Search

An occupancy map coding method to compress 3D point cloud data is proposed. A 3D point cloud can be coded by projecting into a texture, depth, and occupancy map. This paper presents an efficient way to signal consecutive fully occupied occupancy coding units with a single bit for each coding unit row of an object in the occupancy map is presented. The results showed that the proposed algorithm could save 3.02% of bits without coding loss compared to an existing algorithm.

This paper describes a study and experimental demonstration on a magnetron operating at 2.45 GHz. We checked the characteristics of the 1 kW magnetron. There were two noise sources of magnetron at frequencies of 0.5 Hz and 75 kHz. In order to suppress these noises, we used an external injection locking method. Measurement results showed that the frequency noise suppression was down up to 30 dBc and the phase fluctuation is reduced to 4 degrees when injection input power was 7 W. Power combining experiments were performed using two identical magnetrons. An initial result showed an output power of 2 kW, corresponding to combining efficiency $\pmb{ > 93\%}$ .

This paper proposes a parallelization method for a deblocking filter in a high-efficiency video coding (HEVC) decoder based on complexity estimation. A deblocking filter of HEVC is generally considered to be appropriate for data-level parallelism (DLP) because there are no data-level dependencies among adjacent blocks in the horizontal and vertical filtering processes. However, an imbalanced workload can increase the idle time on some of the threads, and thus, the maximum parallel performance cannot be achieved with only DLP. To alleviate this problem, the proposed method estimates the computational complexity by utilizing the coding unit (CU) segment information and the on/off flag of the deblocking filter in advance. Then, the workload is distributed equally across all threads. The experimental results indicate that the proposed method can accelerate the decoding speed by a factor of 3.97, with six threads on top of the sequential deblocking filtering. In addition, the ratio of the maximum elapsed time to ideal elapsed time is reduced to approximately 21 %, as compared to conventional DLP-based parallel deblocking filtering methods that do not implement a complexity estimation method.

In this paper, we propose a scalable coding method for high dynamic range (HDR) and standard dynamic range (SDR) videos based on Scalable High Efficiency Video Coding (SHVC). The proposed method has multi-layer coding architecture that consists of base layer for SDR videos and enhancement layer for HDR videos to support the backward compatibility with legacy codec and display devices. Also, to improve coding efficiency of enhancement layers, a global inverse tone mapping is applied to the reconstructed SDR video and the compensated frames are referred for coding of the enhancement layer. The proposed method is found to achieve BD-Rate gain of 43.0% on average (maximum 76.3%) for the enhancement layer and 15.7% on average (maximum 31%) for dual-layer against the SHM 7.0 reference software.

In this paper, we propose a parallelization method for a High Efficiency Video Coding (HEVC) deblocking filter with transform unit (TU) split information. HEVC employs a deblocking filter to boost perceptual quality and coding efficiency. The deblocking filter was designed for data-level parallelism. In this paper, we demonstrate a method of distributing equal workloads to all cores or threads by anticipating the deblocking filter complexity based on the coding unit depth and TU split information. We determined that the average time saving of our proposed deblocking filter parallelization method has a speed-up factor that is 2% better than that of the uniformly distributed parallel deblocking filter, and 6% better than that of coding tree unit row distribution parallelism. In addition, we determined that the speed-up factor of our proposed deblocking filter parallelization method, in terms of percentage run-time, is up to 3.1 compared to the run-time of the HEVC test model 12.0 deblocking filter with a sequential implementation.

In this paper, we propose a new intra coding method by unidirectional prediction for improvement of intra-frame coding efficiency of H.264/AVC. There are , , and intra prediction modes in the current H.264/AVC. For the intra prediction, coding efficiency is achieved by accurate prediction with small block size in relatively complicated regions, and the intra prediction method can predict more accurately compared to intra prediction with only one directional information in relatively homogeneous regions. We propose a unidirectional intra prediction method adopting a small-size prediction and one directional prediction approaches. In order to improve coding efficiency, the proposed method is conducted by block and their prediction directions are all the same, resulting that we need to send only one directional information for each macroblock. For intra-frame coding setting, we achieve 10.47% and 1.57% coding efficiency in BD-bitrate for only intra mode and , intra mode, respectively.

In this paper, we propose an effective stereo-view video coding method that considers stereo-view and displayer characteristics. Current many stereo video displayers are designed for not only stereo display but also conventional single view display. In these systems, the resolution of two input videos for a stereo mode is half of that of single view for compatibility with conventional single view video services. In this raper, we propose a stereo video codec to deal with both single view and stereo view services by encoding whole left image and down-sampled right image. However, direct disparity estimation is not possible between two views because the resolution of a left image is different from that of the corresponding right image. So, we propose a disparity estimation method to make use of full information of the left reference image without down-sampling. In experimental result, we achieved coding gain, compared with several conventional algorithms.

In this paper, we propose an improved distributed multi-view video coding method that is robust to illumination changes among different views. The use of view dependency is not effective for multi-view video because each view has different intrinsic and extrinsic camera parameters. In this paper, a modified distributed multi-view coding method is presented that applies illumination compensation when generating side information. The proposed encoder codes DC values of discrete cosine transform (DCT) coefficients separately by entropy coding. The proposed decoder can generate more accurate side information by using the transmitted DC coefficients to compensate for illumination changes. Furthermore, AC coefficients are coded with conventional entropy or channel coders depending on the frequency band. We found that the proposed algorithm is about 0.1~0.5 ㏈ better than conventional algorithms.

In this paper, we propose a new distributed video coding (DVC) method based on adaptive slice size using received motion vectors (MVs). In the proposed algorithm, the MVs estimated at a DVC decoder are transmitted to a corresponding encoder. In the proposed encoder, a predicted side information (PSI) is reconstructed with the transmitted MVs and key frames. Therefore, the PSI can be generated same to side information (SI) at the decoder. We can, also, calculate an exact crossover probability between the SI and original input frame using PSI and the original frame. As a result, the proposed method can transmit minimum parity bits to maximize error correction ability of a channel decoder with minimal computational complexity. Experimental results show that the proposed algorithm is better than several conventional DVC methods.

In this paper, we propose a new side information generation (SIG) method which is applicable to distributed video coding (DVC). The proposed method adaptively changes a search range depending on a confidence level in hierarchical motion estimation (ME) and reconstructs the hole regions using the proposed uni-directional prediction and linear interpolation. In order to improve reliability of the hierarchical ME, ME for each block is performed in descending order of block variance values. Also, in order to alleviate errors from inaccurate motion vector (MV) estimation, search range is adaptively adjusted according to reliability of ME. Experimental results show that the proposed algorithm is better than several conventional methods for DVC. We also found that block artifacts and blur artifacts are significantly diminished by the proposed algorithm.

In this paper, we propose an efficient rate-control algorithm which considers characteristics of multi-view video coding (MVC). A rate control algorithm is one of the most important elements of video coding. There are many existing algorithms to control the bit rate but they are designed for single-view video coding. The rate control algorithm for MVC should be also conducted at view level. Conventional rate-control algorithms for single view videos do not use QP values of B frames in computing a GOP initial QP. However, we have to take into account QP values of B frames because the MVC has many B views which are composed of only B frames. In addition, other views also have many B frames because the MVC employ the hierarchical B for coding efficiency. In the proposed algorithm, initial QP of GOP should be computed with QP values of B frames. In our research, the proposed algorithm can allocate proper bitrates for B views which are composed of only B frames and QP values of B frames can affect the initial QP of GOP. The proposed method can control total bitrate of multiple views to be acquired and displayed at the same time. In our experimentation, we found that the proposed method can control bitrates for all the views according to target bitrates

In this paper, a new residual signal compression method is proposed based on the blind signal decomposition for video coding. Blind signal decomposition is derived based on the fact that most of the natural signals in the real world could be decomposed into their basis signals and their weight values used in the composition process. In the proposed video coding system, composite data generated by adding two or more blocks are coded. Then the proposed decoder parses the coded bitstream and reconstructs the composite residual. The reconstructed composite residual is decomposed into the original residual blocks based on the blind signal decomposition. In the proposed system, the blind source separation is selectively used, depending on the performance of source separation. It is found that we can achieve approximately 2 ∼ 3dB gain by embedding our algorithm into an MPEG-4 baseline encoder.

In this paper we propose a new range-based face recognition for significant improvement in the recognition rate using an optimized stereo acquisition system. The optimized 3D acquisition system consists of an eyes detection algorithm, facial pose direction distinction, and principal component analysis (PCA). The proposed method is carried out in the YCbCr color space in order to detect the face candidate area. To detect the correct face, it acquires the correct distance of the face candidate area and depth information of eyes and mouth. After scaling, the system transfers the pose change according to the distance. The face is finally recognized by the optimized PCA for each area with the facial pose elements detected. Simulation results with face recognition rate of 95.83% (100cm) in the front and 98.3% with the pose change were obtained successfully. Therefore, proposed method can be used to obtain high recognition rate with an appropriate scaling and pose change according to the distance.