• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.355-358
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• 2002

In this paper, we propose RTP(Real-Time Transport Protocol) based image transport system to transport still images in real-time after JPEG2000 compression, which is still image compression standard for next generation. To add RTP packet on UDP packet, the image transport system inserts packetizer and depacketizer process into transmitter and receiver of RTP data, respectively. We apply the proposed system to several image and compare the transport time to TCP-based method.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.665-666
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• 2006

By adding user interface to the usual router, an improved functional router is implemented In this paper, we design the DWT(Discrete Wavelet Transform) for JPEG2000 CODEC. The DWT is developed based on ARM-based Excalibur, and the system contains DMA processor, Slave interface, DWT filter, Controller. The architecture of the prposed DWT is verified using Altera QuartusII.

• Review of KIISC
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• v.6 no.1
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• pp.65-78
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• 1996

본 논문에서는 JPEG 알고리즘을 이용하여 화상데이터를 부호화할때 디지털 서명문과 같은 기밀 데이터를 몰래 집어넣어 합성하는 방식에 대하여 고찰한다 그 기본원리는 DCT 계수를 양자화 할 때 필연적으로 생기는 오차를 이용하는 것으로 0이 아닌 양자화 계수를 합성하고자 하는 기밀데이터에 따라 근처의 정수로 조절하는 것이다. 이 방식을 SIDBA 표준화상에 적용하여 화상의 열화는 무시할 정도로 작으면서 원하는 크기의 기밀 데이터를 합성할 수 있음을 보인다. 또한, 화질의 열화를 최소화시키면서 일정량의 기밀 데이터를 합성시키기 위하여 블록당 1화소를 적절히 선택하여 제3자의 공격에 대한 안전성을 향상시키는 방법을 제시하고 컴퓨터 시뮬레이션을 통하여 성능을 분석한다.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.193-196
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• 2008

In this paper a detail study of existing steganographic methods are presented. An example is given of LSB substitution with uncompressed domain i.e., BMP image. In case of compressed domain JPEG image steganography is presented. Almost all popular steganographic algorithms, such as JPEG JSteg, F3, F4 and Selective Block Steganography (SBS) are described. The applications of steganographic methods are also presented briefly.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.89-92
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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 JPEG 알고리즘을 연구하여 허프만코팅 기반의 엔트로피 디코더의 불규칙적인 데이터 입출력타이밍의 효과적인 제어를 통해 Motion JPEG에서 동작 가능한 디코더를 C언어를 통해 시뮬레이션하고 최적화된 결과를 VHDL로 구현하였다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3150-3156
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• 1999

In this paper, VTQM(Variable Threshold Quantization Method) is proposed, which enhances PSNR by composing the advantages of round-off and truncation quantization methods. From vast experiments, PSNR's of JPEG images with the method are compared with that of standard JPEG methods. At the boundary which affects the compression ratio, VTQM quantizes with a new threshold to reduce the length of compressed data; otherwise, VTQM employs the round-off quantization method to preserve the original image information. As a result, VTQM reduces bit rate while preserving the image quanity. The experimental results show that VTQM enhances PSNR by 0.2-0.3dB., 0.4-0.5dB, with the same bit rate than those of the traditional truncation and round-off quantization methods, respectively.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.2
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• pp.185-190
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• 2013

The previous steganographic methods by using the interpolation were difficult to estimate the distortion because the size of cover image is extended by interpolation algorithms. In this paper, to solve the problems of previous methods proposed the improved steganographic method based on the pixel replacement algorithms. In our method, we cannot extend a cover image, but also can estimate exactly the distortion of the stego-images. In the experimental results, the estimated distortion and embedding capacity of stego-image are shown on three pixel replacement methods.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.832-835
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• 2004

In this paper, we proposed a blind watermarking algorithm to use characteristics of a scalar quantizer which is similar with the recommended in the JPEG2000 and JPEG. This algorithm shifts a quantization index according to the value of each watermark bit to prevent losing the watermark information during the compression by quantization. Therefore, the watermark is embedded during the process of quantization, not an additional process for watermarking, and adaptively applied as an assigned quantizer according to application area. In the embedding process, a LFSR(Linear feedback shift register) is used to hide the watermarking positions. Therefore the embedded watermark can be extracted by only the owner who knows the initial value of LFSR without the original image. The experimental results showed that the proposed algorithm satisfies the robustness and imperceptibility corresponding to the major requirement of watermarking.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.561-564
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• 2005

In this paper, we present a new JPEG (Joint Photograph Experts Group) compression architecture which compresses still image into fixed size of bitstream to use restricted system memory efficiently. The size of bitstream is determined by the complexity of image and the quantization table. But the quantization table is set in advance the complexity of image is the essential factor. Therefore the size of bitstream for high complexity image is large and the size for low complexity image is small. This means that the management of restricted system memory is difficult. The proposed JPEG encoder estimates the size of bitstream using the correlation between consecutive frames and selects the quantization table suited to the complexity of image. This makes efficient use of system memory.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.967-970
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• 2005

The Music Player MAF Player Format of ISO/IEC 23000-2 FDIS consists of MP3 data, MPEG-7 metadata and one optional JPEG image data based on MPEG-4 File Format. However, the current Music Player MAF format does not allow multiple JPEG image data or timed text data. It is helpful to use timed text data and multiple JPEG images in the various multimedia applications. For example, listening material for the foreign language needs an additional book which has text and images, the audio contents which can get image and text data can be helpful to understand the whole story and situations well. In this paper, we propose the detailed file structure in conjunction with MPEG-4 File Format in order to improve the functionalities, which carry multiple image data and text data with synchronization information between MP3 data and other resources.