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Detection of defects on displays based on microscopic and optical coherence tom...
Pereira, Hugo Martins; Freitas, Ruben Brandão; Esteves, Bruno Miguel Carpinteiro; Santos, C. P.; Carvalho, Pedro; Compadrinho, Paulo; Rodrigues, Carlos[Excerpt] Introduction The use of displays in control car panels, smartphones, notebooks and LCD TVs has increased in the last decade. The large-scale manufacturing of new products emphasizes the need for fault detection at an early stage in the assembly process to detect the presence of scratches and particles. Therefore, fast, reliable and efficient displays inspection equipment is essential in order to reduc...
Improved performance of polyimide Cirlex-based dielectric barrier discharge pla...
Nunes-Pereira, E. J.; Rodrigues, F. F.; Abdollahzadeh, M.; Páscoa, J. C.,; Lanceros-Méndez, S.Dielectric barrier discharge (DBD) plasma actuators are simple electrohydrodynamic devices, which are able to provide effective aerodynamic control. One of the main components of these devices is the thin dielectric layer, which allows to separate and prevent the arc between the high voltage electrodes. Different materials can be used as dielectric layer to reduce the power consumption or boost the flow control...
Polarization-coded material classification in automotive LIDAR aiming at safer ...
Nunes-Pereira, E. J.; Peixoto, H.; Teixeira, J.; Simões, João Henrique Vivas SantosLIDAR sensors are one of the key enabling technologies for the wide acceptance of autonomous driving implementations. Target identification is a requisite in image processing, informing decision making in complex scenarios. The polarization from the backscattered signal provides an unambiguous signature for common metallic car paints and can serve as one-point measurement for target classification. This provide...
Oblique astigmatism and field curvature measured with light-field imaging
Ferreira, Flávio Pedro Gonçalves Fernandes; Sousa, Marco A.; Duarte, Moises A. S.; Bret, Boris P. J.; Nunes-Pereira, E. J.The testing of astigmatism and field curvature of an optical system with light-field imaging is proposed. The method consists in measuring the depth map, obtained with a plenoptic camera, of the image of a test pattern formed by the optical system. To demonstrate the accuracy of the method, the virtual image formed by a piano-convex lens was tested. The resulting depth map was compared with the sagittal and tan...
The LiDAR hop-on-hop-off route: visiting the LiDARs past, present, and future l...
Nunes-Pereira, E. J.; Peixoto, H.; Teixeira, J.; Simões, João Henrique Vivas SantosLiDAR technology is bounded with great expectations. This is a result of the high market prospects from several industries (notably the automotive) as well as LiDAR being a key enabling technology for automation. We will drive along the current two main avenues of LiDAR, targeted to autonomous driving. We will stop at minute technicalities of LiDAR implementations. However, occasionally we will also rise high, ...
Single shot plenoptic optical imaging inspection of a head-up display: Projecti...
Duarte, Moises A. S.; Nunes-Pereira, E. J.; Bret, Boris P. J.; Forte, Paulo M. F.; Ferreira, Flávio Pedro Gonçalves Fernandes; Sousa, Marco A.A single shot automatic optical inspection system for evaluating the projection distance, astigmatism, field curvature and geometric distortions of a virtual image created by a Head-Up Display (HUD) prototype is presented. The system uses plenoptic or light-field imaging. Although results are only presented for a Augmented Reality (AR)/Mixed Reality (MR) HUD application, the inspection workflow is also applicab...