• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.856-873
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• 2011

Reversible watermarking is an open problem in information hiding field, with embedding the encoded bit '1' or '0' into some sensitive images, such as the law enforcement, medical records and military images. The technique can retrieve the original image without distortion, after the embedded message has been extracted. Histogram-based scheme is a remarkable breakthrough in reversible watermarking schemes, in terms of high embedding capacity and low distortion. This scheme is lack of capacity control due to the requirement for embedding large-scale data, because the largest hidden capacity is decided by the amount of pixels with the peak point. In this paper, we propose a reversible watermarking scheme to enlarge the number of pixels with the peak point as large as possible. This algorithm is based on an adaptive edge-guided interpolation, furthermore, hides messages by interpolation-error, i.e. the difference between the original and interpolated image value. Simulation results compared with other state-of-the-art reversible watermarking schemes in this paper demonstrate the validity of the proposed algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.81-86
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• 2011

Watermarking is one of the methods that insist on a copyright as it append digital signals in digital informations.(image, video, ets) In this paper, we proposed a digital watermarking algorithm which improved Gradient of DCT Coefficient. This method targets MPEG-2 TM5 system and watermarking process is to be performed during Quantization DCT. Watermark was inserted on Y components of each frames. The PSNR difference between the compressed images with and without watermarking was only 0..23dB. In each case that the resulting image was reusable the normalized correlation between the extracted watermark and the original one was above 0.99.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1224-1228
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• 2003

The use of digital imaging technique and digital contents based on internet has grown rapidly for last several years, and the needs of digital image protection become more important. For the purpose of copyright protection on digital image, the verification of authentication techniques like content authentication, ownership authentication, illegal copy and etc are needs. Digital watermarking, the invisible encryption technique to insert digital watermarking into image, the sophisticated perceptual information should be used for providing transparency and robustness of images on watermarking process. In this paper, we implement the algorithm for preventing forged attack. ownership protection and authentication by transforming the wavelet algorithms in frequency domain in terms of human visual system.

• 전자공학회논문지 IE
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• v.43 no.2
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• pp.87-92
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• 2006

Many watermarking methods for protecting the intellectual property right and authentication multimedia data have been proposed in recent years. In image authentication watermarking, watermark is inserted into an image to detect any malicious alteration. So, watermark for authentication and integrity should be erased easily when the image is changed by scaling or cropping etc. We propose in this paper a fragile watermarking algorithm for image integrity verification and tamper localization proofing using special hierarchical structure. In the proposed method, the image to be watermarked is divided into blocks in a multi-level hierarchy and calculating block digital signatures in thus hierarchy. At each level of the hierarchy, a digital signature for each block is calculated using the seven most significant bit(MSBs)-plane values of all pixels within the block. And the resulting signature is incorporated into the LSBs of selected pixels within the block. We provide experimental results to demonstrate the effectiveness of the proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.413-416
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• 2005

Developement of computer and digitalizing of medical implement are being caused digitalizing of medical image. Medical Images are being managed more by PACS. In this situation comes out many problem about ownership, the right of properity of the medical images and notice wheather the data are modified. Digital watermarking can solve this problem. The proposed schemes have a two weak point that Non-blind method need a original image and Blind method use gaussian watermarking. In this paper, we propose a blind watermarking using binary image in order to easily recognize result of watermark This proposed scheme using wavelet transform and Circular Input method that input in medium-band of frequency domain.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.163-166
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• 2006

The field of medical images has been digitalized as the development of computer and the digitalization of the medical instruments. As a result it causes a lot of problems such as an illegal copy related to medical images and property right of the medical images. Therefore, digital watermarking is used for discrimination whether the data are modified or not. It is also used to protect both the property right of medical images and the private life of many patients. The proposed theories, the Non-blind and the Blind method, have two problems. One is needed an original image and the other is using a gaussian watermarking. This paper proposes the new Blind Watermarking using binary images in order to easily recognize the results of watermark. This algorithm is described that an watermark of a binary image is wavelet-transformed, and then a transformed watermark is inserted in medium-band of frequency domains of original image by the Circular Input method. The propose method presented the good performance of over 0.97 in NC.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.624-634
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• 2006

This paper presents a new watermarking scheme that is robust against geometrical attacks such as translation and rotation. The proposed method is based on the conventional PSADT(Polar Coordinates Shape Adaptive Discrete Transform) method which is an robust watermarking scheme for an arbitrarily-shaped image such as character images. The PSADT method shows perfect robustness against geometrical attack if there is no change in the shape of the image object. However, it cannot be utilized to watermark general rectangular images because of the missing alignment between the watermarked signals in the embedding and extracting side. To overcome this problem we propose a new watermarking scheme that aligns the watermark signal using the image inherent feature, especially corner. Namely the proposed method decides a consistent target region whose shape and position isn't changed by any malicious attack and then embeds the watermark in it using the PSADT method. Experimental results show the robustness of the proposed method against geometrical attacks as well as image compression.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1402-1411
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• 2014

Buyer-seller watermarking protocol is defined as the practice of imperceptible altering a digital content to embed a message using watermarking in the encryption domain. This protocol is acknowledged as one kind of copyright protection techniques in electronic commerce. Buyer-seller watermarking protocol is fundamentally based on public-key cryptosystem that is operating using the algebraic property of an integer. However, in general usage, digital contents which are handled in watermarking scheme mostly exist as real numbers in frequency domain through DCT, DFT, DWT, etc. Therefore, in order to use the watermarking scheme in a cryptographic protocol, digital contents that exist as real number must be transformed into integer type through preprocessing beforehand. In this paper, we presented a new watermarking scheme in an encrypted domain in an image that is based on the block-DCT framework and homomorphic encryption method for buyer-seller watermarking protocol. We applied integral-processing in order to modify the decimal layer. And we designed a direction-adaptive watermarking scheme by analyzing distribution property of the frequency coefficients in a block using JND threshold. From the experimental results, the proposed scheme was confirmed to have a good robustness and invisibility.

• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.342-354
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• 2014

This paper deals with digital watermarking methods to protect ownership of image with targeting the ultra-high multi-view or free-view image service in which an arbitrary viewpoint image should be rendered at the user side. The main purpose of it is not to propose a superior method to the previous methods but to show how difficult to construct a watermarking scheme to overcome the viewpoint translation attack. Therefore we target the images with various attacks including viewpoint translation. This paper first shows how high the error rate of the extracted watermark data from viewpoint-translated image by basic schemes of the method using 2DDCT(2D discrete cosine transform) and the one using 2DDWT(2D discrete wavelet transform), which are for 2D image. Because the difficulty in watermarking for the viewpoint-translated image comes from the fact that we don't know the translated viewpoint, we propose a scheme to find the translated viewpoint, which uses the image and the corresponding depth information at the original viewpoint. This method is used to construct the two non-blind watermarking methods to be proposed. They are used to show that recovery of the viewpoint affect a great deal of the error rate of the extracted watermark. Also by comparing the performances of the proposed methods and the previous ones, we show that the proposed ones are better in invisibility and robustness, even if they are non-blind.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.4
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• pp.187-193
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• 2012

An image authentication scheme for gray scale image through embedding a digital watermark by quantization of Integer Wavelet Transform (IWT) coefficients of the image is proposed in this paper. Proposed method is designed to detect modification of an image and to identify tampered location of the image. To embed the watermark mid-frequency band of a second level IWT was used. An approximation of the original image based on LL band was stored in LSB bits of the pixel data as a recovery mark for restoration of the image. Watermarked image has achieved a good PSNR of 40 dB compared to original cover image. Restored image quality was also very good with a PSNR of more than 35 dB compared to unmodified watermarked image even when 25% of the received image is cropped. Thus, the proposed method ensures a proper balance between the fidelity of the watermarked image and the quality of the restored image.