• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.6
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• pp.703-711
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• 2001

In this paper, we propose efficient multispectral image compression using variable block size vector quantization (VQ). In wavelet domain, we perform the variable block size VQ to remove intraband redundancy for a reference band image that has the lowest spatial variance and the best correlation with other band. And in wavelet domain, we perform the classified interband prediction to remove interband redundancy for the remaining bands. Then error wavelet coefficients between original image and predicted image are residual variable block size vector quantized to reduce prediction error. Experiments on remotely sensed satellite image show that coding efficiency of the proposed method is better than that of the conventional method.

• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1080-1087
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• 2005

Significant computations for full search (FS) motion estimation have been a big obstacle in real-time video coding and recent MPEG-4 AVC (advanced video coding) standard requires much more computations than conventional MPEG-2 for motion estimation. To reduce an amount of computation of full search (FS) algorithm for fast motion estimation, we propose a new and fast matching algorithm without any degradation of predicted images like the conventional FS. The computational reduction without any degradation in predicted image comes from fast elimination of impossible candidate motion vectors. We obtain faster elimination of inappropriate motion vectors using efficient matching units from localization of complex area in image data and dithering order based matching scan. Our algorithm reduces about $30\%$ of computations for block matching error compared with the conventional partial distortion elimination (PDE) algorithm, and our algorithm will be useful in real-time video coding applications using MPEG-4 AVC or MPEG-2.

• Journal of Advanced Navigation Technology
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• v.18 no.6
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• pp.600-608
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• 2014

In this paper, CABAC H/W module is developed using co-design method. After entire H.264/AVC encoder was developed with C using reference SW(JM), CABAC H/W IP is developed as a block in H.264/AVC encoder. Context modeller of CABAC is included on the hardware to update the changed value during binary encoding, which enables the efficient usage of memory and the efficient design of I/O stream. Hardware IP is co-operated with the reference software JM of H.264/AVC, and executed on Virtex-4 FX60 FPGA on ML410 board. Functional simulation is done using Modelsim. Compared with existing H/W module of CABAC with register-level design, the development time is reduced greatly and software engineer can design H/W module more easily. As a result, the used amount of slice in CABAC is less than 1/3 of that of CAVLC module. The proposed co-design method is useful to provide hardware accelerator in need of speed-up of high efficient video encoder in embedded system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.512-515
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• 2003

MPEG-4 has mediocrity Standing encoding personality to process multimedia data including audio and video etc in the Internet and computer. It can use extensively without being limited to one territory of communication, computer, broadcasting, Mobile etc. Like this, according as digital contents do fetters to MPEG-4 is circulated, copyright problem was risen. So, people had a lot of interests to protect and manage copyright. Hereupon, MPEG of the ISO/IEC established IPMP(Intellectual Property Management and Protection) standard, and supplements and corrects continuously standard. Therefore, existing system does fetters to MPEG-4 need system that process IPMP information. Hereupon, in this paper, designed system module that is processed by IPMP extension standard that progress now, and embodied copyright protection and management system that user can insert and update IPMP information efficiently within whole or specification part of MPEG-4 digital contents.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.113-116
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• 2007

T-DMB (Terrestrial-DMB) service is now available in the metropolitan area, but due to the bandwidth limitation, it is allowed to provide up to CIF resolution. As users' requests for high-quality mobile multimedia services are rapidly increasing and additional bandwidth can be provided by adopting the hierarchical modulation transmission technology, the research on the Advanced Terrestrial-DMB(AT-DMB) service using the SVC(Scalable Video Coding) scheme is being actively studied. In this paper, through computer simulations, first, while keeping the current T-DMB service unchanged, the visual qualities of AT-DMB services are investigated by varying the additional bandwidth. Then, by considering the cases that the overall bandwidth can be allowed to dynamically allocate to the T-DMB/AT-DMB video services, the performance characteristics between two layers are compared over the different kinds of video sequences.

• Journal of the Korea Computer Industry Society
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• v.10 no.5
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• pp.227-234
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• 2009

The Paper introduces a new technique for block matching motion estimation. since the temporal correlation of a animation sequence between the motion vector of current block and the motion vector of previous block. In this paper, we propose the scene change detection algorithm for block matching using the temporal correlation of the animation sequence and the center-biased property of motion vectors. The proposed algorithm determines the location of a better starting point for the search of an exact motion vector using the point of the smallest SAD(sum of absolute difference) value by the predicted motion vector from the same block of the previous frame and the predictor candidate point on each search region. Simulation results show that the PSNR values are improved as high as 9~32% in terms of average number of search point per motion vector estimation and improved about 0.06~0.21dB on an average except the FS(full search) algorithm.

• Journal of Broadcast Engineering
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• v.2 no.1
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• pp.24-35
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• 1997

Basic and transmission video quality testing was performed in real-time mode using hardware video codec based on MPEG-2 MP@ML standard including subsequent transmitting and receiving satellite simulator unit. The double-stimulus Impairment scale method and the double-stimulus continous quality scale method based on CCIR 500-5 were used as an evaluation method. The whole digital broadcasting satellite system consisting of MPEG-2 codec, system mux/demux, channel codec, channel, modem, antenna, etc. was put into the overall video quality testbed and the basic and transmission error quality assessment was performed at various bitrates and BER for an integrated system performance evaluation. In transmission error video quality testing, transmission error video quality maintained on average above 3.9 point on the 5-point scale. The low-bit rate quality such as film mode(@2Mbps) highly depended on the statitical characteristics of video source and maintained on average around 2.7 point.

• The Journal of the Korea Contents Association
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• v.8 no.5
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• pp.29-37
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• 2008

To transmit video bit stream over low bandwidth such as wireless channel, high compression algorithm like H.264 codec is exploited. In transmitting high compressed video bit-stream over low bandwidth, packet loss causes severe degradation in image quality. In this paper, a new algorithm for recovery of missing or erroneous motion vector is proposed. Considering that the missing or erroneous motion vectors in blocks are closely correlated with those of neighboring blocks. Motion vector of neighboring blocks are clustered according to average linkage algorithm clustering and a representative value for each cluster is determined to obtain the candidate motion vector sets. As a result, simulation results show that the proposed method dramatically improves processing time compared to existing H.264/AVC. Also the proposed method is similar to existing H.264/AVC in terms of visual quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10C
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• pp.1000-1010
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• 2006

This paper proposes a new architecture for DCT-based motion estimation and compensation. Previous methods do riot take sufficient advantage of the sparseness of 2-D DCT coefficients to reduce execution time. We first derive a recursion equation to perform DCT domain motion estimation more efficiently; we then use it to develop a wavefront array processor (WAP) consisting of processing elements. In addition, we show that the recursion equation enables motion predicted images with different frequency bands, for example, from the images with low frequency components to the images with low and high frequency components. The wavefront way Processor can reconfigure to different motion estimation algorithms, such as logarithmic search and three step search, without architectural modifications. These properties can be effectively used to reduce the energy required for video encoding and decoding. The proposed WAP architecture achieves a significant reduction in computational complexity and processing time. It is also shown that the motion estimation algorithm in the transform domain using SAD (Sum of Absolute Differences) matching criterion maximizes PSNR and the compression ratio for the practical video coding applications when compared to tile motion estimation algorithm in the spatial domain using either SAD or SSD.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1405-1409
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• 2004

This paper is studied new block mode decision algorithm for H.264/AVC. The fast block mode decision algorithm is consist of block range decision algorithm. The block range decision algorithm classifies the block over 8$\times$8 size or below for 16${\times}$16 macroblock to decide the size and type of sub blocks. As the sub blocks of 8$\times$8, 8r4, 4$\times$8 and 4$\times$4, which are the blocks below 8$\times$8 size, include important motion information, the exact sub block decision is required. RDC(RDO cost) is used as the matching parameter for the exact sub block decision. RDC is calculated with motion strength which is the mean value of neighbor pixels of each sub block. The sub block range decision reduces encoding arithmetic amount by 34.62% on the average more than the case not using block range decision. The block mode decision using motion strength shows improvement of PSNR of 0.05[dB].