7 resultados para structure from motion

em Universidade Federal do Rio Grande do Norte(UFRN)


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Visual Odometry is the process that estimates camera position and orientation based solely on images and in features (projections of visual landmarks present in the scene) extraced from them. With the increasing advance of Computer Vision algorithms and computer processing power, the subarea known as Structure from Motion (SFM) started to supply mathematical tools composing localization systems for robotics and Augmented Reality applications, in contrast with its initial purpose of being used in inherently offline solutions aiming 3D reconstruction and image based modelling. In that way, this work proposes a pipeline to obtain relative position featuring a previously calibrated camera as positional sensor and based entirely on models and algorithms from SFM. Techniques usually applied in camera localization systems such as Kalman filters and particle filters are not used, making unnecessary additional information like probabilistic models for camera state transition. Experiments assessing both 3D reconstruction quality and camera position estimated by the system were performed, in which image sequences captured in reallistic scenarios were processed and compared to localization data gathered from a mobile robotic platform

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3D Reconstruction is the process used to obtain a detailed graphical model in three dimensions that represents some real objectified scene. This process uses sequences of images taken from the scene, so it can automatically extract the information about the depth of feature points. These points are then highlighted using some computational technique on the images that compose the used dataset. Using SURF feature points this work propose a model for obtaining depth information of feature points detected by the system. At the ending, the proposed system extract three important information from the images dataset: the 3D position for feature points; relative rotation and translation matrices between images; the realtion between the baseline for adjacent images and the 3D point accuracy error found.

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In Simultaneous Localization and Mapping (SLAM - Simultaneous Localization and Mapping), a robot placed in an unknown location in any environment must be able to create a perspective of this environment (a map) and is situated in the same simultaneously, using only information captured by the robot s sensors and control signals known. Recently, driven by the advance of computing power, work in this area have proposed to use video camera as a sensor and it came so Visual SLAM. This has several approaches and the vast majority of them work basically extracting features of the environment, calculating the necessary correspondence and through these estimate the required parameters. This work presented a monocular visual SLAM system that uses direct image registration to calculate the image reprojection error and optimization methods that minimize this error and thus obtain the parameters for the robot pose and map of the environment directly from the pixels of the images. Thus the steps of extracting and matching features are not needed, enabling our system works well in environments where traditional approaches have difficulty. Moreover, when addressing the problem of SLAM as proposed in this work we avoid a very common problem in traditional approaches, known as error propagation. Worrying about the high computational cost of this approach have been tested several types of optimization methods in order to find a good balance between good estimates and processing time. The results presented in this work show the success of this system in different environments

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This paper is a case study that aims to discuss the effects of drug abuse by a person with psychotic structure from a psychoanalytical perspective. The interest in this subject was born from an internship experience in the Mental Health area in which a psychotic patient had a drug abuse problem and the service treating him had difficulties dealing with this. In order to accomplish the objective of this work four theoretical chapters were written and the case is discussed throughout them articulating the theoretical issues with clinical practice. A literature review revealed that Freud and Lacan did not dedicate themselves to the study of the effect of drug use by psychotic patients but they made important contributions unfolding the theoretical and clinical psychoanalytical practice. Contemporary psychoanalytic authors suggest that the drug use made by psychotics differs from the use by neurotics, because of the particularity of the psychotic structure. It was found that drug use in psychosis can operate in three different ways: the first refers to drug use as substitute of a missing signifier helping the psychotic patient building a social bond. The second function is to intensify psychotic phenomena and the third function is to operate as an attempt to diminish those same phenomena. We conclude that, while the use of drugs in neurosis provides an individualist way of satisfaction, that excludes social aspects. For psychosis such use may operate differently and may play a role in social integration, among others effects. Such discussion can help move forward the direction of treatment of psychosis when the case involves drug use

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This dissertation aims to answer the question: What are the specifics of psychoanalytical clinic with children in neurosis and psychosis and its consequences for the treatment direction? It constitutes a theoretical study based on Freud, Lacan and the current productions of Lacanian psychoanalysts about the clinic with children. It presents some clinical vignettes. To answer this question, were constructed four chapters. The chapter The subject constitution treats the psychoanalysis subjectivity, based on a structure from the relationship with the Other. Key concepts of Lacanian psychoanalysis are shown, necessary to understand what becomes present in clinic with children. The second chapter, The clinic of neurosis, reveals the structure of the subject in its oedipal mooring held by the Name-of the-Father, that separates the mother-child dual relationship. The child neurosis is the effect of psyche constitution and the symptoms are an interpretation of what child picks up from parents and helps him/her on the passage through the Oedipus. The analyst is there to help him/her through this path. The next chapter is entitled The clinic of psychosis. In psychosis the non-occurrence of the Name-of-the-Father is concerned. The subject is stuck in duality with the mother, and becomes what fills the Other s gap. To protect themselves, they have to be in incessant work. The analyst will be a child s partner in daily work already carried out by him/her. The last chapter, The consequences for the treatment direction, shows that the standard analytic treatment works well to the clinic of neurosis. To psychosis it s not true. Psychoanalysts thought about a different way of psychotic children treatment: the practice held in a multiprofessional team work. The practice shared by many has been a team strategy applied to the institutional practice that aims to attenuate the invasive character of the Other, facilitating the partnership between the analyst and the child in treatment and the Other contention

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Chondroitin sulfate (CS) is a naturally glycosaminoglycan found in the extracellular matrix of connective tissues and it may be extracted and purified those tissues. CS is involved in various biological functions, which may be related to the having structural variability, despite the simplicity of the linear chain structure from this molecule. Researches in biotechnology and pharmaceutical field with wastes from aquaculture has been developed in Brazil. In recent decades, tilapia (Oreochromis niloticus), native fish from Africa, has been one of the most cultivated species in various regions of the world, including Brazil. The tilapia farming is a cost-effective activity, however, it generates large amount of wastes that are discarded by producers. It is understood that waste from tilapia can be used in research as a source of molecules with important biotechnological applications, which also helps in reducing environmental impacts and promote the development of an ecofriendly activity. Thus, nile tilapia viscera were subjected to proteolysis, then the glycosaminoglycans were complexed with ion exchange resin (Lewatit), it was fractionated with increasing volumes of acetone and purified by ion exchange chromatography DEAE-Sephacel. Further, the fraction was analyzed by agarose gel electrophoresis and nuclear magnetic resonance (NMR). The electrophoretic profile of the compound together the analysis of 1H NMR spectra and the HSQC correlation allow to affirm that the compound corresponds to a molecule like chondroitin sulfate. MTT assay was used to assess cell viability in the presence of CS tilapia isolated and showed that the compound is not cytotoxic to normal cells such as cells from the mouse embryo fibroblast (3T3). Then, this compound was tested for the ability to reduce the influx of leukocytes in model of acute peritonitis (in vivo) induced by sodium thioglycolate. In this context, it was done total and differential leukocytes counting in the blood and peritoneal fluid collected respectively from vena cava and the peritoneal cavity of the animals subjected to the experiment. The chondroitin sulfate for the first time isolated from tilapia (CST ) was able to reduce the migration of leukocytes to the peritoneal cavity of inflamed mice until 80.4 per cent at a dose 10µg/kg. The results also show that there was a significant reduction (p<0.001) of the population of polymorphonuclear leukocytes from peritoneal cavity in the three tested doses (0.1µg/kg; 1µg/kg and 10µg/kg) when it was compared to the positive control (just thioglycolate). Therefore, since the CST structure and mechanism of action has been completely elucidated, this compound may have potential for therapeutic use in inflammatory diseases

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This work presents a new ceramic material obtained through the incorporation of solid waste from the steel industry and known as dedusting powder PAE - in ceramic formulations based on clay, potassium and sodium feldspars, kaolin and talc. Formulations were prepared with ceramic residue levels of 0% (basic mass - MB), 2%, 4% and 8%, subjected to firing at temperatures of 1000 ° C, 1050ºC, 1100ºC and 1150ºC for periods of 15 min. and 120 min. The physicchemical and mechanical properties of these ceramic formulations were determined based on the firing temperature, residence time in the oven and the percentage of waste. Since the physicochemical and mechanical properties of the sintered materials were evaluated by chemical analysis techniques (fluorescence X-rays - FRX), particle size distribution, specific surface area, apparent density, structural analysis by diffraction of X-rays (DRX) and characterization of surface by scanning electron microscopy (SEM). The magnetic response characteristics and the pattern of magnetic ferrites of the samples were analyzed in the assay conditions, having noticed that the saturation magnetic susceptibility depend on the sintering temperature of the material and it is associated with its crystal structure. From the analysis results, it was concluded that the ceramic material with better physical and mechanical properties is obtained when the 8% from PAE residue is added to standard formulation under the burn time of 15 minutes and temperature of 1150ºC.