6 documents found, page 1 of 1
Wireless Capsule Endoscope Location and a Robotic Validation Experiment
Figueiredo, Isabel N.; Pinto, Luís; Perdigoto, Luís; Oliveira, Marina; Araújo, Hélder; Figueiredo, Pedro N.We present results concerning the validation of a novel approach for wireless capsule endoscope localization, using as ground truth a simulated biological/mechanical environment experiment. The approach relies essentially on image-based methods. It involves a hybrid multi-scale affine and elastic image registration procedure which is afterwards appropriately complemented with calibration and visual odometry tec...
Dissimilarity Measure of Consecutive Frames in Wireless Capsule Endoscopy Video...
Figueiredo, Isabel Narra; Leal, Carlos; Pinto, Luis; Figueiredo, Pedro N.; Tsai, RichardIn a previous work we have shown that the curve representing the dissimilarity measure between consecutive frames of a wireless capsule endoscopic video of the small bowel, obtained by means of an image registration method, can be regarded as a rough indicator of the speed of the capsule, and simultaneously, it is also a valuable auxiliary medical tool. In effect, this curve enables a global and fast interpreta...
Computer-assisted bleeding detection in wireless capsule endoscopy images
Figueiredo, Isabel N.; Kumar, Sunil; Leal, Carlos; Figueiredo, Pedro N.Wireless capsule endoscopy (WCE) has revolutionised the diagnosis and treatment of gastrointestinal tract, especially the small intestine where traditional endoscopies cannot reach. However, this new technology leads to the inspection of a large number of images, which is a time-consuming process and also too hard by naked eyes for doctors. In this paper, we propose a new computerised method for bleeding detect...
Automatic Polyp Detection in Pillcam Colon 2 Capsule Images and Videos: Prelimi...
Figueiredo, Pedro N.; Figueiredo, Isabel N.; Prasath, Surya; Tsai, RichardBackground. The aim of this work is to present an automatic colorectal polyp detection scheme for capsule endoscopy. Methods. PillCam COLON2 capsule-based images and videos were used in our study. The database consists of full exam videos from five patients. The algorithm is based on the assumption that the polyps show up as a protrusion in the captured images and is expressed bymeans of a P-value, defined by g...
A coupled convection-diffusion level set model for tracking epithelial cells in...
Figueiredo, Isabel N.; Leal, Carlos; Leonori, Tommaso; Romanazzi, Giuseppe; Figueiredo, Pedro N.; Donato, M. ManuelColorectal cancer is initiated in colonic crypts as a consequence of alterations leading to the disruption of the normal colonic cellular process. We propose a new model, which couples a convection-di usion type equation with a level set equation, for tracking the time evolution of an epithelial cell set, inside a colonic crypt, until it reaches the top of the crypt. The convection-di usion equation describes t...
A mathematical model for a comprehensive approach to the dynamics of human colo...
Figueiredo, Isabel N.; Figueiredo, Pedro N.; Leal, Carlos; Urbano, José MiguelIn this paper, we propose mathematical models for the growth dynamics of aberrant crypt foci in the human colon, as well as for some of their characteristics, namely the apoptosis and proliferation indices. The models rely on logistic type differential equations and clinical observations at different times, and can arguably be used as an auxiliary screening tool for colon cancer. We report several results using...