Pre-procés i segmentació en imatges d’ultrasons 2D i 3D de la pròstata

Aquest projecte s'ha dut a terme amb el Grup de visió per computador del departamentd'Arquitectura i Tecnologia de Computadors (ATC) de la Universitat de Girona. Està enfocat a l'anàlisi d'imatges mèdiques, en concret s'analitzaran imatges de pròstata en relació a desenvolupaments que s'estan realitzant en el grup de visió esmentat. Els objectius fixats per aquest projecte són desenvolupar dos mòduls de processamentm d'imatges els quals afrontaran dos blocs important en el tractament d'imatges, aquests dos mòduls seran un pre-processat d'imatges, que constarà de tres filtres i un bloc de segmentació per tal de cercar la pròstata dintre de les imatges a tractar. En el projecte es treballarà amb el llenguatge de programació C++, concretament amb unes llibreries que es denominen ITK (Insight Toolkit ) i són open source enfocades al tractament d'imatges mèdiques. A part d'aquesta eina s'utilitzaran d'altres com les Qt que és una biblioteca d'eines per crear entorns gràfics

Estudi i implementació d’un mètode de reconstrucció 3D basat en SfM i registre de vistes 3D parcials

Aquest projecte es basarà en reconstruir una imatge 3D gran a partir d’una seqüència d’imatges 2D capturades per una càmera. Ens centrem en l’estudi de les bases matemàtiques de la visió per computador així com en diferents mètodes emprats en la reconstrucció 3D d’imatges. Per portar a terme aquest estudi s’utilitza la plataforma de desenvolupament MatLab ja que permet tractar operacions matemàtiques, imatges i matrius de gran tamany amb molta senzillesa, rapidesa i eficiència, per aquesta raó s’usa en moltes recerques sobre aquest tema. El projecte aprofundeix en el tema descrit anteriorment estudiant i implementant un mètode que consisteix en aplicar Structure From Motion (SFM) a pocs frames seguits obtinguts d’una seqüència d’imatges 2D per crear una reconstrucció 3D. Quan s’han creat dues reconstruccions 3D consecutives i fent servir un frame com a mínim en comú entre elles, s’aplica un mètode de registre d’estructures 3D, l’Iterative Closest Point (ICP), per crear una reconstrucció 3D més gran a través d’unir les diferents reconstruccions obtingudes a partir de SfM. El mètode consisteix en anar repetint aquestes operacions fins al final dels frames per poder aconseguir una reconstrucció 3D més gran que les petites imatges que s’aconsegueixen a través de SfM. A la Figura 1 es pot veure un esquema del procés que es segueix. Per avaluar el comportament del mètode, utilitzem un conjunt de seqüències sintètiques i un conjunt de seqüències reals obtingudes a partir d’una càmera. L’objectiu final d’aquest projecte és construir una nova toolbox de MatLab amb tots els mètodes per crear reconstruccions 3D grans per tal que sigui possible tractar amb facilitat aquest problema i seguir-lo desenvolupant en un futur

Reconstrucció 3D : comparativa d'algoritmes de correspondència

En aquest projecte s'analitzen dos algoritmes de correspondència entre imatges amb l'objectiu d'accelerar el procés de reconstrucció 3D mitjançant MVS. S'analitza tot el procés de reconstrucció i a partir d'un software existent es fa la comparació de l'algoritme SIFT i l'algoritme BRISK. A partir dels tests realitzats es conclou que el BRISK és més ràpid i millor per a una reconstrucció 3D.

Trinocular System for 3D motion and Dense Stucture Estimation

The relief of the seafloor is an important source of data for many scientists. In this paper we present an optical system to deal with underwater 3D reconstruction. This system is formed by three cameras that take images synchronously in a constant frame rate scheme. We use the images taken by these cameras to compute dense 3D reconstructions. We use Bundle Adjustment to estimate the motion ofthe trinocular rig. Given the path followed by the system, we get a dense map of the observed scene by registering the different dense local reconstructions in a unique and bigger one

Identification of geometrically consistent interest points for 3D scene reconstruction

We propose an algorithm that extracts image features that are consistent with the 3D structure of the scene. The features can be robustly tracked over multiple views and serve as vertices of planar patches that suitably represent scene surfaces, while reducing the redundancy in the description of 3D shapes. In other words, the extracted features will off er good tracking properties while providing the basis for 3D reconstruction with minimum model complexity

SIMSAFADIM-CLASTIC: A new approach to mathematical 3D forward simulation modelling for terrigenous and carbonate marine sedimentation

Most sedimentary modelling programs developed in recent years focus on either terrigenous or carbonate marine sedimentation. Nevertheless, only a few programs have attempted to consider mixed terrigenous-carbonate sedimentation, and most of these are two-dimensional, which is a major restriction since geological processes take place in 3D. This paper presents the basic concepts of a new 3D mathematical forward simulation model for clastic sediments, which was developed from SIMSAFADIM, a previous 3D carbonate sedimentation model. The new extended model, SIMSAFADIM-CLASTIC, simulates processes of autochthonous marine carbonate production and accumulation, together with clastic transport and sedimentation in three dimensions of both carbonate and terrigenous sediments. Other models and modelling strategies may also provide realistic and efficient tools for prediction of stratigraphic architecture and facies distribution of sedimentary deposits. However, SIMSAFADIM-CLASTIC becomes an innovative model that attempts to simulate different sediment types using a process-based approach, therefore being a useful tool for 3D prediction of stratigraphic architecture and facies distribution in sedimentary basins. This model is applied to the neogene Vallès-Penedès half-graben (western Mediterranean, NE Spain) to show the capacity of the program when applied to a realistic geologic situation involving interactions between terrigenous clastics and carbonate sediments.

Slow dynamis in the 3D gonihedric model

We provide analytical evidence of stochastic resonance in polarization switching vertical-cavity surface-emitting lasers (VCSELs). We describe the VCSEL by a two-mode stochastic rate equation model and apply a multiple time-scale analysis. We were able to reduce the dynamical description to a single stochastic differential equation, which is the starting point of the analytical study of stochastic resonance. We confront our results with numerical simulations on the original rate equations, validating the use of a multiple time-scale analysis on stochastic equations as an analytical tool.

SIMSAFADIM-CLASTIC: A new approach to mathematical 3D forward simulation modelling for terrigenous and carbonate marine sedimentation

Most sedimentary modelling programs developed in recent years focus on either terrigenous or carbonate marine sedimentation. Nevertheless, only a few programs have attempted to consider mixed terrigenous-carbonate sedimentation, and most of these are two-dimensional, which is a major restriction since geological processes take place in 3D. This paper presents the basic concepts of a new 3D mathematical forward simulation model for clastic sediments, which was developed from SIMSAFADIM, a previous 3D carbonate sedimentation model. The new extended model, SIMSAFADIM-CLASTIC, simulates processes of autochthonous marine carbonate production and accumulation, together with clastic transport and sedimentation in three dimensions of both carbonate and terrigenous sediments. Other models and modelling strategies may also provide realistic and efficient tools for prediction of stratigraphic architecture and facies distribution of sedimentary deposits. However, SIMSAFADIM-CLASTIC becomes an innovative model that attempts to simulate different sediment types using a process-based approach, therefore being a useful tool for 3D prediction of stratigraphic architecture and facies distribution in sedimentary basins. This model is applied to the neogene Vallès-Penedès half-graben (western Mediterranean, NE Spain) to show the capacity of the program when applied to a realistic geologic situation involving interactions between terrigenous clastics and carbonate sediments.

Modelización Gravimétrica 3D del diapiro de Cardona, Cuenca del Ebro (NE de España)

En este trabajo se presentan los resultados derivados de la interpretacón de 320 estaciones gravimétricas realizadas sobre el diapiro de Cardona con el objetivo de obtener información sobre su geometría tridimensional. Para obtener una distribución tridimensional de la masa salina que explique las anomalías observadas se ha aplicado un método iterativo de ajustes sucesivos basado en un algoritmo de inversión automática. Esta metodología ha mostrado ser muy rápida, fácil de usar y con suficiente poder de resolución para perfilar no sólo la geometría del cuerpo salino, sino también la de estructuras similares. El diapiro salino de Cardona presenta un mínimo gravimétrico relacionado con el anticlinal de Pins-Cardona que se prolonga hacia el SW. El análisis cualitativo de la anomalía residual permite apreciar que el diapiro muestra una cierta vergencia hacia sur con un flanco sureste subvertical y un flanco noroeste con pendientes más suaves.

3D solutions in transmission electron (Cryo) -microscopy in biology

One of the main problems in transmission electron microscopy in thebiological field is the tri-dimensionality. This article explains the technicalprocedures and requirements to prepare biological specimens preserving themclosest to their native state to perform 3D reconstruction of the macromolecularcomplexes and cellular structures in their natural environment.

Restitución 3D de la topografía de la antigua ciudad de Tarraco en un entorno SIG: propuestas metodológicas y primeros resultados

Durante los últimos años el Institut Català d’Arquelogia Clàssica, el Museu d’Història de Tarragona, contando con la colaboración de la Generalitat de Catalunya, han desarrallado el proyecto Planimetría Arqueológica de Tárraco, destinado a la elaboración de una planta arqueológica global en la cual se recogieran intervenciones y noticias referentes a los hallazgos arqueológicos existentes. Este trabajo fue publicado utilizando como plataforma de trabajo un SIG construido para tal fin (Macias et al. 2007). Sin embargo, un problema de difícil solución arqueológica venía dado por las transformaciones urbanísticas de la ciudad, sufridas en su mayor parte a lo largo de los siglos XIX y XX. Éstas habían provocado la pérdida irremediable de gran parte de la elevación que acogiera la ciudad romana, cambiando substancialmente su aspecto original. Ante esta situación y como proyecto paralelo a la realización de la Planimetría Arqueológica de Tarragona se plantearon formas de cubrir este vacío. Se presenta en esta comunicación una propuesta metodológica para la reconstrucción de los grandes «vacíos topográficos » originados por la evolución urbanística de Tarragona mediante la obtención e integración en un SIG de diversos tipos de información documental. En estas zonas rebajadas no resulta posible la obtención de información estratigráfica y arqueológica, por lo que es imprescindible la definición de vías metodológicas alternativas basadas en la extrapolación de datos extraídos de la cartografía histórica, panorámicas del XVI o fotografías tomadas en los siglos XIX y XX. Esta técnica permite aplicar los resultados obtenidos en los nuevos análisis interpretativos, complementando así la interpretación arqueológica de la topografía urbana de la ciudad romana. A partir de esta información, y aplicando funciones y técnicas de interpolación propias de un GIS, se propone aquí un modelo de relieve de la ciudad de Tarraco.

The Application of 3D Reconstruction Techniques in the Analysis of Ancient Tarraco’s Urban Topography

The widespread implementation of GIS-based 3D topographical models has been a great aid in the development and testing of archaeological hypotheses. In this paper, a topographical reconstruction of the ancient city of Tarraco, the Roman capital of the Tarraconensis province, is presented. This model is based on topographical data obtained through archaeological excavations, old photographic documentation, georeferenced archive maps depicting the pre-modern city topography, modern detailed topographical maps and differential GPS measurements. The addition of the Roman urban architectural features to the model offers the possibility to test hypotheses concerning the ideological background manifested in the city shape. This is accomplished mainly through the use of 3D views from the main city accesses. These techniques ultimately demonstrate the ‘theatre-shaped’ layout of the city (to quote Vitrubius) as well as its southwest oriented architecture, whose monumental character was conceived to present a striking aspect to visitors, particularly those arriving from the sea.

Forecasting coal resources and reserves in heterogeneous coal zones using 3D facies models (As Pontes Basin, NW Spain)

Forecasting coal resources and reserves is critical for coal mine development. Thickness maps are commonly used for assessing coal resources and reserves; however they are limited for capturing coal splitting effects in thick and heterogeneous coal zones. As an alternative, three-dimensional geostatistical methods are used to populate facies distributionwithin a densely drilled heterogeneous coal zone in the As Pontes Basin (NWSpain). Coal distribution in this zone is mainly characterized by coal-dominated areas in the central parts of the basin interfingering with terrigenous-dominated alluvial fan zones at the margins. The three-dimensional models obtained are applied to forecast coal resources and reserves. Predictions using subsets of the entire dataset are also generated to understand the performance of methods under limited data constraints. Three-dimensional facies interpolation methods tend to overestimate coal resources and reserves due to interpolation smoothing. Facies simulation methods yield similar resource predictions than conventional thickness map approximations. Reserves predicted by facies simulation methods are mainly influenced by: a) the specific coal proportion threshold used to determine if a block can be recovered or not, and b) the capability of the modelling strategy to reproduce areal trends in coal proportions and splitting between coal-dominated and terrigenousdominated areas of the basin. Reserves predictions differ between the simulation methods, even with dense conditioning datasets. Simulation methods can be ranked according to the correlation of their outputs with predictions from the directly interpolated coal proportion maps: a) with low-density datasets sequential indicator simulation with trends yields the best correlation, b) with high-density datasets sequential indicator simulation with post-processing yields the best correlation, because the areal trends are provided implicitly by the dense conditioning data.

Integration of a 3D rendering engine with a physics simulator

The goal of this project is the integration of a set of technologies (graphics, physical simulation, input), with the azm of assembling an application framework in phyton. In this research, a set of key introductory concepts are presented in adoption of a deep study of the state of the art of 3D applications. Phyton is selected an justified as the programing language due to the features and advantages that it offers in front of other languages. Finally the design and implementation of the framework is presented in the last chapter with some client application examples.