• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.109-112
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• 2002

In this paper, we propose the efficient digital watermarking scheme to transmit effectively the compressed medical image that embedded with watermarking data in mobile Internet access channel. The wireless channel error based on multiple access interference (MAI) is closely related to the length of spreading sequence in CDMA system. Also, the fixed length coded medical image with watermark bit stream can be classified by significance of source image. In the simulation, we compare the peak signal to noise ratio (PSNR) performance when the watermarked image with a simple symbol and when the watermarked image with a text file is transmitted using variable length of spreading sequences in case of limited length of spread sequence.

• Journal of Information Processing Systems
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• 제19권6호
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• pp.756-766
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• 2023

To effectively track the illegal use of digital images and maintain the security of digital image communication on the Internet, this paper proposes a reversible multipurpose image watermarking algorithm based on a deep residual network (ResNet) and perceptual hashing (also called MWR). The algorithm first combines perceptual image hashing to generate a digital fingerprint that depends on the user's identity information and image characteristics. Then it embeds the removable visible watermark and digital fingerprint in two different regions of the orthogonal separation of the image. The embedding strength of the digital fingerprint is computed using ResNet. Because of the embedding of the removable visible watermark, the conflict between the copyright notice and the user's browsing is balanced. Moreover, image authentication and traitor tracking are realized through digital fingerprint insertion. The experiments show that the scheme has good visual transparency and watermark visibility. The use of chaotic mapping in the visible watermark insertion process enhances the security of the multipurpose watermark scheme, and unauthorized users without correct keys cannot effectively remove the visible watermark.

• 한국멀티미디어학회논문지
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• 제3권1호
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• pp.53-62
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• 2000

디지털 워터마킹은 디지털 컨텐츠의 저작권을 보호하기 위한 중요한 기술로 취급되어 오고 있다. 삽입되는 워터마크는 압축, 필터링에서 cropping에 이르기까지 다양한 공격에 대하여 견고하여야 한다. 특히, JPEG은 인터넷 응용을 위한 뛰어난 정지 영상 압축 표준이기 때문에 JPEG 압축에 견관 디지털 워터마킹 기법이 특별히 요구된다. 지금까지 제안된 대부분의 디지털 워터마킹 기법은 JPEG의 품질수준(quality level)을 고려하지 않고 픽셀이나 계수를 변조하여 처리한다. 이것은 워터마크의 제거가 쉽게 이루어진다. 본 논문에서는 JPEG 압축시에 발생되는 영상의 손실을 계산하기 위해 JPEG 압축의 품질 계수를 워터마크 삽입 시의 파라메터로써 이용하여 JPEG 압축에 의한 차를 계산한다. 인간 시각의 성질 중에서 밝기 차의 식별력을 고려함과 동시에 영상의 에지 정보를 이용한 시각 성분을 계산한다. 이와 같이 JPEG 압축에 의한 영상의 손실과 인간의 시각 성질을 고려한 워터마크를 구성한 후에 영상에 삽입하는 새로운 디지털 워터마킹 기법을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권4호
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• pp.1499-1513
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• 2014

This paper proposes a novel blind image watermarking scheme exploiting Block Truncation Coding (BTC). Most of existing BTC-based watermarking or data hiding methods embed information in BTC compressed images by modifying the BTC encoding stage or BTC-compressed data, resulting in watermarked images with bad quality. Other than existing BTC-based watermarking schemes, our scheme does not really perform the BTC compression on images during the embedding process but uses the parity of BTC quantization data to guide the watermark embedding and extraction processes. In our scheme, we use a binary image as the original watermark. During the embedding process, the original cover image is first partitioned into non-overlapping $4{\times}4$ blocks. Then, BTC is performed on each block to obtain its BTC quantized high mean and low mean. According to the parity of high mean and the parity of low mean, two watermark bits are embedded in each block by modifying the pixel values in the block to make sure that the parity of high mean and the parity of low mean in the modified block are equal to the two watermark bits. During the extraction process, BTC is first performed on each block to obtain its high mean and low mean. By checking the parity of high mean and the parity of low mean, we can extract the two watermark bits in each block. The experimental results show that the proposed watermarking method is fragile to most image processing operations and various kinds of attacks while preserving the invisibility very well, thus the proposed scheme can be used for image authentication.

• 한국콘텐츠학회논문지
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• 제6권7호
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• pp.90-98
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• 2006

디지털 워터마킹은 이미지, 사운드와 같은 멀티미디어 데이터에 지각할 수 없도록 비밀 정보를 삽입하는 기법이다 일반적으로 주파수 영역 워터마킹 기법에서는 원 이미지에 대해 주파수 변환을 하고, 그 변환 면에 부호화된 워터마크 데이터를 삽입한다. 본 논문에서 우리는 Fresnel 변환을 이용한 새로운 컬러 이미지 워터마킹 기법을 제안한다. 워터마크 이미지를 Fresnel 변환시켜 얻은 패턴의 값들을 컬러 이미지에 삽입한다. 본 워터마킹 모델은, 컬러 이미지에 대한 워터마크 삽입을 위해 원 이미지를 RGB 성분에서 YCrCb 성분으로 분해를 한 후 Y 성분에 워터마크 이미지의 Fresnel 변환된 패턴의 실수와 허수 값을 삽입하는 기법이다. 제안된 기법의 유효성을 검증하기 위한 워터마크 삽입 추출 실험 결과 유효성을 입증 할 PSNR 값을 나타냈으며, 또한 JPEG와 같은 손실 압축 공격에 대해 내성을 지니고 있음을 보였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.519-522
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• 2000

Digital watermarking has been proposed as a solution to the problem of copyright protection of the multimedia documents. In this paper a new watermarking method for digital images operating in the frequency domain is proposed. In our approach, DCT coefficients of the watermark are added to the low frequency region of the host image, and extract it using the Wiener Filter. Due to the characteristic of the wiener filtering, the watermark is robust to various image processing techniques. Experimental results show that it is possible to reliably extract the watermark without degrading image quality.

• International Journal of Internet, Broadcasting and Communication
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• 제13권1호
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• pp.187-193
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• 2021

In this paper, we propose an image watermarking technique that effectively hides confidential data in the LSB of image pixels by utilizing the characteristics of the image. In the proposed technique, the image is precisely divided into boundary surface and normal region other than the boundary surface and performs different processing. The boundary surface existing in the image is created by meeting different regions and contains important information of the image. One bit of confidential data is concealed in the LSB of the pixel at the boundary surface to preserve the characteristics of the boundary surface. In normal region other than the boundary surface, the pixel values are similar, and the change with the adjacent pixel values is smooth. Based on this property, even if the 2 bits of confidential data are hidden in the lower 2 bits of the pixel in the normal region, the difference cannot be visually distinguished. When confidential data is concealed in an image as described above, the amount of confidential data concealed in an image can be increased while maintaining excellent image quality. Concealing confidential data by applying the proposed method increases the amount of confidential data concealed by up to 84.6% compared to the existing method. The proposed technique can be effectively used for commercial image watermarking that hides copyright information.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.175-179
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• 2003

We propose a new watermarking scheme that can be used to embed multiple bits and also resilient to JPEG compression and geometrical transforms such as scaling, rotation, and cropping based on holographic watermark that allows multiple watermark recovery without original content(cover image).

• Journal of Information Processing Systems
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• 제11권4호
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• pp.601-615
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• 2015

Region of interest (ROI) is the most informative part of a medical image and mostly has been used as a major part of watermark. Various shapes ROIs selection have been reported in region-based watermarking techniques. In region-based watermarking schemes an image region of non-interest (RONI) is the second important part of the image and is used mostly for watermark encapsulation. In online healthcare systems the ROI wrong selection by missing some important portions of the image to be part of ROI can create problem at the destination. This paper discusses the complete medical image availability in original at destination using the whole image as a watermark for authentication, tamper localization and lossless recovery (WITALLOR). The WITALLOR watermarking scheme ensures the complete image security without of ROI selection at the source point as compared to the other region-based watermarking techniques. The complete image is compressed using the Lempel-Ziv-Welch (LZW) lossless compression technique to get the watermark in reduced number of bits. Bits reduction occurs to a number that can be completely encapsulated into image. The watermark is randomly encapsulated at the least significant bits (LSBs) of the image without caring of the ROI and RONI to keep the image perceptual degradation negligible. After communication, the watermark is retrieved, decompressed and used for authentication of the whole image, tamper detection, localization and lossless recovery. WITALLOR scheme is capable of any number of tampers detection and recovery at any part of the image. The complete authentic image gives the opportunity to conduct an image based analysis of medical problem without restriction to a fixed ROI.

• 한국융합학회논문지
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• 제9권2호
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• pp.151-156
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• 2018

본 논문에서는 효율적인 가역 워터마킹 알고리즘을 제안하였다. 제안된 기법을 사용하여, 커버 이미지에 은닉할 수 있는 저작권관련 정보의 양을 증가시킬 수 있다. 공간적 지역성과 표면 특성에 따라, 주변 픽셀들을 사용하여 픽셀 값을 정밀하게 예측할 수 있다. 예측된 픽셀 값과 커버 이미지의 원본 픽셀 값이 거의 같게 되면, 커버 이미지의 원본 픽셀 값과 예측 픽셀 값의 차이가 매우 적게 된다. 그러므로 차분 시퀀스에 대한 히스토그램의 피크 포인트에서의 빈도수가 크게 증가하게 된다. 따라서 커버 이미지에 은닉할 수 있는 기밀 데이터의 양이 크게 증가하게 된다. 실험 결과를 통하여 제안된 워터마킹 알고리즘이 기존의 알고리즘보다 우수함을 확인 할 수 있다.