• 제목/요약/키워드: jpeg

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Watermaking for still images in the DCT domain (DCT 영역에서의 정지 영상 Watermarking)

  • 권오형;김영식;박래홍
    • Journal of Broadcast Engineering
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    • v.4 no.1
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    • pp.68-75
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    • 1999
  • In this paper. we propose a digital watermarking method for still images in the discrete cosine transform (DCT) domain. The adaptive watermark insertion method in the high frequency region within a given image is employed to increase the invisibility of the inserted watermark in images, in which variable block-size method is used for selection of the high frequency region. Experimental results show that the proposed watermarking method is robust to several common image processing techniques. including joint photographic experts group (JPEG) compression, lowpass filtering, multiple watermarking, and croppIng.

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A study of Image Compression Algorithm using DCT (DCT를 이용한 영상압축 알고리즘에 관한 연구)

  • 한동호;이준노
    • Journal of Biomedical Engineering Research
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    • v.13 no.4
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    • pp.323-330
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    • 1992
  • A Study of Image Compression Algorithm using DCT This paper describes the system that implement a JPEG(Joint Photographic Experts Group) algorithm based on DCT(Discrete Cosine Transform) uslng CCD kameva, Image Grabber, and IBM PC. After cosine transforms the acquisited image, this algorithm quantize and entropy encode the coefficients by JPEG code table. The coefficients are reconstructed by the Huffman decoding, dequantized procedure, and Inverse cosine transform. The results obtained from the impleulented system are as follows. (1) For effcient storage and easy implementation, this system save Image as a PCX formal (2) Thls system get 7:1 compression ratio(3.8 RMSE value) without large distortion. (3) With a low pass filtering, thls system eliminate high frequency components and get 20% enhanced compression ratio. (4) Thls system enhance the reconstructed Image using histogram modeling.

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A study on Color Management Application in Digital Image (디지털 이미지의 컬러 매니지먼트 적용에 관한 연구)

  • Cho, Young-Kwon;Koo, Chul-Whoi;Cho, Ga-Ram
    • Journal of the Korean Graphic Arts Communication Society
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    • v.22 no.2
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    • pp.163-178
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    • 2004
  • In this study, the CIE RGB color space which was one of the most popular device-dependent application program in digital image processing was adopted to make the profile with the device information. The profile was applied to the digital image of a JPEG file format. The result was compared with the color reproduction of another digital image of a JPEG file format, which was made in the e-sRGB color space that had the color spaces allocated to each reproduced color of an image and device-independent colors. In this way it was investigated which color space was more appropriate for digital image processing for web printing and if the e-sRGB color space was good as a color management tool that didn't depend on a device in processing a digital image for web printing.

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R, G, B rate variance based Text Information Hiding scheme Robust against Various Attacks (다양한 이미지 공격에 강한 R, G, B 비율 분산 기반의 문자 정보 은닉 알고리즘)

  • Sohn, Il Gwon;Heo, Jun
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2011.07a
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    • pp.278-280
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    • 2011
  • 본 논문은 이미지가 갖는 R, G, B 비율의 분산을 이용하여, 공간 영역에서 정보를 은닉하는 알고리즘을 제시한다. 웹 상에서 Jpeg, bmp, gif 등의 포멧을 갖는 이미지를 raw 파일로 변환한 후, R,G,B 비율을 구한다. 그 중 사람의 눈에 가장 둔감한 B 비율 분산을 조작하여 정보를 은닉하는데 이용한다. 또한 오류율을 낮추기 위하여 (15,7)BCH Code 를 사용한다. 제안된 알고리즘이 JPEG(Joint Photographic coding Experts Group) compression, scale(이미지의 크기 변화), Mediancut 과 같은 이미지 변화에 강한 특성과 정보은닉 후에도 화질열화가 발생하지 않는 특성을 실험을 통해 보인다.

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A New DM/SS Image Watermarking Scheme for Copyrighter Protection (저작권 보호를 위한 새로운 DM/SS 이미지 워터마킹 기법)

  • Park, Young;Lee, Joo-Shin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.10B
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    • pp.1428-1435
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    • 2001
  • 본 논문에서는 이미지 데이터의 저작권 보호를 위해 영상변형, JPEG 손실 압축 및 임펄스 잡음에 효과적인 새로운 DM/SS (Direct Matrix/Spread Spectrum) 이미지 워터마킹 기법을 제안한다. 제안하는 기법은 워터마크 영상을 저작권자의 개인 ID (IDentification)로 확산시킨 다음, 원 영상에 삽입하고 역확산시켜 복원하는 방법이다. 원터마크 영상은 2진 영상을 사용하고, 워터마크 시스템에서 요구되는 비가시성과 외부 공격에 대한 워터마크의 강인성을 확인하기 위하여 PSNR (Peak Signal to Noise Ratio)과 워터마크 영상의 복원율 (reconstructive rate)을 구한다. 실험 결과, 워터마크가 삽입된 영상의 PSNR은 93.75 dB로 화질저하가 거의 없었고, 확산 이득으로 인하여 32$\times$32 워터마크 영상이 삽입된 영상에서 우수한 워터마크 영상의 복원율을 얻는다는 것을 보인다. 영상변형 및 JPEG 손실 압축 하에서도 우수한 워터마크 복원 결과를 보였고, 임펄스 잡음이 첨가된 영상의 PSNR이 5.54 dB인 경우에도 효과적으로 워터마크 영상을 복원할 수 있다는 것을 알 수 있었다.

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Image Compressing of Color tone image by transformed Q-factor (Q-factor변형에 의한 색조영상 압축에 관한 연구)

  • Choi, Kum-Su;Moon, Young-Deck
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.781-783
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    • 1999
  • A storage or transmission of image is difficult without image compression processing because the numbers of generated or reborned image data are very much. In case of the random signal, image compression efficiency is low doing without loss of image information, but compressibility by using JPEG is better. We used Huffman code of JPEG, it assigne the low bit value for data of a lot of generated frequency, assigne the high bit value for data of a small quantity. This paper improved image compression efficiency with transformming Q-factor and certified the results with compressed image. A proposed method is very efficience for continuos a color tone image.

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Implementation of Web Based Embedded Digital Frame Using Nios II Embedded Processor and ${\mu}Clinux$ (Nios II 임베디드 프로세서와 ${\mu}Clinux$를 이용한 웹기반 임베디드 디지털 액자 구현)

  • Jeong, Mun-Su;Yang, Heui-Hwan;Jeong, Je-Myung
    • Proceedings of the Korean Information Science Society Conference
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    • 2008.06d
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    • pp.327-331
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    • 2008
  • 본 논문에서는 ALtera Cyclone II FPGA와 VGA Controller, ISP1362 Host Controller, DM9000A Ethernet Controller를 사용하여 FPGA를 구성하고, ${\mu}Clinux$를 포팅하여 Nano-X 기반에서 JPEG 파일을 디스플레이 시키는 임베디드 디지털 액자를 구현한다. 구현한 시스템은 일반적인 마이크로프로세서를 사용하지 않고 Altera 사의 Cyclone II FPGA를 이용해 직접 프로세서를 설계하고, ISP1362 Host Controller를 이용하여 USB 드라이브를 인식하며, DM9000A를 통해 웹과 연결하여 웹서버로부터 전송되어진 JPEG 이미지를 Display 할 수 있도록 설계하였다.

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Template Recovery of DWT-DFT Composite Watermarking Scheme Using Collinear Cross-Ratio

  • Sepsirisuk, Kasemsuk;Atsuta, Kiyoaki;Kondo, Shozo
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.225-228
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    • 2005
  • According to a popularization of the Internet and digital lifestyle, digital watermarks have been proposed for protection of copyrighted multimedia content. In blind watermark detection, which an original image is not provided, robustness against geometric distortion and compression remains challenging. In this paper, we propose a new perceptual blind discrete wavelet transform - discrete Fourier transform (DWT-DFT) composite watermarking scheme that is robust against both general linear transform and JPEG compression. This algorithm constructs an image-dependent watermark in the most significant DWT coefficients, which is determined by using a hierarchical tree structure. Strength of watermark is determined from a just-noticeable difference (JND) profile of a perceptual model. Furthermore, a desired template is inserted into DFT domain of the watermarked image. In new manner, a cross-ratio of four collinear points is used for detecting the template. Experimental results have showed that the proposed scheme is robust against general linear distortion, JPEG compression and various general kinds of attacks in the Stirmark 3.1 watermark evaluation tool.

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Development of telePACS using world-wide-web and satellite data communication system (WWW 기반과 위성 데이터 통신을 이용한 원격 PACS의 개발)

  • 황선철;정태섭;김희중;이명호
    • Proceedings of the IEEK Conference
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    • 1998.06a
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    • pp.557-560
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    • 1998
  • In this paper, we presetn the WWW (world-wide-web) base dtelePACS, which uses the communication network as asymmetric satellite data communication system (ASDCS). Web-based telePACS is imple-mented with JAVA language. Through the internet, web-based TelePACS can make it possible for remote hospital or doctor to access PACS data and information easily and cheaply. The ASDCS uses receive-only satellite links for data delivery and PSTN (Public switched telephone Network) modem or N-ISDN (narrow band integrate services digital network) for communication. The satellite communication linking shows the very high-seed performance such as 10-30 times faster than the modem linking.To solve the speed limits of internet, JPEG and wavelet compression methods were adapted in WWW-based TelePACS and were evaluated by PSNR (peak signal-to-noise ratio) and by radiological experts that 10:1 or less JPEG and wavelet compression may be acceptable for diagnostic purposes. Consequently, we get the conslusion that our system is suitable for tele-radiology and telemedicine world widely.

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Progressive Wavelet Transform Coding for Image Communication (영상통신을 위한 점진적 웨이브렛 변환 부호화)

  • 김정일;유재휘
    • Journal of the Korea Society of Computer and Information
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    • v.3 no.3
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    • pp.89-98
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    • 1998
  • In this paper, we propose new image coding using wavelet transform. The new method constructs hierarchical bit plane and progressively transports each bit plane. The proposed algorithm not only supports multi-resolution, dividing original image into special band and various resolution but also reduces blocking effects that come into JPEG In encoding time, this algorithm considers each band characters and priority of transport order, and applies to fast search of image.

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