Geert Depovere

Video watermarking system for broadcast monitoring

This paper presents a video watermarking technology for broadcast monitoring. The technology has been developed at the Philips Research Laboratories in Eindhoven in the context of the European ESPRIT project VIVA (Visual Identity Verification Auditor). The aim of the VIVA project is to investigate and demonstrate a professional broadcast surveillance system. The key technology in the VIVA project is a new video watermarking technique by the name of JAWS (Just Another Watermarking System). The JAWS system has been developed such that the embedded watermarks (1) are invisible, (2) are robust with respect to all common processing steps in the broadcast transmission chain, (3) have a very low probability of false alarms, (4) have a large payload at high rate, and (5) allow for a low complexity and a real-time detection. In this paper we present the basic ingredients of the JAWS technology. We also briefly discuss the performance of JAWS with respect to the requirements of broadcast monitoring.

Improved watermark detection reliability using filtering before correlation

A digital watermark is a perceptually unobtrusive signal embedded in some multimedia asset carrying additional information: e.g. copyright information of a video clip. For nearly all watermarking schemes published so far, detection is based on some form of correlation. We show that the detection reliability can be significantly improved by applying filtering prior to correlation. This improvement is analysed using a theoretical model based on statistical communication and detection theory. Finally, the improvements predicted by the theory are verified in a number of experiments.

The VIVA project: digital watermarking for broadcast monitoring

The main objective of the VIVA project (Visual Identity Verification Auditor) is to investigate and demonstrate a professional broadcast surveillance system. Broadcast material is pre-encoded with an invisible and unique watermark identifier. By automatically monitoring television broadcasts and registering which assets have been pre-encoded, a mechanism for IPR protection is provided. The applications of such a system include copyright protection and proof of ownership, verification of commercial transmissions, assessment of sponsorship effectiveness, protection against illegal transmission, statistical data collection and analysis of broadcast content. The watermarking technology is optimised for the high picture quality needed in a broadcast environment. At the same time, the watermark survives signal processing operations which routinely occur in broadcasting systems such as digital to analogue conversion, editing and compression. The monitoring system detects a 36-bit payload every second, which guarantees an operation time of more than 13 years, without recourse to repeat identifiers. The detection algorithm has reasonably low complexity, enabling real time watermark detection for many broadcast channels simultaneously. We report on the first results of a field trial, using a satellite link between Sweden and Belgium, proving the feasibility of the system.

Modelling the False Alarm and Missed Detection Rate for Electronic Watermarks

Theoretical modeling of watermarks allow prediction of the detector reliability and facilitates the development of more reliable systems. In particular, mathematical evaluation is relevant to estimate the rate at which “false alarms” occur. In this paper, the probability of incorrect detection (missed detection or false alarm) is expressed in terms of the watermark-energy-to-image-luminance-variance ratio. We present some counterintuitive results which show for instance that the reliability of detection significantly depends on spatial correlation in watermark. Moreover we find that a small but uncompensated random DC component in the watermark can have a significant effect on the reliability.

Exploiting shift invariance to obtain a high payload in digital image watermarking

Robust, invisible watermarking of digital images or video very often has to satisfy a set of mutually conflicting requirements. These requirements include invisibility, robustness to image processing and geometric transformations, low false positive probabilities, high payload, fast detection and embedding, etc. In this paper we show how invariance to translations can be exploited to increase the payload. This is achieved by simultaneous embedding of several shifted watermark patterns, such that the information content is hidden in the relative shifts of the patterns. The principles of this are illustrated for the case of JAWS, a spatial domain watermark method developed by Philips. The method can easily be applied to other watermark methods which are able to detect shifted versions of watermarks.

Performance measurements of a real-time digital watermarking system for broadcast monitoring

At present it is very easy to distribute and copy multimedia content. Digital watermarking is a technical solution to the copyright problem. In its basic form a digital watermark is a small signal added to a multimedia asset and carrying sufficient data to provide IPR (Intellectual Properly Right) protection. In the European Esprit project VIVA (Visual Identity Verification Auditor) this digital watermarking technology is used to investigate, design and demonstrate a professional broadcast surveillance system. A real-time digital watermark embedder and detector for broadcast monitoring are implemented in software on a powerful DSP (digital signal processor). In this paper a short overview of the watermarking algorithms and their implementation is given. Measurements are done in a laboratory environment under real-time conditions and are very convincing. The experimental results reveal that the watermark can survive much common processing in the broadcast chain.

How to achieve robustness against scaling in a real-time digital watermarking system for broadcast monitoring

In the European Esprit project VIVA (Visual Identity Verification Auditor) a real-time digital watermarking system for broadcast monitoring has been investigated and implemented. On top of the usual requirements for watermarks, the VIVA watermarking system has to satisfy an additional number of constraints. One of the most important constraints in a broadcast environment is the robustness of the watermark against scaling. This paper describes how robustness against scaling is achieved in the VIVA project. Furthermore, a real-time implementation of the algorithms is discussed. Experimental results prove the effectiveness of the algorithms.

On the Design of a Watermarking System: Considerations and Rationales

This paper summarizes considerations and rationales for the design of a watermark detector. In particular, we relate watermark detection to the problem of signal detection in the presence of (structured) noise. The paper builds on the mathematical results from several previously published papers (by our own research group or by others) to verify and support our discussion. In an attempt to unify the theoretical analysis of watermarking schemes, we propose several extensions which clarify the interrelations between the various schemes.

Ultra fabrication-tolerant fully packaged micro-optical polarization diversity hybrid

We report on a novel fully packaged micro-optical polarization diversity hybrid, which shows excellent performance in combination with large fabrication and assembly tolerances. Our novel design employs highly parallel glass plates, which results in parallel and equidistant input and output beams. Critical fabrication and alignment procedures are thus avoided. At the target wavelength of 1.55 /spl mu/m, typical fiber-to-fiber insertion loss is 0.7 dB, balancing is 50/spl plusmn/3%, polarization extinction ratios are better than 25 dB, and measured optical back reflection is smaller than -58 dB. Wavelength insensitive behavior has been observed, resulting in a wide usable spectral operating range in excess of 90 nm. The micro-optical hybrid has been successfully tested in a dual-balanced polarization-diversity coherent CPFSK transmission experiment at 2.5 Gbt/s. >

Secret key watermarking with changing keys

We consider a digital watermarking application where multiple parties can embed additional information using their watermark embedder. These parties are not supposed to influence each other and each watermark detector needs to be able to decode the information embedded by any of the embedder systems. One approach would be to use a single secret key and to assign part of the payload to identify the particular embedder. However, it is generally accepted that for security reasons, each embedder should better have its own secret key. A major drawback of this last approach is related to the detector implementation complexity, which increases linearly with the number of embedders. It is shown that this drawback can be overcome by changing the key in the watermarking system dependant on features of the incoming signal.