JPH08181967A - Scrambler and descrambler - Google Patents

Abstract

PURPOSE: To scramble video images without causing deterioration onto a reproduced video image by using sets of blocks and sets of scanning lines as line blocks and rearranging the position of the line blocks so as to connect the blocks to a digital video transmission system compressing data in the unit of blocks via an analog IF. CONSTITUTION: In the case of processing one frame of a video signal whose one frame is made up of 48 scanning lines and whose scanning line is made up of 72 picture elements, line blocks 801-806 are respectively made up of 8 scanning lines. At first the scrambler rearranges the position of the line blocks 801-806 in a frame with respect to an original image (b). The rearrangement is conducted based on control of a PN (pseudo random number). The scrambled image is subject to compression processing in the unit of blocks and then subject to expansion processing after that (c). Finally the descrambler rearranges the line blocks 801-806 by using the same PN control as that of the scramble processing with respect to the image after expansion processing (d).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for secret communication in a video transmission system for transmitting / receiving or recording / reproducing by wire, wireless or storage media after compressing the data amount of a video signal by compression processing. The present invention relates to a scramble device and a descramble device.

[0002]

2. Description of the Related Art A conventional scrambler and descrambler is disclosed in US Pat. No. 5,208,857: "Met.
hod and Device foe Scrambling-unscrambling Digital
ImageData "by Telediffusion de France". A conventional scramble device is used in a digital video transmission system in which a video signal is subjected to compression processing by DCT (discrete cosine transform) and then transmitted.

First, the principle of compression processing will be described.
The compression process realizes the reduction of the amount of transmission data by utilizing the high correlation between neighboring pixel signals in the video data. In DCT, one screen is divided into DCT blocks composed of a plurality of pixels, and the correlation between pixel signals is high in each DCT block, and when converted into frequency components, most of them become DC components and low frequency components. This property is basically used. That is, after conversion into frequency components, the DC component of the data of each frequency component gives many bits, and the AC component realizes compression by reducing the number of bits given to the higher frequency components.

When a plurality of video signals are compressed by the same compression processing, the degree to which they can be compressed depends on the nature of the video signals. That is, the DCT having a high correlation between pixel signals
As for the block, the high frequency component of the converted data becomes small, and as a result of the compression processing, the data can be represented by a small number of bits. The fact that the data can be represented with a small number of bits by the compression process is called high compression efficiency. On the contrary, for a DCT block in which the correlation between pixel signals is low, the high frequency component of the converted data becomes large,
As a result of the compression process, many bits are required to represent the data. The compression process requires a large number of bits to represent the data, which means that the compression efficiency is low.

Next, the operation of the conventional scrambler will be described. FIG. 15 is a schematic diagram used for explaining the operation of the scramble device of the conventional example. FIG. 15A shows one frame of the original image before scramble, and FIG.
Represents one frame of the scrambled image generated from the original image by the conventional scrambler. Further, in FIGS. 15A and 15B, each of the squares with letters A to L indicates one DCT block. The outline of the scramble process will be described below with reference to FIG.

The scrambler inputs the original image shown in FIG. 15 (a), swaps the positions of its DCT blocks, generates the scrambled image shown in FIG. 15 (b) as a result, and after scrambling Output. For example, DCT block A is moved to the place where DCT block F was by scrambling. Further, the descrambling device performs the inverse conversion of the replacement process performed by the scramble device. That is, FIG.
Conversion from (b) to FIG. 15 (a) is performed.

When the correlation between the pixel signals in the DCT block is destroyed by scrambling, the compression efficiency is lower than that of the video signal before being scrambled. Usually, there is an upper limit to the amount of data (transmission rate) after compression, and if it exceeds that, data is truncated. Therefore, in the DCT block with reduced compression efficiency, more data is truncated, and as a result, the reproduced image deteriorates.

Therefore, according to the conventional scrambler, the signal of each DCT block does not change. Therefore, as long as the conventional scrambler and the digital video transmission system accompanied by the compression process are connected by the digital IF, the signal in the DCT block is not changed. It does not break the correlation between image signals and does not affect the compression efficiency. Therefore, the reproduced image can be agitated without deterioration.

[0009]

However, the above-mentioned conventional scrambler and descrambler have the first problem that the reproduced image is deteriorated through the analog IF. The reason for this will be described below.

In recent video equipment, an example in which a video signal is digitized inside to perform signal processing is increasing.
Most of the IFs between devices are analog signals. When a video signal is transmitted by such an analog IF, a discontinuous portion in the scanning line, that is, a portion having a sudden change in amplitude is filtered, and the change in amplitude is relaxed. Also, in the image as shown in FIG. 15B after being processed by the conventional scramble device,
A discontinuity that does not exist in the original image of FIG. 15A occurs at the boundary of the DCT block in the scanning line. Therefore, FIG.
When the image as shown in (b) is D / A converted and transmitted by the analog IF, the signal at the boundary portion of the DCT block changes,
DCT when returning to the original position by descrambling
It appears as a deterioration of the image at the boundary between blocks.

Further, the above-described conventional scrambler and descrambler have a second problem that a reproduced image is deteriorated when color difference frames for compression are filtered in the scanning line direction. It was The reason for this will be described below.

When a video signal composed of a luminance frame and a color difference frame is processed as a digital video signal, the color signal may be filtered in the scanning line direction in order to reduce the amount of data. Many. When such a color filter in the scanning line direction is applied to the image as shown in FIG. 15B after being processed by the conventional scrambler, the filtered signal generated by the filtering process across DCT blocks is deteriorated. It becomes a signal that did.

The present invention solves the above-mentioned problems, and can be connected via an analog IF to a digital video transmission system involving compression processing for performing compression in block units, and furthermore, a reproduced image does not deteriorate and a video image is generated. It is an object of the present invention to provide a scrambler and a descrambler that can stir the mixture.

[0014]

In order to achieve this object, a first invention is connected to a digital video transmission system in which compression processing is performed in block units, and the set of blocks and the set of scanning lines are lined. The scrambling device is characterized in that the positions of the line blocks are replaced by blocks.

A second invention is connected to a digital video transmission system in which compression processing is performed in block units, the set of blocks and the set of scanning lines are line blocks, and the position of the line block is the position of the first invention. It is a descrambling device that performs the reverse replacement of the scrambling device.

A third aspect of the present invention is connected to a digital video transmission system in which compression processing is performed in block units, and the set of blocks and the set of scanning lines are set as line blocks, and the positions of pixels in the line blocks are symmetrical. A scrambler and a descrambler which are characterized by moving.

A fourth aspect of the invention is connected to a digital video transmission system in which compression processing is performed in block units, and the set of blocks and the set of scanning lines are line blocks, and one or more of the line blocks are: A scrambler and a descrambler which perform level inversion on all pixel signals in a line block with an intermediate value of the dynamic range as a boundary.

A fifth aspect of the present invention is connected to a digital video transmission system in which a video signal composed of a luminance frame and a color difference frame is processed, and filtering in the scanning line direction for the color difference frame and compression processing in block units are performed. In the scrambler and the descrambler, the process of changing the position of the block is performed on the luminance frame, and the process is not performed on the color difference frame.

[0019]

According to the first aspect of the present invention, scrambling is realized by exchanging the positions of the line blocks with the above-mentioned configuration. As a result, the order of transmission of each scan line changes, but the signal of each scan line does not change. Therefore, no discontinuity that does not exist in the original image occurs within the scan line. Also,
The blocks of each compression process do not change at all due to scrambling. As a result, the reproduced image does not deteriorate due to scramble even when passing through the analog IF.

The second aspect of the present invention has the above-mentioned structure.
The original image can be restored from the image agitated by the scrambler according to the first invention. Also, the third
According to the invention described above, scrambling is realized by symmetrically moving the positions of the pixels in one or more line blocks with the above-described configuration. As a result, the order in which each pixel is transmitted is changed, the pixel signal itself does not change, and the adjacent pixels are also changed left and right or top and bottom, and the correlation between pixels does not change. Therefore, the correlation between pixels within each scan line and within each compression block does not change.
As a result, the reproduced image does not deteriorate due to the effect of scrambling even when passing through the analog IF. Furthermore, it can be used in combination with the scrambler and descrambler of the first invention.

According to the fourth aspect of the invention, according to the above construction,
The scrambling is realized by inverting the levels of all the pixels in the scanning lines in the one or more line blocks.
As a result, the level of all pixels in each scanning line is inverted, so that the difference between adjacent pixels is only reversed in sign, and discontinuity points and frequency components that are not in the original signal within the scanning line Does not happen. Further, since the correlation between pixels in the line block does not change, the correlation between pixels in all blocks of the compression process does not change. As a result, the reproduced image does not deteriorate due to the effect of scrambling even when passing through the analog IF. Further, the first invention and the second invention
And / or the scrambler and descrambler of the third invention.

According to the fifth aspect of the present invention, the transmission order of the blocks of the compression processing is changed only for the luminance frame, and nothing is processed for the color difference frame. Further, the signal of the block of each compression process does not change at all. As a result, even if the color difference frame of the scrambled video signal is filtered in the scanning line direction, the reproduced image is not deteriorated due to the influence of the scramble.

Further, according to the fifth aspect of the invention, according to the above configuration,
If there is a luminance frame, the contents of the video signal can be considerably recognized, but the contents of the video signal are hardly understood by the color difference frame alone. Therefore, it is difficult to guess the original image if only the luminance frame is processed.
Sufficient stirring results are obtained.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A scrambler and a descrambler according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the concept of this embodiment. FIG. 1 shows, as an example, a case where one frame of a video signal in which one frame consists of 48 scanning lines and each scanning line consists of 72 pixels is processed.

<a> FIG. 1A is an original image.
In (a), reference numerals 801 to 806 denote line blocks. Each of the line blocks 801 to 806 is composed of eight scanning lines.

<B> First, the scrambler of the first embodiment performs a process of replacing the positions of the line blocks in the frame on the original image. This processing is called line block replacement processing. FIG. 1B shows the scrambled image. The replacement of the line blocks is performed under the control of PN (pseudo random number). For example, in the case of the example in FIG. 1B, PNs 1 to 6 are generated as (2, 6, 5, 1, 4, 3), and the line block 801 has a second position and a line. Block 802
Are sequentially replaced, such as the sixth position.

<C> Next, compression processing is performed on the scrambled image in block units, and then decompression processing is performed. FIG. 1C is an image showing a block of compression processing. In the compression and decompression processing, each line block is divided into nine DCT blocks consisting of 8 scanning lines × 8 pixels as shown in the figure, and DCT and inverse DCT are performed for each DCT block.

<D> Finally, for the image after the expansion processing,
The descrambling device of the first embodiment performs a process of exchanging line blocks. FIG. 1D shows a descrambled image. This processing is realized by performing the line block replacement processing which is the reverse of the scrambling processing under the same PN control as used in the scrambling processing of <b>.

Next, specific configurations of the scrambler and the descrambler in the first embodiment of the present invention will be described with reference to the drawings. First, the scrambler and descrambler according to the first embodiment of the present invention will be described.
A scramble transmission system applied to a conventional digital video transmission system will be described. FIG. 2 shows a block diagram of the scramble transmission system in the first embodiment of the present invention.

In FIG. 2, 91 is a scrambler,
Reference numeral 92 is a digital video transmission system, 93 is a descrambler, and in the digital video transmission system 92, 921 is an A / D device, 922 is a compression device, and 923.
Is a transmission line, 924 is a decompression device, and 925 is a D / A device.

A portion surrounded by a broken line, excluding the scramble device 91 and the descramble device 93 from the scramble transmission device of the first embodiment shown in FIG. 2, becomes a conventional digital video transmission system 92. The operation of the digital video transmission system 92 is described in JP-A-6-24.
It is disclosed in Japanese Patent No. 5189. First, this operation will be briefly described.

First, the A / D device 921 inputs an analog video signal and converts it into a digital video signal. Here, the analog video signal is composed of a plurality of frames, each frame is composed of two fields, and is a standard television signal transmitted for each field. The generated digital video signal is a standard television signal in the component signal format composed of a plurality of frames. Here, there are a Y frame that represents luminance, a BY frame and an RY frame that represent color differences, and each frame consists of two fields. In FIG. 1, the number of scanning lines in one frame and the number of pixels in one scanning line of the digital video signal generated by the A / D device 921 are described here as 48 scanning lines × 72 pixels, but the number is not limited to this. However, any number such as 480 scanning lines × 720 pixels may be used. Further, the digital video signal to be generated is assumed to be a component type standard television signal composed of Y, RY and BY frames, but it may be any component type standard television signal composed of Y, U and V frames. The configuration of the TV signal is acceptable.

The compression device 922 is for performing a compression processing operation, and is a DC for performing data conversion in DCT block units.
The amount of data is reduced by T, and the resulting compressed video signal is output. The compression device 922 is not limited to the above configuration, and any configuration that performs compression processing in block units, such as DST (discrete sine transform) and variable length coding in block units, may be used. I don't mind.

The compressed video signal output from the compression device 922 is transmitted via the transmission line 923. Transmission line 923
May be a recording medium such as a magnetic tape, a magnetic disk or an optical disk, may be wireless via a terrestrial antenna or satellite, or may be a wire such as a copper wire, a coaxial cable or an optical fiber.

Next, the decompression device 924 performs a decompression operation and generates a digital video signal from the compressed video signal and outputs it. The decompression process in the decompression device 924 is a decompression process for the compression process performed in the compression device 922. Finally, the D / A device 925 is the expansion device 92.
The digital video signal output from 4 is input and converted into an analog video signal.

The scrambler 91 and the descrambler 93 input the same PN (pseudo-random number) and perform processing. As a method of transmitting the PN, the PN may be held in the device, may be transmitted using the transmission path 923 of the digital video transmission system, or may be transmitted by another medium such as an IC card. Any method may be used. Further, it is desirable that this PN is safely transmitted by a method using encryption as shown in Chapter 8 of "Encryption and Information Security" (published by Shokodo Publishing; Shigeo Tsujii et al.).

Next, the configuration of the scrambler 91 according to the first embodiment of the present invention will be described. FIG. 3 is a configuration diagram showing the configuration of the scrambler 91 of the first embodiment. In FIG. 3, 11 is an A / D device, 12 is a line block replacement device, 13 is a D / A device,
In the line block replacement device 12, 121 is a memory circuit and 122 is a read / write address generation circuit.
The operation of the scrambler configured as described above will be described below.

First, the A / D device 11 converts an analog video signal into a digital video signal. Next, the line block replacement device 12 inputs the PN and the digital video signal, and performs the line block replacement processing for switching the position of the line block of the video signal in the frame under the control of the PN as described in FIG. Finally, the read digital video signal is converted into an analog video signal by the D / A device 13. Line block replacement device 12
The operation of will be described in more detail.

The line block replacement device 12 records the input signal at the position designated by the write address of the memory circuit 121, and outputs the data at the position designated by the read address of the memory circuit 121. The memory circuit 121 is composed of two field memories, and the write address and the read address are output from the read / write address generation circuit 122. These write address and read address always specify different field memories. Further, when the data for one field, that is, all the data on the field memory has been designated, the write address and the read address designate different field memories. Further, the write address indicates the position to be moved by the line block replacement processing, and the read address sequentially indicates the position on the field. The read / write address generation circuit 122 outputs the write address and the read address.
Works.

According to the scrambler having the configuration as shown in FIG. 3, the line block replacement processing as described with reference to FIG. 1B can be realized. 4 is a block diagram of the descrambling device according to the first embodiment. The descrambler performs the inverse conversion of the scramble processing of the scrambler in the present embodiment. In FIG. 4, 11
Is an A / D device, 14 is a block replacement device, 121 is a memory device, 142 is a read / write address generation device, 13
Is a D / A device. The operation of the descrambling device will be described below.

In the descrambling device, the operations of the A / D device 11, the D / A device 13, and the memory device 121 are the same as those of the scramble device having the same reference numeral, and therefore the description thereof is omitted here. In addition, the operation of the memory read / write control device 142 is as follows.
It reverses the write address and read address output by. That is, the memory read / write control device 12
The write address output by 2 becomes the read address output by the memory read / write control device 142, and the read address output by the memory read / write control device 122 becomes the write address output by the memory read / write control device 142.

The descrambling device having the configuration shown in FIG. 4 can perform the inverse conversion of the scrambling device shown in FIG. Here, the configurations of the memory read / write control device 122 and the memory read / write control device 142 of the scramble device of the first embodiment are shown as above, but the write address and the read address of each of them are reversed. Is also good.

Here, the configurations of the scrambler and the descrambler of the first embodiment are shown in FIGS. 3 and 4, but this is an example, and the line block replacement as described with reference to FIG. 1 is performed. Any configuration may be used as long as it performs processing.

As described above, according to the scrambler of the first embodiment, the transmission order of the line blocks only changes. Here, since the line block is a set of scanning lines, the signal of each scanning line does not change. Therefore, there is no discontinuity in the scan line that is not in the original signal, and therefore no deterioration occurs when converted into an analog signal. Also, since all DCT blocks are completely included in any of the line blocks, the data in each DCT block does not change at all. Therefore, since the compression efficiency does not change due to the scramble, the reproduced image does not deteriorate due to the effect of the scramble.

As described above, according to the scrambler and the descrambler of the first embodiment of the present invention, the reproduced image is deteriorated when connected to the digital video transmission system in which the compression processing is performed through the analog IF. It is possible to configure a scrambler and a descrambler that can realize image agitation without performing the above.

Next, a scrambler and a descrambler according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a schematic diagram used to describe the second embodiment. In the description of the second embodiment, FIG. 1 used in the description of the first embodiment will be used. The second embodiment is
1 (a), 1 (c) and 1 (d) are common to the first embodiment, but FIG. 1 (b) is different and can be replaced by FIG. 5 (a). The difference will be mainly described below.

A case will be described below in which one frame of a video signal in which one frame consists of 48 scanning lines and each scanning line consists of 72 pixels is processed. <a> Same as Example 1. <B> The scrambler according to the second embodiment performs the scanning line reversal process, which is a process for changing the positions of the scanning lines included in the line block, on the original image. As a result,
The scrambled image of (a) is created. The scanning line inversion process will be described in more detail with reference to FIGS. FIG. 5B shows one line block of the original image, and reference numerals 701 to 708 denote scanning lines. FIG. 5C shows one line block on which the scanning line inversion processing has been performed. As shown in the figure, in the line block on which the scanning line inversion processing is performed, the order in which the scanning lines are lined upside down is reversed. To do. This scanning line inversion process is performed on the line block designated by PN. In the example of FIG. 5A, a 6-bit PN is generated as (0, 1, 0, 1, 0, 1), and the line block 80 has a PN of 1.
Scan line reverse processing is performed on 2, 804 and 806,
The line blocks are 822, 824, and 826.

<C> Same as in Example 1. <D> Finally, for the decompressed image, the descrambler according to the second embodiment performs the scan line inversion process on the scrambler according to the same PN instruction as used in the scrambler. Scan line inversion processing is performed on the block. As a result, the descrambled image shown in FIG. 1D is restored.

Next, specific configurations of the scrambler and the descrambler in the second embodiment of the present invention will be described with reference to the drawings. The description of the scramble transmission system in which the scramble apparatus and the descramble apparatus according to the second embodiment of the present invention are applied to the conventional digital video transmission system is described in the scramble transmission according to the first embodiment of the present invention shown in FIG. Since it is the same as the system, its explanation is omitted.

Next, the structure of the scrambler 91 according to the second embodiment of the present invention will be described. FIG. 6 is a block diagram showing the configuration of the scrambler of the second embodiment. In FIG. 6, 11 is an A / D device, 22 is a scanning line reversing device, and 13 is a D / A device.
In the figure, 221 is a memory circuit and 222 is a read / write address generation circuit. The operation of the scrambler configured as described above will be described below.

First, the A / D device 11 and the D / A device 1
With respect to No. 3, since the same operation as that of the device having the same reference numeral in the first embodiment is performed, the description thereof will be omitted. Scan line reversing device 22
Inputs PN and digital video signal, and
As described with reference to, the scan line inversion processing is performed on the line block selected by the PN, in which the order in which the scan lines are arranged in the line block is vertically inverted. Scan line reversing device 2
The operation of No. 2 will be described in more detail.

The scanning line reversing device 22 records the input signal at the position designated by the write address of the memory circuit 221, and outputs the data at the position designated by the read address of the memory circuit 221. Memory circuit 22
Reference numeral 1 is composed of two frame memories, and write address and read address are read / write address generation circuit 2
It is output from 22. These write address and read address always specify different frame memories.
Further, when one frame of data, that is, all the data on the frame memory has been designated, the write address and the read address designate different frame memories. Further, the write address indicates the position moved by the scanning line inversion process, and the read address sequentially indicates the position on each field of the frame. The read / write address generation circuit 222 operates so as to generate such a write address and a read address.

According to the scrambler having the configuration as shown in FIG. 6, the scanning line inversion processing as described with reference to FIGS. 1 and 5 can be realized. The descrambling device according to the second embodiment has exactly the same configuration and operation as the scrambling device according to the second embodiment shown in FIG.
According to this descrambling device, since the scanning line inversion processing is performed again for the line block that has been subjected to the scanning line inversion processing by the scramble device, the original position is restored.

Here, the configurations of the scrambler and the descrambler of the second embodiment are shown in FIG. 6, but this is only an example, and the scanning line inversion as described with reference to FIGS. 1 and 5 is performed. Any configuration may be used as long as it performs processing.

As described above, according to the scrambler of the second embodiment, the image is agitated by vertically reversing the order of arrangement of the scanning lines in the line block selected by PN. According to this, only the order of transmission of the scanning lines is changed, and the signals of the scanning lines are not changed at all by scrambling. Therefore, a discontinuous point which is not present in the original signal does not occur in the scanning line, and deterioration does not occur when converted into an analog signal. In addition, the adjacency of scanning lines does not change due to agitation, and the correlation between pixels in a line block does not change. Therefore, since all the DCT blocks are completely included in any of the line blocks, the correlation between pixels in each DCT block does not change and the compression efficiency does not change, so that the reproduced image is deteriorated due to the influence of scrambling. There is no such thing.

As described above, according to the scrambler and the descrambler of the second embodiment, when the digital video transmission system in which the compression processing is performed is connected via the analog IF, the reproduced image is not deteriorated. It is possible to configure a scrambler and a descrambler capable of realizing image agitation.

Although the scrambling device and the descrambling device according to the second embodiment have a structure in which the scanning line inversion processing is performed such that the order of arranging the scanning lines in the line block is reversed upside down, Any structure may be used as long as the pixels are symmetrically moved in the line block, such as a pixel column inversion process in which a vertical pixel column is horizontally reversed in the line block. According to this, since the correlation between the pixels in the line block does not change due to the agitation, the reproduced image is not deteriorated due to the influence of scrambling. Further, in order to realize the pixel column inversion processing, it is sufficient to have a structure in which the order of arrangement of pixels of each scanning line in the line block selected by PN is reversed left and right, and therefore two memory circuits 221 are provided. This can be realized by using a line memory, and the circuit scale can be reduced.

Next, a scrambler and a descrambler according to a third embodiment of the present invention will be described below with reference to the drawings. FIG. 7 is a schematic diagram used to describe the second embodiment. In the description of the third embodiment, FIG. 1 used in the description of the first embodiment will be used. The third embodiment is
1 (a), 1 (c) and 1 (d) are common to the first embodiment, but FIG. 1 (b) is different and can be replaced with FIG.
The difference will be mainly described below.

The following is a case of processing one frame of a video signal in which one frame consists of 48 scanning lines and each scanning line consists of 72 pixels. <a> Same as Example 1. <B> The scrambler according to the third embodiment performs inversion processing on the original image in which all pixel signals in the line block are level-inverted with the intermediate value of the dynamic range as a boundary.
As a result, the scrambled image of FIG. 7 is created. This inversion process is performed on the line block designated by PN. For example, in the example of FIG. 7, 6-bit PN is generated as (0, 0, 1, 0, 1, 1), and the level inversion processing is performed on the line blocks 803, 805, and 806 whose PN is 1. Done, line blocks 833, 8
35 and 836.

<C> Same as in the first embodiment. <D> Finally, the descrambling apparatus according to the third embodiment converts the decompressed image into a line block that has been subjected to the inversion processing by the scrambling apparatus according to the same PN instruction used in the scrambling apparatus. On the other hand, reverse processing is performed. As a result, the descrambled image of FIG. 1D is restored.

Next, specific configurations of the scrambler and the descrambler according to the third embodiment of the present invention will be described with reference to the drawings. The description of the scramble transmission system in which the scramble device and the descramble device of the third embodiment of the present invention are applied to the conventional digital video transmission system is described in the scramble transmission of the first embodiment of the present invention shown in FIG. Since it is the same as the system, its explanation is omitted.

Next, the structure of the scrambler 91 according to the third embodiment of the present invention will be described. FIG. 8 is a configuration diagram showing the configuration of the scrambler according to the third embodiment. In FIG. 8, 11 is an A / D device, 32 is a reversing device, and 13 is a D / A device. The operation of the scrambler configured as described above will be described below.

First, the A / D device 11 and the D / A device 1
With respect to No. 3, since the same operation as that of the device of the same reference numeral in the first embodiment is performed, the description thereof will be omitted. The reversing device 32 is PN
And a digital video signal are input, and with respect to the line block selected by PN, as described with reference to FIGS. 1 and 7, all pixel signals in the line block are level-inverted at the middle value of the dynamic range. Inversion processing is performed.

According to the scrambler having the configuration shown in FIG. 8, the inversion process as described with reference to FIGS. 1 and 7 can be realized. The descrambling device according to the third embodiment has exactly the same configuration and operation as the scrambling device according to the third embodiment shown in FIG. According to this descrambling device, the line block subjected to the inversion process by the scramble device is subjected to the inversion process again, so that the original level is restored.

Here, the configurations of the scrambler and the descrambler of the third embodiment are shown in FIG. 8, but this is only an example, and the inversion processing as described with reference to FIGS. 1 and 7 is performed. Any configuration may be used as long as it is performed.

As described above, according to the scrambling device of the third embodiment, the scrambling is realized by inverting the levels of all the pixels in the line block selected by PN. According to this, the difference between the pixel signals in each line block is only positive and negative reversed, and the correlation does not change. Since the line block is a set of scanning lines, the correlation between the pixels in each scanning line does not change, and discontinuity points and frequency components that do not exist in the original signal do not occur. Therefore, no deterioration occurs when converted into an analog signal. Further, since all DCT blocks are included in any of the line blocks, the correlation between pixels in the DCT blocks does not change due to the agitation. Therefore, since the compression efficiency does not change, the reproduced image does not deteriorate due to the effect of scrambling.

As described above, according to the scrambler and the descrambler of the third embodiment, when the digital image transmission system in which the compression processing is performed is connected via the analog IF, the reproduced image is not deteriorated. It is possible to configure a scrambler and a descrambler capable of realizing image agitation.

Next, a scrambler and a descrambler according to a fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 9 is a schematic diagram used to describe the fourth embodiment. In the description of the fourth embodiment, FIG. 1 used in the description of the first embodiment will be used. A fourth embodiment is:
1 (a), 1 (c), and 1 (d) are common to the first embodiment, but FIG. 1 (b) is different and can be replaced with FIG.
The difference will be mainly described below.

A case will be described below in which one frame of a video signal in which one frame consists of 48 scanning lines and each scanning line consists of 72 pixels is processed. <a> Same as Example 1. <B> First, the scrambler of the fourth embodiment first performs line block replacement processing on the original image, then scan line inversion processing, and then inversion processing. As a result, the scrambled image of FIG. 9 is created. The line block replacement process is the same as the process performed by the scrambler of the first embodiment, and the scanning line inversion process is the same as the process performed by the scrambler of the second embodiment. This is the same as the processing performed by the scrambler of the third embodiment, and a detailed description of each processing will be omitted because it was performed at the time of describing each embodiment. Here, the PN used is the first PN and the second PN.
It is a set of three PNs, PN and third PN. The first PN is used for the line block replacement process, the second PN is used for the scanning line inversion process, and the third PN is used for the inversion process.

Regarding the scrambled image of FIG. 9 shown as an example, first, the positions of the line blocks are switched by the control of the first PN, and the scrambled image of FIG. 1B is generated. Next, the scanning line inversion processing is performed on the second, fourth, and sixth line blocks selected by the second PN, that is, the line blocks 801, 805, and 802, and the line block 82 as shown in FIG.
1, 825, 822. Next, the inversion processing is performed on the third, fifth, and sixth line blocks selected by the third PN, that is, the line blocks 806, 803, and 822, and the line block 8 is generated as shown in FIG. 9B.
36, 833, 842.

<C> Same as in the first embodiment. <D> Finally, the descrambling apparatus of the fourth embodiment first performs the inversion processing on the line block selected by the third PN for the image after the decompression processing by the same PN instruction used in the scrambling apparatus. Then, the scanning line inversion process is performed on the line block selected by the second PN, and then the line block exchange process in the scrambler is reversed by the control of the first PN. As a result, the descrambled image of FIG. 1D is restored.

Next, specific configurations of the scrambler and the descrambler in the fourth embodiment of the present invention will be described with reference to the drawings. The description of the scramble transmission system in which the scramble device and the descramble device of the fourth embodiment of the present invention are applied to the conventional digital video transmission system is described in the scramble transmission of the first embodiment of the present invention shown in FIG. Since it is the same as the system, its explanation is omitted. Next, the configuration of the scrambler 91 in the fourth embodiment of the present invention will be described. FIG. 10 is a configuration diagram showing the configuration of the scrambler of the fourth embodiment. In FIG. 3, 11 is an A / D device, 42 is a replacement device, 32 is a reversing device, and 1 is a device.
3 is a D / A device, 45 is a PN division device, and in the replacement device 42, 421 is a memory circuit, and 422 is a read / write address generation circuit. The operation of the scrambler configured as described above will be described below.

Here, the A / D device 11 and the D / A device 1
No. 3 performs the same operation as the device having the same code in the first embodiment, and the reversing device 32 performs the same operation as the device having the same code in the third embodiment using the third PN. Omit it. PN divider 45 is PN
Is input, and this is divided into a first PN, a second PN, and a third PN. Further, the exchange device 42 inputs the first PN, the second PN and the digital video signal, and as described with reference to FIGS. 1 and 9, the line block exchange processing of exchanging the line blocks in the frame under the control of the first PN, For the line block selected by the second PN,
Scan line inversion processing is performed in which the order of arranging the scan lines in the line block is reversed upside down. The operation of the replacement device 42 will be described in more detail.

The exchanging device 42 records the input signal at the position designated by the write address of the memory circuit 421, and outputs the data at the position designated by the read address of the memory circuit 421. Memory circuit 421
Is composed of two frame memories, and the write address and the read address are the read / write address generation circuit 42.
It is output from 2. These write address and read address always specify different frame memories. Further, when one frame of data, that is, all the data on the frame memory has been designated, the write address and the read address designate different frame memories.
In addition, the write address indicates the position to be moved by the line block replacement process and the scanning line inversion process,
The read address sequentially indicates the position on each field of the frame. The read / write address generation circuit 422 operates so as to generate such a write address and a read address.

According to the scrambler having the configuration as shown in FIG. 10, the scramble processing combining the line block replacement processing, the scanning line inversion processing and the inversion processing as described in FIGS. 1 and 9 can be realized.

FIG. 11 shows a block diagram of the descrambling device in the fourth embodiment. The descrambler performs the inverse conversion of the process of the scrambler in this embodiment. In FIG. 11, 11 is an A / D device, 32 is an inverting device, 44 is a block replacement device, 421 is a memory device, 442 is a read / write address generation device, and 13 is D /
A device and 45 are PN dividers. The operation of the descrambling device will be described below.

In the descrambling device, the A / D device 11, the D / A device 13, the PN dividing device 45, and the reversing device 3
The operations of the memory device 421 and the memory device 421 are the same as those of the scrambler device having the same reference numeral, and therefore description thereof will be omitted here. The operation of the read / write address generator 442 reverses the write address and read address output by the read / write address generator 422.
That is, the write address output by the read / write address generation device 422 becomes the read address output by the read / write address generation device 442, and the read address output by the read / write address generation device 422 becomes the write address output by the read / write address generation device 442. Become.

The descrambling device having the structure shown in FIG. 11 can perform the inverse conversion of the scrambling device shown in FIG. Here, the configurations of the scrambler and descrambler of the fourth embodiment are shown in FIGS. 10 and 11, but this is only an example, and FIGS.
Any configuration may be used as long as the scramble processing described with reference to FIG.

As described above, according to the scrambler of the fourth embodiment, an analog signal is converted into an analog signal for the same reason as described in the first embodiment, the second embodiment and the third embodiment. When converted, no deterioration occurs, and the reproduced image does not deteriorate due to the effect of scrambling.

Further, according to the scrambler of the fourth embodiment, the first embodiment, the second embodiment and the third embodiment.
It is possible to further increase the degree of stirring as compared with the scrambler of the embodiment.

As described above, according to the scrambler and the descrambler of the fourth embodiment of the present invention, the scrambler and the descrambler are applied to the digital video transmission system in which the compression processing is performed, and the reproduced image is not changed. It is possible to configure a scrambler and a descrambler that can stir images and can obtain a higher degree of stirring than in the first, second, and third embodiments.

Further, in the scrambler of the fourth embodiment, the scanning line inversion processing is performed after the line block exchange processing, but the order may be reversed. At this time, it is necessary to reverse the order even in the descrambling device.

Further, in the scrambler of the fourth embodiment, the reversing device 32 and the exchanging device 42 may be connected in reverse order. In this case, even in the descrambling device, the connection order of the reversing device 32 and the replacing device 44 needs to be reversed.

The scrambler and the descrambler of the fourth embodiment have the structures shown in FIGS. 10 and 11, but the invention is not limited to this.
The reversing device 32 may be omitted. Alternatively, the replacement devices 42 and 44 may be replaced with the line block replacement devices 12 and 14 of the scrambler and descrambler of the first embodiment, respectively. Alternatively, the replacing devices 42 and 44 may be replaced with the scanning line reversing device 22 in the scrambler and descrambler of the second embodiment. That is,
It is also possible to perform two processes of the line block replacement process, the scanning line inversion process, and the inversion process.
In this case, the degree of agitation is reduced, but the circuit size can be reduced.

In the scrambler and descrambler of the first to fourth embodiments, for the sake of simplicity, it is assumed that an image in which one frame consists of 48 scanning lines × 72 pixels is the object of processing. There is. However, 4
Even if one frame is larger, such as 80 scanning lines × 720 pixels, a similar effect can be obtained by scrambling a set of scanning lines having the size of one DCT block as one line block. It goes without saying that you can get it. For example, 1 frame is 480 scanning lines ×
In the case of 720 pixels and the DCT block is 8 scanning lines × 8 pixels, one frame is divided into 60 line blocks.

Although the scrambler and descrambler of the first to fourth embodiments have a structure in which the line block is composed of eight lines, the present invention is not limited to this. Each line block may completely include the DCT block, and one DCT block may not be divided by two or more line blocks, and the reproduced image is not deteriorated.

Further, in the scrambler of the first to fourth embodiments, in order to adapt to the conventional digital video transmission system 92 for performing the compression processing shown in FIG. 2, a line block unit consisting of eight scanning lines is used. However, when applying to a digital video transmission system that performs other compression processing, it is necessary to completely include at least one minimum data unit of the compression processing performed by the applied digital video transmission system. A similar effect can be obtained by selecting a line block for the line and performing a replacement or an inversion.

For example, in the compression device 922 of the digital video transmission system 92 to be connected, one frame cannot be divided into a DCT block of 8 scanning lines × 8 pixels, and a DCT block of 16 scanning lines × 4 pixels at the end of the screen. If you are using
The same effect can be obtained if the scanning line is composed of a book. However, one line block may be composed of eight scanning lines. In this case,
Since the DCT block in which the correlation is broken is only at the edge of the screen, even if the reproduced image is deteriorated, it is hardly noticeable, and the reproduced image is deteriorated to the extent that there is no practical problem.

In the compression device 922 of the connected digital video transmission system 92, a set of a plurality of DCT blocks is used as a compression block, and adaptive quantization is performed so that the data length of the compressed block after compression becomes a fixed length. In such a case, each line block may completely include a compressed block, and one compressed block may not be divided by two or more line blocks, so that the reproduced image does not deteriorate. Is obtained.

In the scrambler and descrambler of the first to fourth embodiments, the line block replacement process, the scanning line inversion process and the inversion process are used individually or in combination, but the invention is not limited to this. Not a thing. As with these processes, any process may be performed as long as the correlation between the pixel signals in the line block is not broken, and the same effect can be obtained.

A scrambler and a descrambler according to the fifth embodiment of the present invention will be described below with reference to the drawings. First, a scramble transmission system in which the scramble device and the descramble device according to the fifth embodiment of the present invention are applied to a conventional digital video transmission system will be described. FIG. 12 shows the configuration of a scramble transmission system according to the fifth embodiment of the present invention.

In FIG. 12, 94 is a scramble device, 95 is a digital video transmission system, and 96 is a descramble device, which is a digital video transmission system 95.
In the figure, 951 is a color filter device, 922 is a compression device, 923 is a transmission line, 924 is a decompression device, and 955 is a color inverse filter device.

The part surrounded by the dotted line, excluding the scramble device 94 and the descramble device 96 from the scramble transmission device of the first embodiment shown in FIG. 2, becomes the conventional digital video transmission system 95.

This digital video transmission system 95 is
The digital video transmission system 92 of the first embodiment shown in FIG.
Replace the A / D device 921 of
Since the / A device 925 is replaced with the color inverse filter 955, only the difference will be described here. The input / output signal of the digital video transmission system 95 is a digital video signal, which is a standard television signal of a component signal format composed of a plurality of frames. Here, the frame includes a luminance frame indicating luminance and a color difference frame indicating color. The color filter 951 inputs such a digital video signal and performs a pixel reduction process on the color difference frame. At this time, instead of simply thinning out pixels, filtering processing is performed so that the result calculated from several pixels in the scanning line direction is set as a new pixel. The color inverse filter 955 reversely interpolates and increases pixels.

Next, the configuration of the scrambler 94 in the fifth embodiment of the present invention will be described. FIG.
FIG. 9 is a configuration diagram showing a configuration of a scrambler according to a fifth exemplary embodiment. In FIG. 13, 51 is a dividing device and 52 is DC.
A T block replacement device, and 53 is a synthesizing device. The operation of the scrambler configured as described above will be described below.

First, the dividing device 51 divides the input digital video signal into a luminance frame and a color difference frame.
Next, the DCT block replacement device 52 inputs the PN and the luminance frame, and D in the luminance frame is controlled by the PN.
DCT block replacement processing is performed to replace the positions of CT blocks. The DCT block replacement device 52 has the same configuration as the scramble device of the conventional example.
Performs the same operation. Finally, the luminance frame output from the DCT block replacement device 52 and the color difference frame output from the dividing device 51 are combined by the combining device 53. The operation of the synthesizing device 53 is the inverse conversion of the dividing device 51.

FIG. 14 is a block diagram of the descrambling device according to the fifth embodiment. The descrambler performs the inverse conversion of the scramble processing of the scrambler in the present embodiment. In FIG. 14, 51 is a dividing device, 54 is a DCT block replacing device, and 53 is a synthesizing device. The operation of the descrambling device will be described below.

In the descrambling device, the dividing device 5
1. The operation of the synthesizing device 53 is the same as that of the device of the same code in the scramble device, and therefore the description is omitted here.
The DCT block replacement device 54 replaces the DCT blocks in the reverse order of the DCT block replacement device 52, and has the same configuration as the descramble device of the conventional example and performs the same operation.

The descrambling device having the configuration shown in FIG. 14 can perform the inverse conversion of the scrambling device shown in FIG. As described above, according to the scrambler of the fifth embodiment, the transmission order of DCT blocks is changed only for the luminance frame, and nothing is processed for the chrominance frame. Therefore, even if the color difference frame of the scrambled video signal is filtered in the scanning line direction, the reproduced image is not deteriorated.

Further, if there is a luminance frame, the contents of the video signal can be recognized considerably, but the contents of the video signal can hardly be understood only by the color difference frame. Therefore,
If only the luminance frame is processed, it is difficult to guess the original image, and a sufficient stirring result can be obtained.

As described above, according to the scrambler and the descrambler of the fifth embodiment of the present invention, when connected to a digital video transmission system in which scanning line direction filtering and compression processing are performed on color signals. In addition, it is possible to configure a scrambler and a descrambler that can realize sufficient image mixing without deteriorating the reproduced image.

Although the scrambler and descrambler of the first to fourth embodiments are connected to the digital video transmission system 92 as shown in FIG. 2, the present invention is not limited to this. The configuration may be such that it is connected to a digital video transmission system 95 as shown in FIG. At this time, since the correlation of the pixel signals in each scanning line of the scrambled image does not change at all, it does not affect the processing of the color filter device 951 in the scanning line direction.

[0103]

As described above, according to the first aspect of the present invention, when used in a digital communication system involving compression processing, it is possible to realize a scrambler capable of agitating images without causing deterioration in reproduced images. , Its practical effect is great.

According to the second invention, it is possible to realize a descrambler which can restore an original image from a video scrambled by the scrambler of the first invention, and its practical effect is great.

According to the third aspect of the invention, when used in a digital communication system involving compression processing, a reproduced image does not deteriorate, and the appearance is different from that of the first aspect.
It is possible to realize a scrambler and a descrambler capable of mixing images, which can be used in combination with the devices of the first and second inventions, and the practical effects thereof are great.

According to the fourth aspect of the invention, when used in a digital communication system involving compression processing, a reproduced image does not deteriorate and the appearance is different from that of the first to third aspects. A scrambler and a descrambler capable of stirring an image can be realized in combination with the first and second inventions and / or the third invention, and the practical effects thereof are great.

According to the fifth aspect of the invention, when connected to a digital video transmission system in which scanning signals are filtered and compressed in the scanning line direction, a reproduced image is not deteriorated and a sufficient image is obtained. A scrambler and a descrambler that can achieve
Its practical effect is great.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating operations of a scrambler and a descrambler according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a scramble transmission system in which a scramble device and a descramble device according to the first embodiment of the present invention are combined with a digital video transmission system.

FIG. 3 is a configuration diagram of a scrambler according to a first embodiment of the present invention.

FIG. 4 is a configuration diagram of a descrambling device according to a first embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating operations of a scrambler and a descrambler according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a scrambler and a descrambler according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating operations of a scrambler and a descrambler according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram of a scrambler and a descrambler according to a third embodiment of the present invention.

FIG. 9 is a schematic diagram illustrating operations of a scrambler and a descrambler according to a fourth embodiment of the present invention.

FIG. 10 is a block diagram of a scrambler according to a fourth embodiment of the present invention.

FIG. 11 is a block diagram of a descrambling device according to a fourth embodiment of the present invention.

FIG. 12 is a configuration diagram of a scramble transmission system in which a scramble device and a descramble device according to a fifth embodiment of the present invention are combined with a digital video transmission system.

FIG. 13 is a configuration diagram of a scrambler according to a fifth embodiment of the present invention.

FIG. 14 is a configuration diagram of a descrambling device according to a fifth embodiment of the present invention.

FIG. 15 is a schematic diagram illustrating operations of a conventional scrambler and a descrambler.

[Explanation of symbols]

91, 94 Scrambler 93, 96 Descrambler 12, 14 Line block interchanger 22 Scan line reversal 32 Inverter 42, 44 Interchanger 121, 221, 421 Memory circuit 122, 142, 222, 422, 442 Read / write address generation Device 92,95 Digital video transmission system 922 Compressor 923 Transmission line 924 Expander 11,921 A / D device 13,925 D / A device 951 Color filter device 955 Color inverse filter device 45 PN divider 51 Divider 53 Synthesizer 52, 54 DCT block replacement device 801, 802, 803, 804, 805, 806 line block 822, 824, 826, 821, 825 line block 833, 835, 836 line block 842 line Lock 701,702,703,704,705,706,7
07,708 scan lines

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hironori Murakami 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (11)

[Claims] 1. A scrambler, which is connected to a digital video transmission system in which compression processing is performed in block units, wherein a set of the blocks and a set of scanning lines are line blocks, and the positions of the line blocks are exchanged. 2. The scrambler according to claim 1, wherein a set of 8 or 16 scanning lines is used as a line block. 3. A scrambler according to claim 1, which is connected to a digital video transmission system in which compression processing is performed on a block-by-block basis, and the set of blocks and the set of scanning lines are line blocks, and the position of the line blocks is opposite to that of the scrambler according to claim 1. A descrambling device that replaces the 4. The descrambling device according to claim 3, wherein a set of 8 or 16 scanning lines is used as a line block. 5. Connected to a digital video transmission system in which compression processing is performed in block units, the set of blocks and the set of scanning lines are line blocks, and pixel positions are symmetrical in one or more of the line blocks. A scrambler and a descrambler characterized by being mobile. 6. The scrambler and descrambler according to claim 5, wherein the order of arrangement of the scanning lines in one or more line blocks is reversed upside down. 7. A set of pixels located at the same position of each scanning line in a line block is defined as a pixel column, and the positions of the respective pixel columns in one or more of the line blocks are reversed left and right. The scrambler and descrambler according to claim 5. 8. The scrambler and descrambler according to claim 5, wherein a set of 8 or 16 scanning lines is used as a line block. 9. A digital video transmission system in which compression processing is performed in block units, wherein a set of the blocks and a set of scanning lines is a line block, and one or more of the line blocks include a line block. A scrambler and a descrambler which perform level inversion on all pixel signals with an intermediate value of the dynamic range as a boundary. 10. The scrambler and descrambler according to claim 9, wherein a set of 8 or 16 scanning lines is used as a line block. 11. A video signal composed of a luminance frame and a chrominance frame is processed and is connected to a digital video transmission system in which scanning in the scanning line direction for the chrominance frame and compression processing is performed in block units. On the other hand, the scrambler and the descrambler are characterized by performing the process of changing the position of the block and not performing the process on the color difference frame.