Percorrer por autor "Figueiredo, Isabel N."
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- Registration of Consecutive Frames From Wireless Capsule Endoscopy for 3D Motion EstimationPublication . Oliveira, Marina; Araujo, Helder; Figueiredo, Isabel N.; Pinto, Luís; Curto, Eva; Perdigoto, LuísWireless Capsule Endoscopy (WCE) is a non-invasive medical procedure devised for painless in vivo inspection of the gastrointestinal (GI) tract. It is especially valuable for the examination of the small intestine since it is difficult to reach by traditional endoscopic procedures. The setup includes a camera with an embedded light source and a circuit capable of acquiring and transmitting the video. The main challenge of this technology is the identification of the position and trajectory of the capsule as it travels through the GI tract, which is particularly relevant during the detection of anomalies in the tissue. Given only the information provided by the recorded images, it is possible to estimate the 3D motion of the camera capsule and provide a full trajectory reconstruction. A critical yet difficult step in this process is the image registration between sequential frames. Therefore, being able to determine accurate correspondences between points, regions or features in two consecutive frames is crucial for the computation of the relative rotation and translation of the capsule. This paper comprises a comparative assessment of methodologies to address this problem with a porcine colon dataset obtained with our experimental setup.
- Wireless Capsule Endoscope Location and a Robotic Validation ExperimentPublication . 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 techniques. The capsule was fixed at the extremity of a robotic arm and moved along a part of an ex-vivo mammalian bowel. The first validation results indicate a good correlation between the ground truth velocity and distance traveled by the capsule and the velocity and distance given by the proposed approach.