Publications de Francesca De Simone

Visual Distortions in 360-degree Videos

Pascal Frossard, Francesca De Simone, Roberto Gerson De Albuquerque Azevedo

Omnidirectional (or 360-degree) images and videos are emergent signals being used in many areas such as robotics and virtual/augmented reality. In particular, for virtual reality applications, they allow an immersive experience in which the user can intera ...

2020

Spherical Clustering of Users Navigating 360° Content

Pascal Frossard, Francesca De Simone, Laura Toni

In Virtual Reality (VR) applications, understanding how users explore the omnidirectional content is important to optimize content creation, to develop user-centric services, or even to detect disorders in medical applications. Clustering users based on th ...

IEEE2019

Graph-Based Detection of Seams In 360-Degree Images

Pascal Frossard, Francesca De Simone, Sohyeong Kim, Roberto Gerson De Albuquerque Azevedo

In this paper, we propose an algorithm to detect a specific kind of distortions, referred to as seams, which commonly occur when a 360-degree image is represented in planar domain by projecting the sphere to a polyhedron, e.g, via the Cube Map (CM) project ...

2019

Visual Distortions in 360-degree videos (Dataset)

Pascal Frossard, Francesca De Simone, Roberto Gerson De Albuquerque Azevedo

Here we catalog, visually demonstrate, and discuss the main causes of commonly encountered visual distortions into current 360-degree video processing pipelines. The main goal of the samples in this dataset is to demonstrate the visual distortions discusse ...

2019

Visual Distortions in 360-degree Videos

Pascal Frossard, Francesca De Simone, Roberto Gerson De Albuquerque Azevedo

Omnidirectional (or 360-degree) images and videos are emergent signals in many areas such as robotics and virtual/augmented reality. In particular, for virtual reality, they allow an immersive experience in which the user is provided with a 360-degree fiel ...

2018

Dynamic Adaptive Streaming for Multi-Viewpoint Omnidirectional Videos

Pascal Frossard, Francesca De Simone, Xavier Corbillon

Full immersion inside a Virtual Reality (VR) scene requires six Degrees of Freedom (6DoF) applications where the user is allowed to perform translational and rotational movements within the virtual space. The implementation of 6DoF applications is however ...

ASSOC COMPUTING MACHINERY2018

Rate Distortion Optimized Graph Partitioning for Omnidirectional Image Coding

Pascal Frossard, Francesca De Simone, Thomas Maugey, Mira Rizkallah

Omnidirectional images are spherical signals captured by cameras with 360-degree field of view. In order to be compressed using existing encoders, these signals are mapped to planar domain. A commonly used planar representation is the equirectangular one, ...

IEEE COMPUTER SOC2018

Deformable block based motion estimation in omnidirectional image sequences

Pascal Frossard, Francesca De Simone

This paper presents an extension of block-based motion estimation for omnidirectional videos, based on a camera and translational object motion model that accounts for the spherical geometry of the imaging system. We use this model to design a new algorith ...

2017

360-Degree Video Head Movement Dataset

Francesca De Simone, Xavier Corbillon

While Virtual Reality applications attract the attention of developers and business analysts, the behavior of users watching 360-degree videos with Head-Mounted Display (HMD) has still to be understood. This paper introduces a dataset of the head movements ...

2017

Geometry-driven quantization for omnidirectional image coding

Pascal Frossard, Francesca De Simone

In this paper we propose a method to adapt the quantization tables of typical block-based transform codecs when the input to the encoder is a panoramic image resulting from equirectangular projection of a spherical image. When the visual content is project ...

2016

Objective quality metrics for video scalability

Touradj Ebrahimi, Francesca De Simone, Adrien Georges Jean Besson

Scalable video coding is emerging as an efficient alternative to simulcast encoding to distribute the same video content si- multaneously to many users having different terminals and network conditions. In order to select the best combination of video scal ...

2013

Evaluation of Visual privacy Filters Impact on Video Surveillance Intelligibility

Touradj Ebrahimi, Francesca De Simone

Since privacy issues are becoming important with growth of the video surveillance, many tools are proposed for protection of personal privacy in the video. However, little is understood regarding the effectiveness of such tools and their effect on the unde ...

2012

Quality Assessment of Asymmetric Stereo Pair Formed From Decoded and Synthesized Views

Touradj Ebrahimi, Philippe Hanhart, Francesca De Simone

When a stereo pair is formed from a decoded view and a synthesized view, it is unclear how the overall quality of the stereo pair should be assessed through objective quality metrics. In this paper, this problem is addressed considering a 3D video represen ...

2012

Subjective Study of Privacy Filters in Video Surveillance

Touradj Ebrahimi, Francesca De Simone

Extensive adoption of video surveillance, affecting many aspects of the daily life, alarms the concerned public about the increasing invasion into personal privacy. Therefore, to address privacy issues, many tools have been proposed for protection of perso ...

Ieee2012

Quality assessment of multidimensional video scalability

Touradj Ebrahimi, Francesca De Simone, Jong Seok Lee

Scalability is a powerful concept for adaptive video content delivery to many end users having heterogeneous and dynamic characteristics of networks and devices. In order to maximize users' quality of experience by selecting appropriate combinations of mul ...

Institute of Electrical and Electronics Engineers2012

Selected Contributions on Multimedia Quality Evaluation

Francesca De Simone

Multimedia signals, such as digital images and video sequences, are captured, processed and finally presented to human observers who directly or indirectly judge their quality. During the data acquisition, as well as the many steps of the processing chain, ...

EPFL2012

Subjective quality evaluation via paired comparison: application to scalable video coding

Touradj Ebrahimi, Francesca De Simone, Jong Seok Lee

Scalable video coding is a powerful solution for content delivery in many interactive multimedia services due to its adaptability to varying terminal and network constraints. In order to successfully exploit such adaptability, it is necessary to understand ...

2011

Subjective quality evaluation of foveated video coding using audio-visual focus of attention

Touradj Ebrahimi, Francesca De Simone, Jong Seok Lee

This paper presents a foveated coding method using audio-visual focus of attention and its evaluation through extensive subjective experiments on both standard definition and high definition sequences. Regarding a sound-emitting region as the location draw ...

2011

Efficient Video Coding based on Audio-Visual Focus of Attention

Touradj Ebrahimi, Francesca De Simone, Jong Seok Lee

This paper proposes an efficient video coding method using audio-visual focus of attention, which is based on the observation that sound-emitting regions in an audio-visual sequence draw viewers' attention. First, an audio-visual source localization algori ...

Elsevier2011

Towards High Efficiency Video Coding: Subjective Evaluation of Potential Coding Technologies

Touradj Ebrahimi, Francesca De Simone, Jong Seok Lee, Lutz Goldmann

This paper describes the details and the results of the subjective quality evaluation performed at EPFL, as a contribution to the effort of the joint collaborative team on video coding (JCT-VC) for the definition of the high efficiency video coding (HEVC) ...

Elsevier2011