Embedded landmark acquisition system for visual slam using star identification based stereo correspondence descriptor

Orientador : Prof. Dr. Eduardo TodtDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 13/04/2015Inclui referênciasResumo: O uso de câmeras como sensores principais em Localização e Mapeamento Simultâneos (Simultaneous Localization and Mapping), o que é denominado SLAM Visual (Visual SLAM), tem crescido recentemente devido à queda nos preços das câmeras. Ao mesmo tempo em que imagens trazem informações mais ricas do que outros sensores típicos empregados em aplicações SLAM, como lasers e sonares, há um custo adicional de processamento significativo quando elas são utilizadas. A informação de profundidade adicional proveniente de configurações estéreo de câmeras às fazem mais interessantes para aplicações SLAM. Nesta abordagem em especial, grande parte do custo de processamento adicional vem da extração de pontos únicos ou pedaços em ambas as imagens em estéreo e da solução do problema de correspondência entre eles. Com posse dessa informação, a disparidade horizontal entre o par de imagens pode ser utilizada para recuperar a informação de profundidade. Esse trabalho explora a utilização de uma plataforma embarcada do tipo system-ona- chip (SoC) que integra um processador ARM multinúcleo com lógica FPGA como um módulo de processamento para visão estéreo. O detector de cantos Harris e Stephens (Harris & Stephens, 1988) é usado para encontrar pontos de interesse (Points of Interest, POIs) em imagens estéreo em um coprocessador soft sintetizado no FPGA para acelerar a extração de características e livrar o processador principal deste processo altamente paralelizável. As tarefas restantes tais como correção das imagens pela calibração de câmeras, encontrar um descritor único para as características detectadas e a correspondência entre os POIs no par de imagens estéreo são solucionadas em software executando no processador principal. A arquitetura proposta para o coprocessador permite que a tarefa de extração de cantos seja executada em aproximadamente metade do tempo necessário pelo processador principal sem auxílio algum. Após encontrar os POIs, para cada um dos pontos um descritor único é necessário para que seja possível encontrar o POI correspondente na outra imagem. Esse trabalho também propõe um descritor inovador que considera o relacionamento espacial bidimensional global entre os pontos detectados para descrevê-los individualmente. Para cada imagem, cada ponto da nuvem de pontos detectada pelo algoritmo de Harris e Stephens é descrito considerando-se apenas as posições relativas entre ele e seus vizinhos. Quando somente a posição é considerada, um padrão de céu estrelado noturno é formado pelos POIs. Com o padrão de POIs sendo considerado como estrelas, descritores já utilizados em problemas de identificação de estrelas podem ser reaplicados para identificar unicamente POIs. Um protótipo do descritor baseado do algoritmo de grade de Padgett e KreutzDelgado (Padgett & KreutzDelgado, 1997) é escrito e seus resultados comparados com os descritores normalmente utilizados para este propósito, mostrando que a informação espacial bidimensional pode ser utilizada por si só para resolver o problema de correspondência. O número de correspondências úteis é comparável ao atingido com o SIFT, o descritor com melhor desempenho neste quesito, enquanto a velocidade foi superior ao BRIEF, o descritor mais rápido utilizado na comparação, na plataforma ARM, com um speedup de 1,64 e 1,40 nas bases de dados dos testes. Palavras-chave: Harris; FPGA; SLAM; Hardware Reconfigurável; VHDL; Processamento de Imagem; Visão Estéreo; Computer Vision; Arquitetura Híbrida; Sistemas Embarcados; Pontos de Interesse; Keypoints; Correspondência; Correspondência Estéreo; Identificação de Estrelas; Descrição de Características; Percepção de Profundidade.Abstract: The use of cameras as the main sensors in Simultaneous Localization and Mapping, what is called Visual SLAM, has risen recently due to the fall in camera prices. While images bring richer information than other typical SLAM sensors, such as lasers and sonars, there is significant extra processing cost when they are used. The extra depth information available from stereo camera setups makes them preferable for SLAM applications. In this particular approach, great part of the added processing cost comes from extracting unique points or image patches in both stereo images and solving the correspondence problem between them. With this information, the horizontal disparity between the pair can be used to retrieve depth information. This work explores the use of an embedded system-on-a-chip (SoC) platform that integrates a multicore ARM processor with FPGA fabric as a stereo vision processing module. The Harris and Stephens corner detector (Harris & Stephens, 1988) is used to find Point of Interests (POIs) in stereo images in a hardware soft co-processor synthesized in the FPGA to speed up feature extraction and relieve this highly parallelizable process from the main embedded processor. Remaining tasks such as image correction from camera calibration, finding unique descriptor for the detected features and the correspondence between POIs in the stereo pair are solved in software running on the main processor. The proposed architecture for the co-processor enabled the corner extraction task to be performed in about half the time taken by the main processor without aid. After finding the POIs, for each point a unique descriptor is needed for finding the correspondent POI in the other image. This work also proposes an innovative descriptor that considers a global two-dimensional spatial relationship between the detected points to describe them individually. In each image, every point in the cloud of points detected by the Harris and Stephens algorithm is described by considering only the relative position between it and its neighbors. When position alone is considered, a starry night pattern is formed by the POIs. With the POI pattern being considered as stars, the descriptors already used in star identification problems can be reapplied to uniquely identify POIs. A prototype of the descriptor based on the Padgett and KreutzDelgado's grid algorithm (Padgett & KreutzDelgado, 1997) is written and the results compared with common descriptors used for this purpose, showing that two-dimensional spatial information alone can be used to solve the correspondence problem. The number of useful matches was comparable to what was obtained with SIFT, the best performing descriptor in this matter, while the speed was superior to BRIEF, the fastest descriptor used in the comparison, on the ARM platform, with a speedup of 1.64 and 1.40 on the tested datasets. Keywords: Harris; FPGA; SLAM; Reconfigurable Hardware; VHDL; Image Processing; Stereo Vision; Computer Vision; Hybrid Architecture; Embedded Systems; Point Of Interest; Keypoints; Matching; Stereo Correspondence; Star Identification; Feature Description; Depth Perception

Universal Verification Platform and Star Simulator for Fast Star Tracker Design

Developing star trackers quickly is non-trivial. Achieving reproducible results and comparing different algorithms are also open problems. In this sense, this work proposes the use of synthetic star images (a simulated sky), allied with the standardized structure of the Universal Verification Methodology as the base of a design approach. The aim is to organize the project, speed up the development time by providing a standard verification methodology. Future rework is reduced through two methods: a verification platform that us shared under a free software licence; and the layout of Universal Verification Methodology enforces reusability of code through an object-oriented approach. We propose a black-box structure for the verification platform with standard interfaces, and provide examples showing how this approach can be applied to the development of a star tracker for small satellites, targeting a system-on-a-chip design. The same test benches were applied to both early conceptual software-only implementations, and later optimized software-hardware hybrid systems, in a hardware-in-the-loop configuration. This test bench reuse strategy was interesting also to show the regression test capability of the developed platform. Furthermore, the simulator was used to inject specific noise, in order to evaluate the system under some real-world conditions

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

Peer reviewe

Search for a light pseudoscalar Higgs boson in the boosted mu mu tau tau final state in proton-proton collisions at root s=13 TeV

A search for a light pseudoscalar Higgs boson (a) decaying from the 125 GeV (or a heavier) scalar Higgs boson (H) is performed using the 2016 LHC proton-proton collision data at root s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), collected by the CMS experiment. The analysis considers gluon fusion and vector boson fusion production of the H, followed by the decay H -> aa -> mu mu tau tau, and considers pseudoscalar masses in the range 3.6 aa -> mu mu tau tau, down to 1.5 (2.0)x10(-4) for m(H) = 125 (300) GeV. Model-dependent limits on B(H -> aa) are set within the context of two Higgs doublets plus singlet models, with the most stringent results obtained for Type-III models. These results extend current LHC searches for heavier a bosons that decay to resolved lepton pairs and provide the first such bounds for an H boson with a mass above 125 GeV.Peer reviewe

Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

Observation of the Production of Three Massive Gauge Bosons at root s=13 TeV

The first observation is reported of the combined production of three massive gauge bosons (VVV with V = W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb(-1). The searches for individualWWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combinedVVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02(-0.23)(+0.26). The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported