KEYWORDS: Video, Video compression, Video processing, Feature extraction, Data processing, Computer programming, Multimedia, Cameras, Color difference, Signal detection
This paper presents a highlight extraction scheme for sports videos. The approach makes use of the transition
logos inserted preceding and following the slow motion replays by the broadcaster, which demonstrate highlights
of the game. First, the features of a MPEG compressed video are retrieved for subsequent processing. After the
shot boundary detection procedure, the processing units are formed and the units with fast moving scenes are
then selected. Finally, the detection of overlaying objects is performed to signal the appearance of a transition
logo. Experimental results show the feasibility of this promising method for sports videos highlight extraction.
Data hiding in JPEG-2000 compressed images is investigated in this research. The challenges of covert communication in this state-of-the-art image codec are analyzed and a steganographic scheme is then proposed to embed high-volume data into the JPEG-2000 bit-stream secretly and reliably. A special mode of JPEG-2000 is employed, and its usage and functions are explained and justified. Experimental results are given to demonstrate the performance of the proposed algorithm.
The loss of synchronization caused by geometrical modifications of an image, such as cropping, rotation and scaling, increases the difficulty of watermark detection, especially for block-based watermarking schemes. In this research, we consider an algorithm to embed an invisible grid structure into watermarked images to overcome this problem. A fixed-size 2D pseudo-random pattern is repeatedly embedded along horizontal and vertical directions of an image after the watermark is embedded in the image. In watermark detection, the affine matrix as well as horizontal/vertical shifts associated with certain geometrical attacks are determined by calculating the auto- correlation of the extracted grid structure and the cross- correlation between the folded grid and the embedded pattern. Synchronization is then recovered, and the watermark can be more easily detected. The applicability and advantages of the proposed algorithm are demonstrated by experimental results.
Most of the watermarking schemes are based on the additive spread-spectrum method since the embedded watermark can resist more serious content distortion and noises. However, they usually fail to be detected when the image undergoes geometrical modifications, such as cropping, rotation, scaling, or even change of the aspect ratio. In this research, we propose a spatial-frequency composite digital image watermarking scheme to make the embedded watermark survive the generalized geometrical transformations. Two watermarks will be embedded, one in the spatial-domain and the other in the frequency-domain of the image. Both embedding processes are based on the spread-spectrum approach. The frequency-domain watermark contains the desired information that will be carried with the host image. The watermark is embedded in the Discrete Fourier Transform (DFT) magnitude so that it is not affected by image translation. The spatial-domain watermarking is used to help recover the image to its original orientation and scale so that the hidden information can then be successfully determined. Experimental results show that the embedded watermark survives generalized geometrical or affine transformations.
Digital watermarks can be classified into two categories according to the embedding and retrieval domain, i.e. spatial- and frequency-domain watermarks. Because the two watermarks have different characteristics and limitations, combination of them can have various interesting properties when applied to different applications. In this research, we examine two spatial-frequency composite watermarking schemes. In both cases, a frequency-domain watermarking technique is applied as a baseline structure in the system. The embedded frequency- domain watermark is robust against filtering and compression. A spatial-domain watermarking scheme is then built to compensate some deficiency of the frequency-domain scheme. The first composite scheme is to embed a robust watermark in images to convey copyright or author information. The frequency-domain watermark contains owner's identification number while the spatial-domain watermark is embedded for image registration to resist cropping attack. The second composite scheme is to embed fragile watermark for image authentication. The spatial-domain watermark helps in locating the tampered part of the image while the frequency-domain watermark indicates the source of the image and prevents double watermarking attack. Experimental results show that the two watermarks do not interfere with each other and different functionalities can be achieved. Watermarks in both domains are detected without resorting to the original image. Furthermore, the resulting watermarked image can still preserve high fidelity without serious visual degradation.
KEYWORDS: Digital watermarking, Data communications, Fourier transforms, Linear filtering, Wavelets, Distortion, Signal detection, Interference (communication), Algorithm development, Signal processing
Digital audio watermarking embeds inaudible information into digital audio data for the purposes of copyright protection, ownership verification, covert communication, and/or auxiliary data carrying. In this paper, we first describe the desirable characteristics of digital audio watermarks. Previous work on audio watermarking, which has primarily focused on the inaudibility of the embedded watermark and its robustness against attacks such as compression and noise, is then reviewed. In this research, special attention is paid to the synchronization attack caused by casual audio editing or malicious random cropping, which is a low-cost yet effective attack to watermarking algorithms developed before. A digital audio watermarking scheme of low complexity is proposed in this research as an effective way to deter users from misusing or illegally distributing audio data. The proposed scheme is based on audio content analysis using the wavelet filterbank while the watermark is embedded in the Fourier transform domain. A blind watermark detection technique is developed to identify the embedded watermark under various types of attacks.
A digital audio watermarking scheme of low complexity is proposed in this research as an effective way to deter users from misusing or illegally distributing audio data. Previous work on audio watermarking has primarily focused on the inaudibility of the embedded watermark and its robustness against attacks such as compression and noise. In this research, special attention is paid to the synchronization attack caused by casual audio editing or malicious random cropping, which is a low-cost yet effective attack to watermarking algorithms developed before. The proposed scheme is based on audio content analysis and watermark embedding in the Fourier transform domain. A blind watermark detection technique is developed to identify the embedded watermark under various types of attacks.
KEYWORDS: Digital watermarking, Image compression, JPEG2000, Image quality, Image processing, Signal processing, Wavelets, Visualization, Signal to noise ratio, Computer programming
In this research, we propose an approach to combine the image compression and the image watermarking schemes in an effective way. The image coding scheme under our consideration is EBCOT (Embedded Block Coding with Optimized Truncation) which is the basis of JPEG2000 VM (Verification Model). The watermark is embedded when the compressed bit-stream is formed, and can be detected on the fly during image decompression. With the proposed integrated method, watermark embedding and retrieval processes can be done very efficiently compared with existing watermarking schemes. The embedded watermark is robust against various signal processing attacks including compression and filtering while the resulting watermarked image maintains good perceptual quality. Furthermore, the watermark can be detected progressively and ROI (Region of Interest)-based watermarking can be easily accomplished.
KEYWORDS: Digital watermarking, Raster graphics, Wavelets, Image compression, Visualization, Image quality, Signal processing, Image processing, Information security, Binary data
Cartoon/map images are synthetic graphics without complicated color and texture variation, which makes the embedding of invisible and robust digital watermarks difficult. In this research, we propose wavelet-based, threshold-adaptive watermarking scheme (TAWS) which can embed invisible robust watermarks into various kinds of graphical images. TAWS selects significant subbands and inserts watermarks in selected significant coefficients. The inserted watermarks are adaptively scaled by different threshold values to maintain the perceptual integrity of watermarked images and achieve robustness against compression and signal processing attacks. Another major contribution of this work is that the cast watermark is retrieved without the knowledge of the original image. The so-called blind watermark retrieval technique is very useful in managing a large cartoon, trademark and digital map databases. Finally, a company logo that clearly identifies the copyright information can be embedded in cartoon and map images without serious perceptual loss. Experimental results are given to demonstrate the superior performance of TAWS.
A wavelet-based watermark casting scheme and a blind watermark retrieval technique are investigated in this research. An adaptive watermark hiding method is first developed to determine significant wavelet subbands and to select a couple of significant wavelet coefficients in these subbands automatically. Then, a blind watermark retrieval technique that can detect the embedded watermark in the wavelet domain without the help from the original image is proposed. Experimental results show that the embedded images's watermark can be retrieved successfully without the original image even after the JPEG compression with a quality factor of 20 percent and the wavelet based compression attack with the 64 to 1 compression ratio. With the help of original image, the watermark can be detected after more serious attacks.
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