Choong-Hoon Lee

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In this paper, we propose an autocorrelation function (ACF) based watermarking scheme in the discrete wavelet transform (DWT) domain. Conventional ACF-based watermarking embeds a watermark in the spatial domain due to its detection mechanism.We show that the autocorrelation (AC) peaks, which play an important role in estimating the applied geometric attacks(More)
This paper addresses an effective technique for digital fingerprinting for video. While orthogonal modulation technique is a straightforward and widely used method for digital fingerprinting, it shows limitations in computational costs, signal effectiveness, and robustness against averaging attacks. Code modulation technique that uses averaging collusion(More)
This paper presents an adaptive video watermarking using motion information. Because video data have one more dimension than image data, simple adoptation of image watermarking method to video data would reveal some types of visual artifact such as flickering. In the proposed scheme, same watermark information is embedded for same region in each frame to(More)
By taking advantage of the merits of the low power consumption and hardware simplicity of SAR ADCs, 2b/cycle conversion structures in SAR ADCs have been actively studied in recent years for enhanced conversion rates and excellent FoM [1-3]. However, many error sources in the 2b/cycle SAR ADCs, such as mismatches between DACs and comparators, and the(More)
With the rapid growth of multimedia application, there has been significantly bared a crucial need for effective copyright protection mechanisms. Therefore, digital image, video, audio and text watermarking has recently become a very active research area of signal and information processing, as a solution to this problem. Many important issues have been(More)
We propose an improved autocorrelation function (ACF)based image watermarking that is robust to combined geometric and removal attacks. ACF-based watermarking is thought of as one of the most effective watermarking schemes that resist geometric attacks. In this watermarking scheme, the autocorrelation peaks of the watermark play an important role for(More)
Digital watermarking is the enabling technology to prove ownership on copyrighted material, detect originators of illegally made copies, monitor the usage of the copyrighted multimedia data, and analyze the spread spectrum of the data over networks and servers. Most watermarking methods for images and video can be viewed as a communications problem in which(More)
This paper addresses a geometrically invariant watermarking method for digital images. Most previous watermarking algorithms perform weakly against geometric distortions, which desynchronize the location for the inserted watermark. Watermark synchronization, which is a process for finding the location for watermark insertion and detection, is crucial for(More)
This paper addresses feature-based image watermarking methods for digital contents. Most previous watermarking algorithms suffer from geometric distortion attacks that desynchronize the location of the inserted watermark. In order to synchronize the watermark location, watermark synchronization should be performed. One solution for watermark synchronization(More)