• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3885-3895
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• 2000

The emergence of digital imaging and digital networks has made duplication of original artwork easier. In order to protect these creations, new methods for signing and copyrighting visual data are needed. In the last few years, a large number of schemes have heen proposed for hiding copyright marks and other information in digital image, video, audio and other multimedia objects. In this paper, we propose a technique for embedding the watermark of visually recognizable patterns into the frequency domain of images. The embedded watermark can be retrieved from the decoded sequence witbout knowledge of the original. Because the source image is not required to extract the watermark, one cannot make the fake original that is invertible to watermarking scheme from the waternlarked image. In order to recover the embedded signature data without knowledge of the original, a prediction of the original value of the pixel containing the information is needed. The prediction is based on a averaging of amplitude values in a neighborhood around the pixel itself. Additionally the projxJsed technique could survive several kinds of image processings including JPEG lossy compression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6317-6321
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• 2014

Multimedia documents can be transferred quickly and easily across the Internet, and has attracted considerable interest in multimedia security and multimedia copyright protection. This paper proposes an animage watermarking scheme embedding a binary watermark image using Discrete Wavelet Transform (DWT) coefficients. The original image is transformed to the wavelet domain and decomposed in subbands. The binary watermark image, as a sequence of bits, is embedded into the middle frequency subbands. The original image is not needed to detect the watermark image. The proposed method detected fewer watermark bits but produced an approximately 10dB higher PSNR than the max/min method.

• The KIPS Transactions:PartB
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• v.19B no.2
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• pp.83-92
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• 2012

Multimedia contents can be copied and manipulated without quality degradation. Therefore, they are vulnerable to digital forgery and illegal distribution. In these days, with increasing the importance of multimedia security, various multimedia security techniques are studied. In this paper, we propose a content authentication algorithm based on reversible watermarking which supports JPEG compression commonly used for multimedia contents. After splitting image blocks, a specific authentication code for each block is extracted and embedded into the quantized coefficients on JPEG compression which are preserved against lossy processing. At a decoding process, the watermarked JPEG image is authenticated by extracting the embedded code and restored to have the original image quality. To evaluate the performance of the proposed algorithm, we analyzed image quality and compression ratio on various test images. The average PSNR value and compression ratio of the watermarked JPEG image were 33.13dB and 90.65%, respectively, whose difference with the standard JPEG compression were 2.44dB and 1.63%.

• The Journal of the Acoustical Society of Korea
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• v.21 no.8
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• pp.719-726
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• 2002

In this paper, we present a layered watermarking technique for digital audio data that is capable of detecting timing change and adapting complexity in detection. The proposed watermarking uses echo hiding as the first layer, which enables the detector to estimate linear speed change. The spread spectrum watermark is then inserted in the second layer which includes additional information like copyright data. We use two kinds of sequences in the second layer, one of which is for synchronization and the other is for data. The results of previous layer are used to make estimate of timing change in the next layer. The detector in the presented method can select detecting range form the first layer to the first layer, second pre-layer, or second main-layer due to the required system specification. Experimental results show that the proposed watermarking technique is robust to several processing attacks including timing change.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.04a
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• pp.277-281
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• 2005

본 논문은 일반 사형변환에 대한 워터마킹의 전처리 방법을 제안하였다. 일반 사형변환 공격을 막기 위해 원본 영상에 워터마크를 삽입하기 전에 영상 정규화를 하였다. 워터 마크 삽입율에 관한 세가지 영상 정규화 방식을 비교하였다. 세가지 방식 모두 x-sharing, y - sharing 그리고 중앙 모멘트를 사용한 scaling 분해법 방식들에 기초를 두고 있다. 실험을 통하여 Zhang et al[4].에 의한 두번째 방식이 Zhang et, al[9]와 Dong et. al[10]에 의한 방식들보다 더 성능이 우수함을 보였다.

• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.729-736
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• 2005

In this paper. the proposed method for the digital watermarking is based on the multiresolution wavelet transform. The 1-level Discrete Wavelet Transform(DWT) coefficients of a $2N_{wx}{\times}2N_{wy}$ binary logo image used as a watermarks. The LL band and middle frequency band of the host image that the 3-level DWT has been performed are divided into $N_{wx}{\times}N_{wy}$ size and we use large coefficients at the divided blocks to make threshold. we set the thresholds that completely insert the watermark in each frequency of the host image. The thresholds in each frequency of the host image differ each other. The watermarks where is the same positions are added to the larger coefficients than threshold in the blocks at LL band and middle frequency band in order to prevent the quality deterioration of the host image. The watermarks are inserted in LL band and middle frequency band of the host image. In order to be invisibility of the watermark, the Human Visual System(HVS) is applied to the watermark. We prove the proper embedding method by experiment. We rapidly detect the watermark using this watermarking method. And because the small size watermarks are inserted by HVS, the results confirm the superiority of the proposed method on invisibility and robustness.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.100-106
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• 2006

In this paper, we proposed a TxID(Transmitter Identification) system using ZCD (Zero Correlation Duration) code as interference-cancelled spread codes for single frequency network of ATSC terrestrial DTV broadcasting. ZCD codes are simply implemented and have ZCD characteristics. Then, Proposal system can fundamentally solve interference problems caused by ICI(Inter Code Interference) and MPI(Multi-Path Interference) which happens in TxID system using spread coding method. Also, those can cancel truncated error which happens at watermarking for TxID since those can remove its period. In this paper, we identified the availability of TxID system applying interference-cancelled ZCD codes by analyzing DER (Detection Error Rate) which is simulated in various interference environments such as AWGN, ICI, and MPI.

• Journal of Digital Contents Society
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• v.6 no.2
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• pp.95-99
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• 2005

Recently it is important to protect the digital contents copyright because the multimedia industry is growing rapidly and the network technology is highly developed. Current digital content protection methods have disadvantage that there is very hardly accessible to the digital contents and also it has a limit that it cannot protect the contents once the encrypted contents decrypt. In order to solve this problem, digital watermarking technology has been introduced. This study presents the trend of digital watermarking technology, especially standardization and the trend of digital watermarking algorithms.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.150-153
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• 2020

부채널 정보를 사용하여 마이크로 컨트콜러 상에서 표절 된 코드를 탐지하는 새로운 방법을 제시한다. 제안 기법은 애플리케이션을 보호하기 위해 추가로 워터 마킹 할 필요가 없이 코드를 실행하는 마이크로 컨트롤러의 유출데이터를 워터 마크로서 사용 할 수 있다. 두 가지 다른 구현의 각각 하나의 부채널 파형에 대한 절대 상관 계수를 기반으로 분석 한다. 어셈블리 언어로 작성된 다양한 테스트 응용 프로그램을 사용 Xmaga128 마이크로 컨트롤러에서 평가하였다. 제안 기법은 어셈블리 코드를 수정하는 공격자에게도 강력하며 코드에 대한 정보와 입력에 대한 접근이 불가능 하여도 탐지가 가능하다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.1
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• pp.96-102
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• 2003

Video copy detection is a complementary approach to watermarking. As opposed to watermarking, which relies on inserting a distinct pattern into the video stream, video copy detection techniques match content-based signatures to detect copies of video. Existing typical content-based copy detection schemes have relied on image matching. This paper proposes two new sequence matching techniques for copy detection and compares the performance with color techniques that is the existing techniques. Motion, intensity and color-based signatures are compared in the context of copy detection. Comparison of experimental results are reported on detecting copies of movie clips.