28 documents found, page 1 of 3
Complexity Estimation for Load Balancing of 360-Degree Intra Versatile Video Co...
Filipe, Jose N.; Monteiro Carreira, João Filipe; Tavora, Luis M. N.; Faria, Sergio; Navarro, Antonio; Assuncao, Pedro A. A.The ever increasing demand for image and video content poses new requirements to support higher resolutions and richer representation formats, creating new challenges in coding algorithms. The forthcoming Versatile Video Coding (VVC) standard aims to increase the coding efficiency of existing algorithms and it is particularly suitable for Ultra-High Definition (UHD) resolutions and 360° video. However, since co...
Optimized Reference Picture Selection for Light Field Image Coding
Monteiro, J. S. Ricardo; Nunes, J. L. Paulo; M. M. Rodrigues, Nuno; Faria, SergioThis paper proposes a new reference picture selection method for light field image coding using the pseudovideo sequence (PVS) format. State-of-the-art solutions to encode light field images using the PVS format rely on video coding standards to exploit the inter-view redundancy between each sub-aperture image (SAI) that composes the light field. However, the PVS scanning order is not usually considered by the ...
Light field image coding: objective performance assessment of Lenslet and 4D LF...
Monteiro, Ricardo; M. M. Rodrigues, Nuno; Faria, Sergio; Nunes, pauloState-of-the-art light field (LF) image coding solutions, usually, rely in one of two LF data representation formats: Lenslet or 4D LF. While the Lenslet data representation is a more compact version of the LF, it requires additional camera metadata and processing steps prior to image rendering. On the contrary, 4D LF data, consisting of a stack of sub-aperture images, provides a more redundant representation r...
Light Field Image Coding using High Order Prediction Training
Monteiro, Ricardo J. S.; Nunes, Paulo J. L.; Faria, Sergio; M. M. Rodrigues, NunoThis paper proposes a new method for light field image coding relying on a high order prediction mode based on a training algorithm. The proposed approach is applied as an Intra prediction method based on a two-stage block-wise high order prediction model that supports geometric transformations up to eight degrees of freedom. Light field images comprise an array of micro-images that are related by complex persp...
Evaluation of cutaneous microcirculation patterns by laser speckle imaging
Bento, L.; de Oliveira Pegado de Noronha E Távora, Luís Miguel; Assunção, Pedro; Faria, Sergio; Fonseca-Pinto, RuiAtherosclerosis is a chronic systemic process affecting distal circulation, a condition known as Peripheral Artery Disease (PAD). Epidemiological and clinical studies indicate a strong association between PAD and death due to cardiovascular diseases, thus the early detection of DAP by measuring perfusion levels of distal body regions is critical to prevent ischemic events. This work proposes a new methodology f...
Lossless coding of light field images based on minimum-rate predictors
Santos, João M.; Assunção, Pedro; Cruz, Luis A. da Silva; de Oliveira Pegado de Noronha E Távora, Luís Miguel; Fonseca-Pinto, Rui; Faria, SergioRecent developments in light field acquisition and computational photography are driving new research efforts on light field encoding methods, capable of exploiting the specific features of this type of visual data. This paper presents a research study of lossless light field image compression, using Minimum-Rate Predictors (MRP) and mainstream image and video encoders. The research is focused on three light fi...
Silhouette Enhancement in Light Field Disparity Estimation Using the Structure ...
Lourenço, Rui; Assunção, Pedro; Távora, Luís M.N.; Fonseca-Pinto, Rui; Faria, SergioThis paper presents a method to improve disparity maps computed from light field images using structure tensor methods, which tend to expand the borders of the occluding objects, enlarging their silhouette. The proposed method relies on the fact that such regions of the silhouette are defined by a mismatch between the disparity map edges, computed by the structure tensor, and those of the corresponding epipolar...
A Two-Stage Approach for Robust HEVC Coding and Streaming
Carreira, João F. M.; Assunção, Pedro; Faria, Sergio; Ekmekcioglu, Erhan; Kondoz, AhmetThe increased compression ratios achieved by the High Efficiency Video Coding (HEVC) standard lead to reduced robustness of coded streams, with increased susceptibility to network errors and consequent video quality degradation. This paper proposes a method based on a two-stage approach to improve the error robustness of HEVC streaming, by reducing temporal error propagation in the case of frame loss. The predi...
Using local binary patterns in speckle image analysis
Bento, L.; de Oliveira Pegado de Noronha E Távora, Luís Miguel; Assunção, Pedro; Faria, Sergio; Fonseca-Pinto, RuiFirstly described by Newton in the 17th century, speckle is an optical phenomenon which can be translated into image patterns produced by wave interferences of diffused reflections. In fact, the speckle pattern is generated by the multiple interference phenomena that occur when a rough surface is illuminated with a coherent source of light, producing randomly distributed reflected waves of the same frequency bu...
Motivations and experiences of literary tourists: Semana Roseana – Cordisburgo ...
Faria, Diomira; Faria, Sergio; Araújo, Maria; Flecha, Bruna; Silva, ThamaraThe present research aims to identify the profile of the literary tourist and to reflect on the factors that motivate people to visit places where attraction is literature. For this, a theoretical review was developed on the concepts related to literary tourism; a survey was conducted with a representative sample of the visitors of a literary event – Semana Roseana, held in the city of Cordisburg...