Quan Huynh-thu

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Papers by Quan Huynh-thu

Objective perceptual quality measurement of 3G video services

Fifth IEE International Conference on 3G Mobile Communication Technologies (3G 2004) The Premier Technical Conference for 3G and Beyond, 2004

... http://www.dvb.org/documents/DVB-H_Outline.pdf [5] Q. Huynh-Thu and AW Rix. ... [8] "Sub... more ... http://www.dvb.org/documents/DVB-H_Outline.pdf [5] Q. Huynh-Thu and AW Rix. ... [8] "Subjective video quality assessment methods for multimedia applications", ITU-T Recommendation P ... II test validation of objective models of video quality assessment", ¡TU-T Contribution COM9 ...

<title>Depth-based representations: Which coding format for 3D video broadcast applications?</title>

Stereoscopic Displays and Applications XXII, 2011

ABSTRACT D Video (3DV) delivery standardization is currently ongoing in MPEG. Now time is to choo... more ABSTRACT D Video (3DV) delivery standardization is currently ongoing in MPEG. Now time is to choose 3DV data representation format. What is at stake is the final quality for end-users, i.e. synthesized views&#39; visual quality. We focus on two major rival depth-based formats, namely Multiview Video plus Depth (MVD) and Layered Depth Video (LDV). MVD can be considered as the basic depth-based 3DV format, generated by disparity estimation from multiview sequences. LDV is more sophisticated, with the compaction of multiview data into color- and depth-occlusions layers. We compare final views quality using MVD2 and LDV (both containing two color channels plus two depth components) coded with MVC at various compression ratios. Depending on the format, the appropriate synthesis process is performed to generate final stereoscopic pairs. Comparisons are provided in terms of SSIM and PSNR with respect to original views and to synthesized references (obtained without compression). Eventually, LDV outperforms significantly MVD when using state-of-the-art reference synthesis algorithms. Occlusions management before encoding is advantageous in comparison with handling redundant signals at decoder side. Besides, we observe that depth quantization does not induce much loss on the final view quality until a significant degradation level. Improvements in disparity estimation and view synthesis algorithms are therefore still expected during the remaining standardization steps.

Method and apparatus for image signal normalisation

Method and apparatus for measuring blockiness in video images

Method and apparatus for generation of a video quality parameter

Perceptual quality assessment of communications-grade video with temporal artefacts

Towards adapting current 3DTV for an improved 3D experience

Stereoscopic Displays and Applications XXIII, 2012

ABSTRACT The variability among color-normal observers poses a challenge to modern display colorim... more ABSTRACT The variability among color-normal observers poses a challenge to modern display colorimetry because of their peaky primaries. But such devices also hold the key to a future solution to this issue. In this paper, we present a method for deriving seven distinct colorimetric observer categories, and also a method for classifying individual observers as belonging to one of these seven categories. Five representative L, M and S cone fundamentals (a total of 125 combinations) were derived through a cluster analysis on the combined set of 47-observer data from 1959 Stiles-Burch study, and 61 color matching functions derived from the CIE 2006 model corresponding to 20-80 age parameter range. From these, a reduced set of seven representative observers were derived through an iterative algorithm, using several predefined criteria on perceptual color differences (delta E*00) with respect to actual color matching functions of the 47 Stiles-Burch observers, computed for the 240 Colorchecker samples viewed under D65 illumination. Next, an observer classification method was implemented using two displays, one with broad-band primaries and the other with narrow-band primaries. In paired presentations on the two displays, eight color-matches corresponding to the CIE 10° standard observer and the seven observer categories were shown in random sequences. Thirty observers evaluated all eight versions of fifteen test colors. For majority of the observers, only one or two categories consistently produced either acceptable or satisfactory matches for all colors. The CIE 10° standard observer was never selected as the most preferred category for any observer, and for six observers, it was rejected as an unacceptable match for more than 50% of the test colors. The results show that it is possible to effectively classify real, color-normal observers into a small number of categories, which in certain application contexts, can produce perceptibly better color matches for many observers compared to the matches predicted by the CIE 10° standard observer.

Subjective and objective evaluation of an audiovisual subjective dataset for research and development

by Quan Huynh-thu, Margaret Pinson, and Audrey Younkin

2013 Fifth International Workshop on Quality of Multimedia Experience (QoMEX), 2013

ABSTRACT In 2011, the Video Quality Experts Group (VQEG) ran subjects through the same audiovisua... more

Visual storytelling in 2D and stereoscopic 3D video: effect of blur on visual attention

Human Vision and Electronic Imaging XVIII, 2013

ABSTRACT Visual attention is an inherent mechanism that plays an important role in the human visu... more ABSTRACT Visual attention is an inherent mechanism that plays an important role in the human visual perception. As our visual system has limited capacity and cannot efficiently process the information from the entire visual field, we focus our attention on specific areas of interest in the image for detailed analysis of these areas. In the context of media entertainment, the viewers&#39; visual attention deployment is also influenced by the art of visual storytelling. To this date, visual editing and composition of scenes in stereoscopic 3D content creation still mostly follows those used in 2D. In particular, out-of-focus blur is often used in 2D motion pictures and photography to drive the viewer&#39;s attention towards a sharp area of the image. In this paper, we study specifically the impact of defocused foreground objects on visual attention deployment in stereoscopic 3D content. For that purpose, we conducted a subjective experiment using an eyetracker. Our results bring more insights on the deployment of visual attention in stereoscopic 3D content viewing, and provide further understanding on visual attention behavior differences between 2D and 3D. Our results show that a traditional 2D scene compositing approach such as the use of foreground blur does not necessarily produce the same effect on visual attention deployment in 2D and 3D. Implications for stereoscopic content creation and visual fatigue are discussed.

55.1: Diversity and Coherence of 3D Crosstalk Measurements

SID Symposium Digest of Technical Papers, 2011

Physiological-Based Affect Event Detector for Entertainment Video Applications

IEEE Transactions on Affective Computing, 2012

ABSTRACT

3D cinema to 3DTV content adaptation

by Quan Huynh-thu and L. Yasakethu

Stereoscopic Displays and Applications XXIII, 2012

ABSTRACT 3D cinema and 3DTV have grown in popularity in recent years. Filmmakers have a significa... more ABSTRACT 3D cinema and 3DTV have grown in popularity in recent years. Filmmakers have a significant opportunity in front of them given the recent success of 3D films. In this paper we investigate whether this opportunity could be extended to the home in a meaningful way. &quot;3D&quot; perceived from viewing stereoscopic content depends on the viewing geometry. This implies that the stereoscopic-3D content should be captured for a specific viewing geometry in order to provide a satisfactory 3D experience. However, although it would be possible, it is clearly not viable, to produce and transmit multiple streams of the same content for different screen sizes. In this study to solve the above problem, we analyze the performance of six different disparity-based transformation techniques, which could be used for cinema-to-3DTV content conversion. Subjective tests are performed to evaluate the effectiveness of the algorithms in terms of depth effect, visual comfort and overall 3D quality. The resultant 3DTV experience is also compared to that of cinema. We show that by applying the proper transformation technique on the content originally captured for cinema, it is possible to enhance the 3DTV experience. The selection of the appropriate transformation is highly dependent on the content characteristics.

Method and simulation to study 3D crosstalk perception

Stereoscopic Displays and Applications XXIII, 2012

ABSTRACT To various degrees, all modern 3DTV displays suffer from crosstalk, which can lead to a ... more ABSTRACT To various degrees, all modern 3DTV displays suffer from crosstalk, which can lead to a decrease of both visual quality and visual comfort, and also affect perception of depth. In the absence of a perfect 3D display technology, crosstalk has to be taken into account when studying perception of 3D stereoscopic content. In order to improve 3D presentation systems and understand how to efficiently eliminate crosstalk, it is necessary to understand its impact on human perception. In this paper, we present a practical method to study the perception of crosstalk. The approach consists of four steps: (1) physical measurements of a 3DTV, (2) building of a crosstalk surface based on those measurements and representing specifically the behavior of that 3TV, (3) manipulation of the crosstalk function and application on reference images to produce test images degraded by crosstalk in various ways, and (4) psychophysical tests. Our approach allows both a realistic representation of the behavior of a 3DTV and the easy manipulation of its resulting crosstalk in order to conduct psycho-visual experiments. Our approach can be used in all studies requiring the understanding of how crosstalk affects perception of stereoscopic content and how it can be corrected efficiently.

Effect of the accommodation-vergence conflict on vergence eye movements

Vision Research, 2014

With the broader use of stereoscopic displays, a flurry of research activity about the accommodat... more With the broader use of stereoscopic displays, a flurry of research activity about the accommodationvergence conflict has emerged to highlight the implications for the human visual system. In stereoscopic displays, the introduction of binocular disparities requires the eyes to make vergence movements. In this study, we examined vergence dynamics with regard to the conflict between the stimulus-toaccommodation and the stimulus-to-vergence. In a first experiment, we evaluated the immediate effect of the conflict on vergence responses by presenting stimuli with conflicting disparity and focus on a stereoscopic display (i.e. increasing the stereoscopic demand) or by presenting stimuli with matched disparity and focus using an arrangement of displays and a beam splitter (i.e. focus and disparity specifying the same locations). We found that the dynamics of vergence responses were slower overall in the first case due to the conflict between accommodation and vergence. In a second experiment, we examined the effect of a prolonged exposure to the accommodation-vergence conflict on vergence responses, in which participants judged whether an oscillating depth pattern was in front or behind the fixation plane. An increase in peak velocity was observed, thereby suggesting that the vergence system has adapted to the stereoscopic demand. A slight increase in vergence latency was also observed, thus indicating a small decline of vergence performance. These findings offer a better understanding and document how the vergence system behaves in stereoscopic displays. We describe what stimuli in stereo-movies might produce these oculomotor effects, and discuss potential applications perspectives.

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Skin-color extraction in images with complex background and varying illumination

Sixth IEEE Workshop on Applications of Computer Vision, 2002. (WACV 2002). Proceedings., 2002

A skin-color extraction algorithm is proposed to detect human faces in color images with varying ... more A skin-color extraction algorithm is proposed to detect human faces in color images with varying illumination condition and presence of complex background. The approach is based on both a Gaussian mixture model of human skin-color distribution and image segmentation using all automatic and adaptive multi-thresholding technique. Detected regions are then refined by morphological operations. Experimental results on images presenting a

Transforming 3D cinema content for an enhanced 3DTV experience

by Quan Huynh-thu and L. Yasakethu

2011 International Conference on 3D Imaging (IC3D), 2011

ABSTRACT 3D cinema and 3DTV are at two different levels in the screen size spectrum. When the sam... more ABSTRACT 3D cinema and 3DTV are at two different levels in the screen size spectrum. When the same stereoscopic-3D content is viewed on a cinema screen and 3DTV screen, it will produce a different 3D impression. As a result, it is difficult to fulfill the requirements of 3DTV with content captured for 3D cinema. Thus, it is important to properly address the issue of 3DTV content creation to avoid possible delays in the deployment of 3DTV. In this paper, we first explore the effects of using the same content for 3D cinema and 3DTV and then analyze the performance of several disparity based transformations for 3D cinema to 3DTV content conversion, by subjective testing. Effectiveness of the transformations is analyzed in terms of both depth quality and visual comfort of 3D experience. We show that by using a simple shift-based disparity transformation technique, it is possible to enhance the 3DTV experience from a common input signal which is originally captured for cinema viewing.

Sparse shift-DCT spatial prediction

2010 IEEE International Conference on Image Processing, 2010

In this paper, we propose a new intra prediction scheme based on hard thresholding applied on shi... more In this paper, we propose a new intra prediction scheme based on hard thresholding applied on shift-DCT coefficients. The explored intra prediction method, validated in an H.264/AVC framework, aims at better predicting complex 2D patterns that cannot be properly extrapolated using H.264/AVC directional intra prediction modes. The basic explored algorithm makes use of neighbor pixels of the current block to predict the current signal using a shift-DCT based extrapolation. Different versions of the algorithm, corresponding to different hard thresholding parameter derivation processes, are described. Experimental results show that the proposed intra coding prediction method can significantly improve the coding efficiency compared to the directional predictive modes of H.264/AVC, with an average BD-rate gain of 6.2% observed on a various pictures test set.

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No-reference temporal quality metric for video impaired by frame freezing artefacts

2009 16th IEEE International Conference on Image Processing (ICIP), 2009

This paper describes a no-reference temporal quality metric to model the impact of frame freezing... more This paper describes a no-reference temporal quality metric to model the impact of frame freezing impairments on perceived video quality. The proposed metric shows a high correlation with subjective data and is equally applicable to any type of objective video quality assessment model: full-reference, reduced-reference or no-reference. This temporal metric is a parameter of the video quality assessment algorithm in ITU-T Recommendation J.247 Annex C for the objective perceptual quality measurement of multimedia video.

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Asymmetrical temporal masking near video scene change

2008 15th IEEE International Conference on Image Processing, 2008

ABSTRACT

Modelling of spatio–temporal interaction for video quality assessment

Signal Processing: Image Communication, 2010

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