NON-LINEAR CAMERA CALIBRATION FOR 3D RECONSTRUCTION USING STRAIGHT LINE PLANE OBJECT

One critical aspect to 3D reconstruction of human motion using videogrammetry is related to the need for an accurate calibration of large volumes. Most of calibration methods used in biomechanics requires the construction, transportation and measurement of rigid structures and this is more difficult when larger volumes are involved. Recently, alternative approaches have been proposed to overcome this critical aspect (Cerveri et al., 1998; Zhang, 2000). This work presents preliminary results of the proposition and evaluation of a non-linear camera calibration method for 3D reconstruction using a plane object containing straight lines

Avaliação da intensidade de tráfego e carga de um forwarder sobre a compactação de um latossolo vermelho-amarelo.

A operação de baldeio florestal está relacionada ao uso de máquinas, as quais trafegam numa mesma linha várias vezes ou aleatoriamente, o que pode causar compactação do solo, alterando o meio onde o sistema radicular se desenvolve e reduzindo a produtividade. Além do número de passadas, a carga de madeira transportada pode afetar a compactação do solo quando as pressões aplicadas pelas máquinas excederem a capacidade de suporte de carga desse solo. Os objetivos deste estudo foram: a) propor modelo de capacidade de suporte de carga para Latossolo Vermelho-Amarelo no Município de Santa Maria de Itabira, MG, em razão da pressão de pré-consolidação e da umidade; e b) determinar, com o uso deste modelo, o efeito da intensidade de tráfego e da carga de Forwarder sobre a estrutura do solo. Para a obtenção dos modelos de capacidade de suporte de carga, 20 amostras indeformadas de solo foram coletadas nas profundidades de 0-3 e 10-13 cm no local onde não houve tráfego. Foram também coletadas 10 amostras indeformadas em cada profundidade, onde o Forwarder trafegou duas, quatro e oito vezes e no local onde o Forwarder trafegou quatro vezes com 1/3 (3 m3), 2/3 (6 m3) e 3/3 (9 m3) de sua carga. As amostras indeformadas foram utilizadas nos ensaios de compressão uniaxial. Determinaram-se também a textura, o teor de matéria orgânica e a densidade de partículas e densidade dos solos. O modelo de capacidade de suporte de carga do LVA é expresso pela equação σp = 10(2,71 - 1,36 U). Todas as intensidades de tráfego causaram compactação no solo nas duas profundidades estudadas, sendo quatro passadas as que causaram maior compactação do solo, e, à medida que a carga do Forwarder aumentou, a compactação do solo também aumentou nas duas profundidades

UNDERWATER NON-LINEAR CAMERA CALIBRATION: AN ACCURACY ANALYSIS

One of the most challenging problems associated with underwater 3D movement analysis is the accurate calibration of the cameras. Additional sources of errors are present in underwater acquisitions such as the nonlinear distortion caused by water interface, camera lenses (ex. wide angle) and housing’s glasses. Despite this, in the literature, systems based on a linear calibration model (DLT) were proposed (Yanai et al., 1996; Machtsiras & Sanders, 2009; Gourgoulis, et al. 2008). However, the results of underwater accuracy were not similar to those obtained out of the water. In Kwon, et al. 1999, the use of a modified DLT algorithm to model the distortion was proposed but the results of accuracy were not substantially improved, with Root Mean Square (RMS) values ranging from 5.6 to 7.2mm. Recently, alternative approaches were proposed to non-linear camera calibration and submillimeter accuracy was reached (Cerveri et al., 1998; Zhang, 2000; Pribanić, Sturm & Cifrek, 2008). However, these approaches were not applied underwater. In previous work, a new non-linear calibration method using a straight line plane object was proposed and tested out of the water (Silvatti et al., 2009 available in http://calib.googlecode.com). In this work, this novel method was tested in underwater conditions and its accuracy evaluated

Lithography-Free, Omnidirectional, CMOS-Compatible AlCu Alloys for Thin-Film Superabsorbers

Superabsorbers based on metasurfaces have recently enabled the control of light at the nanoscale in unprecedented ways. Nevertheless, the sub‐wavelength features needed to modify the absorption band usually require complex fabrication methods, such as electron‐beam lithography. To overcome the scalability limitations associated with the fabrication of metallic nanostructures, engineering the optical response of superabsorbers by metal alloying is proposed, instead of tuning the geometry/size of the nanoscale building blocks. The superior performance of thin film AlCu alloys as the metallic component of planar bilayer superabsorbers is numerically demonstrated. This alloy outperforms its pure constituents as well as other metals, such as Ag, Au, and Cr. As a model system, a Si/AlCu structure is analyzed that presents \u3e99% absorption at selected wavelength ranging from the visible to the near‐infrared regions of the spectrum, depending on the subwavelength thickness of the semiconductor. The multi‐wavelength near‐unity absorption behavior of Si/AlCu persists even for oblique angle of incidence, up to 70°. Additionally, the findings are validated by fabricating and testing a‐Si/AlCu superabsorbers, where good agreement is found between the numerically and experimentally determined optical response. The system investigated here is relevant for integration in complementary metal‐oxide‐semiconductor (CMOS) technologies

Indifferentiated osteoclastic-type giant cell carcinoma

Initially described 40 years ago (Rosai), the undifferentiated osteoclastic-type giant cell carcinoma (IOGCC) is a variant of ductal adenocarcinoma and accounts for less than 1% of exocrine pancreatic tumors. Its extreme rarity, with consequent existence of few reports and clinical experience, leads to the arousal of doubts with regard to its histogenesis, types of approach and therapeutical attitudes. It is important to note that in Portugal no similar case is registered in medical literature. A 61 year old patient admitted to the Internal Medicine Ward 3 at Coimbra University Hospital presents with a volumous intra-abdominal mass in the left hypochondrium and microcytic anemia. During the investigation, a pancreatic neoplasm was identified, and the patient was submitted to surgical resection, the anatomo-pathological study of the tumor having revealed IOGCC. The particularities of the case, current available therapeutical options and its evolution are discussed, as well as a revision of the existing literature

Estimation of carbon stock and nitrogen in the semiarid region.

The management and use of the soil in semi-arid areas, over time have caused significant decreases of carbon (C) and nitrogen (N) in these soils, due to the fact that it is a region where normally enough conditions are found favorable to the different decomposition processes of MOS, with man being the main agent responsible for these phenomena

Hyperendemicity, heterogeneity and spatial overlap of leprosy and cutaneous leishmaniasis in the southern Amazon region of Brazil

Neglected tropical diseases characterized by skin lesions are highly endemic in the state of Mato Grosso, Brazil. We analyzed the spatial distribution of leprosy and Cutaneous Leishmaniasis (CL) and identified the degree of overlap in their distribution. All new cases of leprosy and CL reported between 2008 and 2017 through the national reporting system were included in the study. Scan statistics together with univariate Global and Local Moran's I were employed to identify clusters and spatial autocorrelation for each disease, with the spatial correlation between leprosy and CL measured by bivariate Global and Local Moran's I. Finally, we evaluated the demographic characteristics of the patients. The number of leprosy (N = 28,204) and CL (N = 24,771) cases in Mato Grosso and the highly smoothed detection coefficients indicated hyperendemicity and spatial distribution heterogeneity. Scan statistics demonstrated overlap of high-risk clusters for leprosy (RR = 2.0; p <0.001) and CL (RR = 4.0; p <0.001) in the North and Northeast mesoregions. Global Moran's I revealed a spatial autocorrelation for leprosy (0.228; p = 0.001) and CL (0.311; p = 0.001) and a correlation between them (0.164; p = 0.001). Both diseases were found to be concentrated in urban areas among men aged 31-60 years, of brown-skinned ethnicity and with a low educational level. Our findings indicate a need for developing integrated and spatially as well as socio-demographically targeted public health policies