• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.268-272
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• 2003

Large medical images in PACS are compressed for saving storage space and improving network speed. The integrated compression environment was designed and developed for uniting of various compression methods. Various compression algorithm-RLE compression, lossless JEPG, JPEG, was built into it, complying with DICOM. A image compression using DWT was also implemented in it. And a unified algorithm of lossless compression and lossy compression was designed to improve images quality and to make compression ratios high. And integrated compression environment was operating together with a database program for efficient and user-friendly management.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.912-915
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• 2002

In this report, we propose a non-separable two-dimensional (2D) Lossless Wavelet Transform (LWT) for image compression. Filter characteristics of our proposed LWT are the same as those or conventional 2D LWT based on applying 1D LWT twice but our coding performance is better due to reduction of rounding effects. Simulation results confirm effectiveness of our proposed LWT.

• 방송공학회논문지
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• 제19권2호
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• pp.174-183
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• 2014

본 논문에서는 다양한 재생환경에서 적응적으로 홀로그램 비디오를 서비스하기 위한 스케일러블 코딩 방법을 제안한다. 이 방법은 광원정보와 디지털 홀로그램 모두를 스케일러블 부호화 및 복호화에서 사용하는 방법으로, 복원된 영상의 해상도, 즉 영상의 크기를 스케일링하는 해상도-스케일러블 코딩 방법이다. 이 방법은 광원정보와 디지털 홀로그램 각각의 차영상을 압축하는 방식을 사용하고 있으며, 디지털 홀로그램의 차영상은 손실압축, 광원정보의 차영상은 무손실압축 방법으로 압축한다. 제안하는 방법을 실험한 결과 기존의 방법에 비해 압축률 대비 화질이 매우 우수하고, 특히 압축률이 증가할수록 기존방법보다 월등한 성능을 보였다.

• 대한전자공학회논문지SP
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• 제38권5호
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• pp.548-555
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• 2001

본 논문에서는 인간시각시스템 모델에 기반하여 회전과 이동은 물론 유손실 압축과 잘라내기 및 신축에 대해서도 견고한 디지털 영상 워터마킹을 제안하였다. 기존의 퓨리에 변환과 로그폴라맵핑을 이용하여 회전및 이동에 불변하도록함과 동시에 인간시각스템 모델의 공간주파수 감도를 감안하여 비가시성이 떨어지지 않는 범위 내에서 워터마크 에너지를 최대한 인가하고, 각 워터마크 비트들의 정보를 임의 섞음하여 전 영역에 분산 삽입하였다. 이와 같이 함으로써 잘라내기와 유손실 압축과 같은 영상처리나 회전, 이동 및 신축과 같은 기하학적 변형 등에 대해 워터마크 견고성을 더욱 향상시켰다. 또한 워터마크와 템플릿을 교차하지 않게 삽입함으로써 이들의 교차로 인한 비가시성과 견고성의 저하를 방지하였다. 실험을 통하여 제안한 워터마킹 방법은 유손실 압축, 잘라내기 및 신축에 대하여 기존방법보다 약 30∼75 [%]정도 더 견고성이 향상됨을 확인하였다.

• International Journal of Computer Science & Network Security
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• 제23권11호
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• pp.73-76
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• 2023

We introduce DCNN and DRAE appraoches for compression of medical videos, in order to decrease file size and storage requirements, there is an increasing need for medical video compression nowadays. Using a lossy compression technique, a higher compression ratio can be attained, but information will be lost and possible diagnostic mistakes may follow. The requirement to store medical video in lossless format results from this. The aim of utilizing a lossless compression tool is to maximize compression because the traditional lossless compression technique yields a poor compression ratio. The temporal and spatial redundancy seen in video sequences can be successfully utilized by the proposed DCNN and DRAE encoding. This paper describes the lossless encoding mode and shows how a compression ratio greater than 2 (2:1) can be achieved.

• 방송공학회논문지
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• 제12권4호
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• pp.377-380
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• 2007

본 논문에서는 H.264/AVC에서 무손실 압축을 위하여 향상된 CABAC 엔트로피 부호화 방법을 제안한다. 0.264/AVC의 CABAC은 손실 압축을 지원하기 위해 개발되었기 때문에 무손실 압축에서 사용할 경우 압축 성능이 좋지 않다. 실제로 0.264/AVC Advanced 4:4:4 프로파일의 무손실 압축을 위한 엔트로피 부호화에도 기존의 방법을 수정 없이 그대로 사용하고 있기 때문에 엔트로피 측면에서 비효율성을 노출하고 있다. 따라서 0.264/AVC Advanced 4:4:4의 무손실 압축을 위해 잔여 신호의 통계적 특성을 고려한 이진화 방법을 제안하였다. 실험 결과, 제안된 방법은 기존의 무손실 부호화와 비교하여 약 3.4%의 비트율을 절약할 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4624-4642
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• 2014

Image compression is a popular research issue that focuses on the problems of reducing the size of multimedia files. Vector Quantization (VQ) is a well-known lossy compression method which can significantly reduce the size of a digital image while maintaining acceptable visual quality. A locally adaptive scheme (LAS) was proposed to improve the compression rate of VQ in 1997. However, a LAS needs extra indicators to indicate the sources, consequently the compression rate of LAS will be affected. In this paper, we propose a novel method to eliminate the LAS indicators and so improve the compression rate. The proposed method uses the concept of data hiding to conceal the indicators, thus further improving the compression rate of LAS. From experimental results, it is clearly demonstrated that the proposed method can actually eliminate the extra indicators while successfully improving the compression rate of the LAS.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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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.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.286-289
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• 2006

This paper analyzed the JPEG compression performance of MTSAT-1R(Multi-functional Transport Satellite - 1 Replacement), which is offering the LRIT/HRIT(Low Rate Information Transmissio / High Rate Information Transmission) service now, in order to design the system regarding LRIT/HRIT of COMS(Communication, Ocean and Meteorological Satellite). To do so, we analysed Lossy and Lossless JPEG compression performance regarding the MTSAT-1R LRIT/HRIT data for 10 days, and made comparison to the image characteristics, and understood the JPEG compression characteristics regarding JPEG compression of geostationary meteorological satellite. This result of compression performance analysis is expected to be a reference not only to the system design and realization of COMS LRIT/HRIT but also to those who develop other meteorological satellite receiving systems.

• 대한원격탐사학회지
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• 제22권5호
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• pp.463-468
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• 2006

This paper analyzed the JPEG compression performance of MTSAT-lR (Multi-functional Transport Satellite-1 Replacement), which is offering the LRIT/HRIT (Low Rate Information Transmissio/High Rate Information Transmission) service now, in order to design the system regarding LRIT/HRIT of COMS (Communication, Ocean and Meteorological Satellite). To do so, we analysed Lossy and Lossless JPEG compression performance regarding the MTSAT-1R LRIT/HRIT data for 10 days, and made comparison to the image characteristics, and understood the JPEG compression characteristics regarding JPEG compression of geostationary meteorological satellite. This result of compression performance analysis is expected to be a reference not only to the system design and realization of COMS LRIT/HRIT but also to those who develop other meteorological satellite receiving systems.