Publications by Touradj Ebrahimi

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Digital data representation provides an efficient and fast way to access to information and to exchange it. In many situations though ownership or copyright protection mechanisms are desired. For still images and video, one possible way to achieve this is through watermarking. Watermarking consists of an imperceptible information embedded within a given media. Parallel ProcessingWatermarking Embedding Schemes have demonstrated to be efficient from a computational and memory usage point of view for very larg

Ultra high definition (UHD) TV is rapidly replacing high definition (HD) TV but little is known of its effects on human visual attention. However, a clear understanding of this effect is important, since accurate models, evaluation methodologies, and metri ...

Tracking moving objects is a critical step for smart video surveillance systems. Despite the complexity increase, multiple camera systems exhibit the undoubted advantages of covering wide areas and handling the occurrence of occlusions by exploiting the di ...

Spatial filtering is a widely used dimension reduction method in electroencephalogram based brain-computer interface systems. In this paper a new algorithm is proposed, which learns spatial filters from a training dataset. In contrast to existing approaches the proposed method yields spatial filters that are explicitly designed for the classification of event-related potentials, such as the P300 or movement-related potentials. The algorithm is tested, in combination with support vector machines, on several

Recent efforts by MPEG and research community to standardize high dynamic range (HDR) video compression require efficient objective metrics. This paper investigates how well the currently available metrics measure perceptual quality of HDR video. For this ...

The new Motion JPEG 2000 standard is providing with some compelling features. It is based on an intra-frame wavelet coding, which makes it very well suited for wireless applications. Indeed, the state-of-the-art wavelet coding scheme achieves very high coding efficiency. In addition, Motion JPEG 2000 is very resilient to transmission errors as frames are coded independently (intra coding). Furthermore, it requires low complexity and introduces minimal coding delay. Finally, it supports very efficient scalab

Nowadays, tags play an important role in the search and retrieval process in multimedia content sharing social networks. As the amount of multimedia contents explosively increases, it is a challenging problem to find a content that will be appealing to the ...

With the rapid growth of digital photography, sharing of photos with friends and family has become very popular. When people share their photos, they usually organize them in albums according to events or places. To tell the story of some important events ...

This paper presents a video-based camera tracker that combines marker-based and feature point-based cues in a particle filter framework. The framework relies on their complementary performances. Marker-based trackers can robustly recover camera position an ...

Sharing photos online has become an extremely popular activity, raising a wide concern on privacy issues related to the shared content. ProShare, a photo-sharing solution developed by Multimedia Signal Processing Group of EPFL addresses some of these priva ...

In this paper, we analyze the performance of Motion JPEG2000 for wireless applications. This new standard is based on intra-frame wavelet coding. Motion JPEG2000 is offering a number of very compelling advantages when compared to state-of-the-art MPEG-4 video coding. Wavelet coding achieves very high coding efficiency. Furthermore, because frames are intra coded, it is very error-resilient. Finally, Motion JPEG2000 requires low complexity, supports very efficient scalability, and introduces minimal coding d

This paper proposes an efficient method to estimate the distance between discrete 3D surfaces represented by triangular 3D meshes. The metric used is based on an approximation of the Hausdorff distance, which has been appropriately implemented in order to reduce unnecessary computations and memory usage. Results show that when compared to similar tools, a significant gain in both memory and speed can be achieved

As applications using immersive media gained increased attention from both academia and industry, research in the field of point cloud compression has greatly intensified in recent years, leading to the development of the MPEG compression standards V-PCC a ...

This paper proposes an efficient video coding method which utilizes audio-visual information, based on the observation that sound-emitting regions in a video sequence attract observer’s attention. The regions responsible for the sound are identified by an ...

In this paper, we address the problem of privacy in video surveillance systems. More specifically, we consider the case of H.264/AVC which is the state-of-the-art in video coding. We assume that Regions of Interest (ROI), containing privacy-sensitive infor ...

Recent advances in high dynamic range (HDR) capturing and display technologies attracted a lot of interest to HDR imaging. Many issues that are considered as being resolved for conventional low dynamic range (LDR) images pose new challenges in HDR context. ...

Stereoscopic three-dimensional (3-D) services do not always prevail when compared with their two-dimensional (2-D) counterparts, though the former can provide more immersive experience with the help of binocular depth. Various specific 3-D artefacts might ...

The issue of privacy protection in video surveillance has drawn a lot of interest lately. However, thorough performance analysis and validation is still lacking, especially regarding the fulfillment of privacy-related requirements. In this paper, we put fo ...

Learning-based image codecs produce different compression artifacts, when compared to the blocking and blurring degradation introduced by conventional image codecs, such as JPEG, JPEG~2000 and HEIC. In this paper, a crowdsourcing based subjective quality e ...

Touradj Ebrahimi

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Influence of a Large Image Watermarking Scheme Parallelization on Possible Attacks

Emerging Visual Iot Technologies For Future Communications And Networks

Impact of Ultra High Definition on Visual Attention

Multi-view video segmentation and tracking for video surveillance

Spatial filters for the classification of event-related potentials

Subjective and objective evaluation of HDR video compression

Error-Resilient Video Coding Performance Analysis of Motion JPEG 2000 and MPEG-4

Multimedia content analysis for emotional characterization of music video clips

Social Game Epitome versus Automatic Visual Analysis

Particle filter-based camera tracker fusing marker- and feature point-based cues

Privacy-preserving photo sharing based on blockchain

Motion JPEG 2000 for Wireless Applications

MESH: Measuring Errors between Surfaces using the Hausdorff distance

Assessing objective quality metrics for JPEG and MPEG point cloud coding

Efficient video coding in H.264/AVC by using audio-visual information

H.264/AVC Video Scrambling for Privacy Protection

Subjective quality assessment database of HDR images compressed with JPEG XT

Assessment of Stereoscopic Crosstalk Perception

A Framework for the Validation of Privacy Protection Solutions in Video Surveillance

Large-Scale Crowdsourcing Subjective Quality Evaluation of Learning-Based Image Coding