Search results for "Segmentation"
showing 10 items of 674 documents
Stellenwert der Spirometertriggerung für die hochauflösende Computertomographie der Lunge in Inspiration und Exspiration
1998
PURPOSE To compare mean lung density (MLD) of paired inspiratory and expiratory thin-section CT scans acquired after patient instruction or using spirometric gating. MATERIALS AND METHODS 21 patients (13 m, 8 f. median age 59 years, two with normal lung function, 15 with obstructive, 4 with restrictive impairment) underwent thin-section CT. Paired inspiratory and expiratory scans were performed in the upper, middle and lower lung fields. They were acquired after automatic patient instruction with constant intervals between instruction and scan. Spirometrically gated scans were acquired within 4 days at 80% and 20% of vital capacity (VC) which has been determined on the CT scanner in supine …
Magnetic resonance image segmentation and heart motion tracking with an active mesh based system
2002
International audience; Abstract: The work presented here relates to a method fir motion tracking in sequences of medical images. The purpose is to. quantify the general motions and the local deformations of a beating heart during a cardiac cycle. In order to achieve this goal, we first tessellate the,first image of the sequence into triangular patches. A Delaunay triangulation is applied to find the optimal set of triangles describing this image, giving a mesh covering the organs. One imposes the contours of the organs to correspond to edges of triangles so that each part of the heart (left ventricle, right ventricle, myocardium) can he described as a different set of triai izles, each set…
Segmentation algorithm for non-stationary compound Poisson processes
2010
We introduce an algorithm for the segmentation of a class of regime switching processes. The segmentation algorithm is a non parametric statistical method able to identify the regimes (patches) of a time series. The process is composed of consecutive patches of variable length. In each patch the process is described by a stationary compound Poisson process, i.e. a Poisson process where each count is associated with a fluctuating signal. The parameters of the process are different in each patch and therefore the time series is non-stationary. Our method is a generalization of the algorithm introduced by Bernaola-Galván, et al. [Phys. Rev. Lett. 87, 168105 (2001)]. We show that the new algori…
The Impact of Consulting Service on Spanish Firms
2003
Introduction Specialized services that help in efficient decision-making in company management--that is consulting service--undoubtedly make up one of the most dynamic sectors of the economy in most European countries and in Spain (Rubalcaba 1997; Camacho 1998; Gonzalez 1999). There is a huge amount of literature available on the subject of consulting, and it often is stated that the consultant contributes a large dose of common sense to a management situation that is not always rational. (1) However, the consultant is not a magician who discovers what the client did not know, although the consultant is able to look at the problem from a more appropriate angle and his or her services should…
Detection and Isolation of Switches in Point Clouds of the German Railway Network
2015
In order to obtain an automated system of railway management, it is necessary to automatically detect, isolate and identify all switches in a point cloud which represents the railway. To realize this automated system of detection, a set of pre-processing steps is applied. The system begins by detecting and isolating tracks through application of a mask on each section of the point cloud. Then, it does a denoising through mathematical morphology and a compression in replacing a group of points by their centroid. Finally, it closes tracks holes through extrapolation. After that, the system does a low-level processing to search for all intersections between tracks, and records information on t…
Assessing preferences of some predefined consumer profiles for attributes of small fruit
2015
Small fruit (commonly referred to as berries), represents a potential high-value niche-market crop in Italy. This fruit grows naturally in many localities of northern Italy, but favorable environmental conditions for this crop can be found also in southern regions where this production may support local farmers' incomes. According to literature and to official statistics, small fruit's health benefiting properties are well known in the international market, but little is known about the reason of a low commercialization rate of fresh small fruit in Italy. The objective of this study was to assess, in the domestic market, consumer preferences for small fruit according to consumer rankings ap…
UNA PROCEDURA AUTOMATIZZATA PER LA DETERMINAZIONE DELLE CARATTERISTICHE MICROSTRUTTURALI DELLE SABBIE MEDIANTE ANALISI DI IMMAGINI DI SEZIONI SOTTILI
2012
È ben noto che il comportamento meccanico microscopico delle sabbie - e in generale dei terreni granulari - trae origine dalle loro caratteristiche microstrutturali, quali, per esempio, il numero di coordinazione dei singoli grani, l’indice di contatto intergranulare (grain contact ratio) e l’indice di addensamento dei grani (packing density index). Appare, quindi, di notevole importanza la determinazione degli indici predetti con alto grado di affidabilità e di ripetibilità. Lo studio dell’assetto dei contatti intergranulari e il calcolo degli indici che lo caratterizzano, viene condotta comunemente su immagini piane dell’insieme di grani mediante esame visuale e restituzione grafica assis…
Image Segmentation based on Genetic Algorithms Combination
2005
The paper describes a new image segmentation algorithm called Combined Genetic segmentation which is based on a genetic algorithm. Here, the segmentation is considered as a clustering of pixels and a similarity function based on spatial and intensity pixel features is used. The proposed methodology starts from the assumption that an image segmentation problem can be treated as a Global Optimization Problem. The results of the image segmentations algorithm has been compared with recent existing techniques. Several experiments, performed on real images, show good performances of our approach compared to other existing methods.
Segmentation and feature extraction in capillaroscopic videos
2015
This contribution describes a method to select regions of interest as capillaries of the oral mucosa and to extract their main features useful for real diagnosis purposes. A discrete version of the wavelet transform has been adopted for segmenting the images coming from video sequences acquired by a prototype capillaroscopic, able to put in evidence the red blood flow. A set of proper characteristics is automatically computed for a correct evaluation of the peripheral microcirculation.
A Fuzzy One Class Classifier for Multi Layer Model
2009
The paper describes an application of a fuzzy one-class classifier (FOC ) for the identification of different signal patterns embedded in a noise structured background. The classification phase is applied after a preprocessing phase based on a Multi Layer Model (MLM ) that provides a preliminary signal segmentation in an interval feature space. The FOC has been tested on synthetic and real microarray data in the specific problem of DNA nucleosome and linker regions identification. Results have shown, in both cases, a good recognition rate.