JP2001145080A - Compressed image scramble transmitter, its receiver, its transmitter-receiver, its transmission method, its reception method, its transmission reception method and its recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a normal image to a rightful person and an image with image quality, which is deteriorated to such a degree that people can vaguely grasp the contents, to a non-rightful person by scrambling only a motion vector part of a compressed image at the transmission of the compressed image and descrambling the scrambled compressed image at its expansion. SOLUTION: A compressed image scrambler that applies compression to an image consisting of an input image signal and scrambling processing to the compressed image, consists of encoding means (22, 24-31) that apply encoding to the input image signal, a motion detection means 23 that calculates motion vectors from the input image signal, and a means 33 that applies scramble processing to motion vectors selected among data which have the same bit length as that of substantial motion vectors and which are taken in the bit length in the scrambling of the motion vectors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed image scrambler, and more particularly to an authorized contractor who pays a fee when transmitting a compressed image over the Internet or wirelessly or when distributing it on a storage medium such as a CD or DVD. The present invention relates to a device for providing a normal image, and a non-contractor can provide an image having a low image quality, although the content of the image can be understood to some extent.

[0002]

2. Description of the Related Art Conventionally, when a compressed image is transmitted, the entire image data is scrambled, and a normal image can be viewed only when a formal contract with a distributor is provided. Could not be done.

[0003]

However, if a person who does not have a formal contract with a distributor is interested in it and can make a formal contract, the utility value is improved. Further, when the entire compressed image is scrambled, other than the contractor-specific decompression device breaks down, and in some cases, it is difficult to return to the normal operation. Therefore, the present invention provides a scrambling method that does not cause a failure even though the image quality is reduced even in a receiving device other than the contractor.

[0004]

According to a first aspect of the present invention, there is provided a compressed image scramble transmitting apparatus in which a supplied input image signal is image-compressed and a scramble process is performed only on a motion vector portion. Encoding means for encoding the input image signal, motion detecting means for calculating a motion vector from the input image signal, and scrambling of the motion vector has the same bit length as the bit length of the original motion vector. And a scramble processing means for performing a scramble process by selecting from data that can be taken with the bit length in accordance with a predetermined scramble format. In the invention of Item 2, the supplied input image signal is image-compressed, and only the motion vector portion is scrambled. A compressed image scramble receiving apparatus for receiving a compressed image scrambled signal to be processed, wherein decoding means for decoding the compressed image scrambled signal, the scramble of the motion vector has the same bit length as the bit length of the original motion vector. And a descramble processing means for descramble processing according to a predetermined scramble format from data that can be taken in the bit length. The third invention is
An input image signal to be supplied is subjected to image compression, and a scrambled image transmitting apparatus in which only a motion vector portion is scrambled is a coding means for coding the input image signal, and calculates a motion vector from the input image signal. And a scrambler for scrambling the motion vector, wherein the scramble of the motion vector is the same as the bit length of the original motion vector, and a scramble process is performed by selecting from data that can be taken with the bit length according to a predetermined scramble format. A compressed image scramble receiving device configured to include a processing unit and receive an output signal of the compressed image scramble transmitting device; a decoding unit that decodes a received signal of the receiving device; A bit length equal to the bit length of the motion vector, and 5. A compressed image scramble transmitting / receiving apparatus characterized by comprising descramble processing means for performing descramble processing by selecting from data that can be taken according to a predetermined scramble format. The present invention provides a compressed image scramble transmission method in which a supplied input image signal is image-compressed and a scramble process is performed only on a motion vector portion, wherein an encoding step of encoding the input image signal, A motion detection step of calculating a motion vector more, and the scrambling of the motion vector has the same bit length as the original motion vector, and
And a scramble processing step of performing a scramble processing by selecting from data that can be taken in the bit length in accordance with a predetermined scramble format. The present invention relates to a compressed image scramble receiving method for receiving a compressed image scramble signal in which a supplied input image signal is image-compressed and a scramble process is performed only on a motion vector portion, wherein a decoding step of decoding the compressed image scramble signal And the descrambling of the motion vector has the same bit length as the bit length of the original motion vector, and includes a descrambling process step of performing descrambling according to a predetermined scrambling format from data that can be taken with the bit length. That you have configured The present invention provides a compressed image scramble transmission method in which a supplied input image signal is image-compressed and a scramble process is performed only on a motion vector portion. An encoding step for encoding the signal;
A motion detecting step of calculating a motion vector from the input image signal, and the scrambling of the motion vector has a bit length equal to the bit length of the original motion vector, and a predetermined scrambling format from data that can be taken with the bit length. And a scrambling process step of performing a scrambling process by selecting according to the above. The compressed image scramble receiving method of receiving a signal transmitted by the compressed image scramble transmission method is performed by the compressed image scramble transmission method. A decoding step of decoding a signal, wherein the scrambling of the motion vector has the same bit length as the bit length of the original motion vector, and
A descrambling process step of performing a descrambling process by selecting from data that can be taken in the bit length according to a predetermined scrambling format. According to a seventh aspect of the present invention, there is provided a compressed image scramble recording medium in which a supplied input image signal is image-compressed and a scramble process is performed only on a motion vector portion, and the scramble of the motion vector is an original. A signal having the same bit length as the bit length of the motion vector, and a signal processed by a compressed image scrambling method that is selected from data that can be taken with the bit length according to a predetermined scramble format is recorded. Of compressed image scrambled recording media Is shall.

[0005]

FIG. 1 is a block diagram showing an embodiment of a compressed image scramble transmitting / receiving apparatus according to the present invention. As shown in FIG. 1, one embodiment of the compressed image scramble transmission / reception apparatus of the present invention includes a VTR apparatus 1, a digital converter 2, a motion vector scramble processing apparatus 3, an image compression apparatus 4, a distribution apparatus 5, a communication Road 6, receiving terminal device 7,
It comprises an image decompression device 8, an analog converter 9, a display device 10, and a motion vector descramble processing device 11.

[0006] Image data input from the VTR device 1 is converted into digital data by a digital converter 2 and input to an image compression device 4. The image compression device 4 performs a normal compression operation and performs Huffman coding. When only the motion vector is converted into the Huffman code, the motion vector scramble processing device 3 performs a scrambling process, and forms a compressed stream as it is. The stream is delivered to the user via the communication path (communication line) 6 by the delivery device 5.

[0007] The distributed compressed stream is received by the receiving terminal device 7. The data is decompressed by the decompression device 8 to separate the Huffman code, only the motion vector portion is separated, and the motion vector descramble processing device 11 converts the data into the original data, becomes a normal motion vector, and can decode the image normally.

[0008] The digital data is converted into an analog signal by the analog conversion device 9, and an image is displayed on the image display device 10. The decoding operation can be completed even in a general image decoding device that does not have the descrambling device 11.
However, since the video performs motion compensation different from the original, the portion where the motion occurs is disturbed, and although the outline of the image content can be understood, the details are difficult to see.

An embodiment of a compressed image scramble transmitting / receiving apparatus according to the present invention will be described below with reference to the drawings. In the compressed image scramble transmission / reception device shown in FIG. 1, the signal of the VTR device 1 is digitally converted by a digital converter 2 using an A / D converter, and the image compression device 4 performs, for example, the MPEG1 standard (ISO / IEC / 1172). Image compression is performed according to -2). It is compressed using an intra-coded frame (I), a forward predictive coded frame (P), and a bidirectional predictive coded frame (B), resulting in a coded data sequence as shown in FIG.

In FIG. 2, these I, B, and P frames are arranged substantially periodically, and a GOP (Group of
Pictures) header, and one cycle is approximately 15 frames. Among these coded frames, those having a motion vector are a P frame and a B frame, and the I frame has no motion vector. That is, there is an I frame every approximately 15 frames, which means that a normal video can be decoded only from the I frame in the conventional decoding apparatus.

<Image Compression Processing> FIG. 3 is a block diagram showing an embodiment of an image compression apparatus according to the present invention. One embodiment of the image compression apparatus 4 of the present invention shown in FIG. 3 includes a motion vector scramble processor 3, a reference image memory 22, a motion detector 23, a difference calculator 24, a DCT converter 25, a quantizer 26, It comprises an encoder 27, an inverse quantizer 28, an inverse DCT transformer 29, an adder 30, and a predicted image memory 31.

Here, a case of a unidirectional prediction P frame will be described for simplicity. The image data input 21 input to the image compression device 4 is divided into macroblocks composed of 16 × 16 pixels, and each macroblock is divided into four 8 × 8 blocks. First, a motion vector 32 that minimizes an error between the image data input 21 and the already encoded reference image 22 is calculated using a motion detector 23 for each macroblock.

According to the calculated motion vector 32, a predicted image memory 31 which is a result of encoding and decoding has already been obtained.
Then, motion compensation data is created from the image data of, and a difference calculator 24 calculates a difference of each pixel from the image data input 21. The difference value for each block is supplied to a DCT calculator 25 to perform DCT transform, and further quantized by a quantizer 26, which is converted into a Huffman code by an encoder 27.

At this time, only the Huffman-coded data of the motion vector portion is scrambled by a motion vector scramble processor 3 to be described later to form a compressed stream 34 of an image.

On the other hand, the data quantized by the quantizer 26 is inversely quantized by the inverse quantizer 28, and inverse DCT is performed by the inverse DCT unit 29. The output signal that has been subjected to the inverse DCT transformation is added to the motion compensated data from the image data in the predicted image memory 31 by the adder 30 to obtain the next predicted image data. The predicted image data, which is the output signal of the adder 30, should match the result of the decompression work.

In the above description, P which is one-way prediction is used.
Although the case of a frame has been described, a B frame, which is bidirectional prediction, can be compressed in a similar manner.

<Motion Vector Scramble Processing> The data of the code of the motion vector are shown in Table 1 below. For the motion vector, the coordinate X is in the horizontal direction toward the screen, the right is positive, the vertical coordinate is Y, and the downward is positive. As a result of the operation, the motion vector is, for example, x = 1
When 2, y = −5, the Huffman code is 11 bits of 00000100000 for x and 0 for y according to Table 1.
0001011 and 8 bits are allocated respectively.

In the scrambling of the motion vector in the compressed image scrambling apparatus of the present invention, the scrambling is performed on the data of the codes shown in Table 1. However, it cannot be randomly scrambled.

If the scrambling is performed randomly and the code (bit) length is not adjusted,
If x = 12 is 00110000110, a decoder (device)
Now, replace the code 00110000110 with the first half of 0011 and the second half of 0
000110, and two codes x = −2 and y = 4 are generated, and the decoder is broken.

Therefore, possible values for x = 12 are:
Code (bit) lengths are aligned, and 11, 12, 13, 14, 15, 16, -11 and -1 having the same code length as x = 12
Select from 12 types of 2, -13, -14, -15 and -16.

Similarly, possible values for y = -5 are the same code length as -5, 5, 6, 7, -5, -6,
Select from six types of -7. No scrambling is applied to 0, 4, and -4 that do not have the same code length.

[0022]

[Table 1]

<Scramble Processing> FIG. 4 shows an embodiment of a motion vector scramble processing apparatus according to the present invention. In this embodiment, a compressed signal is scrambled using an M-sequence signal generator. As an irreducible polynomial of the M-sequence signal generator,
X ³² +, which is an example of a scrambled format with ^{X 7 + X 5 + X 3} + X 2 + X + 1.

This irreducible polynomial is converted to the shift register 1 shown in FIG.
(43) and an exclusive OR circuit 47. The scramble initial value (scramble key) 41 of the irreducible polynomial is described in the user data portion of the GOP header shown in FIG. 2, and is an 8-byte value.
Separating the 8 bytes into upper 4 bytes and lower 4 bytes,
Exclusive OR is performed on each of the 32 bits, and the result is
The 2-bit scramble initial value 41 is used.

The scramble initial value 41 is taken into the scramble initial value setting circuit 42 and taken into the shift register 43 as the shift register initial value 44 in the next frame of the GOP header. The scrambled data 45 produced in this manner is supplied to the shift register 2 (50) and converted into 4 bits so that 16 types of data can be produced.

The possible values of the motion vector data 51 are:
Since there are 33 types in Table 1, numerical values are created in the ROM 52 in advance based on the above-described constraint on the scrambleable range of the motion vector.

That is, as shown in Table 1, 12 types of 11 bits having the same code length (11 to 16, -11 to-
16), 6 types with a code length of 10 bits (8 to 1)
0, -8 to -10), 6 types of code length 8 bits (5 to 7, -5 to -7), 5 bits of code length 2
Type (3, -3), two types with a code length of 4 bits (2, -2), two types with a code length of 3 bits (1,
A numerical value such as -1) is created in the ROM 52 in advance.

However, 0, 4, which do not have the same code length,
-4 is not scrambled. Thus, the scrambled motion vector 53 is obtained.
The shift registers 43 and 50 are controlled by a control circuit 49.
Whenever one motion vector is generated, the motion vector control signal 48 becomes active, and the shift registers 43 and 50 are advanced by one clock. Also, the ROM 52 is controlled so that the normal motion vector data 51 itself is not selected as the output of the scrambled motion vector 53.
Is composed.

There is also a simpler method that does not use the ROM 52. When the scramble data 45 is detected, if it is 1, the sign of the motion vector 51 is inverted, and if it is 0, it is not inverted. However, in this case as well, those having motion vector values of 0, 4, and -4 are not scrambled.

<Decoding Process> Next, an embodiment of the image decompression device of the present invention will be described with reference to the drawings. As shown in FIG. 5, one embodiment of the image decompression device 8 includes a Huffman code decoder 62, an inverse quantizer 63, and an inverse DCT transformer 6.
4, a motion vector descramble processor 11, a motion compensator 67, an adder 68, a predicted image generator 69, and an image reference memory 70.

A compressed stream input 61 is supplied to a Huffman code decoder 62, and a header of the compressed stream or a scrambled motion vector 65, a quantized DC
The T coefficient and the like are solved for the Huffman code. The DCT coefficients quantized in macroblock and block units are inversely quantized by an inverse quantizer 63, and inverse DCT transforms by an inverse DCT transformer 64.
It is T-transformed and returned to the original DCT coefficients.

On the other hand, the scrambled motion vector 6
5 is a scramble initial value (scramble key) transmitted in the user data portion of the GOP header in FIG.
41 to provide the motion vector descramble processor 11
Is restored to the original normal motion vector according to the scramble format.

The motion vector descramble processor (device) 11 may have exactly the same configuration as the scrambler used for encoding shown in FIG. 4, and only the contents of the ROM are different. The previously decoded reference image is read from the reference image memory 70 using the restored motion vector, and the motion compensator 67 performs motion compensation.

The output image of the motion compensator 67 and the image subjected to the inverse DCT transformation by the inverse DCT transformer 64 are added by the addition calculator 68, and the predicted image is generated by the predicted image generator 69. Then, an image is output (image output 71) in synchronization with the synchronization signal of the video display device. By compressing and decoding in this way, a normal image can be displayed.

If the data is decoded by a general decoding apparatus having no motion vector descrambler 11,
Since the Huffman code length of the motion vector is the same as the original bit length, it can be decoded. However,
Since the values of the motion vectors are different, the predicted image of the predicted image generator 69 is different from the normal one, and is a slightly distorted image.

However, since the image is disturbed to the extent that the contents can be understood a little, and since only the I frame that is repeated approximately every 0.5 seconds can be decoded normally, the image contents can be understood. It has become something.

As described above, according to the present invention, a legitimate contractor can decode normally and see a normal image, and a non-authorized person can also decode the image. The image quality is slightly poor, and the image has a false contour and color blur. However, the content is of an image quality that can be understood to some extent. For this reason, it is possible to greatly reduce a situation in which a contract is made without knowing the content at all as in the related art, and a complaint or dissatisfaction with the image content is made later.

Although the embodiments of the present invention have been described on the assumption that a communication path (communication line) is used, the present invention is not limited to this, and is not limited to tapes, CDs, DVDs, and solid-state memories. The same can be applied to those using such a package recording medium.

[0039]

As described above, according to the compressed image scrambling of the present invention, a legitimate contractor can decode normally and see a normal image, and can decode even a person who has not contracted and has a normal apparatus. Is possible, the image quality is a little bad, but the content can be understood to some extent, so there is also a desire to see more accurately with a clearer image by contracting, as in the past, contracting without understanding the content at all, Complaints and dissatisfaction with the image content can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a compressed image scramble transmitting / receiving apparatus according to the present invention.

FIG. 2 shows a block diagram of compressed image data.

FIG. 3 is a block diagram showing an embodiment of an image compression apparatus according to the present invention.

FIG. 4 is a block diagram showing an embodiment of a motion vector scramble processing device of the image compression device of the present invention.

FIG. 5 is a block diagram showing an embodiment of an image decompression device according to the present invention.

[Explanation of symbols]

Reference Signs List 1 VTR device 2 Digital converter 3 Motion vector scramble processing device (motion vector scramble processor, scramble processing means) 4 Image compression device (encoding means) 5 Distribution device 6 Communication path (communication line) 7 Receiving terminal device 8 Image expansion Apparatus (decoding means) 9 Analog converter 10 Display device 11 Motion vector descramble processing device (motion vector descramble processor, descramble processing means) 21 Image data input 22 Reference image memory (encoding means) 23 Motion detector ( Motion detecting means) 24 difference calculator (encoding means) 25 DCT transformer (encoding means) 26 quantizer (encoding means) 27 encoder (encoding means) 28 inverse quantizer (encoding means) 29 Inverse DCT transformer (encoding means) 30 Addition operation unit (encoding means) 31 Predicted image memo (Encoding means) 32 motion vector 34 compressed stream output 41 scramble initial value (scramble key) 42 scramble initial value setting circuit 43 shift register 1 44 shift register initial value 45 scramble data 46 shift register control signal 47 exclusive logic Sum circuit 48 motion vector control signal 49 control circuit 50 shift register 2 51 motion vector data 52 ROM 53,65 scrambled motion vector 61 compressed stream input 62 Huffman code decoder (decoding means) 63 inverse quantizer (decoding means) 64 inverse DCT transformer (decoding means) 67 motion compensator (decoding means) 68 addition operation unit (decoding means) 69 predicted image generator (decoding means) 70 image reference memory (decoding means) 71 image output B inter-frame encoding (Both directions Measuring) GOP GOP header I plane coded P frame interframe coding (unidirectional prediction)

Claims (7)

[Claims] An input image signal supplied is subjected to image compression,
What is claimed is: 1. A compressed image scramble transmitting apparatus in which a scrambling process is performed only on a motion vector part, an encoding unit that encodes the input image signal, a motion detection unit that calculates a motion vector from the input image signal, and the motion vector Has the same bit length as the bit length of the original motion vector, and has scramble processing means for performing a scramble process by selecting from data that can be taken with the bit length according to a predetermined scramble format. A compressed image scramble transmission device characterized by the above-mentioned. 2. An input image signal supplied is subjected to image compression,
What is claimed is: 1. A compressed image scramble receiving apparatus for receiving a compressed image scramble signal in which a scramble process is performed only on a motion vector portion, wherein decoding means for decoding the compressed image scramble signal; A descrambling means for descramble processing in accordance with a predetermined scrambling format from data that can be taken with the same bit length as the bit length, and a descrambling processing unit configured to perform the descrambling process. . 3. An input image signal supplied is image-compressed,
A compressed image scramble transmission device in which scramble processing is performed only on a motion vector portion, an encoding unit that encodes the input image signal, a motion detection unit that calculates a motion vector from the input image signal,
The scramble of the motion vector has the same bit length as the bit length of the original motion vector, and has scramble processing means for performing scramble processing by selecting from data that can be taken with the bit length according to a predetermined scramble format. The compressed image scramble receiving device that receives the output signal of the compressed image scramble transmitting device, a decoding unit that decodes the received signal of the receiving device, and the scrambling of the motion vector is the bit length of the original motion vector. Compressed image scramble transmission / reception characterized by comprising: descrambling processing means for performing descrambling processing by selecting data according to a predetermined scramble format from data that can be taken with the same bit length and the bit length. apparatus. 4. An input image signal supplied is image-compressed,
A compressed image scramble transmission method in which a scrambling process is performed only on a motion vector portion, wherein: an encoding step of encoding the input image signal; a motion detecting step of calculating a motion vector from the input image signal; Has the same bit length as the bit length of the original motion vector, and has a scramble processing step of performing a scramble process by selecting from data that can be taken with the bit length according to a predetermined scramble format. A compressed image scramble transmission method, characterized in that: 5. An input image signal supplied is subjected to image compression,
A compressed image scramble receiving method for receiving a compressed image scramble signal in which a scramble process is performed only on a motion vector portion, wherein a decoding step of decoding the compressed image scramble signal, and the scrambling of the motion vector is performed using bits of an original motion vector. A descrambling step of performing a descrambling process in accordance with a predetermined scrambling format from data that can be taken with the same bit length as the bit length, and a descrambling process. . 6. The supplied input image signal is subjected to image compression,
A compressed image scramble transmission method in which only a motion vector portion is scrambled, an encoding step of encoding the input image signal, a motion detection step of calculating a motion vector from the input image signal, and a scrambling of the motion vector. Has a bit length equal to the bit length of the original motion vector, and a scramble processing step of performing a scramble process by selecting from data that can be taken with the bit length in accordance with a predetermined scramble format, A compressed image scramble receiving method for receiving a signal transmitted by the compressed image scramble transmitting method, a decoding step of decoding a signal transmitted by the compressed image scramble transmitting method, and a scrambling of the motion vector is performed by using bits of the original motion vector. Same bits as length In, and the compressed image scrambling transceiver wherein the constructed and a descrambling processing step of performing a descrambling process by selecting in accordance with a predetermined scramble format from the data which can be taken by the bit length. 7. The supplied input image signal is image-compressed,
In a compressed image scrambled recording medium recorded by a compressed image scrambling method in which only a motion vector portion is scrambled, the scramble of the motion vector has the same bit length as the bit length of the original motion vector, and the bit length A compressed image scramble recording medium characterized by recording a signal processed by a compressed image scrambling method which is selected from data that can be obtained according to a predetermined scramble format.