• Title/Summary/Keyword: jpeg

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Development of Digital Watermark Embedding Algorithm using Fourier Series Expansion (푸리에 급수전개를 이용한 워터마크 삽입 알고리즘의 개발)

  • Min, Jun-Yeong;Choe, Jong-Uk
    • Journal of KIISE:Computer Systems and Theory
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    • v.26 no.6
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    • pp.662-669
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    • 1999
  • Digital watermarking이란 영상이나 비디오, 오디오, 텍스트 등의 저작물에 잘 식별되지 않는 표시를 삽입하여 저작권을 보호하는 방법으로 소유권자의 동의없이 저작물을 배포, 복사되는 것을 방지하는 법이다. 본 논문은 watermark를 삽입하기 위해서 sin과 cos 함수를 이용한 Fourier 급수전개를 이용하였다. 우선 , 원 이미지를 주파수 영역으로 변환한 다음 watermark를 삽입할 위치를 M $\times$Nro의 Random Sequence를 발생하여 결정하였으며, M개의 파형을 가장 직교성이 좋다고 하는 sin 함수와 cos 함수를 이용하여 Fourier 급수전개를 하였다. 이 때, sin과 cos의 n의 고조파 역시 Random Sequence를 발생하여 결정하였다. 제안한 알고리즘은 이와 같이 Fourier 급수전개를 했을 때 각 항의 Fourier 계수를 산출하여 이 Fourier 계수에 watermark를 삽입하였다. 실험 결과 JPEG 압축, Blurring, 노이즈삽입 등의 이미지 왜곡에 대하여 watermark 상관관계가 최소 0.1979에서 최대 0.9732까지의 견고성(robustness)을 보였다.

RST Invariant Digital Watermarking Based on Image Representation by Wedges and Rings

  • Kim, Ki-Jung
    • International Journal of Contents
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    • v.5 no.2
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    • pp.26-31
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    • 2009
  • This paper describes a new image watermarking scheme invariant to rotation, scaling and translation (RST) attacks. For obtaining the invariance properties we propose to present an image of watermark by wedges and rings to convert its rotation to shift and then utilize the shift invariance property of the Direct Fourier Transform (DFT). But in contrast to conversional schemes based on the Fourier-Mellin transform (FMT), we do not use a log-polar mapping (LPM). As a result, our scheme preserves high quality of original image since it is not underwent to LPM For withstanding against JPEG compression, noise addition and low-pass (LP) filtering attacks a low frequency watermark is embedded into middle frequencies of the original image. Experiments with various attacks show the robustness of the proposed scheme.

Segmentation-based Wavelet Coding Method for MR Image (MR 영상의 영역분할기반 웨이블렛 부호화방법)

  • Moon, N.S.;Lee, S.J.;Song, J.S.;Kim, J.H.;Lee, C.W.
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.05
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    • pp.95-100
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    • 1997
  • In this paper, we propose a coding method to improve compression efficiency for MR image. This can be achieved by combining coding and segmentation scheme which removes noisy background region, which is meaningless for diagnosis, in MR image. The wavelet coder encodes only diagnostically significant foreground regions refering to segmentation map. Our proposed algorithm provides about 15% of bitrate reduction when compared with the same coder which is not combined with segmentation scheme. And the proposed scheme shows better reconstructed image Qualify than JPEG at the same compression ratio.

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Remote Control and Monitoring System Using PDA (PDA를 이용한 원격 제어 및 모니터링 시스템)

  • Ji, Yang-Hwan;Jo, Yong-Byum;Nam, Boo-Hee
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.905-907
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    • 2005
  • In this paper, we propose the system that can monitor and control the camera in the remote place using the PDA. The server PC attached to the PLC (Programmable Logic Controller) acquires the current status (On/Off) of the devices through the RS-232 serial communications. Also, the moving image frames captured from the wireless camera is compressed in the JPEG format and is stored in the server. The PDA, which is connected to the server through wireless internet, receives the data about the status of the devices and controls the devices according to the circumstances of them. Also, it can receive the images from the server simultaneously. So, we ran monitor and control the specified area in the remote place using the PDA through the wireless communication.

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Remote Control and Monitoring System Using PDA (PDA를 이용한 원격 제어 및 모니터링 시스템)

  • Ji, Yang-Hwan;Jo, Yong-Byum;Nam, Boo-Hee
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.3117-3119
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    • 2005
  • In this paper, we propose the system that can monitor and control the camera in the remote place using the PDA. The server PC attached to the PLC (Programmable Logic Controller) acquires the current status (On/Off) of the devices through the RS-232 serial communications. Also, the moving image frames captured from the wireless camera is compressed in the JPEG format and is stored in the server. The PDA, which is connected to the server through wireless internet, receives the data about the status of the devices and controls the devices according to the circumstances of them. Also, it can receive the images from the server simultaneously. So, we can monitor and control the specified area in the remote place using the PDA through the wireless communication.

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Performance Improvement of A Processor with Independent Media Cache (독립적인 미디어 캐시를 채용한 프로세서의 성능향상)

  • Ju, Young-Kwan;Jeon, Joong-Nam;Kim, Suk-Il
    • Annual Conference of KIPS
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    • 2003.11a
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    • pp.143-146
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    • 2003
  • 본 논문에서는 미디어 프로세서에서 메모리 참조시 평균 메모리 참조 지연시간을 줄이기 위하여 지역성이 높으나 재사용성이 떨어지는 미디어 데이터를 지역성과 재사용성이 높은 일반 데이터로부터 분리하여 별도의 캐시에 저장하도록 하는 캐시 구조를 제안하였다. 또한, 미디어 데이터의 선인출 기법을 캐시 운영 전략으로 채택하도록 하여 평균 메모리 지연시간을 단축하였다. EPIC, JPEG 벤치마크에 대한 실험결과, 미디어 데이터를 일반 데이터 캐시와 구분한 이중캐시 구조가 하나의 캐시에 모든 데이터를 저장하는 단일캐시구조에 비하여 캐시미스횟수가 감소하였음을 확인할 수 있었다.

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간단한 데이터 스케줄링 기법을 이용한 2차원 DWT 처리기 설계

  • Kim, Gi-Yeong;Sin, Ho-Cheol;Lee, Sang-Beom;Kim, Yeong-Seop
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2006.10a
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    • pp.174-177
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    • 2006
  • 본 논문에서는 리프팅 기반의 DWT 구조의 단점을 개선하고자 플립핑(Flipping)기법과 5 단 파이프라인 구조(5 Stage Pipeline)를 적용하여 임계경로가 획기적으로 줄어든 1 차원 DWT 구조를 제안하고 이를 활용하여 JPEG2000 표준의 손실 압축 모드에서 이용되는 9/7 필터계수의 2 차원 DWT 를 수행 할 수 있도록 열 방향 DWT 처리기를 설계하였다. 2 차원 DWT 는 1 차원 DWT 의 처리 결과에 대해 열상의 열(Column) 방향으로 2 차원 처리를 수행해야 하므로 1 차원 결과를 저장하기 위한 한 영상 사이즈 만큼의 메모리 버퍼를 필요로 한다. 기존 $N^2$이 필요하던 메모리 사이즈를 14N으로 줄인 2차원 구조를 제안한다.

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Implementation of Embedded Geo-coding System for Image's Geo-Location (영상의 위치 정보를 위한 임베디드 지오코딩 시스템 구현)

  • Lee, Yong-Hwan;Kim, Young-Seop
    • Journal of the Semiconductor & Display Technology
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    • v.7 no.3
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    • pp.59-63
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    • 2008
  • Geo-coding refers to the process of associating data with location information, and the system deals with geographic identifiers expressed as latitude and longitude or street addresses. Although many services have been launched, there still remains a problem for users to create geo-coded photo with manually labeling GPS(Global Positioning System) coordinate or synchronizing with separate devices. In this paper, we design and implement a geo-coding system which utilizes the time and location information embedded in digital photographs in order to automatically categorize a personal photo collection. An included GPS receiver labels a photograph with its corresponding GPS coordinates, and the position of the camera is automatically recorded into the photo image header at the moment of capture. The place and time where the photo was taken allows us to provide context metadata on the management and retrieval of information.

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Architecture of 2-D DCT processor adopting accuracy comensator (정확도 보상기를 적용한 2차원 이산 코사인 변환 프로세서의 구조)

  • 김견수;장순화;김재호;손경식
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.10
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    • pp.168-176
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    • 1996
  • This paper presetns a 2-D DCT architecture adopting accurac y compensator for reducing the hardware complexity and increasing processing speed in VL\ulcornerSI implementation. In the application fields such as moving pictures experts group (MPEG) and joint photographic experts group (JPEG), 2-D DCT processor must be implemented precisely enough to meet the accuracy specifications of the ITU-T H.261. Almost all of 2-D DCT processors have been implemented using many multiplications and accumulations of matrices and vectors. The number of multiplications and accumulations seriously influence on comlexity and speed of 20D DCT processor. In 2-D DCT with fixed-point calculations, the computation bit width must be sufficiently large for the above accuracy specifications. It makes the reduction of hardware complexity hard. This paper proposes the accuracy compensator which compensates the accuracy of the finite word length calculation. 2-D DCT processor with the proposed accuracy compensator shows fairly reduced hardware complexity and improved processing speed.

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A Fast Context Modeling Using Tree-structure of Coefficients from Wavelet-domain

  • Choi, Hyun-Jun;Seo, Young-Ho;Kim, Dong-Wook
    • Journal of information and communication convergence engineering
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    • v.7 no.4
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    • pp.496-500
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    • 2009
  • In EBCOT, the context modeling process takes excessive calculation time and this paper proposed a method to reduce this calculation time. That is, if the finest resolution coefficient is less than a pre-defined transfer factor the coefficient and its descendents skip the context modeling 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. 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.