In the last few years, a large number of schemes have been proposed for hiding copyright marks and other information in digital pictures, video, audio and other multimedia objects. We describe some contenders that have appeared in the research literature and in the field; we then present a number of attacks that enable the information hidden by them to be removed or otherwise rendered unusable.

This dissertation presents algorithms for restoring some of the major corruptions observed in archived film or video material. The two principal problems of impulsive distortion (Dirt and Sparkle or Blotches) and noise degradation are considered. There is also an algorithm for suppressing the inter--line jitter common in images decoded from noisy video signals. In the case of noise reduction and Blotch removal the thesis considers image sequences to be three dimensional signals involving evolution of features in time and space. This is necessary if any process presented is to show an improvement over standard two--dimensional techniques. It is important to recognize that consideration of image sequences must involve an appreciation of the problems incurred by the motion of objects in the scene. The most obvious implication is that due to motion, useful three dimensional processing does not necessarily proceed in a direction `orthogonal' to the image frames. Therefore, attention is giv...

This thesis addresses a number of issues concerned with the restoration of one type of image sequence, namely archived black and white motion pictures. These are often a valuable historical record, but because of the physical nature of the film they can suffer from a variety of degradations which reduce their usefulness. The main visual defects are `dirt and sparkle' due to dust and dirt becoming attached to the film, or abrasion removing the emulsion, and `line scratches' due to the film running against foreign bodies in the camera or projector. For an image

Line scratches are common degradations in motion picture films. This paper presents an efficient method for line scratches detection strengthened by a Kalman filter. A new interpolation technique, dealing with both low and high frequencies (i.e. film grain) around the line artifacts, is investigated to achieve a nearby invisible reconstruction of damaged areas. Our line scratches detection and removal techniques have been validated on several film sequences. 1 Introduction Motion picture industry is 100 years old and chemical film (nowadays polyester, former triacetate or nitrate) is still the main support for motion picture film, despite of fast-growing digital media. It is a fact the film and dye coating for color are not stable over decades. In addition, some old films are reassembled from fragments scattered over various libraries and archives. Only digital processing will ensure the removal of the various artifacts due to age and a well balanced output to a film recorder. The ma...

Many archived motion pictures suffer from what we term replacement noise, that is various degradations such as dirt, scratches, fingerprints etc, where the original picture is replaced by some unrelated information. In this paper we use markov random field based motion field segmentation to detect these areas, and then interpolate into the gaps using a motion-compensated interpolation scheme to restore the frame. INTRODUCTION This paper is concerned with replacement noise, that is, dirt, scratches and other extended regions of the frame where the original grey level information is lost. This form of degradation is often visually more annoying than global white noise and is very common in archived motion pictures. From a single frame a human observer can detect replacement noise using contextual information; our signal processing solution relies on the redundancy inherent in the image sequence -- the grey level observed in an area affected by replacement noise `does not fit' with the r...

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Application of rigid motion geometry to historical film restoration. Historical film restoration involves locating the position of artifacts and replacing the ”missing ” portion of the film (obscured by the artifact) with pixels that had been lost. Computer vision research has recently developed many techniques for constraining and predicting parts of a scene based upon the assumption of rigid motion. In this paper, we show how the constraints can help identify artifacts as well as how the prediction can be used to replace the artefact with natural looking portions of the scene. These techniques can be superior, when the rigid motion assumption is valid, to other techniques for historical film restoration. 1

Hidden copyright marks have been proposed as a solution for solving the illegal copying and proof of ownership problems in the context of multimedia objects. Many systems have been proposed, but it is still di#cult to have even a rough idea of their performances and hence to compare them. So we first describe some general attacks on audio and image marking systems. Then we propose a benchmark to compare image making software on a fair basis. This benchmark is based on a set of attacks that any system ought to survive.