• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.1093-1103
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• 2009

In this paper, we propose a new depth map based distributed multi-view video coding algorithm through an efficient side information generation. A distributed video coding scheme corrects errors between an original image and side information generated at a decoder by using channel coding techniques. Therefore, the more accurate side information is generated, the better performance of distributed video coding scheme is achieved. In the proposed algorithm, a distributed video coding scheme is applied to multi-view video coding based on depth map. Side information is also generated from images of adjacent views through 3D warping by using a depth map and is also combined with MCTI(motion compensated temporal interpolation) which uses images on a temporal axis, and 3D warping. Experimental results show that side information generated by using the proposed algorithm has 0.97dB better average PSNR compared with using MCTI and 3D warping separated. In addition, 8.01% of average bit-rate has been decreased while the same PSNR in R-D curves is kept.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1677-1685
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• 1988

In this paper, a new contour coding algorithm is investigated for use in region based image coding. Generally the contour data may be encoded by its chain codes or chain difference codes. But the data compression efficiency is low because of heavy burden for initial absolute coordinates of each chain. To alleviate this problem, the depth first search in graph traversal algorithm, is applied to the chain difference coding method. The proposed coding scheme is shown to be very efficient for contour images obtained by split-merge segmentation. Finally, we can reuce data about 60% in comparison with modified chain difference coding.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.6
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• pp.23-29
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• 2016

In this paper, we propose a method of depth video coding to find the closest sphere through the depth information when the spherical object is captured. We find the closest sphere to the captured spherical object using method of least squares in each block. Then, we estimate the depth value through the found sphere and encode the depth video through difference between the measured depth values and the estimated depth values. Also, we encode factors of the estimated sphere with encoded pixels within the block. The proposed method improves the coding efficiency up to 81% compared to the conventional DPCM method.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.89-96
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• 2016

The High Efficiency Video Coding (MPEG-H HEVC/ITU-T H.265) is the newest video coding standard which has the quadtree-structured coding unit (CU). The quadtree-structure splits a CU adaptively, and its optimum CU depth can be determined by rate-distortion optimization. Such HEVC encoding requires very high computational complexity for CU depth decision. Motivated that the blob detection, which is a well-known algorithm in computer vision, detects keypoints in pictures and decision of CU depth needs to consider high frequency energy distribution, in this paper, we propose to utilize these keypoints for fast CU depth decision. Experimental results show that 20% encoding time can be saved with only slightly increasing BDBR by 0.45% on all intra case.

• Journal of Broadcast Engineering
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• v.17 no.5
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• pp.716-724
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• 2012

In this paper, we propose a fast decision method of maximum coding depth decision and reference frame selection in HEVC. To reduce computational complexity and encoding time of HEVC, two methods are proposed. In the first method, the maximum depth of each coding unit (CU) in a largest CU (LCU) is constrained by using the maximum coding depth used by adjacent LCUs based on the assumption that the spatial correlation is very high and rate-distortion (R-D) cost. And we constrain the number of reference pictures for prediction unit (PU) performing motion estimation by using the motion information of the upper depth PU. The proposed methods reduce computational complexity of the HEVC encoder by constraining the maximum coding depth and the reference frame. We could achieve about 39% computational complexity reduction with marginal bitrate increase of 1.2% in the comparison with HM6.1 HEVC reference software.

• Smart Media Journal
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• v.2 no.2
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• pp.28-32
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• 2013

In this paper, we present a method to reduce complexity of depth modeling modes (DMM) that are used in the current 3D-HEVC standardization. DMM adds four modes to the existing HEVC intra prediction modes for accurate object edge representation in the depth map. Especially, Mode 3 requires distortion calculation of numerous pre-defined wedgelets, inducing high complexity. The proposed method employs absolute differences of neighboring pixels in the sides of the reference block to find high intensity changing positions. Based on such positions, the number of wedgelet candidates is reduced to six and distortion calculation is skipped for irrelevant wedgelets. Experimental results show complexity reduction by 3.1% on average, while maintaining similar coding performance.

• Journal of Korea Multimedia Society
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• v.20 no.11
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• pp.1711-1719
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• 2017

In this paper, we propose a method of the zoom motion estimation for the depth video coding. The proposed method calculates the zoom ratio using the average of the depth values in the current block and in the reference block. It resizes the reference block by the zoom ratio and interpolates the reference block to size of the current block. It compares the current block with the reference block that is obtained by subtracting the average of pixels from the current block to the reference block in order to find the reference block that is the best closest one to the current block. The results of the simulation for the proposed method show that the motion estimation errors are significantly reduced.

• Journal of Korea Multimedia Society
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• v.15 no.4
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• pp.492-500
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• 2012

In this paper, improved contour region coding method is proposed to accomplish better depth map coding performance. First of all, in order to use correlation between color video and depth map, a structure in SVC is applied to 3DVC. This can reduce bit-rate of the depth map while supporting the video to be transferred via various collection of network. As the depth map is mainly used to synthesize videos from different views, corrupted contour region can damage the overall quality of video. We hereby adapt a new differential quantization method when separating the contour region. The experimental results show that the proposed method can improve video quality by 0.06~0.5dB which translate the bit rate saving by 0.1~1.15%, when compared to the reference software.

• Journal of Broadcast Engineering
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• v.20 no.4
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• pp.545-556
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• 2015

A HEVC-compatible 3D video coding method (3D-HEVC) has been recently developed as an extension of the high efficiency video coding (HEVC) standard. In order to efficiently deal with the multi-view video plus depth (MVD) format, 3D-HEVC exploits an inter-component prediction which allows the prediction between texture and depth map images in addition to a temporal prediction used in the conventional single layer video coding such as H.264/AVC and HEVC. The performance of the inter-component prediction is normally affected by the accuracy of the disparity vector, and thus it is important to have an accurate disparity vector used for the inter-component prediction. This paper, therefore, introduces a disparity derivation method and inter-component algorithms using the disparity vector for the efficient 3D video coding. Simulation results show that the 3D-HEVC provides higher coding performance compared with the simulcast approach using HEVC and the simple multi-view extension (MH-HEVC).

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.41-47
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• 2016

High efficiency video coding (HEVC) employs a coding tree unit (CTU) to improve the coding efficiency. A CTU consists of coding units (CU), prediction units (PU), and transform units (TU). All possible block partitions should be performed on each depth level to obtain the best combination of CUs, PUs, and TUs. To reduce the complexity of block partitioning process, this paper proposes the PU mode skip algorithm with region of interest (RoI) selection using motion vector. In addition, this paper presents the CU depth level skip algorithm using the co-located block information in the previously encoded frames. First, the RoI selection algorithm distinguishes between dynamic CTUs and static CTUs and then, asymmetric motion partitioning (AMP) blocks are skipped in the static CTUs. Second, the depth level skip algorithm predicts the most probable target depth level from average depth in one CTU. The experimental results show that the proposed fast CU decision algorithm can reduce the total encoding time up to 44.8% compared to the HEVC test model (HM) 14.0 reference software encoder. Moreover, the proposed algorithm shows only 2.5% Bjontegaard delta bit rate (BDBR) loss.