling tracking of multiple persons with the same 3D model.

This paper describes a stereo-based approach for gesture recognition that works well under extreme lighting conditions and tolerates a large range of hand poses. The approach proposes a hybrid gesture representation that models the user's arm as a 3D line and uses images to represent the hand gestures. The algorithm finds the arm orientation and the hand location from the disparity data and uses this information to initialize a color based segmentation algorithm that cleanly separates the hand from the background. Finally, our approach uses the arm orientation to compute a frontal view of the hand through perspective unwarping producing easily recognizable hand gesture templates. The classification algorithm uses statistical moments of the binarized gesture templates to find the match. We achieve 96% recognition rates under varying lighting and 3D poses for a set of 6 gestures.

We present a multi-PC/camera system that can perform 3D reconstruction and ellipsoid fitting of moving humans in real time. The system consists of five cameras. Each camera is connected to a PC which locally extracts the silhouettes of the moving person in the image captured by the camera. The five silhouette images are then sent, via local network, to a host computer to perform 3D voxel-based reconstruction by an algorithm called SPOT. Ellipsoids are then used to fit the reconstructed data. By using a simple and user-friendly interface, the user can display and observe, in real time and from any view-point, the 3D models of the moving human body. With a rate of higher than 15 frames per second, the system is able to capture non-intrusively, a sequence of human motions.

The assignments of 1H and 13C NMR spectra for three new triterpene saponins from Silene vulgaris (gypsogenin 3-O-glucuronide, quillaic acid 3-O-glucuronide, and gypsogenin 3-O-glycoside) are reported. In addition to 1D NMR methods, 2D NMR techniques (COSY, HSQC, HMBC, and HSQC-TOCSY) were used for the assignments. Copyright © 2002 John Wiley & Sons, Ltd.

A light field parameterized on the surface offers a natural and intuitive description of the view-dependent appearance of scenes with complex reflectance properties. To enable the use of surface light fields in real-time rendering we develop a compact representation suitable for an accelerated graphics pipeline. We propose to approximate the light field data by partitioning it over elementary surface primitives and factorizing each part into a small set of lower-dimensional functions. We show that our representation can be further compressed using standard image compression techniques leading to extremely compact data sets that are up to four orders of magnitude smaller than the input data. Finally, we develop an image-based rendering method, light field mapping, that can visualize surface light fields directly from this compact representation at interactive frame rates on a personal computer. We also implement a new method of approximating the light field data that produces positive only factors allowing for faster rendering using simpler graphics hardware than earlier methods. We demonstrate the results for a variety of non-trivial synthetic scenes and physical objects scanned through 3D photography.

This paper describes a system for learning a face model that is used for 3D tracking of the human face. The face is modeled as a linear combination of shape basis vectors and action vectors. Shape space models the difference in face shape of different people while action space models the facial expressions. First, real stereo tracking data is used to learn the space of these shape and action vectors using Principal Component Analysis. Then this low-complexity model is used to simultaneously track shape, pose and expression from a monocular image sequence. The main contribution of this paper is in learning shape and action deformation models simultaneously from real data. Results of monocular model-based tracking for subjects not included in the training set show that the model derived from data is robust and generalizes well.

We report a new family of Ce-based heavy-fermion compounds whose electronic specific heat coefficients range from about 400 to over 700mJ/mol-Ce K2. Crystals in this family form as CenTmIn3n-2m, where T = Rh or Ir, n = 1 or 2, and m = 1, with a tetragonal structure that can be viewed as m-layers of CeIn3units stacked sequentially along the c-axis with intervening m-layers of TIn2. Ambient and high-pressure studies show that the quasi-2D layers of CeIn3produce unconventional superconducting and magnetic ground states. This family should enable new understanding of the relationship between magnetism and superconductivity in heavy-fermion materials and more generally of why heavyfermion superconductivity prefers to develop in one structure type and not another. © 2001 Elsevier Science B.V. All rights reserved.

We give a new geometrical interpretation of the well-known algebraic trilinear constraints used in motion analysis from three views observation. We show that those algebraic equations correspond to depth errors appropriately weighted by a function of the relative reliability of the corresponding measurements. Therefore directly minimizing the algebraic trilinear equations, in the least squares sense, is a strategy that works well for estimating motion. In addition, we propose a new scheme for recovering the scale factor for motion estimation that is very insensitive to input noise. All our theoretical statements are supported by experimental results.

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Two regions of the cAspAT gene promoter mediate the glucocorticoid regulation of this gene in the Fao hepatoma cell line. The proximal region was localized by deletion studies and stable transfections in the Fao cells to the sequence −553/−398. This region includes the glucocorticoid-responsive element (GRE) A sequence, which consists of two overlapping GREs and which can mediate the glucocorticoid regulation of a heterologous promoter. DNase I footprinting studies have shown that a site 80 base pairs upstream of the GRE A was protected by liver and brain nuclear extracts (site P8). The binding was displaced by an excess of an oligonucleotide containing a typical NF1 binding site and by NF1-specific antibodies. In electrophoretic mobility shift assay using the P8 oligonucleotide as a probe, several complexes were formed. Most complexes were common to liver and brain but were less abundant when testis extracts were used. At least one complex was specific to the liver. All complexes, with the exception of two, were competed for by the NF1 oligonucleotide. Furthermore, the sequence of the P8 site showed a 7/9-base pair homology with a typical NF1 site. A mutation of the P8 site, which prevents the binding of NF1-like proteins to it, considerably decreases the regulation of the cAspAT promoter fragment by glucocorticoids. Surprisingly, the basal activity of the mutant promoter was increased 2-fold. Thus, the regulation of the cAspAT gene promoter is mediated by a regulatory unit comprising the GRE A and a NF1 binding site.

We assess the usefulness of monocular recursive motion estimation techniques for vehicle navigation in the absence of a model for the environment. For this purpose we extend a recently proposed recursive motion estimator, the Essential filter, to handle scale estimation. We examine experimentally the accuracy with which the motion and position of the vehicle may be computed on an 8000 frame indoors sequence. The issues of sampling time frequency and number of necessary features in the environment are addressed systematically. >

Cytochromes P450 (P450s) are inducible drug-metabolizing enzymes involved in the metabolism of numerous endogenous and exogenous substrates. The regulation of some of these enzymes during experimental diabetes has been reported, but the direct involvement of insulin and the mechanism of its action remain unclear. The aim of our work was to study the effects of insulin on P450 2B and 2E expression in differentiated Fao hepatoma cells. Exposure of the cells to 0.1 microM insulin caused 60% and 80% decreases in the steady state levels of P450 2B and 2E proteins, respectively, within 24 hr. Before this, a rapid decrease in the corresponding messages was observed. Indeed, 5-6 hr of insulin treatment produced 80 and 50% decreases in P450 2B and 2E mRNA levels, respectively. Nuclear run-on transcription and mRNA turnover studies were performed to determine the mechanism (transcriptional and/or post-transcriptional) by which insulin modulated these mRNA levels. From our results, it can be concluded that insulin down-regulates the expression of P450 2B by shortening the half-life of its mRNA (half-lives of 6.9 hr without insulin and 3.6 hr with insulin), whereas it down-regulates the expression of P450 2E both by weak repression of the transcription rate (-30%) and, in particular, by acceleration of its mRNA turnover (half-lives of 8.5 hr without insulin and 3.3 hr with insulin).

Patient controlled analgesia improves titration of analgesic drugs, minimizing individual pharmacodynamic differences between patients, during the postoperative period. We describe the efficacy and the safety of intravenous PCA, based on the follow-up of 300 patients, recovering from upper and lower abdominal surgery. Successful use of PCA requires the choice of two important parameters: the PCA bolus and the lock-out period. In our experience, we only prescribed morphine, with a PCA bolus of 0.5 or 1 mg and a lock-out period of 5 or 10 minutes. Nurses were educated to change the syringes and to assess analgesia and the respiratory function. Patients were mostly hospitalized in surgical wards and only 16% of patients were treated in an intensive care unit. Patient's acceptance proved to be excellent and only 4 patients were not satisfied with PCA therapy. The incidence of respiratory depression was low (0.02%) and only one patient required naloxone. The side effects were dysphoria, nausea, pruritus and urinary retention; their incidence was low.

Brachial plexus block is an alternative and elegant procedure for shoulder surgery. Three main concerns have to be considered when this technique is planed. Firstly, large amounts of local anaesthetic solution are necessary to achieve complete blockade of the region especially when the deeper tissues of the shoulder are concerned by the procedure. Secondly interscalenic cervical plexus block produces homolateral phrenic paralysis and may impair respiratory function in patients at risk or when supplemental IV drugs are administered. Thirdly, when nerve lesions of different mechanisms including plexus block itself occur, the origin of the lesion may be difficulty related to its cause. Indications of cervical block are therefore to be considered cautiously when shoulder surgery is performed.

The aim of our study was to investigate the suitability of Fao cells, derived from the Reuber H35 rat hepatoma as a tool for studying regulation of drug-metabolizing enzymes and drug metabolism. Fao cells express P450 2B, 2E, 3A and GST pi and were used to study the effects different inducers on these enzymes. Ethanol considerably increased the amounts of P450 2E and, to a lesser extent, P450 2B and GST pi mRNA and protein. Dexamethasone decreased the amounts of P450 2B, 3A and GST pi mRNAs, but had no appreciable effect per se upon the protein concentration of these enzymes. However, it antagonized the induction of P450 2E, 2B and GST pi by ethanol, even at the protein level. RU 486 decreased P450 2B protein and P450 2E mRNA and protein levels without effecting P450 3A and GST pi expression. RU 486 did not antagonize the dexamethasone effects, suggesting that at least some of these effects are not mediated by the glucocorticoid receptor. These data indicate that these cells constitute a suitable tool for studying the regulation of drug-metabolizing enzyme expression and drug metabolism.

Caudal anaesthesia was described in 1901 but is now essentially used for paediatric surgery. From their experience of 56 caudal blocks in adult patients scheduled for pelvic surgery or endoscopy, the authors discuss the value of this technique. The anatomical and physiological basis and the main guidelines of caudal anaesthesia are recalled through some references.