Fernando Pereira

Prof. Fernando Pereira


Research Focus & Metrics

Academic Career Length

37Years (1990-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2004 in IEEE Circuits and Systems Magazine
Verified
Journal Article
Closed access
JOJ. Ostermann
J. Ostermann
JBJ. Bormans
J. Bormans
PLP. List
P. List
DMD. Marpe
D. Marpe
MNM. Narroschke
M. Narroschke
TWT. Wedi
T. Wedi
H.264/AVC, the result of the collaboration between the ISO/IEC Moving Picture Experts Group and the ITU-T Video Coding Experts Group, is the latest standard for video coding. The goals of this standardization effort were enhanced compression efficiency, network friendly video representation for interactive (video telephony) and non-interactive applications (broadcast, streaming, storage, video on demand). H.264/AVC provides gains in compression efficiency of up to 50% over a wide range of bit rates and video resolutions compared to previous standards. Compared to previous standards, the decoder complexity is about four times that of MPEG-2 and two times that of MPEG-4 Visual Simple Profile. This paper provides an overview of the new tools, features and complexity of H.264/AVC.

30 April 2008 in IEEE Transactions on Circuits and Systems for Video Technology
Verified
Journal Article
Closed access
CBCatarina Brites
Catarina Brites
FPFernando Pereira
Fernando Pereira
In recent years, practical Wyner-Ziv (WZ) video coding solutions have been proposed with promising results. Most of the solutions available in the literature model the correlation noise (CN) between the original frame and its estimation made at the decoder, which is the so-called side information (SI), by a given distribution whose relevant parameters are estimated using an offline process, assuming that the SI is available at the encoder or the originals are available at the decoder. The major goal of this paper is to propose a more realistic WZ video coding approach by performing online estimation of the CN model parameters at the decoder, for pixel and transform domain WZ video codecs. In this context, several new techniques are proposed based on metrics which explore the temporal correlation between frames with different levels of granularity. For pixel-domain WZ (PDWZ) video coding, three levels of granularity are proposed: frame, block, and pixel levels. For transform-domain WZ (TDWZ) video coding, DCT bands and coefficients are the two granularity levels proposed. The higher the estimation granularity is, the better the rate-distortion performance is since the deeper the adaptation of the decoding process is to the video statistical characteristics, which means that the pixel and coefficient levels are the best performing for PDWZ and TDWZ solutions, respectively.

14 November 2016 in IEEE MultiMedia
Verified
Journal Article
Closed access
TETouradj Ebrahimi
Touradj Ebrahimi
SFSiegfried Foessel
Siegfried Foessel
FPFernando Pereira
Fernando Pereira
PSPeter Schelkens
Peter Schelkens
In discussing the rationale behind the vision for JPEG Pleno and how the new standardization initiative aims to reinvent the future of imaging, the authors review plenoptic representation and its underlying practical implications and challenges in implementing real-world applications with an enhanced quality of experience.

25 July 2018 in IEEE Transactions on Multimedia
Verified
Journal Article
Closed access
PRPaulo de Oliveira Rente
Paulo de Oliveira Rente
CBCatarina Brites
Catarina Brites
JAJoao M. Ascenso
Joao M. Ascenso
FPFernando Pereira
Fernando Pereira
Recently, 3D visual representation models such as light fields and point clouds are becoming popular due to their capability to represent the real world in a more complete and immersive way, paving the road for new and more advanced visual experiences. The point cloud representation model is able to efficiently represent the surface of objects/scenes by means of a set of 3D points and associated attributes and is increasingly being used from autonomous cars to augmented reality. Emerging imaging sensors have made easier to perform richer and denser point cloud acquisitions, notably with millions of points, making impossible to store and transmit these very high amounts of data without appropriate coding. This bottleneck has raised the need for efficient point cloud coding solutions in order to offer more immersive visual experiences and better quality of experience (QoE) to the users. In this context, this paper proposes an efficient lossy coding solution for the geometry of static point clouds. The proposed coding solution uses an octree-based approach for a base layer and a graph-based transform approach for the enhancement layer where an Inter-layer residual is coded. The performance assessment shows very significant compression gains regarding the state-of-the-art, especially for the most relevant lower and medium rates.

11 November 2020 in IEEE Transactions on Multimedia
Verified
Journal Article
Closed access
AJAlireza Javaheri
Alireza Javaheri
CBCatarina Brites
Catarina Brites
FPFernando Pereira
Fernando Pereira
JAJoao M. Ascenso
Joao M. Ascenso
Recently, point clouds have shown to be a promising way to represent 3D visual data for a wide range of immersive applications, from augmented reality to autonomous cars. Emerging imaging sensors have made easier to perform richer and denser point cloud acquisition, notably with millions of points, thus raising the need for efficient point cloud coding solutions. In such scenario, it is important to evaluate the impact and performance of several processing steps in a point cloud communication system, notably the degradations associated to point cloud coding solutions. Moreover, since point clouds are not directly visualized but rather processed with a rendering algorithm before shown on any display, the perceived quality of point cloud data highly depends on the rendering solution. In this context, the main objective of this paper is to study the impact of several coding and rendering solutions on the perceived user quality and in the performance of available objective assessment metrics. Another contribution regards the assessment of recent MPEG point cloud coding solutions for several popular rendering methods which was never presented before. The conclusions regard the visibility of three types of coding artifacts for the three considered rendering approaches as well as the strengths and weakness of objective metrics when point clouds are rendered after coding.

15 October 2007 in IEEE Signal Processing Magazine
Verified
Journal Article
Closed access
CGChristine Guillemot
Christine Guillemot
FPFernando Pereira
Fernando Pereira
LTLuis Torres
Luis Torres
TETouradj Ebrahimi
Touradj Ebrahimi
RLRiccardo Leonardi
Riccardo Leonardi
JOJoern Ostermann
Joern Ostermann
Growing percentage of the world population now uses image and video coding technologies on a regular basis. These technologies are behind the success and quick deployment of services and products such as digital pictures, digital television, DVDs, and Internet video communications. Today's digital video coding paradigm represented by the ITU-T and MPEG standards mainly relies on a hybrid of block- based transform and interframe predictive coding approaches. In this coding framework, the encoder architecture has the task to exploit both the temporal and spatial redundancies present in the video sequence, which is a rather complex exercise. As a consequence, all standard video encoders have a much higher computational complexity than the decoder (typically five to ten times more complex), mainly due to the temporal correlation exploitation tools, notably the motion estimation process. This type of architecture is well-suited for applications where the video is encoded once and decoded many times, i.e., one-to-many topologies, such as broadcasting or video-on-demand, where the cost of the decoder is more critical than the cost of the encoder.