Aliasing phenomenon due to CCD sensors

This article deals with the aliasing phenomenon due to CCD sensors . Those detectors inherently carry out a sampling and a low pass filtering process . We propose a superresolution technique reducing aliasing, and allowing a deconvolution over an extended spectral support to diminish the low pass filtering of CCD cells . This method improves the two restricting factors (low pass filtering and perturbation of low frequencies by folded high frequencies) inherent to this type of detector .Nous montrons dans cet article l'importance du repliement spectral lié à l'utilisation des détecteurs constitués de cellules CCD . Pour cela nous rappelons l'effet sur son spectre de l'échantillonnage et du lissage d'un signal ; ce sont les deux particularités de ces capteurs . Nous proposons une méthode de superrésolution qui réduit l'effet du repliement spectral, et qui permet de déconvoluer le signal sur un support spectral plus étendu afin de diminuer l'effet de lissage des cellules CCD . La méthode proposée permet donc d'améliorer les deux facteurs limitatifs (filtrage passe bas et perturbation de ces basses fréquences par les hautes fréquences) liés à la nature même de ce type de détecteur

Segmentation d'image par déformation multirésolution sur bases d'ondelettes combinant données et modèle

- Nous proposons une nouvelle méthode de segmentation par ajustement d'un modèle actif multirésolution à chaque niveau de résolution de données décomposées sur une base d'ondelettes orthogonales. La combinaison de l'approche multirésolution sur bases d'ondelettes, simultanément sur les données et sur le modèle, apporte une convergence rapide aux plus hautes résolutions. La solution obtenue est plus robuste et plus précise en présence de bruit que celle obtenue par un ajustement de contour actif non multirésolution

Expression patterns of protein C inhibitor in mouse development

Proteolysis of extracellular matrix is an important requirement for embryonic development and is instrumental in processes such as morphogenesis, angiogenesis, and cell migration. Efficient remodeling requires controlled spatio-temporal expression of both the proteases and their inhibitors. Protein C inhibitor (PCI) effectively blocks a range of serine proteases, and recently has been suggested to play a role in cell differentiation and angiogenesis. In this study, we mapped the expression pattern of PCI throughout mouse development using in situ hybridization and immunohistochemistry. We detected a wide-spread, yet distinct expression pattern with prominent PCI levels in skin including vibrissae, and in fore- and hindgut. Further sites of PCI expression were choroid plexus of brain ventricles, heart, skeletal muscles, urogenital tract, and cartilages. A strong and stage-dependent PCI expression was observed in the developing lung. In the pseudoglandular stage, PCI expression was present in distal branching tubules whereas proximal tubules did not express PCI. Later in development, in the saccular stage, PCI expression was restricted to distal bronchioli whereas sacculi did not express PCI. PCI expression declined in postnatal stages and was not detected in adult lungs. In general, embryonic PCI expression indicates multifunctional roles of PCI during mouse development. The expression pattern of PCI during lung development suggests its possible involvement in lung morphogenesis and angiogenesis

Functional outcomes in symptomatic versus asymptomatic patients undergoing incisional hernia repair: Replacing one problem with another? A prospective cohort study in 1312 patients

Background: Incisional hernias can be associated with pain or discomfort. Surgical repair especially mesh reinforcement, may likewise induce pain. The primary objective was to assess the incidence of pain after hernia repair in patients with and without pre-operative pain or discomfort. The secondary objectives were to determine the preferred mesh type, mesh location and surgical technique in minimizing postoperative pain or discomfort. Materials and methods: A registry-based prospective cohort study was performed, including patients undergoing incisional hernia repair between September 2011 and May 2019. Patients with a minimum follow-up of 3–6 months were included. The incidence of hernia related pain and discomfort was recorded perioperatively. Results: A total of 1312 patients were included. Pre-operatively, 1091 (83%) patients reported pain or discomfort. After hernia repair, 961 (73%) patients did not report pain or discomfort (mean follow-up = 11.1 months). Of the pre-operative asymptomatic patients (n = 221), 44 (20%, moderate or severe pain: n = 14, 32%) reported pain or discomfort after mean follow-up of 10.5 months. Of those patients initially reporting pain or discomfort (n = 1091), 307 (28%, moderate or severe pain: n = 80, 26%) still reported pain or discomfort after a mean follow-up of 11.3 months postoperatively. Conclusion: In symptomatic incisional hernia patients, hernia related complaints may be resolved in the majority of cases undergoing surgical repair. In asymptomatic incisional hernia patients, pain or discomfort may be induced in a considerable number of patients due to surgical repair and one should be aware if this postoperative complication

Directorium divini cultus ad Cathedralis Ecclesiae Minoriccensis : eiusque Dioecesis usum

Fecha de imprenta tomada del título

A triangulation algorithm from arbitrary shaped multiple planar contours

International audienceConventional triangulation algorithms from planar contours suffer from some limitations. For instance, incorrect results can be obtained when the contours are not convex, or when the contours in two successive slices are very different. In the same way, the presence of multiple contours in a slice leads to ambiguities in defining the appropriate links. The purpose of this paper is to define a general triangulation procedure that provides a solution to these problems. We first describe a simple heuristic triangulation algorithm which is extended to nonconvex contours. It uses an original decomposition of an arbitrary contour into elementary convex subcontours. Then the problem of linking one contour in a slice to several contours in an adjacent slice is examined. To this end, a new and unique interpolated contour is generated between the two slices, and the link is created using the previously defined procedure. Next, a solution to the general case of linking multiple contours in each slice is proposed. Finally, the algorithm is applied to the reconstitution of the external surface of a complex shaped object: a human vertebra

A 2D texture model based on an autoregressive approach for 3D furlike texture synthesis

International audienc

Compression d'images pour la mission d'exploration planetaire phobos II

L'étude réalisée pour la mission internationale d'exploration planétaire Phobos II dans le cadre d'une coopération franco-soviétique concerne la compression à bord de la sonde d'atterrissage, des images acquises sur Phobos, avant la transmission vers la Terre. La méthode de compression développée utilise la Transformation Cosinus Discrète appliquée sur des blocs de taille 16 x 16. Un seuillage adaptatif est effectué pour le choix des coefficients à garder. Les coefficients sont quantifiés uniformément et codés par des mots binaires de longueur fixe. L'emplacement des coefficients conservés est représenté par quadtree. Les résultats de simulation sont concluants. Les premières images seront reçues et décodées à partir d'avril 1989