Kan Li

Bio: Kan Li is an academic researcher from Ryerson University. The author has contributed to research in topics: Watermark & Digital watermarking. The author has an hindex of 4, co-authored 4 publications receiving 242 citations.

Comments on "An SVD-based watermarking scheme for protecting rightful Ownership"

Abstract: In a recent paper by Tan and Liu , a watermarking algorithm for digital images based on singular value decomposition (SVD) is proposed. This comment demonstrates that this watermarking algorithm is fundamentally flawed in that the extracted watermark is not the embedded watermark but determined by the reference watermark. The reference watermark generates the pair of SVD matrices employed in the watermark detector. In the watermark detection stage, the fact that the employed SVD matrices depend on the reference watermark biases the false positive detection rate such that it has a probability of one. Hence, any reference watermark that is being searched for in an arbitrary image can be found. Both theoretical analysis and experimental results are given to support our conclusion.

Watermark embedding and detecting methods, systems devices and components

Abstract: Method determining lookup table (“LUT”) for embedding watermark. For each quantization cell, calculating probabilities that signal point falls into cell. Selecting cell by probabilities. Setting LUT value to watermark value with largest probability, subject to run constraint. For remaining cells, repeating selecting and setting steps. Other method determining quantization ensemble by calculating probability density function for signal points where the watermark value to be embedded. Distortion and robustness functions are formulated. Given robustness or distortion is selected. Functions optimized, and ensemble of quantizers determined with parameters that comply. Other method quantizing in association with lossy compression. Strength of compression determined. Adapting strength of watermark with strength of compression by a mapping. Other method selecting points for embedding watermark. Determine threshold between large and small signal points using statistical method. Select signal points for embedding according to threshold. Also, processors, computer programs, and systems.

Reliable adaptive watermarking scheme integrated with JPEG2000

Abstract: In this paper, a new digital watermarking method, integrated with the state-of-the-art image compression standard - JPEG2000, is developed. The binary digital watermark is embedded in the quantized wavelet coefficients in subbands with intermediate resolution after the stage of quantization and recovered before dequantization during decompression. Different from previously proposed JPEG2000 based watermarking schemes, the compression ratio, regarded as an important parameter, is used to design the new adaptive watermark encoder. The strength of watermark is designed as proportional to the compression ratio such that the embedded watermark can survive the following code-stream rate allocation procedure without degrading the image quality. The experimental results show that the proposed system is robust to common image distortions and processing.

A new LUT watermarking scheme with near minimum distortion based on the statistical modeling in the wavelet domain

Abstract: This paper presents a new wavelet domain look-up table (LUT) watermarking algorithm that leads to the sub-optimal embedding of watermarks in the sense of minimizing distortion. The algorithm provides a joint distortion-robustness design of the LUT based watermark. There are two key features in the algorithm: (1) a near minimum-distortion LUT with the maximum run of 2 is designed based on the statistical properties of the wavelet coefficients; (2) an expectation-maximization (EM) algorithm based method is employed to model the statistical distribution of wavelet coefficients and select significant coefficients (coefficients with large magnitude) for watermark embedding. The experimental results show that images watermarked by the proposed algorithm have about 1.5-2.5dB peak-signal-to-noise-ratio (PSNR) gain over the conventional odd-even embedding method, while the system presents great robustness. In the case of 0.2bpp (1/40) JPEG2000 compression, the proposed scheme can ensure a reasonably low bit error rate (BER).

Security enhancements of digital watermarks for multi-media content

Abstract: Methods and apparatus for embedding digital watermarks into a digital host content are provided. A digital host content is received, e.g., at a receiver or other device incorporating a receiver. One or more watermark embedding technologies is selected. Multiple embedding opportunities are identified within the host content. A subset of the identified embedding opportunities is selected. A multiplicity of digital watermarks are then embedded into the host content in accordance with the selected subset of embedding opportunities utilizing the one or more selected watermark embedding technologies. The selecting of the subset of embedding opportunities may be adapted to provide a desired tradeoff between levels of robustness, security, and transparency of the watermark. A plurality of watermarking embedding technologies may be selected and used in the embedding step.

System reactions to the detection of embedded watermarks in a digital host content

Abstract: Methods for adapting the operation of a system in response to the detection of embedded watermarks from a digital host content are provided. A digital host content is received and examined for the presence of watermarks. In response to the detection of embedded watermarks and in accordance with the value, type, density or spacing of the detected watermarks, one or more system reactions may take place. These reactions include conditionally allowing the system to resume its normal operation, prohibiting the system from resuming its normal operation, degrading the quality of the digital host content or changing the security status of the digital host content. In response to the extraction of weak watermarks that do not meet the desired system requirements, the extraction operation may be modified or extended to enable the detection of strong watermarks.

Robust blind image watermarking scheme based on Redundant Discrete Wavelet Transform and Singular Value Decomposition

Abstract: Copyright protection and proof of ownership are two of the main important applications of the digital image watermarking. The challenges faced by researchers interested in digital image watermarking applications lie in the creation of new algorithms to serve those applications and to be resistant to most types of attacks, especially the geometrical attacks. Robustness, high imperceptibility, security, and large capacity are four essential requirements in any watermarking scheme. This paper presents a new image watermarking scheme based on the Redundant Discrete Wavelet Transform (RDWT) and the Singular Value Decomposition (SVD). The gray scale image watermark was embedded directly in the singular values of the RDWT sub-bands of the host image. The scheme achieved a large capacity due to the redundancy in the RDWT domain and at the same time preserved high imperceptibility due to SVD properties. Embedding the watermarking pixel's values without any modification inside the wavelet coefficient of the host image overcomes the security issue. Furthermore, the experimental results of the proposed scheme showed a high level of robustness not only against the image processing attacks but also against the geometrical attacks which are considered as difficult attacks to resist.

Remote control signaling using audio watermarks

Abstract: A system for using a watermark embedded in an audio signal to remotely control a device. Various devices such as toys, computers, and appliances, equipped with an appropriate detector, detect the hidden signals, which can trigger an action, or change a state of the device. The watermarks can be used with a “time gate” device, where detection of the watermark opens a time interval within which a user is allowed to perform an action, such as pressing a button, typing in an answer, turning a key in a lock, etc.

An Overview of Digital Video Watermarking

Abstract: The illegal distribution of a digital movie is a common and significant threat to the film industry. With the advent of high-speed broadband Internet access, a pirated copy of a digital video can now be easily distributed to a global audience. A possible means of limiting this type of digital theft is digital video watermarking whereby additional information, called a watermark, is embedded in the host video. This watermark can be extracted at the decoder and used to determine whether the video content is watermarked. This paper presents a review of the digital video watermarking techniques in which their applications, challenges, and important properties are discussed, and categorizes them based on the domain in which they embed the watermark. It then provides an overview of a few emerging innovative solutions using watermarks. Protecting a 3D video by watermarking is an emerging area of research. The relevant 3D video watermarking techniques in the literature are classified based on the image-based representations of a 3D video in stereoscopic, depth-image-based rendering, and multi-view video watermarking. We discuss each technique, and then present a survey of the literature. Finally, we provide a summary of this paper and propose some future research directions.