Abstract:
L'invention concerne un procédé de tatouage d'au moins une image fixe ou animée, ladite image étant associée à un maillage de base constitué d'un ensemble de facettes définies par un ensemble de sommets et d'arêtes, et à des coefficients dans une base d 'ondelettes correspondant à des modifications locales dudit maillage de base, dits coefficients d'ondelettes, chaque coefficient d'ondelettes étant indexé par un sommet dudit maillage de base. Selon l'invention, un tel procédé de tatouage comprend les étapes de : -insertion d'une marque de tatouage dans ladite image par déplacement local d'au moins un sommet dudit maillage de base, de façon à obtenir un maillage de base marqué ; -modification de la valeur d'au moins un desdits coefficients d'ondelettes, de façon à compenser au moins partiellement l'impact visuel de ladite marque de tatouage sur ladite image.
Abstract:
A method (2), an apparatus, a computer readable medium and use of said method for authenticating an audio-visual signal (10), such as a digital image or video, are disclosed. A signature is derived from all image regions, including areas with flat or otherwise un-watermarkable content. By combining signature bits from all regions of the audio-visual signal and spreading the signature bits over the whole audio-visual signal or at least a large area of it, preferably by applying a spread spectrum watermarking technique (2.40), the authenticity of flat regions is verified.
Abstract:
【課題】高い攻撃耐性を持つ新たな電子透かし方式を提供する。 【解決手段】入力画像のn行n列の画素行列Gを記憶する手段と、画素行列Gの固有値s 1 ~s n 及び固有ベクトルp 1 ~p n を求める手段と、固有値s 1 ~s n の中から、異なる値を持つ固有値のペア(s i 、s j )を少なくとも1組選択し、前記選択したペアが同一の値となるように固有値s 1 ~s n を修正する手段と、前記修正した固有値を対角要素とし、前記選択したペアに対応する非対角要素の一方を1としたジョルダン標準形行列S w を作成する手段と、固有ベクトルp 1 ~p n を電子透かしキー情報として出力する手段と、前記作成した行列S w に対して固有ベクトルp 1 ~p n を用いて対角化演算の逆変換を行ってn行n列の画素行列G w を作成し、入力画像の電子透かし埋込画像として出力する手段と、を備える電子透かし埋込装置によって、電子透かし埋込画像を生成する。
Abstract:
A wavelet domain watermark encoder and decoder embed and detect auxiliary signals (1300, 1302) in a media signal (1306), such as a still image, video or audio signal. A watermark orientation signal (1302) is embedded in a wavelet decomposed signal (1304) to facilitate detection of the watermark in a geometrically distorted version of the embedded signal.
Abstract:
A perceptual model performs an analysis of a media signal (100), such as an image or audio signal. The model may be used in media signal processing applications such as digital watermarking and data compression to reduce perceptibility of changes made to code the signal. By comparing the local image strength of various directionally filtered various of the image, the model creates a directional control vector (110). The model takes into account the local contrast (106) of the image and the directional control vector to create a gain vector.
Abstract:
Zur Einbettung von binären Nutzinformationen (122) in ein Trägersignal (110), das beispielsweise ein Audiosignal ist, wird eine Folge von zeitdiskreten Werten des Trägersignals mittels eines Ganzzahl-Transformations-Algorithmus in den Frequenzbereich (116) umgesetzt, um binäre Spektraldarstellungswerte zu erhalten. Bits der binären Spektraldarstellungswerte mit einer Wertigkeit, die kleiner als Signal-Grenzwertigkeit ist, werden ermittelt und gemäß den Nutzinformationen eingestellt (120). Die Signal-Grenzwertigkeit für einen Spektraldarstellungswert ist kleiner als die Wertigkeit des führenden Bits dieses Spektraldarstellungswerts, so daß bei ausreichendem Abstand eine psychoakustisch transparente Einbringung von Informationen erreicht wird. Damit wird eine modifizierte spektrale Darstellung mit eingebrachten Informationen erzeugt, die schließlich wieder in den Zeitbereich umgesetzt wird, und zwar unter Verwendung eines Ganzzahl-Rücktransformationsalgorithmus. Zur Extraktion der Nutzinformationen wird das zeitdiskrete Signal mit den eingebrachten Informationen wieder mit dem Ganzzahl-Vorwärts-Transformationsalgorithmus in eine spektrale Darstellung umgesetzt. Ferner werden Signal-Grenzwertigkeitsinformationen ermittelt, um die Bits der binären Spektraldarstellungswerte zu identifizieren, die keine Informationen hinsichtlich des Trägersignals sondern Informationen hinsichtlich des Nutzsignals enthalten, um diese Bits zu extrahieren. Das erfindungsgemäße Konzept ist in der Implementierung einfach und kann hinsichtlich der Datenrate der einzubringenden Informationen skaliert werden.
Abstract:
Advanced watermark embedders use psycho visual / acoustic models to minimize perception of the embedded watermark in media contents. However, it is expensive to implement such advanced watermark embedders in consumer appliances (3) such as DVD recorders. In accordance with the invention, embedding strength parameters (JND) are calculated (13) off-line at a remote location (1) and transmitted along with the media contents to the consumer appliance (3). A relatively simple embedder (33) uses the received parameters to control the strength of the watermark (36) to be embedded. The parameters may be accommodated in the transmitted signal as payload of a fragile watermark or as user data in an encrypted MPEG stream.
Abstract:
Embodiments of the present invention provide digital watermarking methods that embed a digital watermark in both the low and high frequencies of an image (52) or other production, providing a digital watermark that is resistant to a variety of attacks. The digital watermarking methods of the present invention optimize the strength of the embedded digital watermark such that it is as powerful as possible without being perceptible to the human eye. The digital watermarking (56) methods of the present invention do this relatively quickly, in realtime, and in an automated fashion using an intelligent system, such as a neural network (54). The digital watermarking methods of the present invention may also be used in a variety of new applications, such as the digital watermarking of sensitive aircraft parts and military equipment.
Abstract:
A system and method for inserting a watermark in encoded content are described including receiving encoded content, receiving at least one watermark unit comprising information on the position of an original value to be replaced by an alternative value and alternative values and replacing directly a number of bits starting at the position with one of the alternative values, wherein the alternative value has embedded therein watermark signals. An apparatus and method for generating watermark units are also described including selecting a position where a value in encoded content is to be replaced by an alternative value and calculating the alternative value. Further a system and method for replacing a watermark in encoded content are also described including receiving encoded content, receiving at least one watermark unit and replacing a number of bits starting at a position in the encoded content with a value, wherein the value is specified in the at least one watermark unit and further wherein the position is specified in the at least one watermark unit.