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Mostrando ítems 1-10 de 20

#### Usefulness of cutting planes in the hierarchical segmentation of cardiac anatomical structures

(IOP Publishing, 2019)

A spatial geometric plane is defined by the three-dimensional coordinates of a pair of
spatial points and the direction that the normal vector establishes, which is formed by joining
those points by means of an oriented line segment. This type of planes, in three-dimensional
images, is extremely useful as an alternative solution to the problem of low contrast that exhibit
the anatomical structures present in cardiac computed tomography images. To do this, after using
a predetermined filter bank and in order to define a region of interest, a ...

#### Brain hematoma computational segmentation

(IOP Publishing, 2018)

In computed tomography imaging, brain hematoma (BH) segmentation is a very
challenging process due to a high variability of BH morphology, low contrast and noisy
images. Because of this, BH segmentation is an open problem. In order to approach this
problem, we propose an automatic technique, named nonlinear technique (NLT), based on a
thresholding method, noise suppression filters, intelligent operators, a clustering strategy and a
binary morphological operator. NLT performance is assessed by Jaccard's similarity index
(JSI) used to compare ...

#### Newton-Raphson method initialization for non-analytical equations solution linked to anticipated annuities

(IOP Publishing, 2019)

The series of payments made in equal intervals of time is known, in the world of
financial mathematics, as an annuity. An anticipated annuity is one whose periodic payment
expires at the beginning of the established payment interval. The non-analytical equation that
allows us to calculate the interest rate, linked to the anticipated annuity, can be solved using
several numerical methods, in particular, the numerical method called Newton-Rhapson. The
main problem with this method is its initialization, which requires of one starting point ...

#### Pulmonary adenocarcinoma characterization using computed tomography images

(IOP Publishing, 2019)

Lung cancer is one of the pathologies that sensitively affects the health of human
beings. Particularly, the pathology called pulmonary adenocarcinoma represents 25% of all lung
cancers. In this research, we propose a semiautomatic technique for the characterization of a
tumor (adenocarcinoma type), present in a three-dimensional pulmonary computed tomography
dataset. Following the basic scheme of digital image processing, first, a bank of smoothing filters
and edge detectors is applied allowing the adequate preprocessing over the dataset ...

#### Smart operator for the human liver automatic segmentation, present in medical images

(IOP Publishing, 2019)

The segmentation of the human body organ called liver is a highly challenging problem due to the noise, artifacts and the low contrast exhibited by the anatomical structures located around the liver and that are present in digital images, generated by any modality of medical images. The main modalities are: ultrasound, nuclear emission, magnetic resonance and the gold standard called multi-slice computed tomography. In this paper, with the objective of to address this problem, we consider multi-slice computed tomography images and we propose an ...

#### Usefulness of digital images segmentation in pulmonary transplantation

(IOP Publishing, 2019)

In the presence of pulmonary pathologies such as chronic obstructive pulmonary
disease, diffuse pulmonary disease and cystic fibrosis, among others, it is common to require
the removal or replacement of a portion of lungs. There are several requirements for both
donors and organ receivers (recipients) established in the literature. May be the main one is the
volume that the donor's lungs occupy in the thoracic cavity. This parameter is vital because if
the volume of the lungs exceeds the thoracic cavity of the recipients the transplant, ...

#### New anisotropic diffusion operator in images filtering

(IOP Publishing, 2020)

The anisotropic di usion lters have become in the fundamental bases to address
the medical images noise problem. The main attributes of these lters are: the noise removal
e ectiveness and the preservation of the information belonging to the edges that delimit the
objects of an image. Due to these excellent attributes, through this article, a comparative study
is proposed between a new di usion operator and the Lorentz operator, proposed by the pioneers
of anisotropic di usion. For this, a strategy consisting of two phases is designed. In ...

#### Use of computational realistic models for the cardiac ejection fraction calculation

(IOP Publishing, 2019)

Ejection fraction is one of the most useful clinical descriptors to determine the cardiac
function of a subject. For this reason, obtaining the value of this descriptor is of vital importance
and requires high precision. However, in the clinical routine, to generate the mentioned
descriptor value, a geometric hypothesis is assumed, obtaining an approximate value for this
fraction, usually by excess, and which is a dependent-operator. The aim of the present work is
to propose the accurate calculation of the ejection fraction from realistic ...

#### Semi-automatic detection of the evolutionary forms of visceral leishmaniasis in microscopic blood smears

(IOP Publishing, 2019)

Leishmaniasis is a complex group of diseases caused by obligate unicellular and
intracellular eukaryotic protozoa of the leishmania genus. Leishmania species generate diverse
syndromes ranging from skin ulcers of spontaneous resolution to fatal visceral disease. These
syndromes belong to three categories: visceral leishmaniasis, cutaneous leishmaniasis and
mucosal leishmaniasis. The visceral leishmaniasis is based on the reticuloendothelial system
producing hepatomegaly, splenomegaly and lymphadenopathy. In the present article, a ...

#### Mathematical argumentation in the classroom

(IOP Publishing, 2019)

The article shares some elements of comprehensive type about "mathematical
argumentation in the classroom"; whose analysis, was made from two fundamental categories
in the development of an oral mathematical argumentation process for the conviction,
contradiction and validation of a written mathematical argumentation process. The research
addressed two central categories of argumentation as a discursive form, the first one is the
epistemic position, and the second one is the discursive position that students unveil at the time
of mathematically ...