DSpace collection: 期刊論文

VQ Applications in Steganographic Data Hiding Upon Multimedia Images

Tue, 27 Mar 2012 10:58:38 GMT

title: VQ Applications in Steganographic Data Hiding Upon Multimedia Images abstract: Data hiding is one of the most important techniques to achieve better data and communication protection by hiding information into a media carrier. It provides a secure method to distribute data through a public and open channel. Data hiding for vector quantization (VQ)-based images focuses on the problem of embedding secret data into a cover VQ-based image to achieve secret communication and data protection. This paper provides a state-of-the-art review and comparison of the different existing data-hiding methods for VQ-based images. In this paper, we classify VQ-based data-hiding methods into four nonoverlapping groups according to their reversibility and output formats, introduce the details of the representative methods, summarize the features of the representative methods, and compare the performance of the representative methods using peak signal-to-noise ratio, capacity of secret data, and bit rate. Our paper shows that an irreversible method is very likely a VQ-based data-hiding method that produces a stego-image as its output, and it can embed more secret data than a reversible method. Nonstandard encoding methods (e.g., joint neighboring coding) are becoming popular in reversible data hiding since they can increase the capacity for embedding the secret data. Some methods with high compression rate, such as the search-order coding-based methods, may reduce the compression rate in return for the capacity for the secret data.

Video Motion Interpolation for Special Effect Applications

Tue, 27 Mar 2012 10:58:36 GMT

title: Video Motion Interpolation for Special Effect Applications abstract: Video forgery, also referred as video falsifying, is a technique for generating fake videos by altering, combining, or creating new video contents. For instance, the outcome of a 100 m race in the olympic game is forged as an example in this paper. We track objects and segment motions using a modified mean shift mechanism. The resulting video layers can be played in different speeds and from different reference points with respect to the original video. In order to obtain a smooth movement of target objects, a motion interpolation mechanism is proposed based on reference stick figures (i.e., a structure of human skeleton) and a video inpainting mechanism. The video inpainting mechanism is performed in a quasi-3-D space via guided 3-D patch matching. Interpolated target objects and background layers are then fused. The objective is to create a forged video, which is almost indistinguishable from the original video. We demonstrate the original and the forged videos in our Web site at http://member.mine.tku.edu.tw/www/TSMC09/. Although video forgery may create moral or legal issues, which is beyond the scope of this paper, our intension is to create special effects in video editing applications.

Video Inpainting on Digitized Vintage Films via Maintaining Spatiotemporal Continuity

Tue, 27 Mar 2012 10:58:34 GMT

title: Video Inpainting on Digitized Vintage Films via Maintaining Spatiotemporal Continuity abstract: Video inpainting is an important video enhancement technique used to facilitate the repair or editing of digital videos. It has been employed worldwide to transform cultural artifacts such as vintage videos/films into digital formats. However, the quality of such videos is usually very poor and often contain unstable luminance and damaged content. In this paper, we propose a video inpainting algorithm for repairing damaged content in digitized vintage films, focusing on maintaining good spatiotemporal continuity. The proposed algorithm utilizes two key techniques. Motion completion recovers missing motion information in damaged areas to maintain good temporal continuity. Frame completion repairs damaged frames to produce a visually pleasing video with good spatial continuity and stabilized luminance. We demonstrate the efficacy of the algorithm on different types of video clips.

Timer-Based CDS Construction in Wireless Ad Hoc Networks

Tue, 27 Mar 2012 10:58:31 GMT

title: Timer-Based CDS Construction in Wireless Ad Hoc Networks abstract: The connected dominating set (CDS) has been extensively used for routing and broadcast in wireless ad hoc networks. While existing CDS protocols are successful in constructing CDS of small size, they either require localized information beyond immediate neighbors, lack the mechanism to properly handle nodal mobility, or involve lengthy recovery procedure when CDS becomes corrupted. In this paper, we introduce the timer-based CDS protocols, which first elect a number of initiators distributively and then utilize timers to construct a CDS from initiators with the minimum localized information. We demonstrate that our CDS protocols are capable of maintaining CDS in the presence of changes of network topology. Depending on the number of initiators, there are two versions of our timer-based CDS protocols. The Single-Initiator (SI) generates the smallest CDS among protocols with mobility handling capability. Built on top of SI, the Multi-Initiator (MI) version removes the single point of failure at single-initiator and possesses most advantages of SI. We evaluate our protocols by both the ns-2 simulation and an analytical model. Compared with the other known CDS protocols, the simulation results demonstrate that both SI and MI produce and maintain CDS of very competitive size. The analytical model shows the expected convergence time and the number of messages required by SI and MI in the construction of CDS, which match closely to our simulation results. This helps to establish the validity of our simulation.