• Journal of the Semiconductor & Display Technology
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• v.8 no.1
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• pp.19-25
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• 2009

Abstract JPEG2000 achieve quality scalability through the rate control method used in the encoding process, which embeds quality layers to the code-stream. This architecture might raise two drawbacks. First, when the coding process finishes, the number and bit-rates of quality layers are fixed, causing a lack of quality scalability to code-stream encoded with a single or few quality layers. Second, in Post compression rate distortion (PCRD) the bit streams after the truncation points discarded. Therefore, computational power for the discarded bit streams is wasted. For solving of problem, through bit rate control, there are many researches. Each proposed algorithms have specially target feature that is improved performance like reducing computational power. Research results have strength and weakness. For the mean time, research contents are reviewed and compared, so we proposed research direction in the future.

• Annual Conference of KIPS
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• 2001.10a
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• pp.151-154
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• 2001

본 연구는 웹 카메라에 적용하기 위한 JPEG2000의 주요 블록인 EBCOT(Embedded Block Coding with Optimized Truncation)의 설계 및 구현에 관한 연구이다. EHCOT 블록은 웨이블렛(wavelet)변환에 의해 분할된 각 sub-band에 존재하는 주위 화소 값들과 상위 bit-plane의 값들에 대한 상호 연관성을 조사하여 context을 추출하고 그 context를 이용하여 엔트로피 부호화(entropy coding)를 수행하는 T1(Tier 1) 블록과 bit-stream을 구성하는 T2(Tier 2) 블록으로 구성된다. 본 논문에서는 JPEG2000에서 전체 압축성능을 좌우하는 EBCOT의 T1 블록을 Synopsys tool을 이용하여 설계하고 구현하였다.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.88-88
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• 2002

Satellite Image archiving system requires large storage and long transmission time. A simple and cheap way of overcoming these limitations is to increase the compression ratio. However this requires a feasibility study for accurate applications. Here, a new still image compression standard is being developed, the JPEG2000. It provides lossless and lossy compression, progressive transmission by pixel accuracy and by resolution, region-of-interest coding, user-defined tiling size, random codestream access and processing etc. In this study, we will briefly introduce the JPEG2000 compression standard which provides a new compression technique based on the wavelet technology and offers better compression ratios, and evaluate the compression ratios of JPEG2000 for satellite image by performing various image quality tests. Also, we will compare brief test result using the commercial remote sensing software.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.5063-5073
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• 2016

In this paper, an efficient texture compression method is proposed for fast rendering, which exploits the spatial correlation among blocks through intra-picture block matching. Texture mapping is widely used to enhance the visual quality of results in real-time rendering applications. For fast texture mapping, it is necessary to identify an effective trade-off between compression efficiency and computational complexity. The conventional compression methods utilized for image processing (e.g., JPEG) provide high compression efficiency while resulting in high complexity. Thus, low complexity methods, such as ETC1, are often used in real-time rendering applications. Although these methods can achieve low complexity, the compression efficiency is still lower than that of JPEG. To solve this problem, we propose a texture compression method by reducing the spatial redundancy between blocks in order to achieve the better compression performance than ETC1 while maintaining complexity that is lower than that of JPEG. Experimental results show that the proposed method achieves better compression efficiency than ETC1, and the decoding time is significantly reduced compared to JPEG while similar to ETC1.

• Journal of Korea Multimedia Society
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• v.12 no.12
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• pp.1701-1709
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• 2009

The mobile terminal system plays a key role in medical industries which require in fast and accurate diagnosis from heterogeneous acquisition equipment. The demand for PACS (picture archiving and communication systems) has continued to increase in major hospitals and private clinics. Patient care depends on how fast the medical imaging system provides images and how accurately the images are interpreted by physicians. In this paper, we propose an efficient method to decipher the hundreds of images required by physicians to accurately diagnose patients. By exploring Motion- JPEG (M-JPEG), this paper has demonstrates the possibilities for efficient management of medical images with a newly designed image file format and improvement in imaging diagnoses through the replaying of moving pictures of a patient in a mobile environment.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1331-1344
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• 2017

In this paper, data hiding algorithm using Discrete Wavelet Transform (DWT) and Arnold Transform is proposed. The secret data is scrambled using Arnold Transform to make it secure. Wavelet subbands of a cover image are obtained using DWT. The scrambled secret data is embedded into significant wavelet coefficients of subbands of a cover image. The proposed algorithm is robust to a variety of attacks like JPEG and JPEG2000 compression, image cropping and median filtering. Experimental results show that the PSNR of the composite image is 1.05 dB higher than the PSNR of existing algorithms and capacity is 25% higher than the capacity of existing algorithms.

• Journal of the Korea Society of Computer and Information
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• v.24 no.2
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• pp.41-48
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• 2019

Digital image watermarking techniques have been studied in various fields in order to protect the copyright of multimedia contents mostly composed by images. JPEG compression is a representative copyright attack for image watermarking. The CRT-based watermarking methods in DCT domain have been studied, because these are robust for JPEG compression attack. In this paper, we propose a new method with improved performance compared with the existing CRT based methods in DCT domain. The proposed method selects the DCT block according to the denseness at the watermark insertion phase, and iteratively adjust the CRT Conditional coefficients at the watermark extraction. This paper shows that it is more robust for the JPEG compression attacks through experimental results.

• Annual Conference of KIPS
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• 2013.05a
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• pp.328-331
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• 2013

본 논문에서는 멀티코어 모바일 디바이스에서 최적의 스레드 구성을 측정하기 위해 이미지 코덱을 사용하여 다양한 환경에서 스레드 개수에 따른 인코딩 수행시간을 분석하였다. 인코딩은 Quantization을 사용하여 JPEG 파일들을 하나의 GIF 파일로 변환하는 기능을 수행하며, 듀얼코어와 쿼드코어 안에서 각각의 스레드 개수를 늘려가며 측정하였다. 듀얼코어에서는 스레드 4개였을 경우가 성능이 효율적이였으며, 쿼드 코어에서는 스레드 3개였을 경우가 성능이 효율적이였다. 분석 후 결론은 스레드 개수와 성능은 비례하는 것이 아니며 성능에 크게 영향을 미치지 않는 것으로 확인되었다. 코어와 I/O입출력의 성능 및 데이터 크기에 따라 적당한 스레드 개수를 정하여 사용하는 것이 효율적이다.

• Annual Conference of KIPS
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• 2011.11a
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• pp.302-305
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• 2011

멀티미디어 콘텐츠는 디지털 데이터의 특성상 위 변조 또는 불법유통 등의 문제가 발생할 수 있다. 특히 의료 및 군사, 예술 분야 등 많은 부분에서 멀티미디어 데이터의 보안성이 중요한 이슈가 되고 있다. 본 논문에서는 이러한 기술적 요구에 맞추어 이미지의 무결성을 인증할 수 있는 워터마킹 알고리즘을 제안한다. 제안하는 알고리즘은 JPEG 이미지 압축 과정에서 추가적인 처리를 통해 이미지에 인증코드를 삽입하고, 디코딩 과정에서 삽입 인증코드 추출 및 비교 인증코드 재생성을 통해 이미지의 원본 여부를 블록 단위로 판단할 수 있다. 제안 알고리즘을 통해 생성된 JPEG 이미지 표준 인코딩 이미지 대비 2.44dB 의 화질 저하를 보였고 1.63%의 압축률 차이를 보였다.

• Journal of the Korean Society of Radiology
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• v.6 no.3
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• pp.217-226
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• 2012

This study examines image quality of medical image after compression using JPEG2000 for AAPM CT Performance Phantom in PACS. The compressed images of 15:1 showed change of 1.93% and 0.81% in the CT number of water and the slice thickness, respectively, compared to the original images. The variation of the uniformity did not give a correlation for each measured area. In noise measurements at compressions of 10:1 and 15:1, changes of 1.47% to 10.99% were observed, respectively. The noise showed incremation tendency as increasing over the compression ratio 15:1, and the noise of 81.68% was measured at a compression of 40:1. CT number, uniformity, slice thickness, spatial resolution and contrast resolution for the compressed images were slightly changed by increasing the compression ratio. However, the noise was seriously changed relatively at the compressed images. Thus the noise was a important factor to determine the compression ration. A compression ratio of 10:1 for the AAPM CT Performance Phantom image was appropriate and could be applied to diagnostic images.