Pulse or digital communications – Spread spectrum
Reexamination Certificate
1999-11-03
2003-10-21
Chin, Stephen (Department: 2634)
Pulse or digital communications
Spread spectrum
C375S133000, C375S135000, C375S146000, C375S296000, C380S054000, C382S250000, C348S473000
Reexamination Certificate
active
06636551
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an additional information transmission method for transmitting not only an information signal such as a video signal but also additional information on this information signal, an additional information transmission system, an information signal output apparatus used in this system, an information signal processing apparatus, an information signal recording apparatus and an information signal recording medium.
2. Description of the Related Art
Various contents information such as image information or voice information has been abundantly provided through a video tape, a digital video disk (DVD), internet or broadcasting media. On the other hand, the piracy problem due to the illegal duplication (copy) of such various contents information which have been provided through various media is emerging.
To cope with this problem, various measures are taken, which measures include, for example, adding information for duplication control or copyright information to contents information such as image information to prevent illegal duplication of the contents information and tracking parties involved in the illegal duplication of contents information.
There is also proposed a method of superimposing additional information added to the contents information by means of electronic watermark processing. This electronic watermark processing is to embed information as noise into portions which exist on image data or music data and which are not important for human perception, i.e., portions which are not redundant to music and pictures.
The additional information embedded into the image data or music data by means of such electronic watermark processing is difficult to remove from the image data or music data. Even after the image data or music data has been subjected to filtering or data compression processing, the electronic watermark added information (electronic watermark information) embedded thereinto can be extracted from the image data or music data.
By using the electronic watermark processing as stated above, it is possible to superimpose electronic watermark information on contents information so that the information cannot be easily removed or manipulated and to extract the electronic watermark information superimposed on the contents information at, for example, a recording apparatus. Thus, using the electronic watermark information superimposed on the contents information, the illegal duplication of the content information is prevented and the like.
In the meantime, one of the electronic watermark processings is to use a spectrum spread technique. This is intended to spectrum-spread additional information to turn the information into a low level, wide bandwidth signal so that it can be regarded as noise with respect to an information signal of, for example, a video signal, and to superimpose the additional information on the information signal such as a video signal.
The spectrum spreading of additional information is carried out by multiplying the additional information by a spread code which is generated in a sufficiently short cycle. If spectrum-spreading the additional information, the additional information, which is turned into a low level, wide bandwidth signal, can be extracted as an original high level, narrow bandwidth signal by conducting de-spread for multiplying it with the same spread code as that in spectrum spread at the same timing as that of spectrum spread.
Due to this, the following are proposed. If a spectrum spread signal which is spectrum-spread additional information is superimposed on a video signal, a spread code is generated to be synchronous with a vertical synchronizing signal in, for example, a one-frame cycle or two-frame cycle. Using the spread code, the spectrum-spread additional information is superimposed on the video signal.
By doing so, if the spectrum spread signal superimposed on the vide signal is extracted, the spectrum-spread additional information superimposed on the vide signal can be de-spread by generating the same spread code as that during spectrum spread at the same time while using a vertical synchronizing signal as a reference signal. Thus, it is possible to promptly and accurately extract the spectrum-spread additional information superimposed on the video signal.
Further, even if the additional information on the video signal is superimposed on the video signal with a spectrum spread signal and transmitted as stated above, it is considered that a state in which the spectrum-spread signal is superimposed on the video signal or the content of the additional information transmitted by the spectrum spread signal is illegally detected by various methods.
In that case, there is a fear that the removal or manipulation of the spectrum spread signal superimposed on the video signal is easily made based on the illegally detected information. This may possibly occur not only to a case where additional information is superimposed as a spectrum spread signal on a video signal but also to a case where additional information is superimposed as electronic watermark information on various information signals such as a voice signal and computer data and then transmitted.
Due to this, it is desired that the strength of the additional information superimposed as a spectrum spread signal on the information signal such as a video signal, is intensified against illegal attempts to thereby make it possible to surely, accurately provide the other side with the additional information on the video signal together with the video signal.
Further, a demand for superimposing not only information for duplication control (duplication control information) but also further additional information such as copyright information on the transmitted information signal on the information signal and transmitting them. That is, there is a demand for superimposing both duplication control information serving as additional information and further additional information on an information signal and transmitting the both information.
In this case, it is required to make the additional information difficult to remove or manipulate, to ensure providing the information signal to the side supplied with the information signal and to allow the side supplied with the information signal to surely and accurately detect further additional information provided after being superimposed on the information signal.
Nevertheless, it is difficult to ensure transmitting duplication control information and further additional information and to detect these pieces of information separately from each other only by superimposing further additional information in addition to the duplication control information both serving as electronic watermark information on an information signal such as a video signal.
SUMMARY OF THE INVENTION
In view of the above, an object of the present invention is to provide an additional information transmission method for making higher the concealment characteristics of additional information transmitted as electronic watermark information together with an information signal and for surely, accurately transmitting the additional information, an additional information transmission system using this method, an information signal output apparatus used in this system, an information signal processing apparatus, an information signal recording apparatus and an information signal recording medium.
Further, another object of the present invention is to provide an additional information transmission method, an additional information transmission system as well as an information signal output apparatus and an information signal processing apparatus used in the system which can superimpose a plurality of types of additional information on an information signal using electronic watermark information to surely provide the information to a receiving side and which allows the side supplied with the information signal to surely and accurately detect each of the plural additional information superim
Ikeda Nozomu
Kimura Yuji
Kohashi Takashi
Moriwaki Hisayoshi
Ogino Akira
Ahn Sam K.
Chin Stephen
Frommer William S.
Frommer & Lawrence & Haug LLP
Simon Darren M.
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