Showing papers by "Jeng-Shyang Pan published in 2005"

A Parallel Particle Swarm Optimization Algorithm with Communication Strategies

Abstract: Particle swarm optimization (PSO) is an alternative population-based evolutionary computation technique. It has been shown to be capable of optimizing hard mathematical problems in continuous or binary space. We present here a parallel version of the particle swarm optimization (PPSO) algorithm together with three communication strategies which can be used according to the independence of the data. The first strategy is designed for solution parameters that are independent or are only loosely correlated, such as the Rosenbrock and Rastrigrin functions. The second communication strategy can be applied to parameters that are more strongly correlated such as the Griewank function. In cases where the properties of the parameters are unknown, a third hybrid communication strategy can be used. Experimental results demonstrate the usefulness of the proposed PPSO algorithm.

Robust blind video watermarking with adaptive embedding mechanism

Abstract: In this paper, a novel adaptive approach to spatial domain video watermark- ing is presented. It takes full advantage of both intra-frame and inter-frame information of video content to guarantee the perceptual invisibility and robustness of the watermark. An effective block classifier is delicately designed based on motion information and region complexity. Meanwhile, the idea of bitplane replacement is introduced in the embedding procedure. A major advantage of this technique is that the watermark can be extracted without referring to the original video while embedded adaptively in accordance with the human visual system and signal characteristics. The multi-frame based extraction strat- egy ensures that the watermark can be correctly recovered from a very short segment of video. Individual frames extracted from the video also contain watermark information. Experimental results show that the watermarked video appears visually indistinguishable from the original video, and the proposed watermarking technique is robust enough to common video attacks. Keywords: Copyright protection, Digital watermarking, Video watermarking, Adaptive algorithm

Multipurpose image watermarking in DCT domain using subsampling

Abstract: In this paper, a DCT-based multipurpose image watermarking algorithm is proposed. Through adopting dither modulation in subimages gained by subsampling, two independent robust watermarks can be embedded in the original image. Experimental results demonstrate the effectiveness of the proposed algorithm.

Speech authentication by semi-fragile watermarking

Abstract: This paper proposes a semi-fragile speech watermarking scheme by quantization of Linear Prediction (LP) parameters, i.e. the inverse sine parameters. The watermark decoding performance is analyzed by modelling the parameters estimation error as Laplace distributed noises. The watermark detection threshold is derived according to the requirement of error probability and expected Signal to Noise Ratio (SNR). Experiments show that the proposed watermarking scheme is robust against amplitude scaling and semi-fragile to white noise addition, and thus suitable for speech authentication.

A lossless watermarking technique for halftone images

Abstract: In this paper, a lossless watermarking technique in dealing with halftone images is proposed to achieve both copyright protection and exact recovery of the original halftone image with legal authorization Experimental results show that pattern substitution along with an appropriate block cutting on a halftone image makes possible the positive recovery of the original halftone image after the extraction of a watermark

Multiple description watermarking for lossy network

Abstract: The paper proposes an innovative watermarking scheme based on vector quantization (VQ); it is suitable for media transmission over noisy channels with multiple description coding (MDC). Digital watermarking is one of the applicable tools that can be used to protect digital contents from illegal copying and distribution. In addition to conventional schemes that apply attacks on watermarked media, we focus our application on transmitting over noisy channels to consider both the error-resilient transmission of watermarked media, and the robustness of the watermarking algorithm. By modifying the multiple description vector quantization (MDVQ) algorithm for watermark embedding and extraction, simulation results not only demonstrate the effective transmission of a watermarked image, but reveal the robustness of the extracted watermark.

Hiding watermark in watermark [image watermarking]

Abstract: A hide-watermark-in-watermark approach, based on vector quantisation (VQ), for increasing embedding capacity is presented. The image used for carrying the watermark is first decomposed into nonoverlapping blocks, and the codebook used in the traditional VQ system is split into a number of subcodebooks according to a user key. Then, by referring to the watermark bits to be hidden, a subcodebook is selected and used in the VQ system to code the corresponding block. By applying the above hiding strategy, a binary watermark can be hidden in a gray watermark, and the output result - the watermarked watermark - is then hidden in a cover image.

Robust Fractal Watermarking on Continue-tone Images

Abstract: In this study, a novel fractal watermarking is proposed to enforce the robustness of data hiding against possible attack. The proposed fractal watermarking is mixed of three different approaches: inner/exterior search space, odd/even search space, and two classes of isometric search space. During watermark extraction, the watermark bit is always determined by the result of a voting mechanism on the spatial coordinate with respect to three search spaces mentioned above. Experimental result shows the proposed can react against the attack JPEG compression.

Print and generation copy image watermarking based on spread spectrum technique

Abstract: After a watermarked image is printed, copied several times and scanned, the watermark usually cannot be extracted rightly, as well as distorted by noise In this paper, a spread spectrum technique was introduced to image watermarking which can be applied to print and generation copy The watermarking message is modulated by the key-dependent pseudo-random sequences to produce a spread spectrum signal The watermark is embedded into the cover image by modifying the gray value of each pixel The cover image is not needed when the watermark is detected The watermark is estimated exploiting the properties of HVS(Human Visual System) and extracted through the same key-dependent 2D sequences Experimental results show that the scheme can resist print, generation copy and scan process

Reversible watermarking based on improved patchwork algorithm and symmetric modulo operation

Abstract: Modulo operations are often used in reversible watermarking scheme.However, the modulo operations would cause an annoying visual artifact similar to the salt-and-pepper noise when pixel value close to the maximally allowed value are flipped to zero and vice versa. To prevent the salt-and-pepper noise, the paper presents reversible watermarking scheme using improved patchwork and an improved modulo operation. The improved modulo operation called symmetric modulo operation effectively avoids salt-and-pepper noise by the reasonably reducing the flipping distance. Experimental results show that correctly watermark bits can be retrieved by the patchwork algorithm without the original image and that the original image can be restored perfectly while the perceptual degradation of the watermarked signal remained acceptable.

Shadow watermark extraction system

Abstract: A new watermarking scheme which provides the ability of sharing secret with multi-users is proposed It splits the original watermark into two shares and embeds one share into the cover image to increase the security A polarization procedure is performed to establish a polarity stream from the cover image The second share and the polarity stream are used to generate a master key and several normal keys In our system, only the super user can reveal the genuine watermark directly Other users possess the normal keys can obtain shadow watermarks merely By combining the shadow watermarks together, the real watermark can be recovered

Reversible watermarking based on improved patchwork algorithm and symmetric modulo operation

Abstract: Modulo operations are often used in reversible watermarking scheme.However, the modulo operations would cause an annoying visual artifact similar to the “salt-and-pepper” noise when pixel value close to the maximally allowed value are flipped to zero and vice versa. To prevent the “salt-and-pepper” noise, the paper presents reversible watermarking scheme using improved patchwork and an improved modulo operation. The improved modulo operation called symmetric modulo operation effectively avoids “salt-and-pepper” noise by the reasonably reducing the flipping distance. Experimental results show that correctly watermark bits can be retrieved by the patchwork algorithm without the original image and that the original image can be restored perfectly while the perceptual degradation of the watermarked signal remained acceptable.

An experimental comparison on gabor wavelet and wavelet frame based features for image retrieval

Abstract: The mean and standard deviation of the magnitudes of coefficients of the transform domain are common used in texture image retrieval. This paper performs an experimental comparison on Gabor wavelet and wavelet frame based features for this application. The detail comparison results indicate the performance of the former is not superior over that of the last in the query-by-example retrieval.

Multiple description multi-watermarking with tabu search approaches

Abstract: Digital watermarking is one of the useful solutions for digital rights management systems, and it is also a popular research topic in the last decade. However, most watermarking related literature focus on how to resist intentional attacks by applying benchmarks to watermarked media to estimate the effectiveness of the watermarking algorithm. Only a few papers concentrate on the error resilient transmission of watermarked media. In this paper, we propose an innovative algorithm on vector quantization (VQ) based image watermarking, suitable for error-resilient transmission over noisy channels. By incorporating watermarking with multiple description coding (MDC), our proposed schemes for embedding multiple watermarks can efficiently overcome channel impairments while retaining the capability for copyright and ownership protection. In addition, we employ one optimization technique, called tabu search, to optimize both the watermarked image quality, and the robustness of the extracted watermarks. Simulations demonstrate the utility and practicability of our proposed algorithm.

A reversible watermark scheme combined with hash function and lossless compression

Abstract: The paper presents a reversible watermark scheme based on hash function and lossless compression technology. The paper extracts the abstract information of the image as hash code and lossless compresses the LSB(Least Significant Bit) of the image to make some space where the image hash can be completely inserted. It needs to be done without introducing a large distortion to the image. The scheme can achieve the authentication purpose by hash code and restores the original image by retrieving the watermark sequence completely because of the lossless decompression of the LSB of the image.

Improved image coding with classified VQ and side-match VQ

Abstract: A new scheme for vector quantization (VQ) is proposed in this paper. We employ side-match and classified criteria for designing VQ codebooks to combat blocking effects induced from high compression rates, and then we use the proposed algorithm to improve the reconstructed image quality. Simulation results demonstrate the better image quality to compare with that produced from conventional schemes objectively and subjectively, at the cost of reasonable encoding complexity.

Shadow watermark embedding system

Abstract: A new watermarking approach based on discrete cosine transform (DCT) for digital images is proposed. A reference image is established from the cover image using the user-key. Then, a shadow watermark is created from this reference image and the original watermark. The proposed scheme embeds this shadow watermark into the cover image in the DCT domain to secure the secret content of the original watermark. To reveal the real watermark, the correct keys are required.

Statistical Analysis of Two Polarity Detection Schemes in Speech Watermarking

Abstract: Polarity inversion based speech watermarking scheme hide data in speech by modification of the speech polarity. This paper build a statistical model of the polarity detection problem, based on this model, the original polarity detection scheme and the optimal detection scheme are analyzed and compared. The theoretical analysis results are validated by Monte Carlo simulation, the optimal polarity detector shows significant performance gain compared with the original polarity detection algorithm.