Publications de Philippe Hanhart

Overview and Evaluation of the JPEG XT HDR Image Compression Standard

Standards play an important role in providing a common set of specifications and allowing inter-operability between devices and systems. Until recently, no standard for High Dynamic Range (HDR) image coding had been adopted by the market, and HDR imaging r ...

2019

Evaluation of JPEG XT for high dynamic range cameras

Touradj Ebrahimi, Philippe Hanhart

Modern cameras can be used to capture high dynamic range (HDR) images by taking multiple low dynamic range (LDR) pictures at different exposure settings. However, DSLR cameras often store the multiple exposure pictures, which increases storage requirements ...

Elsevier Science Bv2017

Modeling Immersive Media Experiences by Sensing Impact on Subjects

Touradj Ebrahimi, Philippe Hanhart, Jong Seok Lee, Eleni Kroupi, Martin Rerabek

As immersive technologies target to provide higher quality of multimedia experiences, it is important to understand the quality of experience (QoE) perceived by users from various multimedia rendering schemes, in order to design and optimize human-centric ...

Springer Verlag2016

JPEG XT: A Compression Standard for HDR and WCG Images [Standards in a Nutshell]

Touradj Ebrahimi, Philippe Hanhart

High bit depth data acquisition and manipulation have been largely studied at the academic level over the last 15 years and are rapidly attracting interest at the industrial level. An example of the increasing interest for high-dynamic range (HDR) imaging ...

Institute of Electrical and Electronics Engineers2016

How to Benchmark Objective Quality Metrics from Paired Comparison Data?

Touradj Ebrahimi, Philippe Hanhart

The procedures commonly used to evaluate the performance of objective quality metrics rely on ground truth mean opinion scores and associated confidence intervals, which are usually obtained via direct scaling methods. However, indirect scaling methods, su ...

Ieee2016

Quality of Experience in Immersive Video Technologies

Philippe Hanhart

Over the last decades, several technological revolutions have impacted the television industry, such as the shifts from black & white to color and from standard to high-definition. Nevertheless, further considerable improvements can still be achieved to pr ...

EPFL2016

Subjective and Objective Evaluation of HDR Video Coding Technologies

Touradj Ebrahimi, Philippe Hanhart, Martin Rerabek

This paper reports the details and results of a subjective and objective quality evaluation assessing responses to an MPEG call for evidence (CfE) on high dynamic range (HDR) and wide color gamut video coding. Five HDR video contents, compressed at four bi ...

Ieee2016

Quality Evaluation of HEVC and VP9 Video Compression in Real-Time Applications

Touradj Ebrahimi, Philippe Hanhart, Martin Rerabek

Video consumption over Internet has increased significantly over the recent years and occupies the majority of the overall data traffic. To decrease the load on the Internet infrastructure and reduce bandwidth taken by video, higher efficiency video codecs ...

2015

Subjective Quality Evaluation of High Dynamic Range Video and Display for Future TV

Touradj Ebrahimi, Philippe Hanhart

The main objective of this paper is to verify test methodologies for the assessment of high dynamic range (HDR) video. To achieve this, a next generation HDR monitor by Dolby Laboratories was used to display professionally produced HDR content. Two complem ...

2015

Rate-Distortion Evaluation for Two-Layer Coding Systems

Touradj Ebrahimi, Philippe Hanhart

The Bjontegaard model is widely used to calculate the compression efficiency between different codecs. However, this model is not sufficient to investigate the impact on quality of the interaction of the base and enhancement layer bit rates when comparing ...

2015

Subjective quality assessment database of HDR images compressed with JPEG XT

Touradj Ebrahimi, Philippe Hanhart

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. ...

2015

Benchmarking of objective quality metrics for HDR image quality assessment

Touradj Ebrahimi, Philippe Hanhart

Recent advances in high dynamic range (HDR) capture and display technologies have attracted a lot of interest from scientific, professional, and artistic communities. As any technology, the evaluation of HDR systems in terms of quality of experience is ess ...

Hindawi Publishing Corporation2015

Visual attention in LDR and HDR images

Touradj Ebrahimi, Philippe Hanhart, Hiromi Nemoto

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. ...

2015

Subjective and objective evaluation of HDR video compression

Touradj Ebrahimi, Philippe Hanhart, Martin Rerabek

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 ...

2015

Active crosstalk reduction system for multiview autostereoscopic displays

Touradj Ebrahimi, Philippe Hanhart, Carmelo Di Nolfo

Multiview autostereoscopic displays are considered as the future of 3DTV. However, these displays suffer from a high level of crosstalk, which negatively impacts quality of experience (QoE). In this paper, we propose a system to improve 3D QoE on multiview ...

2015

Subjective evaluation of two stereoscopic imaging systems exploiting visual attention to improve 3D quality of experience

Touradj Ebrahimi, Philippe Hanhart

Crosstalk and vergence-accommodation rivalry negatively impact the quality of experience (QoE) provided by stereoscopic displays. However, exploiting visual attention and adapting the 3D rendering process on the fly can reduce these drawbacks. In this pape ...

Spie-Int Soc Optical Engineering2014

User-independent classification of 2D versus 3D multimedia experiences through EEG and physiological signals

Touradj Ebrahimi, Philippe Hanhart, Jong Seok Lee, Eleni Kroupi, Martin Rerabek

3D image and video have become popular since they can enhance the Quality of Experience (QoE) by adding the depth dimension to the traditional 2D media. In order to design and optimize the human-centric 3D multimedia processing techniques, it is important ...

2014

Subjective evaluation of an active crosstalk reduction system for mobile autostereoscopic displays

Touradj Ebrahimi, Philippe Hanhart, Alexandre Chappuis, Martin Rerabek

The Quality of Experience (QoE) provided by autostereoscopic 3D displays strongly depends on the user position. For an optimal image quality, the observer should be located at one of the relevant positions, called sweet spots, where artifacts reducing the ...

Spie-Int Soc Optical Engineering2014

Calculation of average coding efficiency based on subjective quality scores

Touradj Ebrahimi, Philippe Hanhart

The Bjøntegaard model is widely used to calculate the coding efficiency between different codecs. However, this model might not be an accurate predictor of the true coding efficiency as it relies on PSNR measurements. Therefore, in this paper, we propose a ...

Elsevier2014

HDR image compression: a new challenge for objective quality metrics

Touradj Ebrahimi, Philippe Hanhart

High Dynamic Range (HDR) imaging is able to capture a wide range of luminance values, closer to what the human visual system can perceive. It is believed by many that HDR is a technology that will revolutionize TV and cinema industry similar to how color t ...

2014