A Center for Sustainable Cloud Computing

In early September, scientists, researchers, and industry leaders assembled in Rome for the 26th European Signal Processing Conference (EUSIPCO 2018). This year, the conference received 869 submissions, out of which about 550 were accepted. The reviewers sieved through those hundreds of important research papers to finally announce the Eurasip Best Student Paper Award. The authors of the winning paper are Mira Rizkallah (INRIA, visiting scholar at EPFL), Francesca De Simone (Post-doctoral fellow at EPFL), Thomas Maugey (INRIA), Christine Guillemot (INRIA), and Pascal Frossard (Associate Professor, EPFL).

Their paper, titled “Rate Distortion Optimized Graph Partitioning for Omnidirectional Image Coding,” proposes a graph-based representation for omnidirectional images, which are widely used in virtual reality and immersive communications. The graph-based coder built by the researchers takes cognizance of the spherical geometry and provides a flexible way to efficiently store and compress the visual data. Instead of coding schemes that make it very difficult to control distortion, the efficient graph partitioning strategy proposed in the paper optimizes the smoothness of the signals on the subgraphs. The study also proposes a complete GFT-based lossy compression scheme and compare its performance with the classical DCT-based JPEG coding. Test results confirmed that the partitioning provides an effective tradeoff between the smoothness of signals on the subgraphs and the cost of coding the partition.

Mira Rizkallah worked on omnidirectional images graph-based compression during her stint at EPFL (Oct-Dec 2017) under the supervision of Prof. Pascal Frossard and Dr. Francesca de Simone, both of whom are co-authors in the award-winning research. She is currently PhD Candidate/ Researcher at INRIA, France. Her research areas include graph signal processing, sparse representations and coding of multiview images and videos using GBR. She is working on her thesis “Multiview Video Coding using Graph-Based Representations” under the supervision of Prof. Christine Guillemot and Dr. Thomas Maugey, who also worked on the award-winning paper.

EUSIPCO 2018 was organized by Roma Tre University. It featured inspiring plenary talks as well as tutorials on emerging topics in the field of signal processing, and a high-level technical program.