Automated recognition of lung diseases in CT images based on the optimum-path forest classifier

The World Health Organization estimated that around 300 million people have asthma, and 210 million people are affected by Chronic Obstructive Pulmonary Disease (COPD). Also, it is estimated that the number of deaths from COPD increased 30% in 2015 and COPD will become the third major cause of death worldwide by 2030. These statistics about lung diseases get worse when one considers fibrosis, calcifications and other diseases. For the public health system, the early and accurate diagnosis of any pulmonary disease is mandatory for effective treatments and prevention of further deaths. In this sense, this work consists in using information from lung images to identify and classify lung diseases. Two steps are required to achieve these goals: automatically extraction of representative image features of the lungs and recognition of the possible disease using a computational classifier. As to the first step, this work proposes an approach that combines Spatial Interdependence Matrix (SIM) and Visual Information Fidelity (VIF). Concerning the second step, we propose to employ a Gaussian-based distance to be used together with the optimum-path forest (OPF) classifier to classify the lungs under study as normal or with fibrosis, or even affected by COPD. Moreover, to confirm the robustness of OPF in this classification problem, we also considered Support Vector Machines and a Multilayer Perceptron Neural Network for comparison purposes. Overall, the results confirmed the good performance of the OPF configured with the Gaussian distance when applied to SIM- and VIF-based features. The performance scores achieved by the OPF classifier were as follows: average accuracy of 98.2%, total processing time of 117 microseconds in a common personal laptop, and F-score of 95.2% for the three classification classes. These results showed that OPF is a very competitive classifier, and suitable to be used for lung disease classification

Content-based image retrieval based on relevance feedback and optimum-path forest classifier

Orientadores: Léo Pini Magalhães, Alexandre Xavier FalcãoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Com o crescente aumento de coleções de imagens resultantes da popularização da Internet e das câmeras digitais, métodos eficientes de busca tornam-se cada vez mais necessários. Neste contexto, esta tese propõe novos métodos de recuperação de imagens por conteúdo baseados em realimentação de relevância e no classificador por floresta de caminhos ótimos (OPF - Optimum-Path Forest), sendo também a primeira vez que o classificador OPF é utilizado em conjuntos de treinamento pequenos. Esta tese denomina como guloso e planejado os dois paradigmas distintos de aprendizagem por realimentação de relevância considerando as imagens retornadas. O primeiro paradigma tenta retornar a cada iteração sempre as imagens mais relevantes para o usuário, enquanto o segundo utiliza no aprendizado as imagens consideradas mais informativas ou difíceis de classificar. São apresentados os algoritmos de realimentação de relevância baseados em OPF utilizando ambos os paradigmas com descritor único. São utilizadas também duas técnicas de combinação de descritores juntamente com os métodos de realimentação de relevância baseados em OPF para melhorar a eficácia do processo de aprendizagem. A primeira, MSPS (Multi-Scale Parameter Search), é utilizada pela primeira vez em recuperação de imagens por conteúdo, enquanto a segunda é uma técnica consolidada baseada em programação genética. Uma nova abordagem para realimentação de relevância utilizando o classificador OPF em dois níveis de interesse é também apresentada. Nesta abordagem é possível, em um nível de interesse, selecionar os pixels nas imagens, além de escolher as imagens mais relevantes a cada iteração no outro nível. Esta tese mostra que o uso do classificador OPF para recuperação de imagens por conteúdo é muito eficiente e eficaz, necessitando de poucas iterações de aprendizado para apresentar os resultados desejados aos usuários. As simulações mostram que os métodos propostos superam os métodos de referência baseados em múltiplos pontos de consulta e em máquina de vetor de suporte (SVM). Além disso, os métodos propostos de busca de imagens baseados no classificador por floresta de caminhos ótimos mostraram ser em média 52 vezes mais rápidos do que os métodos baseados em máquina de vetor de suporteAbstract: Considering the increasing amount of image collections that result from popularization of the digital cameras and the Internet, efficient search methods are becoming increasingly necessary. In this context, this doctoral dissertation proposes new methods for content-based image retrieval based on relevance feedback and on the OPF (optimum-path forest) classifier, being also the first time that the OPF classifier is used in small training sets. This doctoral dissertation names as "greedy" and "planned" the two distinct learning paradigms for relevance feedback taking into account the returned images. The first paradigm attempts to return the images most relevant to the user at each iteration, while the second returns the images considered the most informative or difficult to be classified. The dissertation presents relevance feedback algorithms based on the OPF classifier using both paradigms with single descriptor. Two techniques for combining descriptors are also presented along with the relevance feedback methods based on OPF to improve the effectiveness of the learning process. The first one, MSPS (Multi-Scale Search Parameter), is used for the first time in content-based image retrieval and the second is a consolidated technique based on genetic programming. A new approach of relevance feedback using the OPF classifier at two levels of interest is also shown. In this approach it is possible to select the pixels in images at a level of interest and to choose the most relevant images at each iteration at another level. This dissertation shows that the use of the OPF classifier for content based image retrieval is very efficient and effective, requiring few learning iterations to produce the desired results to the users. Simulations show that the proposed methods outperform the reference methods based on multi-point query and support vector machine. Besides, the methods based on optimum-path forest have shown to be on the average 52 times faster than the SVM-based approachesDoutoradoEngenharia de ComputaçãoDoutor em Engenharia Elétric

Urban metabolism and land use modeling for urban designers and planners: A land use model for the Integrated Urban Metabolism Analysis Tool

Predicting the resource consumption in the built environment and its associated environmental consequences (urban metabolism analysis) is one of the core challenges facing policy-makers and planners seeking to increase the sustainability of urban areas. There is a critical need for a single integrated framework to analyze the consequences of urban growth and eventually predict the impacts of sustainable policies on the urbanscape. This dissertation presents the development of an Integrated Urban Metabolism Analysis Tool (IUMAT) – an analytical framework that simulates urban metabolism by integrating urban subsystems in a single comprehensive computational environment. It reviews the existing literature on urban sustainability, urban metabolism, as well as introducing the general framework for IUMAT. IUMAT uses three separate models for quantifying environmental impacts of land-use transition, consumption of resources, and transportation. This work outlines the development of IUMAT Land-Use Model that uses Remote Sensing, GIS, and Artificial Neural Networks (ANNs) to predict land use change patterns. By using Density-Based Spatial Clustering and normal equations, this dissertation introduces a method for generating building-form variables from Light Detection and Ranging (LIDAR) data, which can be used as a new determinant factor in land-use change modeling. The proposed Land-use Model, within IUMAT or other analytical models, can be useful to local planning officials in understanding the complexity of land-use change and developing enhanced land-use policies