JP3940453B2 - Apparatus for adding identification information of moving image data - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention adds identification information for identifying the corresponding moving image data to the moving image data.Apparatus for adding identification information of moving image dataAbout.
[0002]
[Prior art]
Copying various moving images such as movies and game software without the permission of the copyright holder is prohibited by the Copyright Act. In order to detect unauthorized copying performed without permission, it is important to specify the copy source of the illegally copied moving image.
[0003]
In order to specify the copy source of the illegally copied moving image, an identification number as identification information for specifying the corresponding moving image is added to each video tape or disk shipped from the factory.
[0004]
Specifically, for example, in an analog video tape, an identification number is given by the following method.
(1) In the video signal, a signal indicating an identification number is inserted at a time position that does not appear on the TV screen such as a vertical regression time indicating a period during which the scanning line returns from the lowest position to the highest position on the screen.
(2) An identification number is actually displayed at, for example, a corner on the TV screen.
[0005]
[Problems to be solved by the invention]
However, in the method of adding an identification signal to the vertical regression time as described above, since this vertical regression time is originally a no-signal period, it is possible to delete the identification signal using a time gate circuit or the like. Therefore, a malicious third party can easily delete this identification number.
[0006]
When the identification number is actually written on the TV screen, if the signal of the identification number portion in the video signal is deleted, the original image of the background portion of the identification number is also deleted at the same time, and the identification number portion is blank. It becomes. For this reason, it is difficult to delete the merchandise value because it decreases the commercial value. However, since the identification number is always displayed on the screen for those who have obtained it through the regular route, it is an obstacle to see the video.
[0007]
In recent years, in order to protect copyrights, protect pay information from third parties, and the like, techniques have been developed to scramble and transmit digital moving image data.
Furthermore, in order to efficiently transmit moving image data including an enormous amount of information, a technique for compressing and transmitting the moving image data has been developed.
[0008]
Development of an identification number assigning method and an additional apparatus that cannot be easily removed by a third party is also eagerly desired for digital moving image data that has been subjected to scramble processing or image compression processing.
[0009]
  The present invention has been made in view of such circumstances, and the added identification information cannot be seen only by the observer's normal attention and can be easily removed even if advanced digital technology is used. Add unidentifiable identification information to video dataApparatus for adding identification information of moving image dataThe purpose is to provide.
[0012]
[Means for Solving the Problems]
  In order to solve the above problems, the present inventionIn a moving image data identification information adding apparatus for adding identification information for identifying corresponding moving image data to moving image data composed of a plurality of consecutive image frames, the data of each position in the frame of each image frame Means for obtaining each difference value for data at the same position with an adjacent image frame; means for obtaining a position where the maximum difference value of each difference value in the frame is obtained; and predetermined image frame intervals in a plurality of image frames Means for writing identification information to the position where the maximum difference value is obtained in each image frame.
[0013]
  In such a configurationHumanIdentification information is added to the image frame at intervals that cannot be captured visually.It is. And thatThe position in the added frame is the position where the movement is most intense. Therefore, the position where the identification information is added changes in synchronization with the movement of the display image.Become difficult.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below with reference to the drawings.
    (First embodiment)
  Figure 1According to the first embodiment of the present inventionIt is a block diagram which shows schematic structure of the identification information addition apparatus of moving image data.
[0028]
The digital moving image data a input from the input terminal 1 and displayed on, for example, a normal TV receiver includes 30 image frames per second. Each image frame 11 shown in FIG. 2 constituting the digital moving image data a is written into the image storage memory 2 in synchronization with the clock signal CK input from the clock terminal 7.
[0029]
The image storage memory 2 stores data for one image frame to be displayed on the TV screen. Data for each image frame stored in the image storage memory 2 is sequentially read out by the image reading unit 8 in synchronization with the clock signal CK and output from the output terminal 9. The output terminal 10 has a vertical synchronizing signal V of the moving image data a input from the synchronizing signal terminal 5._S Is output as is.
[0030]
The vertical synchronizing signal V input from the synchronizing signal terminal 5_S Is output to the output terminal 10 as it is and also input to the counter 6. This counter 6 has a vertical synchronizing signal V_S The write command signal w is sent to the write timing control unit 4 every time it reaches 30, for example. For example, a 4-digit (16-bit configuration) identification number as identification information input from the input terminal 3 is input and stored in the write timing control unit 4.
[0031]
Then, each time the write command signal w is input, the write timing control unit 4 assigns a four-digit identification number stored and held in advance in a frame in one image frame 11 of the video storage memory 2. The identification number 12 is written in the address position corresponding to the specified position. That is, the image data stored and held at the same address position is overwritten.
[0032]
In the moving image data identification information adding apparatus of the first embodiment configured as described above, moving image data a composed of a plurality of continuous image frames 11 as shown in FIG. Each image frame 11 is once written in the image storage memory 2, read by the image reading unit 8, and output to the output terminal 9.
[0033]
At the timing when each image frame 11 is once written in the image storage memory 2, the identification number 12 is written at a specific position of the frame for every 30 image frames 11. As a result, the image frame 11 in which the identification number 12 is written is mixed in every 30 frames of the plurality of image frames 11 sequentially output from the output terminal 9.
[0034]
Since the identification number 12 that appears at a rate of 1 in 30 sheets, that is, 0.03 seconds, cannot be identified to the extent that a person is paying normal attention, the identification number 12 is uncomfortable for the viewer. Absent.
[0035]
Further, since the identification number 12 is directly overwritten on the image, it is very difficult to completely remove only the identification number 12 even if the digital processing technique is used.
[0036]
Therefore, the identification number 12 that cannot be easily deleted without causing discomfort to the viewer can be added to the moving image data.
(Second Embodiment)
FIG. 3 is a block diagram showing a schematic configuration of a moving image data identification information adding apparatus according to the second embodiment of the present invention. The same parts as those in the first embodiment shown in FIG. Therefore, the detailed description of the overlapping part is omitted.
[0037]
Digital moving image data a in a compressed state inputted from the input terminal 1₁ Is demodulated by the decompression unit (decoder) 13 into normal moving image data a composed of a plurality of original continuous image frames 11. Each image frame 11 of the demodulated moving image data a is sequentially written into the image storage memory 2 in synchronization with the clock signal CK input from the clock terminal 7 one by one. The data for each image frame stored in the image storage memory 2 is sequentially read out by the image reading unit 8 in synchronization with the clock signal CK and output from the output terminal 9.
[0038]
In general, moving image data a composed of a plurality of image frames 11 is compressed by, for example, MPEG (Moving Picture Experts Group) method.₁ In the image frame, a reference I image frame for every fixed number of the plurality of image frames 11, a P image frame obtained by performing prediction from the I image frame or another P image frame, and the passage of time A B image frame obtained by performing bidirectional prediction in the direction or in the reverse direction of the elapsed direction is included.
[0039]
Of these three types of image frames, for example, the data of the P image frame includes only the difference value ΔD from the previous I image frame or another P image frame. The decompression unit 13 inputs the compressed moving image data a₁ And the difference value ΔD of each position on one frame is sent to the next maximum movement position detection unit 14. Further, the decompression unit 13 receives the compressed moving image data a₁ To vertical sync signal V_S Is extracted and sent to the maximum movement position detector 14 and the counter 6.
[0040]
The maximum movement position detection unit 14 generates a vertical synchronization signal V_S Is input to the next writing unit 15 by detecting the position where the maximum difference value ΔDmax of one frame is obtained.
Further, the counter 6 has a vertical synchronization signal V_S The write command signal w is sent to the write unit 15 and the write timing control unit 4 every time it reaches 30, for example. Each time the write command signal w is input, the write timing control unit 4 sends the 4-digit (16-bit) identification number inputted and stored from the input terminal 3 to the next write unit 15. .
[0041]
Each time the write command signal w is input from the counter 6, the writing unit 15 obtains the 4-digit identification number input from the write timing control unit 4 in the maximum in the frame in one image frame 11 of the video storage memory 2. A 4-digit (16-bit) identification number is written at an address position corresponding to the position input from the movement position detection unit 14. That is, the identification number is written at the position where the motion of the image is most intense in one frame (on one screen).
[0042]
In the moving image data identification information adding apparatus of the second embodiment configured as described above, as shown in FIG. 4, for example, the rear image frame 11b in the consecutive image frames 11a and 11b is identified as the 30th frame. In the case of the image frame 11b to which a number is to be added, the difference value ΔD at each position relative to the previous image frame 11a is calculated, and the position of the maximum difference value ΔDmax in the image frame 16 is determined.
[0043]
Next, the identification number 12a is written at the position of the maximum difference value ΔDmax in the image frame 11b. That is, since the identification number 12a is written at the position on the screen where the motion is most intense, the writing position of the identification number 12a changes according to the movement of the image on the screen, and the writing position cannot be specified in advance.
[0044]
The advantage of changing the writing position of the identification number 12a will be described with reference to FIG.
That is, in the case where the identification number 12 is written at the same position on the frame shown in FIG. 2, if a large number of consecutive image frames 11 are stacked, the identification number can be visually confirmed when the number of overlapping images increases. There is a concern.
[0045]
Further, if the difference value between the successive image frames 11 is taken, the difference value ΔD varies greatly between the positions as shown in FIG. On the screen with little movement, as shown in FIG. 5B, the variation of the difference value ΔD is small between the positions. Further, when the background is the same and the image is changed, the characteristics shown in FIG. 5C are obtained. Similarly, the characteristic (waveform) of the difference value ΔD near the position where the identification number 12 is written is the characteristic shown in FIG.
[0046]
Thus, the characteristic when the difference value ΔD between the image frames 11 is taken has a unique characteristic (waveform pattern) depending on the movement target. Therefore, the characteristics when the difference value ΔD between the image frames 11 is taken are classified, the characteristics shown in FIG. 5 (d) are extracted, the writing position of the identification number 12 is specified, It is possible to remove the identification number 12 by performing predetermined digital image processing on the corresponding part.
[0047]
In order to eliminate such inconvenience, in the second embodiment, the writing position of the identification number 12a is changed according to the movement of the image. Therefore, even if a statistical method as shown in FIGS. 3A to 3D is used, the writing position of the identification number 12a cannot be easily found, so that the identification number 12a is removed by a third party. Can be prevented more reliably.
[0048]
(Third embodiment)
FIG. 6 is a block diagram showing a schematic configuration of an apparatus for adding identification information of moving image data according to the third embodiment of the present invention.
[0049]
The apparatus for adding identification information of moving image data is roughly divided into a decoder chip 21 composed of one IC circuit element that cannot be separated, and an identification information composition composed of one IC circuit element that cannot be separated. It consists of a chip 22.
[0050]
Digital moving image data a which has been compressed and scrambled and input from the input terminal 23₂ Is input to the descrambling unit 24 in the decoder chip 21. The descrambling unit 24 uses the descrambling key 25 preset in the decoder chip 21 to input the moving image data a₂ Release the scrambled state of.
[0051]
The moving image data released from the scrambled state is input to the next decompression unit 26. The decompression unit 26 releases the compressed state of the moving image data from which the scrambled state has been released, and once demodulates it into normal moving image data a composed of a plurality of continuous image frames. The demodulated normal moving image data a is scrambled again by the re-scramble processing unit 27. The scrambled moving image data a_Three Is output from the decoder chip 21.
[0052]
Scrambled moving image data a output from the decoder chip 21_Three Is input to the next identification information synthesis chip 22. Moving image data a input to the identification information synthesis chip 22_Three Is input to the descrambling unit 29. The descrambling unit 29 uses the descrambling key 30 set in the identification information synthesis chip 22 to input the moving image data a_Three Release the scrambled state of. Further, the scramble release unit 29 receives the moving image data a_Three And the vertical synchronization signal V of the released moving image data a_S Is extracted and sent to the counter 32.
[0053]
The moving image data a released from the scrambled state is input to the first input terminal of the selection output circuit 31 and the identification information combining unit 33.
The counter 32 generates a vertical synchronization signal V_S The write command signal w is sent to the identification information synthesizing unit 33 every time it reaches 30, for example. The identification information synthesizing unit 33 outputs the 4-digit (16-bit) identification number set in the identification information setting unit 34 from the descrambling unit 29 every time the write command signal w is input. Write in a predetermined position of the image frame of the image data a. Therefore, the moving image data a output from the identification information combining unit 33_Four An image frame in which an identification number is written is mixed in every 30 of the plurality of image frames constituting the image.
[0054]
Moving image data a composed of a plurality of image frames in which identification numbers are written every 30 sheets_Four Is input to the second input terminal of the selection output circuit 31. In the normal state, the selection output circuit 31 has the moving image data a in which the identification number inputted to the second input terminal is written._Four Is selected and sent to the output terminal 36.
[0055]
When the selection output circuit 31 receives a selection signal of the moving image data a in which the identification number designating the password is not written from the selection instruction unit 35, the password is stored in advance in its own storage unit. Only when they coincide with each other, the moving image data a inputted to the first input terminal from the scramble release unit 29 is outputted to the output terminal 36.
[0056]
In the moving image data identification information adding apparatus according to the third embodiment configured as described above, the moving image data a that has been scrambled and compressed.₂ It is possible to effectively add identification information.
[0057]
As described above, when executing a process of adding an identification number to image frames at regular image frame intervals such as 30, it is necessary to release the scrambled state and then release the image compression state.
[0058]
In general, the decompression unit 26 that restores the compression state and the identification number combining unit 33 that adds an identification number are often configured by different devices. In such a system, the moving image data a in a state in which the scrambled state and the image compression state are released is easily captured by a third party in the process of being transmitted through the signal cable connecting both devices.
[0059]
In order to prevent such an unforeseen situation from occurring, the decoder chip 21 for canceling the image compression is composed of one IC circuit element that cannot be divided, and the decoder chip 21 is once scrambled. A scramble processing unit 27 that re-scrambles the released moving image data a is incorporated.
[0060]
As a result, the moving image data a in a state in which the scrambled state and the image compression state are released from the decoder chip 21 is prevented from being output.
Further, since the selection output circuit 31 is provided in the identification information synthesis chip 22, the original moving image data a to which the identification number is not added or the moving image data a to which the identification number is added as necessary._Four You can select and take out.
[0061]
In this case, since the password confirmation function is added to the selection output circuit 31, a person who does not know the password cannot take out the original moving image data a in which the identification number is not written to the output terminal 36. Therefore, the management regarding the copyright of the moving image data can be performed more strictly by the re-scramble process and the password confirmation process.
[0062]
(Fourth embodiment)
FIG. 7 is a block diagram showing a schematic configuration of an apparatus for adding identification information of moving image data according to the fourth embodiment of the present invention.
[0063]
Digital moving image data a composed of a plurality of continuous image frames input from the input terminal 41 is input to the reference image compression unit 42 and also input to the image compression unit 45 via the delay buffer 43.
[0064]
The reference image compression unit 42 compresses the moving image data a obtained by subjecting the digital moving image data a composed of a plurality of input image frames to image compression processing according to the above-described MPEG (Moving Picture Experts Group) method._Five Is output.
[0065]
As is well known, this moving image data a_Five Inside, a large number of GOPs (Grop of Picture), each of which is a group of a plurality of image frames, are arranged. The GOP is used as one unit for moving image data a_Five Random access in the quasi-direction and the reverse direction from any time position is possible.
[0066]
In each GOP, in order to ensure the independence of the GOP, an I image frame formed by only information of the reference image frame is used as a reference for each fixed number of the plurality of image frames. A P image frame obtained by predicting an image frame after a predetermined time from the I image frame or another P image frame with respect to the direction of time, and the time direction or the reverse of this direction. B image frames obtained by performing bidirectional prediction with respect to the direction are included.
[0067]
The moving image data a_Five For example, as shown in FIG. 8, the image frames of I, P, and B are arranged in the following order.
IBBBPBBBPPIBBBBBPBB ... (A)
In some cases, as shown in FIG.
IBBBBPBBPPIBBBBBPBPIBBBBBPBBP …… (B)
It may be arranged like this.
[0068]
In any case, the moving image data a_Five In, each image frame of I, P, and B is output in a pattern having a fixed period.
The output pattern extraction unit 46 outputs the moving image data a output from the reference image compression unit 42._Five 8 is extracted and temporarily stored in the output pattern memory 47 and sent to the specific pattern extraction unit 48. The output pattern P shown in FIG.
[0069]
The specific pattern extraction unit 48 extracts the specific unit pattern Q shown in FIG. 8 or 9 included in the output pattern P. For example, in the case of the output pattern P of (A) described above, the specific unit pattern Q is composed of the first three B image frames when three or more B image frames are continuous as shown in FIG. [BBB] pattern.
[0070]
Further, for example, in the case of the output pattern P of (B) described above, the specific unit pattern Q is the first four B image frames when four or more B image frames are continuous as shown in FIG. [BBBB] pattern configured as follows.
[0071]
As described above, the specific unit pattern Q may be selected and set as an easily distinguishable pattern that appears periodically according to the output pattern P of each of the I, P, and B image frames output from the reference image compression unit 42. .
[0072]
The specific unit patterns Q sequentially extracted by the specific pattern extraction unit 48 are input to the next pattern change unit 49. The pattern changing unit 49 supplies the identification information input unit 50 with the type of the B image frame of the specific position such as the second shown in FIG. 8 or the third shown in FIG. The type is changed to the type of P image frame according to each bit value constituting the identification number displayed by the set binary codes [1] and [0].
[0073]
For example, as shown in FIG. 8, when the bit of the identification number is [1], the second [B] of [BBB] of the specific unit pattern Q is changed to [P]. If the bit of the identification number is [0], the second [B] of [BBB] of the specific unit pattern Q is not changed.
[0074]
In this way, the type of image frame at a specific position in the specific unit pattern Q is sequentially changed. Therefore, for example, when the identification number is composed of 16 bits (4 digits), 16 specific unit patterns Q may be extracted and the type of image frame at a specific position of each specific unit pattern Q may be changed. .
[0075]
Each specific unit pattern Q whose image frame type is modulated (changed) by the identification number₁ Is written (overwritten) in the original output pattern P stored in the output pattern memory 47 by the changed output pattern creation unit 51. For example, the changed output pattern P shown in FIGS.₁ Is created.
[0076]
That is, this change output pattern P₁ Each specific unit pattern Q included in₁ The type of the image frame at the specific position remains [B] or changes to [P] according to the identification number.
[0077]
The change output pattern creation unit 51 creates the created change output pattern P₁ Is sent to the image compression unit 45. The image image compression unit 45 applies the change output pattern P to the moving image data a input from the input terminal 41 and delayed by the delay buffer 43.₁ Using the MPEG method, the compressed video data a₆ Is output to the output terminal 42.
[0078]
Moving image data a output from the image compression unit 45 to the output terminal 52₆ The I image frame, the P image frame, and the B image frame included in the image are changed output patterns P shown in FIG.₂ Are output sequentially in the array shown.
[0079]
Therefore, even if the same moving image data a is input, if a different identification number is set in the identification information input unit 59, the moving image data a to be finally output is displayed.₆ Output pattern P of I image frame, P image frame, and B image frame included in₁ The arrangement of is different.
[0080]
Then, the moving image data a₆ When checking the identification number added to the video data a₆ Output pattern P₁ (Changed output pattern) and moving image data a obtained by compressing the original original moving image data a by the reference image compression unit 42_Five The identification number can be easily detected by comparing the output pattern P.
[0081]
When the moving image data a is compressed using an I image frame, a P image frame, and a B image frame, if the basic framework such as the I image frame or the P image frame described above is satisfied, The pattern change to the extent that a part of the B image frame is changed to the P image frame is a sufficiently acceptable range if a slight change in image quality and compression rate is allowed, and there is no particular problem in practical use.
[0082]
In the moving image data identification information adding apparatus of the fourth embodiment configured as described above, the identification number is not directly written in each image frame constituting the moving image data a, but the moving image data a is stored in the moving image data a. Change output pattern P of three types of image frames, I image frame, P image frame, and B image frame, obtained when image compression is performed₁ Is incorporated into the array.
[0083]
The modified output pattern P once created by the image compression unit 45₁ In order to change the arrangement of the image frames of I and PB shown in FIG.₆ Video data a having another output pattern P using the image compression device again after the image is once decompressed using the decompression device and returned to the original plurality of image frames a.₆ Need to be compressed.
[0084]
In order to compress and decompress this moving image data, the amount of information to be handled becomes enormous, so a complicated hardware configuration and an enormous software configuration are required, and the identification number can be easily deleted or another identification can be made. It cannot be changed to a number.
[0085]
Therefore, it is possible to more strictly manage the protection of the moving image data against the copyright.
Furthermore, an identification number consisting of a plurality of bits may be added to the moving image data a at a constant cycle or continuously. In this way, even if the moving image data a₆ Even if only a part of the file is cut out and copied, that part always includes the identification number, and the copyright can be managed more strictly.
[0086]
(Fifth embodiment)
FIG. 10 is a block diagram showing a schematic configuration of a moving image data identification information adding apparatus according to the fifth embodiment of the present invention. The same parts as those in the fourth embodiment shown in FIG. Therefore, the detailed description of the overlapping part is omitted.
[0087]
In the moving image data identification information adding device of the fifth embodiment, a scramble processing unit 53 is interposed between the image compression unit 45 and the output terminal 52.
The scramble processing unit 53 is a compressed moving image data a output from the image compression unit 45.₆ A scramble process is performed on each of the I, P, and B image frames shown in FIGS.
[0088]
Therefore, the scrambled moving image data a₇ Even if it passes to a third party, since the third party cannot normally see the image itself, the safety of the moving image data a is further improved.
[0089]
The present invention is not limited to the above-described embodiments. For example, in each embodiment, the identification information is an identification number, but other than the number, a symbol or a character that can specify each moving image data a may be used.
[0090]
Further, in the first embodiment apparatus shown in FIG. 1, the description has been made on the assumption that the moving image data is digital data. In this case, a signal synthesis circuit may be provided instead of the image storage memory 2 to remove the signal reading unit 9 and the clock signal CK.
[0091]
【The invention's effect】
  As described above, in the moving image data identification information adding device according to the present invention, in a plurality of continuous image frames constituting moving image data.The writing position of the identification information is automatically set to the position where the difference value with respect to the same position between adjacent image frames is the largest.
[0093]
Therefore, it is possible to add identification information to moving image data that cannot be easily removed even if advanced digital technology is used even if the observer does not see the added identification information only with normal attention. The copyright protection of image data can be managed more strictly.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a moving image data identification information adding apparatus according to a first embodiment of the present invention;
FIG. 2 is a view showing image frames constituting moving image data to which identification information is added by the moving image data identification information adding device;
FIG. 3 is a block diagram showing a schematic configuration of a moving image data identification information adding apparatus according to a second embodiment of the present invention.
FIG. 4 is a view showing image frames constituting moving image data to which identification information is added by the moving image data identification information adding device;
FIG. 5 is a schematic diagram showing characteristics of the identification information adding device for moving image data.
FIG. 6 is a block diagram showing a schematic configuration of a moving image data identification information adding apparatus according to a third embodiment of the present invention.
FIG. 7 is a block diagram showing a schematic configuration of a moving image data identification information adding apparatus according to a fourth embodiment of the present invention.
FIG. 8 is a diagram showing a correlation between an output pattern, an identification number, and a change output pattern obtained by the apparatus for adding identification information of moving image data
FIG. 9 is a diagram showing the interrelationship between an output pattern, an identification number, and a change output pattern obtained by the identification information adding device for the same moving image data.
FIG. 10 is a block diagram showing a schematic configuration of a moving image data identification information adding apparatus according to a fifth embodiment of the present invention.
[Explanation of symbols]
2. Image storage memory
3. Image reading unit
4. Read timing control unit
6, 32 ... Counter
11, 11a, 11b ... image frames
12, 12a ... identification number
13, 26 ... compression release part
14: Maximum movement position detector
21: Decoder chip
22 ... Identification information synthesis chip
24, 29 ... descrambling part
25, 30 ... descrambling key
27. Re-scramble processing unit
31 ... Selection output circuit
33 ... Identification information composition unit
42. Reference image compression unit
45. Image compression unit
46: Output pattern extraction unit
48 ... Specific bartan extraction unit
49 ... Pattern changing section
51. Change pattern creation section

Claims (1)

In a moving image data identification information adding device for adding identification information for identifying corresponding moving image data to moving image data composed of a plurality of continuous image frames,
Means for obtaining each difference value for the data at the same position as the adjacent image frame of the data at each position in the frame of each image frame;
Means for obtaining a position where the maximum difference value among the difference values in the frame is obtained;
An apparatus for adding identification information of moving image data, comprising: means for writing the identification information at a position where the maximum difference value is obtained in an image frame for each predetermined image frame interval in the plurality of image frames.

Images