Bin picking de objetos polimórficos convexos usando perceção 3D

O bin picking é um processo de grande interesse na indústria, uma vez que permite maior automatização, aumento da capacidade de produção e redução dos custos. Este tem vindo a evoluir bastante ao longo dos anos e essa evolução fez com que sistemas de perceção 3D começassem a ser implementados. Este trabalho tem como principal objetivo desenvolver um sistema de bin picking usando apenas perceção 3D. O sistema deve ser capaz de determinar a posição e orientação de objetos com diferentes formas e tamanhos, posicionados aleatoriamente numa superfície de trabalho. Os objetos utilizados para fazer os testes experimentais, são esferas, cilindros e prismas, uma vez que abrangem as formas geométricas existentes em muitos produtos submetidos a bin picking. Após a identi cação e seleção do objeto a apanhar, o manipulador deve autonomamente posicionar-se para fazer a aproximação e recolha do mesmo. A aquisição de dados é feita através de uma câmara Kinect. Dos dados recebidos apenas são trabalhados os referentes à profundidade, centrando-se assim este trabalho na análise e tratamento de nuvem de pontos. O sistema desenvolvido cumpre com os objetivos estabelecidos. Consegue localizar e apanhar objetos em várias posições e orientações. Além disso apresenta uma velocidade de processamento compatível com a aplicação em causa.

Subjective comparison of consumer television technologies for 3D visualization

This paper presents a comparison among different consumer 3D display technologies by means of a subjective assessment test. Therefore, four 55-in displays have been considered: one autostereoscopic display, one stereoscopic with polarized passive glasses, and two with active shutter glasses. In addition, a high-quality 3D video database has been used to show diverse material with both views in high definition. To carry out the test, standard recommendations have been followed considering also some modifications looking for a test environment more similar to real home viewing conditions, with the objective of obtaining more representative conclusions. Moreover, several perceptual factors have been considered to study the performance of the displays, such as picture quality, depth perception, and visual discomfort. The obtained results show interesting issues, like the performance improvement of active shutter glasses technology, the high performance of the polarized glasses technology in terms of quality and comfort, and the need of improvement of the autostereoscopic displays to complement the visual comfort to reach a global high-quality visual experience.

A 3D biomimetic in vitro model: a novel strategy to investigate glioma biology

Gliomas are one of the most frequent primary malignant brain tumors. Acquisition of stem-like features likely contributes to the malignant nature of high-grade gliomas and may be responsible for the initiation, growth, and recurrence of these tumors. In this regard, although the traditional 2D cell culture system has been widely used in cancer research, it shows limitations in maintaining the stemness properties of cancer and in mimicking the in vivo microenvironment. In order to overcome these limitations, different three-dimensional (3D) culture systems have been developed to mimic better the tumor microenvironment. Cancer cells cultured in 3D structures may represent a more reliable in vitro model due to increased cell-cell and cell-extracellular matrix (ECM) interaction. Several attempts to recreate brain cancer tissue in vitro are described in literature. However, to date, it is still unclear which main characteristics the ideal model should reproduce. The overall goal of this project was the development of a 3D in vitro model able to reproduce the brain ECM microenvironment and to recapitulate pathological condition for the study of tumor stroma interactions, tumor invasion ability, and molecular phenotype of glioma cells. We performed an in silico bioinformatic analysis using GEPIA2 Software to compare the expression level of seven matrix protein in the LGG tumors with healthy tissues. Then, we carried out a FFPE retrospective study in order to evaluate the percentage of expression of selected proteins. Thus, we developed a 3D scaffold composed by Hyaluronic Acid and Collagen IV in a ratio of 50:50. We used two astrocytoma cell lines, HTB-12 and HTB-13. In conclusion, we developed an in vitro 3D model able to reproduce the composition of brain tumor ECM, demonstrating that it is a feasible platform to investigate the interaction between tumor cells and the matrix.

Management of a permanent tooth after trauma to deciduous predecessor: an evaluation by cone-beam computed tomography

Impaction of permanent teeth represents a clinical challenge with regard to diagnosis, treatment plan, and prognosis. There is a close relationship between deciduous teeth and permanent teeth germ, and any injury in the deciduous dentition may influence the permanent teeth eruption. The extent of the damage caused to the permanent teeth germ depends on the patient age at the time of injury, type of trauma, severity, and direction of the impact. Conventional radiographic images are frequently used for diagnosis; however, recent developments in three-dimensional (3D) imaging systems have enabled dentistry to visualize structural changes effectively, with better contrast and more details, close to the reality. The cone-beam computed tomography (CBCT) has been used in the diagnosis and treatment plan of these impacted teeth. The purpose of the present case report is to describe a successful conservative management of a retained permanent maxillary lateral incisor with delayed root development after a trauma through the deciduous predecessor in a 9 year-old patient. After clinical and radiographic examination, a CBCT examination of the maxilla was requested to complement the diagnosis, providing an accurate 3D position of the retained tooth and its relationship to adjacent structures. The proposed treatment plan was the surgical exposure and orthodontic traction of the retained tooth. The lateral incisor spontaneously erupted after 6 months. Therefore, this case report suggests that permanent teeth with incomplete root formation have a great potential for spontaneous eruption because no tooth malposition or mechanical obstacles are observed.

Quality assurance and quality control in mammography: a review of available guidance worldwide

Objectives - Review available guidance for quality assurance (QA) in mammography and discuss its contribution to harmonise practices worldwide. Methods - Literature search was performed on different sources to identify guidance documents for QA in mammography available worldwide in international bodies, healthcare providers, professional/scientific associations. The guidance documents identified were reviewed and a selection was compared for type of guidance (clinical/technical), technology and proposed QA methodologies focusing on dose and image quality (IQ) performance assessment. Results - Fourteen protocols (targeted at conventional and digital mammography) were reviewed. All included recommendations for testing acquisition, processing and display systems associated with mammographic equipment. All guidance reviewed highlighted the importance of dose assessment and testing the Automatic Exposure Control (AEC) system. Recommended tests for assessment of IQ showed variations in the proposed methodologies. Recommended testing focused on assessment of low-contrast detection, spatial resolution and noise. QC of image display is recommended following the American Association of Physicists in Medicine guidelines. Conclusions - The existing QA guidance for mammography is derived from key documents (American College of Radiology and European Union guidelines) and proposes similar tests despite the variations in detail and methodologies. Studies reported on QA data should provide detail on experimental technique to allow robust data comparison. Countries aiming to implement a mammography/QA program may select/prioritise the tests depending on available technology and resources.

Microencapsulation technology: a powerful tool for human embryonic stem cells expansion and cryopreservation

Dissertation presented to obtain a Master degree in Biotechnology at the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Development of novel human cellular models for neurotoxicity studies

Dissertation to obtain master degree in Genética Molecular e Biomedicina

Benefits & drawbacks of different means of interaction for placing objects above a video footage

Public Display Systems (PDS) increasingly have a greater presence in our cities. These systems provide information and advertising specifically tailored to audiences in spaces such as airports, train stations, and shopping centers. A large number of public displays are also being deployed for entertainment reasons. Sometimes designing and prototyping PDS come to be a laborious, complex and a costly task. This dissertation focuses on the design and evaluation of PDS at early development phases with the aim of facilitating low-effort, rapid design and the evaluation of interactive PDS. This study focuses on the IPED Toolkit. This tool proposes the design, prototype, and evaluation of public display systems, replicating real-world scenes in the lab. This research aims at identifying benefits and drawbacks on the use of different means to place overlays/virtual displays above a panoramic video footage, recorded at real-world locations. The means of interaction studied in this work are on the one hand the keyboard and mouse, and on the other hand the tablet with two different techniques of use. To carry out this study, an android application has been developed whose function is to allow users to interact with the IPED Toolkit using the tablet. Additionally, the toolkit has been modified and adapted to tablets by using different web technologies. Finally the users study makes a comparison about the different means of interaction.

Automatització integral d'un habitatge

En aquest projecte discutirem i aprovarem la viabilitat d'implementar una automatització integral d'un habitatge utilitzant les tecnologies domòtiques existents a l'actualitat. La idea inicial és substituir tots els elements que integren la construcció (il·luminació, climatització, parts mòbils,...) per dispositius domòtics i implementar un software de visualització sobre aparells mòbils (smartphones, tablets) que ens permeti un control total sobre l'habitacle. S’avaluarà quina és la solució de mercat que millor s’adapta al projecte i s’implementarà integrant-la posteriorment als sistemes de visualització i control.

Calibration of a Structured Light-Based Stereo Catadioptric Sensor

Catadioptric sensors are combinations of mirrors and lenses made in order to obtain a wide field of view. In this paper we propose a new sensor that has omnidirectional viewing ability and it also provides depth information about the nearby surrounding. The sensor is based on a conventional camera coupled with a laser emitter and two hyperbolic mirrors. Mathematical formulation and precise specifications of the intrinsic and extrinsic parameters of the sensor are discussed. Our approach overcomes limitations of the existing omni-directional sensors and eventually leads to reduced costs of production

Modelatge procedural d’edificis

L’objectiu d’aquest PFC és el desenvolupament d’una eina pel modelatge procedural d’edificis i altres estructures arquitectòniques. El modelatge d’edificis és, per si sol, un bon tema on aplicar‐hi la programació procedural. Un edifici normal compte sempre amb elements que es repeteixen en altura i amplada. El fet de “repetir” una tasca suggereix sempre l’aplicació d’algun tipus de procediment per tal de simplificar i reduir la feina de l’usuari a l’hora de desenvolupar aquesta feina

Desenvolupament d’un sistema de visió estereoscòpica per a la reconstrucció tridimensional d’objectes

El projecte consisteix en analitzar, dissenyar i desenvolupar un sistemaestèreo binocular (format per dues càmeres) sobre un suport que ofereixi la mobilitat iportabilitat necessària per utilitzar-lo de forma independent, és a dir, sense necessitat deconnexió a un ordinador, ja que normalment, els sistemes de visió per computador solenincorporar un ordinador amb un frame grabber (placa de captura d’imatges). Per a dur a terme elsistema estèreo més adient, s’analitzaran els requeriments necessaris, s’estudiaran diferentsalternatives, i finalment, es desenvoluparà i es demostrarà el funcionament del sistema en qüestió

Entorn de treball per a visualitzar escenes tridimensionals

Creació d'un entorn de treball per tal de visualitzar models tridimensionals en temps real amb dos objectius: proporcionar una interfície gràfica per poder visualitzar interactivament una escena, modificant-ne els seus elements i aconseguir un disseny que faci el projecte altament revisable i reutilitzable en elfutur, i serveixi per tant de plataforma per provar altres projectes

Visualització de pluja realista en temps real

L’objectiu d’aquest PFC és desenvolupar un sistema de pluja per a videojocs i aplicacions de realitat virtual que sigui acurat, tant en el sentit del realisme visual com del seu comportament. El projecte permetrà al desenvolupador de videojocs incorporar a les seves aplicacions, zones de pluja amb diferents intensitats utilitzant el hardware gràfic més modern, per així evitar que aquesta pluja sigui processada per la CPU i per tant pugui alentir el videojoc que està creant. S’han desenvolupat dos sistemes, el sistema d’edició de pluja i el de visualització en temps real

Sistema d'estereovisió amb una càmera

Els sistemes de visió estèreo es basen en la reconstrucció per triangulació a partir de dues càmeres, permetent la representació d’objectes del món real en tres dimensions. L’objectiu d’aquest projecte consisteix a dissenyar i implementar un sistema estèreo amb una sola càmera amb dos petits vidres d’alta transmissivitat davant de la lent, utilitzant la teoria clàssica desenvolupada a partir de dues càmeres. D’aquesta forma obtindrem un sistema molt més compacte que en el cas de tenir dues càmeres, que serà apte per entorns molt reduïts i per escenes molt properes