Quality Assessment Method For Synthesized Virtual Viewpoint Image

You Yang,Gangyi Jiang,Mei Yu,Yo-Sung Ho 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7

Virtual viewpoint image (VVI) synthesis technology plays an important role in interactive threedimensional audio-video (3DAV) system. Quality of VVI directly affects picture quality of service in 3DAV system. A new quality assessment method for VVI is proposed in this paper. The proposed method combines synthesis technology and fuzzy function to evaluate VVIs. Experimental results show the accordance to biocharacteristics of human vision system (HVS) and the quality of VVIs.

A Perception-based Color Correction Method for Multi-view Images

( Feng Shao ),( Gangyi Jiang ),( Mei Yu ),( Zongju Peng ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.2

Three-dimensional (3D) video technologies are becoming increasingly popular, as it can provide users with high quality and immersive experiences. However, color inconsistency between the camera views is an urgent problem to be solved in multi-view imaging. In this paper, a perception-based color correction method for multi-view images is proposed. In the proposed method, human visual sensitivity (VS) and visual attention (VA) models are incorporated into the correction process. Firstly, the VS property is used to reduce the computational complexity by removing these visual insensitive regions. Secondly, the VA property is used to improve the perceptual quality of local VA regions by performing VA-dependent color correction. Experimental results show that compared with other color correction methods, the proposed method can greatly promote the perceptual quality of local VA regions greatly and reduce the computational complexity, and obtain higher coding performance.

Depth Based Region-of-interest Extraction and Inter-view Tracking Algorithms for Multi-view Video Coding

Yun Zhang,Gangyi Jiang,Mei Yu,Zongju Peng 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7

Region-of-interest (ROI) in multiview video is different from that of conventional single view video because MVV provides three-dimensional perception and makes people more interested in depth discontinuity and regions close to viewers. In this paper, we present depth based ROI extraction algorithm semantic depth perceptual ROIs by jointly using depth, motion and texture information of multiview video plus depth data. To reduce the computational complexity and improve ROI extraction efficiency for group of pictures, we present a novel interview tracking method, in which geometry correlation between views and extracted ROI of neighboring views are utilized to facilitate ROI extraction in view dimension. ROI extraction results for multiview videos show that the proposed ROI tracking and extraction algorithms maintain high extraction accuracy and low complexity.

Color correction method for multi-view video based on background segmentation and dominant color extraction

Feng Shao,Gangyi Jiang,Mei Yu,Yo-Sung Ho 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7

Free viewpoint video (FVV) system is one of the most attracting three-dimensional video applications in the future, which can offer depth impression of the observed scenery and allow interactive selection of viewpoint and direction. A color correction method is proposed in this paper to eliminate un-consistent color appearance between viewpoint images. Experimental results show that the proposed method is quite effective.

Highlight-Detection-Based Color Correction Method for Multiview Images

Feng Shao,Gangyi Jiang,호요성 한국전자통신연구원 2009 ETRI Journal Vol.31 No.4

In multiview imaging systems, color correction is adopted to eliminate color inconsistency between views. However, the influence of highlights on color correction has not been considered before. In this letter, a new color correction method based on highlight detection is proposed. The method is designed to treat highlight and highlight-removal regions independently when calculating correction parameters. Finial correction is implemented with a fusion mechanism. Experimental results show that the proposed method can improve objective and subjective correction performance, while achieving better coding performance than other correction methods.

Asymmetric Coding of Multi-View Video Plus Depth Based 3-D Video for View Rendering

Feng Shao,Gangyi Jiang,Mei Yu,Ken Chen,Yo-Sung Ho IEEE 2012 IEEE transactions on multimedia Vol.14 No.1

<P>The recent years have witnessed three-dimensional (3-D) video technology to become increasingly popular, as it can provide high-quality and immersive experience to end users, where view rendering with depth-image-based rendering (DIBR) technique is employed to generate the virtual views. Distortions in depth map may induce geometry changes in the virtual views, and distortions in texture video may be propagated to the virtual views. Thus, effective compression of both texture videos and depth maps is important for 3-D video system. From the perspective of bit allocation, asymmetric coding of the texture videos and depth maps is an effective way to get the optimal solution of 3-D video compression and view rendering problems. In this paper, a novel asymmetric coding method of multi-view video plus depth (MVD) based 3-D video is proposed on purpose of providing high-quality view rendering. In the proposed method, two models are proposed to characterize view rendering distortion and binocular suppression in 3-D video. Then, an asymmetric coding method of MVD-based 3-D video is proposed by combining two models in encoding framework. Finally, a chrominance reconstruction algorithm is presented to achieve accurate reconstruction. Experimental results show that compared with other methods, the proposed method can obtain higher performance of view rendering under the total bitrate constraint. Moreover, the perceptual visual quality of 3-D video is almost unaffected with the proposed method.</P>

Novel Robust High Dynamic Range Image Watermarking Algorithm Against Tone Mapping

( Yongqiang Bai ),( Gangyi Jiang ),( Hao Jiang ),( Mei Yu ),( Fen Chen ),( Zhongjie Zhu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.9

High dynamic range (HDR) images are becoming pervasive due to capturing or rendering of a wider range of luminance, but their special display equipment is difficult to be popularized because of high cost and technological problem. Thus, HDR images must be adapted to the conventional display devices by applying tone mapping (TM) operation, which puts forward higher requirements for intellectual property protection of HDR images. As the robustness presents regional diversity in the low dynamic range (LDR) watermarked image after TM, which is different from the traditional watermarking technologies, a concept of watermarking activity is defined and used to distinguish the essential distinction of watermarking between LDR image and HDR image in this paper. Then, a novel robust HDR image watermarking algorithm is proposed against TM operations. Firstly, based on the hybrid processing of redundant discrete wavelet transform and singular value decomposition, the watermark is embedded by modifying the structure information of the HDR image. Distinguished from LDR image watermarking, the high embedding strength can cause more obvious distortion in the high brightness regions of HDR image than the low brightness regions. Thus, a perceptual brightness mask with low complexity is designed to improve the imperceptibility further. Experimental results show that the proposed algorithm is robust to the existing TM operations, with taking into account the imperceptibility and embedded capacity, which is superior to the current state-of-art HDR image watermarking algorithms.

Comparative Interactivity Analysis in Multiview Video Coding Schemes

You Yang,Gangyi Jiang,Qionghai Dai,호요성 한국전자통신연구원 2010 ETRI Journal Vol.32 No.4

In a multiview video system, interactivity is important for users and should be considered in the design of multiview video coding (MVC). In this paper, we present an interactivity evaluation model for MVC schemes by using both weighted random graph and Markov approaches. The main factors that affect both the interactivity and rate-distortion (RD) performances of MVC schemes are analyzed and discussed in detail. By taking these factors into consideration, a new MVC scheme is proposed for high interactivity and RD gains. Experimental results show that the proposed scheme has a significant interactivity gain with little coding loss, compared to the state-of-the-art benchmark. As an extension to RD performance analysis, the interactivity evaluation model can be used as a design tool of alternative schemes for a future interactive multiview video system.

View Generation for User Centered Free Viewpoint Video System

Liangzhong Fan,Gangyi Jiang,Mei Yu,Yong-Deak Kim 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7

A new framework of free viewpoint video (FVV) system is presented, which focus on the requirement and capability of user side. View generation is one of the most time consuming parts at the user side. Based on the disparity vector map transmitted from server side, a fast per-pixel disparity refinement scheme is designed to accelerate arbitrary viewpoint rendering. Experimental results show that the speed of the new method is increased about 25 times than the conventional block-based matching method and the quality of virtual view is improved greatly.

A Rapid Convergent Max-SINR Algorithm for Interference Alignment Based on Principle Direction Search

( Zhilu Wu ),( Lihui Jiang ),( Guanghui Ren ),( Gangyi Wang ),( Nan Zhao ),( Yaqin Zhao ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.5

The maximal signal-to-interference-plus-noise ratio (Max-SINR) algorithm for interference alignment (IA) has received considerable attention for its high sum rate achievement in the multiple-input multiple-output (MIMO) interference channel. However, its complexity may increase dramatically when the number of users approaches the IA feasibility bound, and the number of iterations and computational time may become unacceptable. In this paper, we study the properties of the Max-SINR algorithm thoroughly by presenting theoretical insight into the algorithm and by providing the potential of reducing the overall computational cost. Furthermore, a novel IA algorithm based on the principle direction search is proposed, which can converge more rapidly than the conventional Max-SINR method. In the proposed algorithm, it searches along the principle direction, which is found to approximately point to the convergence values, and can approach the convergence solutions rapidly. In addition, the closed-form solution of the optimal step size can be formulated in the sense of minimal interference leakage. Simulation results demonstrate that the proposed algorithm outperforms the conventional minimal interference leakage and Max-SINR algorithms in terms of the convergence rate while guaranteeing the high throughput of IA networks.