Dimitrios Simitopoulos

Robust image watermarking based on generalized Radon transformations

The paper presents a novel watermarking scheme able to resist geometric attacks. The proposed method performs imperceptible watermarking of images in the spatial domain. To generate resistance to scaling and rotation attacks, two generalized Radon transformations of the image are introduced, while resistance to translation is accomplished through a localization of the watermarking method based on feature points of the image. The original image is not required for the detection process. Experimental evaluation demonstrates that the proposed scheme is able to withstand a variety of attacks including common geometric attacks.

Compressed-domain video watermarking of MPEG streams

A new technique for watermarking of MPEG compressed video streams is proposed. The watermarking scheme operates directly in the domain of MPEG program streams. Perceptual models are used during the embedding process in order to preserve the video quality. The watermark is embedded in the compressed domain and is detected without the use of the original video sequence. Experimental evaluation demonstrates that the proposed scheme is able to withstand a variety of attacks. The resulting watermarking system is fast and reliable, and is suitable for copyright protection and real-time content authentication applications.

Encryption and watermarking for the secure distribution of copyrighted MPEG video on DVD

Abstract.This paper presents a complete system for the secure distribution of a copyrighted MPEG-1/2 video stored on a DVD-ROM disc. A combined selective watermarking and encryption method that operates in the compressed MPEG domain is introduced. Watermarking resistant to a number of attacks is used for copyright protection. The video quality deteriorates significantly due to encryption, thus restraining unauthorized viewers from viewing it. The video can only be viewed using the developed Secure MPEG Player, which performs real-time decryption of the encrypted video. The decryption requires a secret key that is extracted from the DVD-ROM disc in a cryptographically secure manner.

Segmentation and content-based watermarking for color image and image region indexing and retrieval

In this paper, an entirely novel approach to image indexing is presented using content-based watermarking. The proposed system uses color image segmentation and watermarking in order to facilitate content-based indexing, retrieval and manipulation of digital images and image regions. A novel segmentation algorithm is applied on reduced images and the resulting segmentation mask is embedded in the image using watermarking techniques. In each region of the image, indexing information is additionally embedded. In this way, the proposed system is endowed with content-based access and indexing capabilities which can be easily exploited via a simple watermark detection process. Several experiments have shown the potential of this approach.

Fast watermarking of MPEG-1/2 streams using compressed-domain perceptual embedding and a generalized correlator detector

A novel technique is proposed for watermarking of MPEG-1 and MPEG-2 compressed video streams. The proposed scheme is applied directly in the domain of MPEG-1 system streams and MPEG-2 program streams (multiplexed streams). Perceptual models are used during the embedding process in order to avoid degradation of the video quality. The watermark is detected without the use of the original video sequence. A modified correlation-based detector is introduced that applies nonlinear preprocessing before correlation. Experimental evaluation demonstrates that the proposed scheme is able to withstand several common attacks. The resulting watermarking system is very fast and therefore suitable for copyright protection of compressed video.

Using intelligent digital cameras to monitor aerodrome surface traffic

An aircraft is most at risk for an accident when its still on the ground - when taxiing before takeoff or after landing. This is because traffic throughput on the ground is limited by inadequate airport infrastructures and is often incapacitated during conditions of poor visibility. The INTERVUSE project, funded by the European Commission, aims to address these problems by developing a cost-effective artificial intelligence system based on a network of intelligent digital cameras. The system uses image-processing techniques to detect traffic and correlates and fuses data to generate a synthetic ground-situation display.

Image watermarking resistant to geometric attacks using generalized Radon transformations

This paper presents a novel watermarking scheme able to resist geometric attacks. The proposed method performs watermarking of images in the raw domain. A perceptual model is used in order to define the strength of the embedded watermark. For resistance to scaling and rotation attacks, two generalized Radon transformations of the image are introduced, while resistance to translation is accomplished through a localization of the watermarking method based on feature points of the image. Experimental evaluation demonstrates that the proposed scheme is able to withstand a variety of attacks including common geometric attacks.

Rigid and Non-Rigid 3D Motion Estimation from Multiview Image Sequences

Multiview image sequence processing has been the focus of considerable attention in recent literature. This paper presents an efficient technique for object-based rigid and non-rigid 3D motion estimation, applicable to problems occurring in multiview image sequence coding applications. More specifically, a neural network is formed for the estimation of the rigid 3D motion of each object in the scene, using initially estimated 2D motion vectors corresponding to each camera view. Non-linear error minimization techniques are adopted for neural network weight update. Furthermore, a novel technique is also proposed for the estimation of the local non-rigid deformations, based on the multiview camera geometry. Experimental results using both stereoscopic and trinocular camera setups illustrate and evaluate the proposed scheme.

Video System for Surface Movement Surveillance at Airports

The Advanced Surface Movement Guidance and Control Systems (A-SMGCS) are intelligent transportation systems that provide routing, guidance, surveillance, and control to aircraft and vehicles in order to keep up the airport capacity under all local weather conditions, while maintaining the required level of safety; however, reflections, multipath, and shadows due to buildings, equipment, and other reflecting objects on the airport surface make it difficult, if not sometimes impossible, for existing A-SMGCS to reliably cover the whole aerodrome. In these cases another sensor must step in to fill those gaps. Digital video cameras not only can solve these kinds of problems filling blind spots in the existing A-SMGCS, but also provide a cost effective solution. This article presents an innovative system for airport surface movement control based on intelligent video cameras.

Fast MPEG watermarking for copyright protection

In this paper, a new technique for watermarking of MPEG compressed video streams is proposed. The watermarking scheme operates directly in the domain of MPEG multiplexed streams. Perceptual models are used during the embedding process in order to preserve the quality of the video. The watermark is embedded in the compressed domain and is detected without the use of the original video sequence. Experimental evaluation demonstrates that the proposed scheme is able to withstand a variety of attacks. The resulting watermarking system is very fast and reliable, and is suitable for copyright protection and real-time content authentication applications.