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Percorrer por autor "Perdigoto, Luís"

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  • Calibration of mirror position and extrinsic parameters in axial non-central catadioptric systems
    Publication . Perdigoto, Luís; Araujo, Helder
    We propose a novel calibration method for catadioptric systems made up of an axial symmetrical mirror and a pinhole camera with its optical center located at the mirror axis. The calibration estimates the relative camera/mirror position and the extrinsic rotation and translation w.r.t. the world frame. The procedure requires a single image of a (possibly planar) calibration object. We show how most of the calibration parameters can be estimated using linear methods (Direct-Linear-Transformation algorithm) and cross-ratio. Two remaining parameters are obtained by using non-linear optimization. We present experimental results on simulated and real images.
    2013-08Artigo científico Acesso restrito Ver mais
  • End-to-End Management System Framework for Smart Public Buildings
    Publication . Jesus, Ivo; Pereira, Tomás; Marques, Pedro; Sousa, João; Perdigoto, Luís; Coelho, Paulo
    This paper presents a project aiming to design a complete framework to measure energy (electricity and gas) and water consumptions in a local Parish Council building and an adjacent Sports Hall located in the central part of Portugal. The goal is an end-to-end solution, from data acquisition to data analysis. Besides acquiring and storing the data, the aim is to make this information available and valuable to enhance better decisions in building management actions, to enable detection of situations of anomalous consumption and also to promote building users' awareness. To pursue this goal, PLCnext technology solutions from Phoenix Contact are adopted. The system is based on a new generation industrial controller that communicates with energy and water meters distributed throughout the building using a standard Information Technology (IT) network. The solution explores Industry 4.0 concept, such as Cloud Data Management, Cybersecurity, and Machine Learning. With historic consumption records available, Machine Learning strategies are being used to predict load profiles in a short-term horizon and also planned to classify untypical consumption behaviors (for monitor and alarm purposes). This project is being deployed in partnership between Polytechnic of Leiria, EduNet International Education Network and involving the local Parish Council, owner of the monitored buildings.
    2021-11Comunicação em conferência Acesso restrito Ver mais
  • Registration of Consecutive Frames From Wireless Capsule Endoscopy for 3D Motion Estimation
    Publication . Oliveira, Marina; Araujo, Helder; Figueiredo, Isabel N.; Pinto, Luís; Curto, Eva; Perdigoto, Luís
    Wireless 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.
    2021-09-03Artigo científico Acesso aberto Ver mais
  • Wireless Capsule Endoscope Location and a Robotic Validation Experiment
    Publication . 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.
    2019-09-25Comunicação em conferência Acesso aberto Ver mais