• Journal of Broadcast Engineering
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• v.10 no.3
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• pp.436-450
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• 2005

In this paper we propose an integrated media format for a photo album including media resources and corresponding meta-data The main purpose of the integrated media is to be more reusable meta-data and to facilitate constructing a photo album from a large number of photo images as well. The proposed media format is based on MAF(multimedia Application Format) which is recently going on progress in MPEG standards. In this paper, we propose the integrated media consisting of JPEG data and content-based meta-data based on MPEG-7 MDS. We verified the usefulness of the proposed media through experiments with implementation of encoder and photo MAF player for the MAF-based media format.

• Journal of Broadcast Engineering
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• v.14 no.5
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• pp.551-560
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• 2009

This paper proposes a method for efficient lossless depth map coding for MPEG 3D-Video coding. In general, the conventional video coding method such as H.264 has been used for depth map coding. However, the conventional video coding methods do not consider the image characteristics of the depth map. Therefore, as a lossless depth map coding method, this paper proposes a bit-plane based lossless depth mar coding method by using the MPEG-4 Part 2 shape coding scheme. Simulation results show that the proposed method achieves the compression ratios of 28.91:1. In intra-only coding, proposed method reduces the bitrate by 24.84% in comparison with the JPEG-LS scheme, by 39.35% in comparison with the JPEG-2000 scheme, by 30.30% in comparison with the H.264(CAVLC mode) scheme, and by 16.65% in comparison with the H.264(CABAC mode) scheme. In addition, in intra and inter coding the proposed method reduces the bitrate by 36.22% in comparison with the H.264(CAVLC mode) scheme, and by 23.71% in comparison with the 0.264(CABAC mode) scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.464-469
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• 2002

In this research, nonvisibility and robustness of image watermarking mixed Key and Logo method were evaluated. The role of the Key was performed by a personal ID of a copyrighter and the logo images were used as the watermark. The standard image of Lena was used for experimental image and binary images of `Park'with size 32${\times}$32 and 64${\times}$64 were used for the watermark, respectively In order to evaluate nonvisibility of the proposed watermarking scheme, PSNR(Peak Signal to Noise Ratio) of the watermarked image was obtained and for robustness reconstructive rates of the reconstructed watermark were obtained from the watermarked image with image transformation of JPEG lossy compression. The experimental results show that nonvisibility is excellent as PSNR of the watermarked image is 93.75dB and the reconstructive rates of the case of 322${\times}$32 watermark was better than the case of the 64${\times}$64 watermark; average 5.9%, 13.9%, 6.5%, and 4.2% in the case of scale-down rates, rotational rates, impulse noise power density, and JPEG lossy compression rates, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9C
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• pp.939-948
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• 2005

In EBCOT, the context extraction process takes excessive calculation time and this paper proposed a method to reduce this calculation time. That is, if a coefficient is less than a pre-defined threshold value the coefficient and its descendents skip the context extraction process. There is a trade-off relationship between the calculation time and the image quality or the amount of output data such that as this threshold value increases, the calculation time and the amount of output data decreases, but the image degradation increases. Therefore, by deciding this threshold value according to the network environments or conditions, it is possible to establish a network-adaptive context extraction method. The experimental results showed that the range of the threshold values for acceptable image quality(better than 30dB) is from 0 to 4. The experimental results showed that in this range the Resulting reduction rate in calculation time was from $3\%\;to\;64\%$ in average, the reduction rate in output data was from $32\%$ to $73\%$ in average, which means that large reduction in calculation time and output data can be obtained with a cost of an acceptable image quality degradation. Therefore, the proposed method is expected to be used efficiently in the application area such as the real-time image/video data communication in wireless environments, etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7C
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• pp.726-734
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• 2005

Traditional watermarking technologies are symmetric method which embedding and detection keys are the same. Although the symmetric watermarking method is easy to detect the watermark, this method has weakness against to malicious attacks remove or modify the watermark information when the symmetric key is disclosure. Recently, the asymmetric watermarking method that has different keys to embed and detect is watched by several researchers as a next generation watermarking technology. In this paper, hybrid asymmetric watermarking algorithm is proposed. This algorithm is composed of correlation detection method and critical criteria method. Each method can be individually used to detect watermark from a watermarked content. Hybrid asymmetric detection is complement between two methods, and more feasible than when each method is used respectively, Private key and public key are generated by secure linear transformation and specific matrix. As a result, we have proved the proposed algorithm is secured than symmetric watermarking algorithms. This algorithm can expand to multi bits embedding watermark system and is robust to JPEG and JPEG2000 compression.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.271-275
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• 2007

본 문서는 JPEG(Joint Photographic coding experts group)에서 새로운 분야로 준비중인 JPSearch의 기술개요와 구조를 소개함으로써 텍스트 기반에서 영상 대 영상 검색 시스템의 전환을 제시한다. 또한 영상 대 영상 검색 시스템의 기본적인 기술특징과 JPSearch에서 요구하는 시스템 구조를 설명한다. JPSearch의 영상 검색 시스템이 사용 가능한 다양한 사용자 경우를 제시하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.175-179
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• 2003

We propose a new watermarking scheme that can be used to embed multiple bits and also resilient to JPEG compression and geometrical transforms such as scaling, rotation, and cropping based on holographic watermark that allows multiple watermark recovery without original content(cover image).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.12
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• pp.1956-1969
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• 1993

The tilted Huffman trees are used in JPEG and MPEG image compression standards for Huffman coding. In this paper we propose a new decoding technique for Huffman code, symbols are decoded by repeatedly obtaining the predefined number of consecutive bits and accessing symbol tables based on the obtaining bits. We show that the size of the symbol table can be small if the Huffman tree is tilted. Specifically, we show an upper bound on the size in this paper. Since the proposed method processes multiple bits at each clock, it can be used for real time processing. We show such evaluation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.155-158
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• 2008

In this paper, we propose a novel blind watermarking Method using 2D CAT (Two dimensional cellular automata transform). In our scheme, firstly, we obtain the gateway values to generate a dual-state, dual-coefficients basis function. Secondly, the basis function transforms images into cellular automata space. Lastly, we use the cellular automata transform coefficients to embed random noise watermark in the cover images. The proposed scheme allows only one 2D CAT basis function per gateway value. Since there are $2^{96}$ possible gateway values, better security is guaranteed. Moreover, the new method not only verifies higher fidelity than the existing method but also stronger stability on JPEG lossy compression, filtering, sharpening and noise through tests for robustness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6C
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• pp.857-864
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• 2004

Many image compression standards such as JPEG, MPEG or H.263 are based on the discrete cosine transform (DCT) and quantization method. Quantization error. is the major source of image quality degradation. The current dequantization method assumes the uniform distribution of the DCT coefficients. Therefore the dequantization value is the center of each quantization interval. However DCT coefficients are regarded to follow Laplacian probability density function (pdf). The center value of each interval is not optimal in reducing squared error. We use mean of the quantization interval assuming Laplacian pdf, and show the effect of correction on image quality. Also, we compare existing quantization error to corrected quantization error in closed form. The effect of PSNR improvements due to the compensation to the real image is in the range of 0.2 ∼0.4 ㏈. The maximum correction value is 1.66 ㏈.