• Journal of Broadcast Engineering
• /
• v.12 no.2
• /
• pp.128-136
• /
• 2007

Since the multi-view video is a set of video sequences captured by multiple array cameras for the same three-dimensional scene, it can provide multiple viewpoint images using geometrical manipulation and intermediate view generation. Although multi-view video allows us to experience more realistic feeling with a wide range of images, the amount of data to be processed increases in proportion to the number of cameras. Therefore, we need to develop efficient coding methods. One of the possible approaches to multi-view video coding is to generate an intermediate image using view interpolation method and to use the interpolated image as an additional reference frame. The previous view interpolation method for multi-view video coding employs fixed size block matching over the pre-determined disparity search range. However, if the disparity search range is not proper, disparity error may occur. In this paper, we propose an efficient view interpolation method using initial disparity estimation, variable block-based estimation, and pixel-level estimation using adjusted search ranges. In addition, we propose a multi-view video coding method based on H.264/AVC to exploit the intermediate image. Intermediate images have been improved about $1{\sim}4dB$ using the proposed method compared to the previous view interpolation method, and the coding efficiency have been improved about 0.5 dB compared to the reference model.

• Journal of KIISE
• /
• v.41 no.11
• /
• pp.900-910
• /
• 2014

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. The computational complexity of multi view video coding increases in proportion to the number of cameras. To reduce computational complexity and maintain the image quality, improved prediction structure and motion estimation method is proposed in this paper. The proposed prediction structure exploits an average distance between the current picture and its reference pictures. The proposed prediction structure divides every GOP into several groups to decide the maximum index of hierarchical B layer and the number of pictures of each B layer. And the proposed motion estimation method uses a hierarchical search strategy. This strategy method consists of modified diamond search pattern, progressive diamond search pattern and modified raster search pattern. Experiment results show that the complexity reduction of the proposed prediction structure and motion estimation method over JMVC (Joint Multiview Video Coding) reference model using hierarchical B pictures of Fraunhofer-HHI and TZ search method can be up to 40~70% while maintaining similar video quality and bit rates.

• Journal of Korea Multimedia Society
• /
• v.17 no.3
• /
• pp.333-341
• /
• 2014

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. Multi-view video coding requires high computational complexity. To reduce computational complexity and maintain the image quality, an effective early termination motion estimation method is proposed in this paper. The proposed method exploiting the characteristic of motion vector distribution uses a hierarchical search strategy. This strategy method consists of multi-grid square search pattern, modified diamond search pattern, small diamond search pattern and raster search pattern. Experiment results show that the speedup improvement of the proposed method over TZ search method and FS(Full Search) method JMVC (Joint Multiview Video Coding) can be up to 1.7~4.5 times and 90 times faster respectively while maintaining similar video quality and bit rates.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.5
• /
• pp.1728-1743
• /
• 2021

Three-dimensional (3D) video scenes are complex and difficult to control, especially when scene switching occurs. In this paper, we propose two algorithms based on an incremental proportional-integral-derivative (PID) algorithm and a similarity analysis between views to improve the method of bit allocation for multi-view high efficiency video coding (MV-HEVC). Firstly, an incremental PID algorithm is introduced to control the buffer "liquid level" to reduce the negative impact on the target bit allocation of the view layer and frame layer owing to the fluctuation of the buffer "liquid level". Then, using the image similarity between views is used to establish, a bit allocation calculation model for the multi-view video main viewpoint and non-main viewpoint is established. Then, a bit allocation calculation method based on hierarchical B frames is proposed. Experimental simulation results verify that the algorithm ensures a smooth transition of image quality while increasing the coding efficiency, and the PSNR increases by 0.03 to 0.82dB while not significantly increasing the calculation complexity.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.190-192
• /
• 2004

In this paper, we propose a low bit-rate embedded video compression scheme with 3-D block partition coding in the wavelet domain. The proposed video compression scheme includes multi-level 3-dimensional dyadic wavelet decomposition, raster scanning within each subband, formation of block, 3-D partitioning of block, and adaptive arithmetic entropy coding. Although the proposed video compression scheme is quit simple, it produces bit-stream with good features, including SNR scalability from the embedded nature. Experimental results demonstrate that the proposed video compression scheme is quit competitive to other good wavelet-based video coders in the literature.

• Journal of Korea Multimedia Society
• /
• v.16 no.5
• /
• pp.539-548
• /
• 2013

Although Motion estimation (ME) plays an important role in digital video compression, it requires a complicated search procedure to find an optimal motion vector. Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. The computational complexity of motion estimation for Multi-view video coding increases in proportion to the number of cameras. To reduce computational complexity and maintain the image quality, a low complexity motion estimation search method is proposed in this paper. The proposed search method consists of four-grid diamond search patten, two-gird diamond search pattern and TZ 2 Point search pattern. These search patterns exploit the characteristics of the distribution of motion vectors to place the search points. Experiment results show that the speedup improvement of the proposed method over TZ search method (JMVC) can be up to 1.8~4.5 times faster by reducing the computational complexity and the image quality degradation is about to 0.01~0.24 (dB).

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.5 no.2
• /
• pp.390-407
• /
• 2011

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.

• KIPS Transactions on Software and Data Engineering
• /
• v.2 no.7
• /
• pp.495-502
• /
• 2013

Motion estimation (ME) that limits the performance of image quality and encoding speed has been developed to reduce temporal redundancy in video sequences and plays an important role in digital video compression. But it is computational demanding part of the encoder. Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. ME for Multi-view video requires high computational complexity. To reduce computational complexity and maintain the image quality, a fast motion estimation method is proposed in this paper. The proposed method uses a hierarchical search strategy. This strategy method consists of modified diamond search patten, multi gird diamond search pattern, and raster search pattern. These search patterns place search points symmetrically and evenly that can cover the overall search area not to fall into the local minimum or exploits the characteristics of the distribution of motion vectors to place the search points. Experiment results show that the speedup improvement of the proposed method over TZ search method (JMVC) can be up to 1.2 ~3 times faster while maintaining similar video quality and bit rates.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.1B
• /
• pp.31-41
• /
• 2000

It has been known that the optical code division multiple access (OCDMA) is a prominent future technology to support many simultaneous users and to increase transmission capacity of optical fiber. In this paper, we proposed the new construction of 2 dimensional code, which can be used as a codeword in temporal/wavelength OCDMA networks. New code family is obtained by extending the concept of Hamming correlation. All optical encoder and decoder for newly proposed code were also developed. In considering bit error ratio, we verified that new coding scheme outperforms conventional coding scheme by simulation. This system is applicable to asynchronous fast local area network, which needs a high security level and a flexible network configuration.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.375-378
• /
• 2005

The multi-view video is a collection of multiple videos capturing the same scene at different viewpoints. The multi-view video can be used in various applications, including free viewpoint TV and three-dimensional TV. Since the data size of the multi-view video linearly increases as the number of cameras, it is necessary to compress multi-view video data for efficient storage and transmission. The multi-view video can be coded using the concept of the layered depth image (LDI). In this paper, we describe a procedure to generate LDI from the natural multi-view video and present a method to encode multi-view video using the concept of LDI.