KR100349190B1 - Subliminal message protection - Google Patents

Abstract

The present invention relates to a method and system for detecting a first context change between two frames. If a second context change between two other frames occurs within a prescribed time interval, the frames included in the two context changes are defined as subliminal messages. Alerts the viewer when a subliminal message is detected.

Description

Method and system for protecting against subliminal message {SUBLIMINAL MESSAGE PROTECTION}

The subliminal message is a message transmitted so that the viewer cannot consciously discover it. Subliminal messages are lurking allusions that can only be perceived by the subconscious. In video cummunication, the subliminal message passes so quickly that the viewer cannot recognize that he or she has seen the message. Nevertheless, the content of the message can affect the viewer. For example, consider the case of a subliminal advertisement sent while the viewer is investigating recently broadcasted news from the stock market. The advertisement may inform the viewer that the ACME chocolate is delicious, but it passes so quickly that the viewer does not recognize that the advertisement has been viewed. However, some viewers may be subconsciously influenced by commercials, and may later feel an unexplained admiration for ACME chocolate.

Terrestrial transmission of television channels is prevented in this form of advertising through ethical and legal constraints. However, international satellite television channels that do not follow local laws and regulations cannot reliably prevent the transmission of subliminal messages. In modern communications such as the Internet and video phones, it is more difficult to protect the viewer from the message.

Subliminal messages may be hidden within the video sequence, as well as still images or what viewers consider to be still images, and audio sequences.

Two mutually consecutive images in the image sequence are not strictly identical. The basic concept of mediation movement (movement) using multiple mutually continuous images is that each image is slightly different from the preceding image. If the image appears rapidly, because the eye has some inertia, the image is perceived as motion by the eye and not felt as an indication for each image. In many cases, only a small portion of the image frame is involved in the actual movement; In this regard, we can compare people walking against a stationary background. This feature is used for various types of video sequence compression such as MPEG2. MPEG2 saves the space of an image sequence by transmitting coarse information describing, among other things, the pixels to be changed. However, this in turn introduces errors into the image sequence, which necessitates synchronizing the image at regular intervals. This consists of a so-called I-picture, containing all the information needed to compile a complete picture.

The image sequence may also include a row of different frames to transmit the video in the most efficient way possible. A frame contains image information represented on a medium with as many frames as possible, to form an image or picture. For example, an interlaced image consists of two frames. The term frame is used in the same sense throughout the specification. The frame means information used to compile an image. The frame itself may be a complete image, only a portion of the image, or may include information from which the image can be calculated. An I-frame is a complete frame containing image information. Since I-frames contain a significant amount of information, it is expensive to transmit them. The new P-frame may be formed from an I-frame or a P-frame. The P-frame (prediction frame) is formed by conveying the motion vector on the receiver side and DFD (Displaced Frame Difference) related to the preceding frame. The motion vector describes how the objects of the preceding frame move to form the P-frame. When a new P-frame is formed, an error occurs, for example, due to rounding-up (cut off). DFD describes how the calculated P-frame differs from the original picture. The difference between the calculated value of each pixel in the frame and the value of each pixel in the original frame can be calculated for the black-white frame. A color frame using RGB (red, green, blue) may be converted into a form in which one part is composed of a light emitter. In this case, the light emitting portion can be used to calculate the DFD. P-frames are more cost effective than I-frames. This is because the motion vector plus DFD contains much less information than the corresponding I-frame can contain. Also included are B-frames calculated from preceding and trailing P-frames.

The expression subliminal message is also used to describe a code in which multiple encrypted messages are encoded within the same symbol set. This has nothing to do with the invention.

U. S. Patent No. 5,151, 788 describes a system for detecting advertisements in a video signal by detecting blank (blank) images and deleting the advertisements from the video signal. The concept of this solution cannot be applied to a subliminal message, since there is usually no blank image before the subliminal message.

French Patent No. 2,622,077 describes a system for detecting discontinuities between images by line-by-line analysis of an analog video signal. This concept is not applicable to the present invention because, when considered on a row basis, the subliminal message cannot be distinguished from other signals.

The present invention relates to a system and method for protecting a viewer from subliminal messages.

1 is a schematic diagram of one embodiment according to the present invention;

2 is a flow chart illustrating one embodiment of the present invention.

3 is a flow chart illustrating another embodiment of the present invention.

4 is a flow chart illustrating detection of a context change in accordance with one embodiment of the present invention.

5 is a flow chart illustrating detection of a context change, in accordance with another embodiment of the present invention.

6 is a flow chart illustrating detection of a context change, in accordance with another embodiment of the present invention.

7 is a flowchart illustrating detection of a subliminal message.

8 is a diagram illustrating a subliminal protection module.

The present invention addresses the above-mentioned problems by detecting the subliminal message and alerting the viewer to the existence of the subliminal message.

Accordingly, it is an object of the present invention to protect viewers from subliminal messages.

The above-mentioned problem is solved by the present invention by detecting the subliminal message, warning the viewer of the existence of the subliminal message, and also detecting the context change between two frames.

In more detail, a first context change between two frames is detected. If a second context change occurs between two other frames within a prescribed time interval, the frames included in the two context changes are defined as subliminal messages. If a subliminal message is detected, an alert is sent to the viewer.

A context change is a major change in the context of a frame, for example a scene change.

The frame point may be referred to as a value of a point in the image that compiles the image along with other frame points.

The present invention provides the advantage of being able to detect and store subliminal messages for later analysis.

Another advantage of the present invention is that in the presence of a subliminal message it is possible to protect the viewer from it and to provide its alert.

The invention is explained in more detail below with reference to the preferred embodiments in conjunction with the accompanying drawings.

1 is a schematic diagram of one embodiment of the present invention. Reference numeral 101 denotes a viewer watching a movie on the television 102. Although the terms film and television have been used to describe this embodiment, terms of equivalent meaning, such as MPGE-sequence and data terminals, may be used instead. Reference numeral 111 denotes a frame sequence transmitted from the source 110 to the television 102. The sequence 111 of frames arrives at the television 102 via an SMP-Subliminal Message Protection 112. Optionally, the SMP-module may be integrated with a video decoder. Source 110 may be, for example, a cable-TV provider, a service provider (SP), or a computer connected to the Internet or an intranet. 1 shows a portion of frame sequence 111, where reference numeral 103 denotes a frame within a normal sequence. Also, reference numeral 104 is a frame in a regular sequence that, in the case illustrated, even if frame 104 constitutes the last frame that occurs in the normal sequence prior to the occurrence of context change 105. Indicates. The context change is a major change in the content of the frame, for example, a scene change. The context change 105 precedes the series of frames that together make up the subliminal message 106. Subliminal message 106 may consist of only one frame or several mutually consecutive frames. Reference numeral 107 denotes a context change that terminates the subliminal message and also reappears a regular frame sequence. Reference numeral 108 denotes the first frame in the normal frame sequence, while reference numeral 109 denotes the frame following. SMP-module 112 detects context changes 105 and 107. As soon as the context changes 105 and 107 occur within a defined time interval, an alert is generated and the subliminal message 106 can also be stored and played back by the viewer 101.

2 is a flow chart illustrating one embodiment of the present invention. Reference numeral 205 denotes a frame sequence. Reference numeral CC1 denotes a context change between the frame forming the normal frame sequence N and the subliminal message S. Reference numeral CC2 denotes a context change between the subliminal message S and the normal frame sequence N. According to box 201, a context change is detected by comparing each frame reaching the SMP module (not shown) with the frame finally arriving. Store the time when the two last context changes occurred. The time difference between the two last context changes that occurred is calculated according to box 202. If the time difference is less than the threshold value Ts, the user alert 203 is triggered according to the box 204 to freeze the image. The viewer can then check whether he has received the subliminal message, and if so, check the nature of the message.

3 is a flowchart illustrating another embodiment of the present invention. Reference numeral 301 denotes a frame sequence reaching an SMP module (not shown). Reference numeral CC1 denotes a context change in the frame sequence. Reference numeral N1 denotes the last frame in the normal frame sequence, while reference numeral S1 denotes the first frame in the subliminal message. Reference numeral S2 denotes the last frame in the subliminal message and reference numeral CC2 denotes the context change between S2 and N2, where N2 denotes the first frame in the regular sequence after the context change (CC2). The SMP-module (not shown) functions to detect a context change, and the time at which this change occurs is stored with the frames N1, N2, S1 and S2 according to the box 302. If the time difference between the last two context changes CC1 and CC2 is less than the given threshold Ts (box 303), then a preliminary alert is triggered according to box 304, e.g. the subliminal message source and the message arrival time. Related data such as is logged. Then test whether there is a context change between frames N1 and N2. If there is no context change between the frames, an alert is triggered (box 306) and the frame sequence is stopped (box 307). From now on, viewers can consciously evaluate the context changes that have occurred through freeze frames and subsequent logging operations.

As in the case of a scene change, the case where the entire frame has been completely changed can be delivered in the I-frame of the frame sequence. When transmission of the subliminal message is started, a scene change occurs that causes most of the frames to change between two mutually consecutive frames. Thus, a context change may occur when the receiver receives an I-frame. If two I-frames are received in succession within a short time interval, it can be considered that the subliminal message is transmitted.

4 is a flow chart illustrating detecting a change with the aid of an I-frame in an MPEG-sequence. Reference numeral 401 denotes a frame sequence reaching an SMP module (not shown). The SMP-Unit receives the frame (box 402) and checks whether the received frame is an I-frame (box 403). Receipt of an I-frame indicates a context change (box 404).

5 is a flow chart illustrating detecting a context change by numerically calculating a change value between two frames. Reference numeral 501 denotes a frame sequence reaching an SMP-unit (not shown). SMP- unit (not shown) receives a frame (N _i) (box 502). The frame _Ni is stored in the memory L ₂ . Prior to this, the value of L ₂ is stored in memory L ₁ (box 503). Then, the difference value E between frames is calculated by adding up the energy measurements of the differences between the corresponding frame points in frames L ₁ and L ₂ (box 504). For example, this energy measurement can be x ² given by the equation

Where I _s is the value of frame point _s in frame L ₂ , and I ' _s is the value of frame point _s in frame L ₁ . According to each of boxes 505 and 506, a context change appears if E is greater than the threshold T _e .

As illustrated in FIG. 6, the context change between two P-frames can be detected by measuring energy in the DFD in a manner similar to that described above. In Fig. 6, reference numeral 601 denotes a frame sequence. An energy is calculated for each received DFD (box 602) (box 603). If the amount of energy contained by the DFD is greater than the threshold (box 604), this indicates that a context change has occurred (box 605).

The SMP may include a library function with data about known subliminal messages, as shown in FIG. Reference numeral 701 denotes a frame sequence. Each received frame (box 707) is compared to a frame stored in the library (box 704), and if there is sufficient similarity (box 704), a user alert is triggered (box 705). This comparison may be performed by filtering each frame to represent a number of characteristic features. The characteristic characteristic is then compared with the characteristic stored in the library function. One advantage of this procedure is that computer power and memory space are saved.

8 illustrates in more detail the SMP-module 802 connected to the monitor 801. The frame sequence arrives at the SMP-unit 803. The frame passes through a system 807 that functions to detect context changes. System 807 includes a portion 804 for measuring the energy content of the frame, a portion 808 for comparing the energy value with a threshold, and a portion for initiating an alert. The SMP also includes means 806 for storing a stream or sequence of frames.

It is to be understood that the invention is not limited to the exemplary embodiments described and described above, but that modifications are possible within the scope of the following claims.

Claims (21)

A method of distinguishing a message of a sequence of a frame in which a first context change between a first frame and a second frame is detected and including image information, the method comprising: Detecting a second context change between the third frame and the fourth frame; Comparing the time interval between the first context change and the second context change with the first threshold value, And displaying the message in accordance with the comparison. The method of claim 1, wherein the data related to the first context change and the second context change and data related to the source of the frame sequence are stored in a memory. The method of claim 1, wherein the second message is displayed according to whether a third context change between the first frame and the fourth frame is detected. The method of claim 1, wherein the first context change is detected by measuring an energy difference between the first frame and the second frame. The method of claim 1, wherein the second context change is detected by measuring an energy difference between the second frame and the third frame. The method according to claim 4 or 5, wherein for each frame point, a difference between the value of the frame point of the first frame and the value of the corresponding frame point of the second frame is calculated, and the square of the calculated difference value is calculated. Calculating energy by measuring a sum of square values calculated for all frame points, thereby measuring energy. The frame of claim 1, wherein the first context change is detected by measuring an energy of a first displacement frame difference DFD and calculating a second frame from the first frame using the measured energy. How to distinguish messages in a sequence. The frame of claim 1, wherein the second context change is detected by measuring energy of a second displacement frame difference DFD and calculating a fourth frame from a third frame using the measured energy. How to distinguish messages in a sequence. 8. The method of claim 7, wherein the energy of the displacement frame difference is compared with a second threshold to indicate a context change in accordance with the comparison. 9. The method of claim 8, wherein the energy of the displacement frame difference is compared with the second threshold value to indicate a context change in accordance with the comparison. The energy of the displacement frame difference (DFD) according to any one of claims 7 to 10, wherein the square of the value of each frame point in the displacement frame difference is calculated to obtain a sum of the calculated values for all frame points. Method for measuring the. The energy of the displacement frame difference (DFD) according to any one of claims 7 to 10, wherein the absolute value of the value of each frame point in the displacement frame difference is calculated and the sum of the calculated values for all frame points is obtained. Message discrimination method of the frame sequence, characterized in that for measuring. The method of claim 1, wherein the first context change is indicated when an I-frame is detected in the MPEG stream. The method of claim 1, wherein the second context change is indicated when an I-frame is detected in the MPEG stream. The method of claim 1, wherein the second frame is compared with the fifth frame stored in the frame library, and the first message is displayed according to the comparison. The method of claim 2, wherein the frame sequence between the first context change and the second context change is stored in the memory. 17. The method of claim 2 or 16, wherein a user can examine the contents of the memory. The method of claim 1, wherein the second frame and the third frame are one and the same frame. A system for automatic detection of subliminal messages in a frame sequence, comprising means 807 for detecting a context change between two frames of a frame sequence, means for alerting 805, and means for storing the frame sequence. Means for calculating the time difference between two context changes, Means for comparing the measured time difference with one threshold value, And a means for issuing an alarm according to the comparison result. delete delete