JP2001211433A - Copy protection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copy protection system which can inhibit copying that audio and image information (primary software) displayed on a screen is photographed by a video camera as they are or that can inhibit reproduction/use of secondary software generated by the copying as above. SOLUTION: The copy protection system inserts and copy protect information in advance to each signal of video information and audio information so that copying without permission can be detected by having only to reproduce and display the copied video information without permission onto a screen or by having only to reproduce and sound the coped audio information without permission in the case that as literary work such as video information and audio information is coped without permission.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical protection means (copy protection) for preventing unauthorized duplication of hot crops such as video software and music CDs, and more particularly, it is insensitive to viewers. And a copy protection method that can be detected only by an electronic device.

[0002]

2. Description of the Related Art In recent years, the quality of an image projected on a display device has been improved even in an analog transmission / reception system.
With the advent of digital transmission / reception systems, further improvement in video quality has been promised. In addition, due to the progress of AV equipment and the like, even if duplication is performed, the information is little degraded or not degraded at all, so that illegal duplication can be easily performed.

[0003] As a result, in response to a strong request from the copyright holder of video software and the like, a number of schemes for preventing unauthorized duplication of video software and the like have been proposed.
ovision) and Watermark (Watermark)
It is actually used as a product.

[0004] The Macrovision system developed by Macrovision Corporation of the United States is the most common copy protection technology used for home VTRs (mainly for VHS software) and the like.

As shown in FIG. 3A, on an actual television screen, an image does not appear to fill 1H × 1V, but
In the portion related to the vertical / horizontal synchronization signal, there is a blanking portion where nothing is shown. Macrovision method
A pulse signal called a macro vision signal is inserted in the vertical blanking period (VBI). FIG.
FIG. 3B shows a signal waveform of a normal vertical synchronization signal.
(C) shows a signal waveform when a macrovision signal is included in the vertical synchronization signal.

The video input of the VTR has an AGC (Auto Gain Control) circuit for keeping the maximum value of the signal to be recorded following the magnitude of the input signal constant. When copying, this circuit malfunctions with the pulse signal. Results recorded
When this is reproduced on the TV screen, screen deterioration such as fluctuation in brightness of the reproduced screen is caused. On the other hand, since the TV receiver does not use the peak AGC, even if the tape (software) before copying is reproduced, the screen is not affected as described above.

As is clear from this description, the macro vision system works on a place other than the screen that the user sees (a vertical blacking period in terms of time), and the receiver and the VT
This is a method that makes good use of the difference in the characteristics of R.

At present, casual copy prevention has been achieved by such a copy protection system, and the copyright holder is satisfied.

Further, a law called copy guard canceller, which regulates the production and distribution of devices that avoid copy protection by criminal penalties, is enforced (in Japan, the Copyright Law in October 1999) The law is being improved, and the prevention of casual copying is becoming more reliable.

[0010]

[0005] However, 525
A new problem arises when the image quality is steadily increasing in P (progressive scanning of 525 effective scanning lines) and high-vision (Hi-vision) systems.

For example, if an image (primary software) projected on a screen according to a high-definition standard such as a high-definition system is photographed as it is with a video camera, a sound / video copy (second image) enough to withstand viewing can be obtained. Next software) can be obtained casually.

However, the current TV image is NTSC (Na
(National Television System Committee) is the mainstream, and the image quality of this type of copy software is of a level that cannot be enjoyed, so it is not considered a problem at present.

As described above, the conventional copy protection method is a method in which a user operates an area other than the screen viewed by the user (that is, a part which is not output from the screen). Is a defense against

Therefore, it is completely vulnerable to the direct duplication of the video projected on the screen and the audio output from the speaker. In other words, a technical means for preventing the video projected on the screen from being duplicated by a method in which the video is directly taken by a video camera, or a technique for prohibiting the use of the secondary software created by such a method. There is no strategic means.

In the coming era, hardware devices (VTRs and TV receivers) to be released will be excluded from the market due to crackdowns except those manufactured in compliance with the law. In order to prevent illegal copying, it is necessary to take multiple preventive measures by adding software (hardware side), a combination of software and hardware, and authentication by exchanging information between hardware (for example, VTR and TV receiver). Conceivable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a part missing from the conventional copy protection method, specifically, a sound or a video (primary software) projected on a screen is used as it is. Duplication such as shooting with a video camera can be prohibited, or secondary software created by such duplication can be played back.
It is an object of the present invention to provide a copy protection method that can prohibit use.

[0017]

In order to solve the above-mentioned problems, the invention of claim 1 reproduces the copied video information copied without permission when the copyrighted work of the video information and audio information is copied without permission. Each of the video information and the audio information is copied so that it is possible to detect the unauthorized copying only by displaying the sound on the screen or reproducing and reproducing the sound of the copied sound without permission. A copy protection method in which copy protection information is inserted and recorded in advance, wherein the insertion period of the copy protection information to be inserted into the video information signal is 1/30 second at maximum, and is inserted into the video information signal. The copy cycle of the copy protection information to be inserted is 1 second to 60 seconds, and the audio signal which is the copy protection information inserted into the audio information signal. The frequency 18kHz to 20
kHz) or 10 Hz to 50 Hz, and the audio signal is inserted into the audio information signal continuously or intermittently at predetermined intervals.

According to a second aspect of the present invention, a unique signal is added before or after the insertion period of the copy protection information.

According to a third aspect of the present invention, the luminance level of the unique information is changed according to the luminance level of the video signal to be copy protected.

According to the present invention, it is possible to prohibit a copying act of directly photographing audio or video (primary software) projected on a screen with a video camera, or to create a copy created by such a copying act. Reproduction and use of the secondary software can be prohibited.

[0021]

Embodiments of the present invention will be described below.

FIGS. 1 and 2 are explanatory diagrams for explaining the copy protection system of the present invention.

The video image is displayed on the viewing screen 5 as several images per second. For example, in the case of a movie shown in a theater, the image projected on the screen is 2 per second.
Four pictures are projected, and in NTSC video,
30 images per second (actually, 30 frames per second, 60 fields) are sent out.

At a certain moment in the video, copy protection information is inserted. In the example of FIG. 2, the video 14 (frame) at a certain moment (here, time t4) is replaced with the image 21 (frame) including the copy protection signal. At the time of this replacement, the entire image 14 may be replaced,
A part of the image 14 may be replaced.

In short, for example, in the conventional macro vision system, as shown in FIG. 3A, a copy protection signal is superimposed on a portion not displayed on the screen (a blanking period). Is to insert a copy protection signal into the image itself displayed in (1).

There are various possible copy protection signals and insertion methods to be inserted, but the important point is that the signal is input in a form that cannot be detected by human eyes, but can be detected by a machine such as a recording device. . That is, it is necessary to set the period and the cycle of inputting the copy protection signal to be equal to or less than the human perception threshold.

For example, in the case of an NTSC video signal, 1
A copy protection signal is inserted for 30 seconds to 1/3000 seconds, and the insertion cycle is 1 second to 60 seconds.

In the case of an audio signal, the frequency is 18 kHz or more (for example, 18 kHz to 20 kHz) or 50 kHz.
Hz or less (e.g., 50 Hz to 10 Hz).
/ 50 seconds to 60 seconds).

Next, the operation of this embodiment will be described with reference to FIG.

The copy protection / timing generator 2 performs frame processing 3 on the original image software 1.
The original picture software 1 here means a video tape, CD
-Indicates all video contents distributed in the market, such as packaged software such as ROM and DVD-ROM, and networked software such as TV broadcasting and the Internet.

The frame processing 3 is, as described above,
This is a process of inserting copy protection information at a certain moment in the video of the original image software 1. The type and content of the copy protection signal to be actually inserted, and the period and timing of the insertion are managed and held by the copy protection / timing generator 2,
It can be set so that the inserted copy protection signal cannot be sensed by the human eyes, that is, is equal to or less than the human perception threshold.

The original image software 4 subjected to the frame processing 3 by the copy protection timing generator 2 is displayed on the screen of the receiver 5.

Since the copy protection signal is inserted into the original image software 4 which has been subjected to the frame processing 3 in a period and a cycle in which it is equal to or less than the human perception threshold, the image projected on the screen of the receiver 5 is The insertion of the copy protection signal cannot be detected by the eyes 6 of the human being. Therefore, the person 6 looking at the screen of the receiver 5 can naturally appreciate the original picture software.

The video projected on the screen of the receiver 5 is directly photographed by a recording device 7 such as a video camera. The recording device 7 is provided with a copy protection signal detection device 10. The copy protection signal detecting device 10 may be built in the recording device, or may be connected externally by a cable or the like.

The image projected on the screen of the receiver 5 has a copy protection signal inserted therein so as not to be detected by the human eyes 6, but is inserted into the recording device 7 such as a video camera to an extent that it can be detected. Therefore, the copy protection signal detecting device 10 attached to the recording device 7 can detect the copy protection signal and forcibly stop the recording by the recording device 7.

Even if the recording is performed by a recording device not provided with the copy protection signal detecting device 10, the recorded tape 8 includes the one inserted in the original image software 4 subjected to the frame processing 3. The same copy protection signal is included. Therefore, when this recording tape 8 is reproduced using the reproducing device 9 to which the copy protection signal detecting device 10 is attached,
The copy protection signal detection device 10 can detect a copy protection signal in the recorded video and forcibly stop the video reproduction process.

As described above, according to the copy protection method according to the present invention, it is possible to prohibit a copying action in which a video or a camera directly captures audio or video (primary software) projected on a screen. Yes, or it is possible to prohibit the reproduction and use of the secondary software created by such copying.

In the present invention, the copy protection signal is used to make one frame of an image black, for example, in a short period of time that cannot be detected by humans, or to make the period of this black frame a period that is impossible for ordinary video. You can do it by doing.

By the way, even if the copy protection signal is mixed in the video and music signals as described above, if the copy protection signal cannot be reliably extracted on the reproducing side, the effect of inhibiting the reproduction and use of the secondary software is obtained. Will not be obtained. That is, the primary software (content image /
It is very important in copy protection processing that the copy recording device, which is the secondary software production side, can detect (extract) the copy protection signal including the primary software sent from the sound) side in a timely and reliable manner. Face to be.

FIG. 4 is a waveform diagram showing an example of a copy protection signal according to another embodiment of the copy protection system of the present invention. Copy protection signal 1 of this example
A unique signal 200 is added to 00 in advance of time. Note that the unique signal 300 may be added after the copy protection signal 200 in time.

The unique signal 200 is not the same as the time-series signal appearing in various contents information, or selects a sequence having a very low appearance probability. For example, after maintaining the brightness level of a bright line (raster) in a display screen of a certain frame used for the purpose of copy protection for a certain time (either one raster or two rasters), the brightness of bit 1 below The level becomes 15% to 70% of the maximum level of the transmission standard, for example, 01001
Sent as a square wave of 001000000001. The above-mentioned bit intervals may be defined as the clock frequency of the unique signal.

Such a unique signal is repeated several to several hundred cycles in consideration of occurrence of an error due to a defect or the like. By defining a signal that follows the unique signal, which can also be referred to as the pull-in signal, after a certain period of time as a copy protection signal, the recording device side (secondary software creation side) can reliably receive the copy protection signal.

The reason why the luminance is set to 15% to 70% or more as described above is to ensure that a unique signal can be detected regardless of whether the copy environment is dark or bright. At this time, the unique signal 2 is set according to the luminance level of the primary content image.
It is also possible to control the unique signal 200 so as not to be perceived by the human eye on a dark screen by changing the luminance level of 00 to 15% to 70%.

As described above, if the unique signal is used, the copy protection signal that comes after that can be used as necessary,
opy never once copy, no mo
copy, copy free, etc. [(1, 1),
(1, 0), (0, 1), (0, 0), etc.], and the convenience is improved.

As in the case of the unique signal, the copy protection signal is repeated several to several hundred cycles in consideration of the defect error. The rules for repeating the unique signal + copy protection signal sequence between frames are based on the rules described in the previous embodiment. Needless to say, in order to ensure the copy protection of the information signal reproduced at the fast-forward and the slow-forward reproduction, it is desired that a copy apparatus corresponding to the frequency change of the unique signal and the copy protection signal within one frame and between frames is desired. .

According to the present embodiment, since the unique signal 300 is added before (or after) the copy protection signal 200 in time, a video reproducing device or the like detects the unique signal 300 and then adds it. The subsequent copy protection signal 200 can be reliably extracted and the copy protection processing can be performed. In addition, since the extraction of the copy protection signal 200 is ensured by the unique signal 300, the copy protection signal 200 can be defined as a signal convenient for copy generation management.

The copy protection method according to the present invention is completely different from a conventional copy protection method such as a macro vision method, and it is of course possible to use both together.

The copy protection method according to the present invention can be applied to the analog transmission / reception method and the digital transmission / reception method in a form corresponding to each method. Further, the NTSC, PAL, Hi- v
Depending on the video signal system of the primary software and the other, the frequency of the copy protection signal photographed by the secondary software and the like are different from each other, but if a standard suitable for various signal systems is determined, It goes without saying that compatibility can be obtained between all devices in a form that suits the purpose.

In the above embodiment, the device configuration is changed to
Although described as the video camera 7, the tape 8, and the recording device 9, these may be replaced with a monitor of a personal computer, a digital video camera, digital media such as a smart card, a personal computer, and the like. In short, the copy protection method according to the present invention covers all kinds of video / audio contents provided to a person who is a viewer.

As described above, the range of the source content is not limited to package software, but can be applied to network-type software such as live broadcasting of entertainment and sports.

Although the embodiment in which the copy protection method according to the present invention is applied to a video image has been described above, the present invention can be similarly applied to an audio field represented by a music CD or the like.

That is, in order to prevent copying of a music CD or the like, a high-frequency sound or a low-frequency sound that is not perceivable by a human ear (below a human perception threshold) is superimposed on a sound output from a speaker as a copy protection signal. By causing only the recording device to recognize the copy protection signal, the object according to the present invention can be achieved.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the embodiments, and various improvements and modifications may be made without departing from the gist of the present invention. .

Therefore, the present invention should be limited only by the matters specifying the invention according to the claims that are reasonable from this disclosure.

[0055]

According to the copy protection method of the present invention, it is possible to prohibit a duplication action such as taking a video or a video (primary software) as it is projected on a screen with a video camera, or It is possible to prohibit the reproduction and use of the secondary software created by such copying, and to surely prevent unauthorized copying of copyrighted works such as video software and music CDs.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a copy protection method according to the present invention.

FIG. 2 is an explanatory diagram for explaining frame processing 3 in FIG. 1;

FIG. 3 is an explanatory diagram for explaining a conventional copy protection method.

FIG. 4 is a waveform diagram showing an example of a copy protection signal according to another embodiment of the copy protection method of the present invention.

FIG. 5 is a flowchart showing a procedure up to the start of copy protection processing when a unique signal example is added.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Original picture software 2 ... Copy protection timing generator 3 ... Frame processing 4 ... Frame processed original picture software 5 ... Receiver 6 ... Human eyes 7 ... Recording equipment 8 ... Recording tape 9 ... Reproduction equipment 10-16 ... Frame Image 21: Frame image with copy protection signal

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Claims (3)

[Claims] 1. When a copyrighted work of video information and audio information is copied without permission, the copied video information copied without permission is reproduced and displayed on a screen, or the copied audio information copied without permission is reproduced. A copy protection method in which copy protection information is inserted and recorded in advance in each signal of the video information and the audio information so that it is possible to detect that copying has been performed without permission only by emitting sound. The insertion period of the copy protection information inserted in the signal is a maximum of 1/30 second, and the insertion cycle of the copy protection information inserted in the video information signal is 1 second to 60 seconds. The frequency of the audio signal, which is the copy protection information inserted into the audio information signal, is 18 kHz to 20 kHz, or 1 kHz.
A copy protection method, wherein the frequency is 0 Hz to 50 Hz, and the audio signal is inserted into the audio information signal continuously or intermittently at predetermined intervals. 2. The copy protection method according to claim 1, wherein the unique signal is added before or after the insertion period of the copy protection information. 3. The copy protection method according to claim 2, wherein a luminance level of said unique information is changed according to a luminance level of said video signal to be protected.