Localização e mapeamento simultâneos de ambientes planos usando visão monocular e representação híbrida do ambiente

The goal of this work is to propose a SLAM (Simultaneous Localization and Mapping) solution based on Extended Kalman Filter (EKF) in order to make possible a robot navigates along the environment using information from odometry and pre-existing lines on the floor. Initially, a segmentation step is necessary to classify parts of the image in floor or non floor . Then the image processing identifies floor lines and the parameters of these lines are mapped to world using a homography matrix. Finally, the identified lines are used in SLAM as landmarks in order to build a feature map. In parallel, using the corrected robot pose, the uncertainty about the pose and also the part non floor of the image, it is possible to build an occupancy grid map and generate a metric map with the obstacle s description. A greater autonomy for the robot is attained by using the two types of obtained map (the metric map and the features map). Thus, it is possible to run path planning tasks in parallel with localization and mapping. Practical results are presented to validate the proposal

Um método para determinação da profundidade combinando visão estéreo e autocalibração para aplicação em robótica móvel

This work proposes a method to determine the depth of objects in a scene using a combination between stereo vision and self-calibration techniques. Determining the rel- ative distance between visualized objects and a robot, with a stereo head, it is possible to navigate in unknown environments. Stereo vision techniques supply a depth measure by the combination of two or more images from the same scene. To achieve a depth estimates of the in scene objects a reconstruction of this scene geometry is necessary. For such reconstruction the relationship between the three-dimensional world coordi- nates and the two-dimensional images coordinates is necessary. Through the achievement of the cameras intrinsic parameters it is possible to make this coordinates systems relationship. These parameters can be gotten through geometric camera calibration, which, generally is made by a correlation between image characteristics of a calibration pattern with know dimensions. The cameras self-calibration allows the achievement of their intrinsic parameters without using a known calibration pattern, being possible their calculation and alteration during the displacement of the robot in an unknown environment. In this work a self-calibration method based in the three-dimensional polar coordinates to represent image features is presented. This representation is determined by the relationship between images features and horizontal and vertical opening cameras angles. Using the polar coordinates it is possible to geometrically reconstruct the scene. Through the proposed techniques combination it is possible to calculate a scene objects depth estimate, allowing the robot navigation in an unknown environment

Geometria e arirmética numa visão multicultural: uma experiência pedagógica

This paper aims to build a notebook of activities that can help the teacher of elementary school mathematics. Topics covered are arithmetic and geometry and the activities proposed here were developed aiming print them a multicultural character. We take as a base line developed by Claudia Zaslavsky multiculturalism and reflected in his books "Games and activities worldwide" and "More games and activities worldwide." We structure our work around four themes: the symbol of the Olympic Games, the pyramids of Egypt, the Russian abacus abacus and Chinese. The first two themes allow you to explore basic concepts of geometry while the latter two themes allow us to explore numerical notation and arithmetic operations

O mundo criado pelas imagens: paisagens e espaços coloniais na obra do holandês Frans Post

The aims of this dissertation is to study formation of the Dutch view seeing the colonial scenery in screens by Frans Post, as well as, to perceive a colonial world constitution through landscape paintings by him with his natural and human representation. The artist was the first to portray South American views, after he landed in Pernambuco with retinue of Dutch governor of colony, John Maurice, Prince of Nassau-Siegen. Post, by his 24 years old, was designated to represent for Dutch people their colony. The text reflects on visual construction of natural and human aspects in landscapes by Dutchman and how that aspects were included in colonizer imaginary about the strange world of America. European (Dutch) look about their conquered possessions in the New World was charged with exoticism and imagination. In order to understand that view, it`s paramount to study imaginary pictures reared by Frans Post, on his return to the Netherlands, and notions of landscape and exotic, wild and unspoiled nature which the Dutch people had when they thought about the Dutch colony in America. Our principal (visual) sources of research are six paintings: Vista da Sé de Olinda (1662), Vista das ruínas de Olinda (undated), Engenho (undated), Engenho (1660), Vista da cidade Maurícia e do Recife (1653), e Paisagem com rio e tamanduá (1649), all these canvases were painted when Frans Post returned to Europe. We seek to work through a methodology that focuses on investigation of primary visual and textual material, because these textual and pictorial representations reflect the 17th-century colonial view of colonial history themes of the - here called - Dutch America

Detecção de predadores por dicromatas e tricromatas humanos e a sua implicação na evolução da visão de cores em primatas

Among placental mammals, primates are the only ones to present trichromatic color vision. However, the distribution of trichromacy among primates is not homogeneous: Old World primates shows an uniform trichromacy (with all individuals being trichromats) and New World primates exhibit a color vision polymorphism (with dichromatic males and dichromatic or trichromatic females). Visual ecology studies have investigated which selective pressures may have been responsible for the evolution of trichromacy in primates, diverging from the dichromat standard found in other mammals. Cues associated with foraging and the socio-reproductive status were analyzed, indicating a trichromatic advantage for the rapid detection of visually conspicuous objects against a green background. However, dichromats are characterized by an efficient capture of cryptic and camouflaged stimuli. These advantages regarding phenotype may be responsible for the maintenance of the visual polymorphism in New World primates and for the high incidence of color blindness in humans (standing around 8% in Caucasian men). An important factor that has not yet been experimentally taken into account is the predation risk and its effect on the evolution of trichromacy in primates. To answer this question, we prepared and edited pictures of animals with different coats: oncillas (Leopardus spp.), puma (Puma concolor) and ferret (Galictis cuja). The specimens were taxidermized and the photographs were taken in three different vegetation scenarios (dense forest, cerrado and grassland). The images of the predators were manipulated so that they fit into two categories of stimulus size (small or large). After color calibration and photo editing, these were presented to 40 humans (20 dichromats and 20 trichromats) by a computer program, which presented a set of four photos at a time (one picture containing the taxidermized animal amid the background vegetation and three depicting only the background vegetation) and recorded the response latency and success rate of the subjects. The results show a trichromatic advantage in detecting potential predators. The predator detection was influenced by the background, the predator species, the dimension of the stimulus and the observer s visual phenotype. As humans have a high rate of dyschromatopsias, when compared to wild Catarrhini or human tribal populations, it is possible that the increased rate of dichromats is a result of reduced pressure for rapid predator detection. Since our species came to live in more cohesive groups and resistant to attack by predators, with the advent of agriculture and the formation of villages, it is possible that the lower risk of predation has reduced the selection in favor of trichromats

Práticas e características do jornalismo alternativo e contra hegemônico de agência de informação: uma visão a partir da rotina produtiva da Adital

The strong presence of the communication and information technologies (TICs) forced the productive routine of some media vehicles to go through significant changes. The same happened to the alternative agencies segment. Having a scarce literature and sources about this subject, this study’s objective is to understand how the Information Agency Frei Tito for Latin America (Adital) develops its proposal of alternative journalism, within the cyberspace, while aiming a Christian communication. For this finality, the study will describe and explain the practices of journalistic production, identifying the subjects involved and the relations maintained between them in this productive routine. Also, it will trace who and where these content replicators are and/or their online address. At first, it was presented a theoretical discussion about the concepts of “counter-hegemony”, alternative journalism and communicative citizenship, what brings us to the studies of Gramsci (2010), Peruzzo (2011), Moraes (2013), Paiva (2008), Coutinho (2008), Mata (2006), among other authors. Next, it will be approached briefly the historical path of the information agencies around the world and in Latin America, so that the study can focus on authors like Aguiar (2009), Pasti (2013) and Moraes (2010). This piece will draught a “methodologic route” for a qualitative approach with an exploratory and descriptive character. We gave up the etnometodological methods, what allow us to analyze the etnomethods or behavioral groups of action, procedures, activities and knowledge that constitutes these groups, giving them recognition and distinction. (COULON, 1995). To achieve the defined objectives, it was also used a bibliographical and documental research techniques, in addition to subject observation and semi-structured interviews. Finally, we analyze the collected data taking into consideration three pivots: the beginning of Adital; the practices, characteristics and subjects involved in the productive routine of the agency; and who are and where are these content replicators of content produced and transmitted by Adital. We can conclude that the production routine of an alternative agency and the counter-hegemonic of information is marked by some singularities regarding to the organization of the journalistic practice and to the obstacles found on the way. Our data allows us, even if there are still some doubts, to believe that Adital is a sort of independent information agency, alternative and counter-hegemonic, ergo, more close to a proposition of communicative citizenship.

Práticas e características do jornalismo alternativo e contra hegemônico de agência de informação: uma visão a partir da rotina produtiva da Adital

The strong presence of the communication and information technologies (TICs) forced the productive routine of some media vehicles to go through significant changes. The same happened to the alternative agencies segment. Having a scarce literature and sources about this subject, this study’s objective is to understand how the Information Agency Frei Tito for Latin America (Adital) develops its proposal of alternative journalism, within the cyberspace, while aiming a Christian communication. For this finality, the study will describe and explain the practices of journalistic production, identifying the subjects involved and the relations maintained between them in this productive routine. Also, it will trace who and where these content replicators are and/or their online address. At first, it was presented a theoretical discussion about the concepts of “counter-hegemony”, alternative journalism and communicative citizenship, what brings us to the studies of Gramsci (2010), Peruzzo (2011), Moraes (2013), Paiva (2008), Coutinho (2008), Mata (2006), among other authors. Next, it will be approached briefly the historical path of the information agencies around the world and in Latin America, so that the study can focus on authors like Aguiar (2009), Pasti (2013) and Moraes (2010). This piece will draught a “methodologic route” for a qualitative approach with an exploratory and descriptive character. We gave up the etnometodological methods, what allow us to analyze the etnomethods or behavioral groups of action, procedures, activities and knowledge that constitutes these groups, giving them recognition and distinction. (COULON, 1995). To achieve the defined objectives, it was also used a bibliographical and documental research techniques, in addition to subject observation and semi-structured interviews. Finally, we analyze the collected data taking into consideration three pivots: the beginning of Adital; the practices, characteristics and subjects involved in the productive routine of the agency; and who are and where are these content replicators of content produced and transmitted by Adital. We can conclude that the production routine of an alternative agency and the counter-hegemonic of information is marked by some singularities regarding to the organization of the journalistic practice and to the obstacles found on the way. Our data allows us, even if there are still some doubts, to believe that Adital is a sort of independent information agency, alternative and counter-hegemonic, ergo, more close to a proposition of communicative citizenship.