• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.706-715
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• 2004

In this paper, to decide the watermark embedding positions and embed the watermark we use the subband tee structure which is presented in the wavelet domain and the edge information in the spatial domain. The significant frequency region is estimated by the subband searching from the higher frequency subband to the lower frequency subband. LH1 subband which has the higher frequency in tree structure of the wavelet domain is divided into 4${\times}$4 submatrices, and the threshold which is used in the watermark embedding is obtained by the blockmatrix which is consists by the average of 4${\times}$4 submatrices. Also the watermark embedding position, Keymap is generated by the blockmatrix for the energy distribution in the frequency domain and the edge information in the spatial domain. The watermark is embedded into the wavelet coefficients using the Keymap and the random sequence generated by LFSR(Linear feedback shift register). Finally after the inverse wavelet transform the watermark embedded image is obtained. the proposed watermarking algorithm showed PSNR over 2㏈ and had the higher results from 2％ to 8％ in the comparison with the previous research for the attack such as the JPEG compression and the general image processing just like blurring, sharpening and gaussian noise.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.378-387
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• 2003

Digital watermarking is the technique that embeds invisible signalsincluding owner identification information, specific code, or pattern into multimedia data such as image, video and audio. Watermarking techniques can be classified into two groups; robust watermarking and fragile(semi-fragile) watermarking. The main purpose of the robust watermarking is the protection of copyright, whereas fragile(semi-fragile) watermarking prevents image or video data from illegal modifications. To achieve this goal watermark should survive from unintentional modifications such as random noise or compression, but it should be fragile for malicious manipulations. In this paper, an invertible semi-fragile watermarkingalgorithm for authentication and detection of manipulated location in MPEG-2 bit-stream is proposed. The proposed algorithm embeds two kinds of watermarks, which are embedded into quantized DCT coefficients. So it can be applied directly to the compressed bit-stream. The first watermark is used for authentication of video data. The second one is used for detection of malicious manipulations. It can distinguish transcodingin bit-stream domain from malicious manipulation and detect the block-wise locations of manipulations in video data. Also, since the proposed algorithm has an invertible property, recovering original video data is possible if the watermarked video is authentic.

• Journal of KIISE:Software and Applications
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• v.31 no.2
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• pp.203-212
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• 2004

The watermarking is a method to achieve the copyright protection of multimedia contents. Among several media, the left documents show very peculiar properties: block/line/word patterning, clear separation between foreground and background areas. So algorithms specific to the text documents are required that meet those properties. This paper proposes a novel watermarking algorithm for the grayscale text document images. The algorithm inserts the watermark signals through the edge direction histograms. A concept of sub-image consistency is developed that the sub-images have similar shapes in terms of edge direction histograms. Using Korean, Chinese, and English document images, the concept is evaluated and proven to be valid over a wide range of document images. To insert watermark signals, the edge direction histogram is modified slightly. The experiments were performed on various document images and the algorithm was evaluated in terms of imperceptibility and robustness.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3C
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• pp.398-407
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• 2004

In this paper, a blind watermarking method which is suitable to the video compression using 2-D discrete wavelet transform was proposed and implemented into the hardware using VHDL(VHSIC Hardware Description Language). The goal of the proposed watermarking algorithm is the authentication about the manipulation of the watermark embedded image and the detection of the error positions. Considering the compressed video image, the proposed watermarking scheme is unrelated to the quantization and is able to concurrently embed or extract the watermark. We experimentally verified that the lowest frequency subband(LL4) is not sensitive to the change in the spatial domain, so LL4 subband was selected for the mark space. And the combination of the bitplanes which has the properties of both the minimum degradation of the image and the robustness was chosen as the embedded Point in the mark space in LL4 subband. Since we know the watermark embedded positions and the watermark is embedded by not varying the value but changing the value, the watermark can be extracted without the original image. Also, for the security when exposing the watermark embedded position, we embed the encrypted watermark by the block cipher. The proposed watermark algorithm shows the robustness against the general image manipulation and is easily transplanted into the image or video compressor with the minimal changing in the structure. The designed hardware has 4037 LABs(24％) and 85 ESBs(3％) in APEX20KC EP20K400CF672C7 FPGA of Altera and stably operates in 82MHz clock frequency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1222-1228
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• 2006

In this paper, I propose a video watermaking method using adaptive threshold value and half-cell motion vector. Conventional method cause a lot of change of motion vectors and bring about a falling-off in invisibility, because it search embedding condition about whole macroblocks and watermarks are embedded in arbitrary motion vectors. Proposed method improve invisibility and decrease in number of change of motion vectors, because it create threshold value by using power of motion vector(PMV), and watermarks are embedded in motion vectors which greater than threshold value. Consequently, proposed method improve invisibility with on an average 5.4 dB ~9.3dB according to video bit-stream.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1113-1124
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• 2004

In this paper, we proposed a hardware(H/W) structure which can compress and recontruct the input image in real time operation and implemented it into a FPGA platform using VHDL(VHSIC Hardware Description Language). All the image processing element to process both compression and reconstruction in a FPGA were considered each of them was mapped into H/W with the efficient structure for FPGA. We used the DWT(discrete wavelet transform) which transforms the data from spatial domain to the frequency domain, because use considered the motion JPEG2000 as the application. The implemented H/W is separated to both the data path part and the control part. The data path part consisted of the image processing blocks and the data processing blocks. The image processing blocks consisted of the DWT Kernel fur the filtering by DWT, Quantizer/Huffman Encoder, Inverse Adder/Buffer for adding the low frequency coefficient to the high frequency one in the inverse DWT operation, and Huffman Decoder. Also there existed the interface blocks for communicating with the external application environments and the timing blocks for buffering between the internal blocks The global operations of the designed H/W are the image compression and the reconstruction, and it is operated by the unit of a field synchronized with the A/D converter. The implemented H/W used the 69%(16980) LAB(Logic Array Block) and 9%(28352) ESB(Embedded System Block) in the APEX20KC EP20K600CB652-7 FPGA chip of ALTERA, and stably operated in the 70MHz clock frequency. So we verified the real time operation of 60 fields/sec(30 frames/sec).

• Journal of Broadcast Engineering
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• v.13 no.4
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• pp.489-500
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• 2008

We propose a novel high-definition content watermarking algorithm that is highly feasible in UCC (User Created Contents) environment. We begin by addressing an association between broadcasting content and UCC in a view of copyrights, then present watermark requirements by analyzing various UCC editing-effect. Also, we provide a brief review of previous watermarking techniques that are supposed to satisfy the requirements. Our proposed scheme inserts a invisible watermark into both DC and AC components on $8{\times}8$ block DCT domain and extracts them after synchronization using DC image. Experimental results show that our technique satisfies the requirements of invisibility and robustness to a variety of attacks such as rotation, scaling, cropping, and JPEG compression, etc. Note that the proposed scheme is highly resilient to UCC edit attacks that are combined by many different types of watermark attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1C
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• pp.78-85
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• 2007

With the advancement of the digital broadcasting and popularity of the Internet, recently, many studies are making on the digital watermarking for the copyright protection of digital data. This paper proposes the minimum modification method of motion vector to minimize the degradation of video quality, hiding subtitles of many language and information of OST(original sound track), character profiles, etc. as well as the copyright protection. Our proposed algorithm extracts feature vector by comparing motion vector data with watermark data, and minimize the modification of motion vectors by deciding the inversion of bit. Thus the degradation of video quality is minimized comparing to conventional algorithms. This algorithm also can check data integrity, and retrieve embedded hidden data simply and blindly. And our proposed scheme can be useful for conventional MPEG-1, -2 standards without any increment of bit rate in the compressed video domain. The experimental result shows that the proposed scheme obtains better video quality than other previous algorithms by about $0.5{\sim}1.5dB$.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.390-390
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• 2022

도시 생활용수 수요는 생활 수준 향상, 도시화 등으로 지속적 증가 추세에 있으며, 최근 기후변화, 시설 노후화, 도시화, 그리고 수질 오염 등의 문제들에 직면해 있다. 이는 물 부족을 심화시켜 현행 상수도시스템에서 한정적인 수자원을 배분하는데 어려움을 가중시킨다. 이를 해결하기 위해 스마트워터그리드 기술이 상수도시스템에 도입이 되면서 지능형 상수도 계량기를 이용한 개별 소비자들의 물 소비량 자료를 보다 정밀하게 실시간으로 모니터링 할 수 있게 되었다. 실시간 실측을 바탕으로 한 물 소비량 자료는 미래 용수 수요 예측과 수운영 관리에 도움을 줄 수 있다. 한편 생활용수는 용도 또는 요금 부과 기준에 따라 가정용, 업무용, 영업용, 욕탕용, 그리고 공업용으로 분류할 수 있다. 미국과 호주 등에서는 용도 분류에 따른 모니터링 강화로 절수 방안을 개발하여 물 부족에 대비하고 있다. 우리나라도 비 가정용수(가정용수를 제외한 용수들)를 체계적으로 분류하기 위한 선행 연구들이 이뤄졌으나 분류체계가 표준화되지 않았는데, 이는 용도에 따른 개별 소비자들의 소비 특성 분석이 충분히 선행되지 않았기 때문이며, 아직까지 많은 지자체에서 물 소비량을 월 단위로 인력검침 하는데 의존하고 있어, 충분한 물 소비량 자료가 부족했기 때문이다. 본 연구에서는 영종도 112 블록에 구축된 스마트워터그리드 파일롯플랜트 527개 개별 소비자들로부터 2018년 1월 1일부터 2020년 1월 1일까지 1시간단위로 수집된 물 소비량 자료를 이용하여, 개별 소비자들의 일평균 첨두 소비량과 발생 시간, 관경, 요일, 계절에 따른 물 수요 특성 분석을 수행했다. 이 때 수집된 자료의 결측치 및 오측치를 보정하여 자료의 신뢰성을 높이고자 했다. 분석결과는 용도별 물 수요 특성을 보다 잘 이해할 수 있게 도와주며, 비가정용수의 용도별 분류에 기초자료로 사용될 수 있을 것이라 사료된다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.1
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• pp.16-26
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• 2000

The proposed method inserts a watermark information not mto a whole Image region but only into regions of interest(ROIs) To extract the ROIs, we divide an original Image into sub-blocks and use modified Shi-Kuo Chang's PIM(picture information measure) as the criteria to select the ROIs Considering the directional information and frequency bands, we insert the watermark information into sub-blocks m the DCT domain. The proposed method can reduce the distortion in comparison With the other methods which utilize the whole Image as an nor The proposed method makes much less damaged Images m comparison to the other methods And those Images processed by the proposed algorithm are more robust to the changes caused by signal processing operations such as resampling, clipping. noise, and so on Also due to the block-based watermark insertion, the proposed method has the robustness to the Image compression processes such as JPEG and MPEG.