Global intensity correction in dynamic scenes

Changing image intensities causes problems for many computer vision applications operating in unconstrained environments. We propose generally applicable algorithms to correct for global differences in intensity between images recorded with a static or slowly moving camera, regardless of the cause of intensity variation. The proposed intensity correction is based on intensity quotient estimation. Various intensity estimation methods are compared. Usability is evaluated with background classification as example application. For this application we introduced the PIPE error measure evaluating performance and robustness to parameter setting. Our approach retains local intensity information, is always operational and can cope with fast changes in intensity. We show that for intensity estimation, robustness to outliers is essential for dynamic scenes. For image sequences with changing intensity, the best performing algorithm (MofQ) improves foreground-background classification results up to a factor two to four on real data

Pixel masks for screen-door transparency

Rendering objects transparently gives additional insight in complex and overlapping structures. However, traditional techniques for the rendering of transparent objects such as alpha blending are not very well suited for the rendering of multiple transparent objects in dynamic scenes. Screen-door transparency is a technique to render transparent objects in a simple and efficient way: No sorting is required and intersecting polygons can be handled without further preprocessing. With this technique, polygons are rendered through a mask: Only where the mask is present, pixels are set. However, artifacts such as incorrect opacities and distracting patterns can easily occur if the masks are not carefully designed. In this paper, first the requirements on the masks are considered. Next, three algorithms are presented for the generation of pixel masks. One algorithm is designed for the creation of small (e.g. 4 $times$ 4) masks. The other two algorithms can be used for the creation of larger masks (e.g. 32 $times$ 32). For each of these algorithms results are presented and discussed

Energy density in the diet of workers from São Paulo, Brazil, and associated socio-demographic factors*

Objective: This paper aims at analyzing the energy density (ED) of the diet of workers from the city of São Paulo, Southeastern Brazil, and the way this is associated with socio-demographic characteristics, as well as evaluating the relationship between ED and nutrient intake. Methods: A cross-sectional study evaluated the diet of 852 workers using the 24-hour dietary recall; one recall was applied to all individuals and a second one was applied to a sub-sample in order to adjust intrapersonal variability. The ED of the diet was calculated using three methods: inclusion of all solid foods and beverages, excluding water (ED 1); inclusion of all solid foods and beverages containing at least 5 kcal/100g (ED 2); and inclusion of all solid foods, excluding all beverages (ED 3). Linear regression was used to analyze the relationship between ED and socio-demographic variables and the relationship between ED and nutrients was evaluated using Pearson coefficient correlation. Results: Considering the workers' diet, the ED values observed were 1.18 kcal/g, 1.22 kcal/g and 1.73 kcal/g for the ED 1, ED 2, ED 3 methods, respectively. In the multiple regression models, only the age variable was maintained in the final model and showed an inverse association with all ED methods. ED 3 showed an increase in energy density for non-white individuals. Of all studied nutrients, protein was the only one that was not significantly correlated with ED 3 (p = 0.899). Conclusion: The young adults studied had a higher energy-density diet, representing a priority group for nutrition interventions. Regardless of the calculation method used, there is a correlation between ED and nutrients.Objetivo: Analisar a densidade energética (DE) da dieta de trabalhadores da cidade de São Paulo e sua associação com características sociodemográficas, bem como avaliar a relação entre DE e ingestão de nutrientes. Métodos: Estudo transversal que avaliou a dieta de 852 trabalhadores, por meio de recordatório de 24 horas, sendo um recordatório aplicado a todos os indivíduos e um segundo para subamostra, a fim de corrigir a variabilidade intrapessoal. A DE da dieta foi calculada por três métodos: inclusão de todos os alimentos sólidos e das bebidas, excluindo apenas água (DE 1); inclusão de todos os alimentos sólidos e bebidas calóricas que contêm, no mínimo, 5 kcal/100g (DE 2); inclusão de todos os alimentos sólidos e exclusão de todas as bebidas (DE 3). Para analisar a relação entre a DE e as variáveis sociodemográficas utilizou-se regressão linear, e a relação entre DE e nutrientes foi avaliada por meio do coeficiente de correlação de Pearson. Resultados: Para a dieta dos trabalhadores, os valores de DE observados foram 1,18 kcal/g, 1,22 kcal/g e 1,73 kcal/g, considerando-se os métodos DE 1, DE 2 e DE 3, respectivamente. Nos modelos múltiplos de regressão, apenas a variável idade apresentou associação negativa com todos os métodos de DE. Para a DE 3, houve incremento da DE para indivíduos não brancos. Dentre os nutrientes estudados, o único que não apresentou correlação significativa foi a proteína, para DE 3 (p = 0,899). Conclusão: Os adultos jovens tinham uma alimentação com maior DE, sendo um grupo prioriatário para intervenções nutricionais. Além disso, independente do método de cálculo, há correlação entre a DE e os nutrientes da dieta.Universidade de São Paulo Faculdade de Saude Publica Programa de Pos Graduacao em NutricaoUniversidade Federal de São Paulo (UNIFESP) Instituto de Saude e Sociedade Departamento de Saude, Clinica e InstituicoesUniversidade de São Paulo Faculdade de Saude Publica Departamento de NutricaoUNIFESP, Instituto de Saude e Sociedade Depto. de Saude, Clinica e InstituicoesSciEL

Dynamic Partition of Collaborative Multiagent Based on Coordination Trees

In team Markov games research, it is difficult for an individual agent to calculate the reward of collaborative agents dynamically. We present a coordination tree structure whose nodes are agent subsets or an agent. Two kinds of weights of a tree are defined which describe the cost of an agent collaborating with an agent subset. We can calculate a collaborative agent subset and its minimal cost for collaboration using these coordination trees. Some experiments of a Markov game have been done by using this novel algorithm. The results of the experiments prove that this method outperforms related multi-agent reinforcement-learning methods based on alterable collaborative teams

Analysis of DNA based measurement methods applied to human chromosome classification

Applied Science