• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.980-985
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• 2002

In this paper, we analyzed satellite image with a high resolution compression performance. We need much time in a fast processing on vast satellite image pixel data. On compressing and decompressing, we should keep the information about road, building, forest, etc. In conclusion, we did analyze and compare the performance of compression and decompression for JPEG and WSQ(wavelet scalar quantization) method. As a result, we knew that WSQ was more efficient than JPEG.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.97-100
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• 2008

정보화 사회가 진행되어감에 따라 카메라 센서, 디지털 카메라, 휴대폰, 영상 관련디지털 기기들이 증가하고 이로 인하여 영상정보 서비스 기술의 중요성이 크게 부각되었다. 특히 멀티미디어 응용서비스 기술에서는 영상 정보가 필수적인데, 그 영상 정보의 양이 너무 방대하여 압축 부호화를 하여 사용되고 있다. 본 논문에서는 정지영상압축 방법 중 JPEG표준에서 제시한 4가지 동작 모드 중 베이스라인을 기반으로 하는 JPEG압축 알고리즘을 연구하여 CMOS 이미지 센서에서 영상을 전송받으면 8*8 블록 단위로 변환 후 DCT 및 양자화 과정을 거쳐 지그재그 스캔을 한 후 허프만 코드를 사용하여 압축 부호화 시키는 JPEG 베이스라인 인코더를 VHDL언어로 설계하였다.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2803-2805
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• 2002

멀티미디어의 표준화에 대한 관심이 컴퓨터, 방송, 통신 등의 분야에서 더욱 높아지고 있다. JPEG2000 표준안은 영상 부호화에 따른 새로운 형태의 영상압축 뿐만 아니라 높은 성능에 부응하고자 하는 것으로 기존의 표준안보다 왜곡율과 특정부분의 영상품질을 한 차원 상승시킬 수 있어서 효율적인 면에서 더욱 우수하다. 영상의 손실 및 무손실 압축, 대용량 영상압축, 그리고 화소의 정밀도와 해상도의 차이에 의한 점진적 전송이나 관심영역의 지정과 처리 등이 그 특징특이다 JPEG2000 표준안은 인터넷, 컬러 팩시밀리, 인쇄, 스캐닝, 디지털 사진, 원격 감지, 휴대기기 등과 의료 영상 디지털 도서관, 전자 상거래 등에 다양하게 응용할 수 있다. 본 논문은 JPEG2000 표준안의 최신동향과 전반적인 기술내역에 대하여 설명하고 영상압축 효율과 화질, 그리고 처리 속도 등을 기존 알고리즘과 비교하여 그 기술적 특징을 실험을 통하여 비교 제시한다.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.99-108
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• 2008

This raper analyzes the effect of visually lossless image compression for efficient distribution of digital cinema. Currently, distribution of digital cinema is carried out based on JPEG 2000 standard that has been selected by DCI. We first summarize characteristics of JPEG 2000, and then define the concept of visually lossless coding that plays an important role in digital cinema distribution. We provide a test for JPEG 2000 compression performance according to DCI specification for visually lossless. Based on the experiment, the result satisfies high quality for cinema distribution.

• The KIPS Transactions:PartA
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• v.13A no.3 s.100
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• pp.185-190
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• 2006

JPEG 2000 is used as an alternative to solve the blocking artifact problem with the existing still image compression JPEG algorithm. However, it has shortcomings such as longer floating point computation time and more complexity in the procedure of enhancing the image compression rate and decompression rate. To compensate for these we implemented with hardware the JPEG 2000 algorithm's filter part which requires a lot of floating point computation. This DWT Filter[1] chip is designed on the basis of Daubechies 9/7 filter[6] and is composed of 3-stage pipeline system to optimize the performance and chip size. Our implemented Filter was 7 times faster than software based Filter in the floating point computation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.97-100
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• 2007

In order to overcome many defects in the current JPEG standard of still image compression, the new JPEG2000 standard has been development. The JPEG2000 standard is based on the principles of DWT and EBCOT Entropy Coding. EBCOT(Embedded block coding with optimized truncation) is the most important technology in the latest image-coding standard, JPEG2000. However, EBCOT occupies the highest computation time to operate bit-level processing. Therefore, many researches have achieved methods to minimize computation speed of EBCOT. Thus, this paper proposes the method of context-extraction that improves computational architecture. This paper proposes efficient context coding method. The proposed algorithm would apply to hard-wired JPEG2000 Encoder that is used for compression of high resolution image.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.9
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• pp.896-903
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• 2011

In this paper, a co-design method for JPEG2000 video compression system using DSP and FPGA is presented. By profiling the complexity of JPEG2000 algorithm, it is noticed that a MQ-coder is the most complex part. Thus, we implement the MQ-coder on FPGA for the parallel processing using VHDL to reduce the complexity. In order to verify the performance of the MQ-coder, JBIG2 standard test vector and images are used. The experimental results show that the proposed MQ-coder enhances the processing time approximately 3 times compared with the previous software MQ-coder.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.1
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• pp.56-63
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• 2009

Nowdays, Most of Internet Contents delivered as a compressed file. It gives many advantages like deduction of communication bandwidth and transmission time etc. In case of JPEG Compression, Quantization is the most important procedure which accomplish the compression. In general signal processing, Quantization is the process which converts continuous analog signal to discrete digital signal. As you known already, Quantization over JPEG compression is to reduce magnitude of pixel value in spatial domain or coefficient in frequency domain. A lot of Data Hiding algorithms also developed to applicable for those compressed files. In this paper, we are going to unveil the influence of quantization table which used in the process of JPEG compression. Even thought most of algorithm modify frequency coefficients with considering image quality, they are ignoring the influence of quantization factor corresponding with the modified frequency coefficient. If existing algorithm adapt this result, they can easily evaluate their performances.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.747-750
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• 2008

JPEG(Joint Photographic Expert Group)은 손실 압축 기법을 사용하여 데이터 양을 20:1 이상으로 현저히 줄이면서도 원 영상과 거의 유사한 영상을 복원할 수 있도록 해주기 때문에, 요즘 디지털 카메라 및 휴대폰 등 영상을 저장할 매 대부분 Exif(Exchangeable image file format)로 JPEG 압축형식을 널리 사용하고 있다. 본 논문은 JPEG 베이스라인 모드로 압축되어진 영상의 디코딩 단계에서 필요한 비계층형 헤더를 파싱하는 모듈의 기능을 소프트웨어로 모델링하고 VHDL을 이용하여 회로를 합성하고 동작을 검증하였다. 설계 결과 Xilinx xc3s1000 fg676-4 환경에서 154.488MHz의 동작속도를 나타내었고, JPEG 디코더의 고속 데이터 처리에 적응 가능하다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.121-130
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• 2007

In this paper, we propose a reversible watermarking scheme in the JPEG compression domain. The reversible watermarking is useful to authenticate the content without the quality loss because it preserves the original content when embed the watermark information. In the internet, for the purpose to save the storage space and improve the efficiency of communication, digital image is usually compressed by JPEG or GIF. Therefore, it is necessary to develop a reversible watermarking in the JPEG compression domain. When the watermark is embedded, the lossless compression was used and the original image is recovered during the watermark extracting process. The test results show that PSNRs are distributed from 38dB to 42dB and the payload is from 2.5Kbits to 3.4Kbits where the QF is 75. Where the QF of the Lena image is varied from 10 to 99, the PSNR is directly proportional to the QF and the payload is around $1.6{\sim}2.8Kbits$.