Abstract: A method of superimposing additional information on a video signal, transmitting it, and detecting the additional information from the transmitted video signal. The additional information is synchronized with a sync signal in the video signal, and generated in N (N≧1) unit intervals of one field of the video signal. Some predetermined unit intervals of the additional information generated in N (N≧1) unit intervals of one field of the video signal, are phase-inverted. The additional information is identified by detecting the information in unit intervals based on the sync signal in the video signal, and detecting that information in some predetermined unit intervals is inverted. The additional information is identified by detecting the information in unit intervals, and integrating the detection results with the information in inverted predetermined unit intervals inverted.

Abstract: The PN code generation controlling means 15 produces a PN code generation clock signal PNCLK to generate the PN code of one chip to one vertical section and supplies this clock signal to an SS duplication preventing control signal generating means 16. The SS duplication preventing control signal generating means 16 generates the PN code of one chip to one vertical section depending on the PN code generation clock signal PNCLK and executes the spectrum spread to the duplication preventing control signal S3 using this PN code to form the SS duplication preventing control signal S5. The SS duplication preventing control signal S5 is superimposed to the image signal and is then output. Thereby, elimination and deterioration of the additional information which has been spectrum spread and is then superimposed into the image signal can be prevented to surely provide the additional information superimposed to the image signal.

Abstract: An anti-duplication control signal detection section detects an anti-duplication control signal added on a video signal S1 and supplies it to a system controller as a duplication prevention control information S2. A write control section of the system controller stops the duplication of the video signal in a disk if the anti-duplication control information is an information which indicates duplication inhibition. In this case, the video signal recorded in the disk is erased under the control from the erasing control section by the time the duplication prevention control corresponding to the anti-duplication control signal becomes active.

Abstract: A method of superimposing additional information on a video signal, transmitting it, and detecting the additional information from the transmitted video signal. The additional information is synchronized with a sync signal in the video signal, and generated in N(N≧1) unit intervals of one field of the video signal. Some predetermined unit intervals of the additional information generated in N(N≧1) unit intervals of one field of the video signal, are phase-inverted. The additional information is identified by detecting the information in unit intervals based on the sync signal in the video signal, and detecting that information in some predetermined unit intervals is inverted. The additional information is identified by detecting the information in unit intervals, and integrating the detection results with the information in inverted predetermined unit intervals inverted.

Abstract: When digital image signals fed in through an input terminal to be recorded on a disc, medium-related information, such as a serial number in a table of contents of the disc, is spectrum-spread in a spectrum spreading additional information generating section and the digital image signals on which the spectrum-spread medium-related information has been superimposed in an spectrum spreading additional information superimposing section are recorded on the disc. When the signals are to be reproduced, the reproduction can be performed if the medium-related information superimposed on the image signals recorded on the disc is consistent with the medium-related information of the disc on which the image signals are recorded. Thus, copying of the information signals can be limited to copying for private use.

Abstract: The PN code generation controlling means 15 produces a PN code generation clock signal PNCLK to generate the PN code of one chip to one vertical section and supplies this clock signal to an SS duplication preventing control signal generating means 16. The SS duplication preventing control signal generating means 16 generates the PN code of one chip to one vertical section depending on the PN code generation clock signal PNCLK and executes the spectrum spread to the duplication preventing control signal S3 using this PN code to form the SS duplication preventing control signal S5. The SS duplication preventing control signal S5 is superimposed on the image signal and is then output. Thereby, elimination and deterioration of the additional information which has been spectrum spread and is then superimposed on the image signal can be prevented to surely provide the additional information superimposed on the image signal.

Abstract: It is the object of this invention to extract spectrally spread additional information superimposed on the video signal rapidly and correctly. The output device 10 generates the PN code string every second vertical interval with reference to the video sync signal, and spectrally spreads the additional information using this PN code string. The spectrally spread additional information is superimposed on the video signal every second vertical interval and outputted. Upon receiving the video signal, in the recording device for recording the video signal on a recording medium, the video signal component is canceled each other between the video signal component in the vertical interval on which the additional information is superimposed and the video signal component in the vertical interval on which the additional information is not superimposed because of the field correlation of the video signal, and only the additional information is extracted.

Abstract: A circuit to extract spectrally spread additional information superimposed on the video signal rapidly and correctly. The output device 10 generates the PN code string every second vertical interval with reference to the video sync signal, and spectrally spreads the additional information using this PN code string. The spectrally spread additional information is superimposed on the video signal every second vertical interval and outputted. Upon receiving the video signal, in the recording device for recording the video signal on a recording medium, the video signal component cancel each other between the video signal component in the vertical interval on which the additional information is superimposed and the video signal component in the vertical interval on which the additional information is not superimposed because of the field correlation of the video signal, and only the additional information is extracted.

Abstract: A spread code string containing a plurality of chips per interval in one horizontal interval or containing a plurality of chips per interval in one vertical interval is generated synchronously with the vertical sync signal at the generation star timing having a period of one vertical period or having a period of a plurality of vertical periods. The generated spread code string repeats over a plurality of horizontal intervals or a plurality of vertical intervals so that the chips having the same data are arranged in spatial direction of the vertical direction or the time axis direction in picture unit. The additional information is spectrally spread so that the chips having the same data are arranged at least in the interval in each 1 horizontal interval or in each 1 vertical interval of the above-mentioned repetition interval, and the generated spectral spread signal is superimposed on the video signal.

Abstract: An additional information f2a previously superimposed repeatedly four times with a period shorter than the decoding period of a spread information on an information signal f1a by way of spectral spread is detected four times by way of an additional information signal detection section by way of inversion spread based on a spectrally spread PN signal f5a from a PN generation section, the coincidence detection section confirms coincidence of four detection results, and thus the superimposition of the additional information f2a is finalized, therefore the additional information f2a is detected within a short time because of a short period of the spectral spread, the additional information f2a is detected with high detection accuracy with a small spread gain by way of confirming the coincidence of four detections, and a write section can perform write inhibition properly based on detection of the additional information f2a.

Abstract: Video signals are converted into one or more blocks for each predetermined unit amount of data, and a discrete cosine transform (DCT) process is performed in the blocks to convert a video signal from a time-base area signal to a DCT coefficient in a frequency area for data compression. One chip of a spread spectrum signal is allocated to each block of the video signal or to each of a plurality of blocks, and additional information is superimposed on the video signal at a constant level corresponding to a chip value for transmission. The video signal on which the additional information consisting of the spread spectrum signal transmitted has been superimposed is received, and from this received signal, a DC component of the DCT coefficient is extracted. Inverse spread spectrum processing is performed for the DC component of the DCT coefficient extracted to detect the additional information.

Abstract: Additional information is superimposed consistently while the disturbance of a picture due to excessive superimposition is suppressed. The device superimposes a spectrally spread additional information on a video signal. Inverse spread processing is performed on the video signal, and an SS additional information detection circuit detects whether additional information is superimposed already on the video signal. Based on the detection result performed by the additional information detection circuit, superimposition of the spectrally spread signal supplied from the spectrally spread signal generator on the video signal is controlled. A superimposition control method such as superimposition ON/OFF control, superimposition level control, or spread code string control is performed.