JP2000152212A - Method and device for ciphering digital compressed encoded image signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cipher a digital compressed encoded image signal so that its contents are grasped without an error by replacing frames or fields of a digital encoded image signal with different frames or fields. SOLUTION: A frame or field extracting means 1 extracts some frames or fields as a digital compressed encoded image signal B from a digital compressed encoded image signal A. A frame or field generating means 2 generates frames or fields of different image contents as a digital compressed encoded image signal C from the digital compressed encoded image signal B. A generating means 3 for a ciphered digital compressed encoded image signal generates the ciphered digital compressed encoded image signal D by replacing frames or fields of I, P or B pictures with frames or fields of pictures corresponding to I pictures of the digital compressed encoded image signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a digital compression coded image signal encryption method and a digital compression coded image signal encryption device for encrypting a digital compression coded image signal.

[0002]

2. Description of the Related Art Conventionally, a frame or field-sequential image is digitized by a digitizing process (AD conversion process) from a frame or field-sequential analog signal image signal obtained from an imaging camera or the like. A signal is generated as a digital image signal, and from the digital image signal, a frame or field sequential digital image subjected to redundancy reduction processing in frame or field units by the frame or field redundancy reduction processing for the digital image signal. Generating a signal as a digital redundancy reduced image signal,
From the digital redundancy-reduced image signal, a quantized frame or field-sequential digital redundancy-reduced image signal is generated as a digital quantized-redundancy-reduced image signal by quantization processing on the digital-quantized-redundancy-reduced image signal. An image signal compression encoding method of generating an encoded frame or field-sequential digital quantization redundancy reduced image signal as a digital compression encoded image signal from the reduced image signal by an encoding process on the reduced image signal is an MPEG method. (Moving Pictur
e Coding Experts Group)
(See, “Comprehensive Multimedia Selection MPEG”, edited by the Institute of Image Information and Television Engineers, published by Ohmsha Co., Ltd. (1st edition on April 20, 1996)).

Conventionally, a digitally compressed and encoded image signal generated by such an image signal compression encoding method is stored in a storage medium such as a CD-ROM, and the storage medium is distributed. At the distribution destination of the medium, the digital compression coded image signal stored in the storage medium is used to generate the digital compression coded image signal from the digital compression coded image signal stored in the storage medium. Reproduce the image signal of the analog signal form of
The reproduced image signal is also displayed on a display surface of a display device.

[0004]

SUMMARY OF THE INVENTION A digital compression-encoded image signal generated by the above-described image signal compression-encoding method is stored in a storage medium as described above, and when the storage medium is distributed, the distribution source is However, there is a case where the user wants to distribute the storage medium as a sample before distributing the storage medium as a regular storage medium.

As described above, when a storage medium storing a digital compression encoded image signal is distributed as a sample, the digital compression encoded image signal stored in the storage medium is distributed by the sample storage medium. Following the distribution, we plan to distribute legitimate storage media,
As long as the image content of the digitally compressed and encoded image signal stored in the storage medium that is regularly distributed can be grasped without fail, the digitally encoded and encoded image signal can be partially encrypted. The digital compression-encoded image signal stored in a storage medium that is properly distributed does not have to be the same in terms of image content.

However, even if it has been conventionally proposed to encrypt all of the digitally compressed and encoded image signals generated by the above-described image signal compression and encoding method, the above-mentioned image signal compression and encoding method has been proposed. The digital compression encoded image signal generated by the above, in a manner that the content is definitely grasped, for a part thereof,
There has been no proposal for a digital compression-encoded image signal encryption method that can be encrypted.

Therefore, according to the present invention, it is possible to encrypt a part of a digital compression-encoded image signal generated by the above-described image signal compression-encoding method in such a manner that its contents can be surely grasped. The present invention proposes a novel digital compression-encoded image signal encryption method and a digital compression-encoded image signal encryption device that can be used.

[0008]

According to a first aspect of the present invention, there is provided a digital compression-encoded image signal encryption method for converting an image signal in the form of an analog signal into a digital image signal by digitizing the image signal. Generated as a digital image signal, and from the digital image signal,
By performing a redundancy reduction process in units of frames or fields, a digital image signal subjected to the redundancy reduction process in units of frames or fields is generated as a digital redundancy reduced image signal, and from the digital redundancy reduced image signal, By the quantization processing for it,
A quantized digital redundancy-reduced image signal is generated as a digital quantized redundancy-reduced image signal, and the digital quantized redundancy encoded by the coding process for the digital quantized redundancy-reduced image signal is encoded. A method for encrypting the digitally compressed image signal, wherein the reduced image signal is generated as a digitally compressed and encoded image signal. For some frames or fields, replace it with frames or fields that have different image content.

In this case, the image signal compression coding method is as follows:
An image signal compression encoding method based on MPEG, wherein a part of frames or fields of the digital compression encoded image signal is generated by means for generating the digital redundancy reduced image signal in the MPEG image signal compression encoding method. A frame or a field composed of an I picture, a P picture or a B picture constituting the digital redundancy reduced image signal to be reproduced, wherein the frame or the field having the different content is a frame or a field composed of the I picture, the P picture or the B picture. The above MPEG having image contents different from
A frame or field of a picture corresponding to the I picture constituting the digital redundancy reduced image signal generated by the means for generating the digital redundancy reduced image signal in the image signal compression encoding method according to Yes.

A digital compression-encoded image signal encrypting device according to a second aspect of the present invention converts an image signal in the form of an analog signal into a digital image signal by digitizing the image signal as a digital image signal. Generating, from the digital image signal, a digital image signal subjected to redundancy reduction processing in frame or field units by a redundancy reduction processing in frame or field units with respect to the digital image signal to generate a digital redundancy reduced image signal, From the digital redundancy-reduced image signal, a quantized digital redundancy-reduced image signal is generated as a digital quantization-redundancy-reduced image signal by quantization processing on the digital-redundancy-reduced image signal. It is encoded by the encoding process Generating a digital quantization redundancy reduction image signal as digital compression coded image signal,
An apparatus for encrypting the digital compression-encoded image signal, which is generated by an image signal compression-encoding method, wherein a part of a frame or a field is extracted from the digital compression-encoded image signal, Means for generating a frame or field having a different image content from the frame or field extracted by the means for extracting the frame or field, and the partial frame or field thereof from the digitally compressed and coded image signal Is replaced with a frame or a field generated by the frame or field generating means to generate an encrypted digital compression encoded image signal.

In this case, the image signal compression coding method is as follows:
An image signal compression encoding method based on MPEG, wherein a frame or field extracted by the means for extracting the frame or field is a part of the digital compression encoded image signal, A frame or a field composed of an I picture, a P picture, or a B picture constituting the digital redundancy reduced image signal generated by the means for generating the digital redundancy reduced image signal in the encoding method; The frame or field generated by the generating unit is a digital redundancy reduced image generated by the unit for generating the digital redundancy reduced image signal in the image signal compression encoding digital compression encoding image signal encryption method according to the MPEG. And allowed to become a frame or field by picture corresponds to I picture constituting the item.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a digital compression coded image signal encryption method and apparatus according to the present invention.

In an embodiment of the method and apparatus for encrypting a digitally compressed coded image signal according to the present invention, a frame or a field is extracted from the digitally compressed coded image signal A by a means 1 for extracting a frame or a field. Is extracted as the extracted digital compression-encoded image signal B.

In this case, the digital compression coded image signal A from which some frames or fields are extracted is M
PEG (Moving Picture Coding)
From an image signal in the form of a frame or field-sequential analog signal as obtained from an imaging camera according to the Experts Group, a digitized frame or field-sequential image signal is digitized by a digitizing process (AD conversion process). Generated as a digital image signal, and from the digital image signal,
A frame or field sequential digital image signal subjected to the frame or field unit redundancy reduction process is generated as a digital redundancy reduced image signal by the frame or field unit redundancy reduction process. From the reduced image signal,
By the quantization process for it, a quantized frame or field sequential digital redundancy reduced image signal is generated as a digital quantized redundancy reduced image signal,
An image signal compression method of generating an encoded frame or field sequential digital quantized redundancy reduced image signal as a digitally compressed and encoded image signal by performing an encoding process on the digital quantized redundancy reduced image signal. Frame or field to be extracted by means 1 for extracting frames or fields, and thus digitally compressed and coded image signals by means 1 for extracting frames or fields. A
The digital compression-encoded image signal B extracted from the image data I constitutes a digital redundancy-reduced image signal generated by means for generating a digital redundancy-reduced image signal in the above-described MPEG image signal compression-encoding method. (I
ntra coded) picture or P (Predi)
active coded) picture or B (bid)
directionally Predictive C
oded) extracted as consisting of a frame or a field of pictures.

Further, the digitally compressed and coded image signal B extracted by the frame or field extracting means 1 is generated by the frame or field generating means 2.
, A frame or field having a different image content is generated as the generated digital compression-coded image signal C. In this case, the generated digitally compressed and coded image signal C is obtained by combining the digitally compressed and coded image signal C extracted by the frame or field extracting means 1 with the digital redundancy in the image signal compression and coding method by MPEG described above. Since the digital redundancy reduced image signal generated by the means for generating the reduced image signal is composed of frames or fields of I pictures, P pictures, or B pictures, the above-mentioned image signal compression encoding digital compression by MPEG A picture (DCT (Discrete Cos) corresponding to an I picture constituting the digital redundancy reduced image signal generated by the means for generating the digital redundancy reduced image signal in the encoded image signal encryption method.
in-transform) is generated as a frame or field.

Further, by means 3 for generating an encrypted digitally compressed and coded image signal, a digitally compressed and coded image signal A obtained through means 1 for extracting a frame or a field and generated by means for generating a frame or a field. Using the generated digital compression coded image signal C and a part of the I picture or P picture or B extracted from the digital compression coded image signal A by the means 1 for extracting the above-described frame or field. By replacing a frame or a field by a picture with a frame or a field of a picture generated by the frame or field generating means 2 and corresponding to the I picture of the digitally compressed and coded image signal C, an encrypted digital compression code is obtained. Generates an image signal D To.

The embodiments of the digital compression encoding image signal encryption method and apparatus according to the present invention have been described above.

According to such a method and apparatus for encrypting digitally compressed and encoded image signals according to the present invention, the encrypted digitally compressed image signals generated by the means 3 for generating the encrypted digitally and compressed image signals are generated. The coded image signal D is a frame or field of a picture corresponding to an I picture in which a frame or field of an I picture or a P picture or a B picture of the digital compression coded image signal A has a different image content. Since the digital compression-encoded image signal D
Is stored in a storage medium such as a CD-ROM, distributed, and digitally encoded by the image signal compression encoding method which has been conventionally proposed in the section of [Prior Art] at the distribution destination. By using the image signal reproducing device, the encrypted digital compression-encoded image signal stored in the storage medium can be partially converted into the original image signal when the digital compression-encoded image signal A is generated. The frame or field can be replayed as an image signal that has been replaced by a frame or field having different image content, and the replayed image signal can be displayed on a display surface of a display device, and thus can be encrypted. From the digitally compressed and coded image signal C, the image content is not the same as the digitally compressed and coded image signal before being encrypted. , It will be apparent that it is possible to obtain an image display in a manner where the image content of the compressed digital encoded image signal before being encrypted is grasped definitely.

Further, a storage medium storing the encrypted digital compression coded image signal D is stored in a picture corresponding to the I picture of the digital compression coded image signal C generated by the frame or field generating means 2. If you distribute with a charge along with information on how to generate a frame or field picture by
It will be apparent that the distribution destination can obtain an image display using the digital compression-encoded image signal A before being encrypted.

In the above description, it has been described that the image signal compression encoding method is an image signal compression encoding method based on MPEG. However, the image signal compression encoding method is essentially based on the analog signal mode image signal. , A digitized image signal is generated as a digital image signal by a digitizing process on the digital image signal, and the redundancy is reduced from the digital image signal in a frame or field unit by a frame or field unit. The reduced digital redundancy reduced image signal is generated as a digital redundancy reduced image signal, and the quantized digital redundancy reduced image signal is digitally quantized from the digital redundancy reduced image signal. Generated as a redundancy-reduced image signal and its digital quantization redundancy From reduced image signals, the encoding process therefor, to generate a compressed digital coded picture signal an encoded digital quantized redundancy reduction image signal, if an image signal compression coding method called, MP
It will be apparent that the image signal compression coding method by EG is not necessarily required.

In addition, various modifications and changes could be made without departing from the spirit of the present invention.

[0022]

According to the present invention, it is possible to easily encrypt a part of a digitally compressed and encoded image signal generated by the image signal compression and encoding method, in such a manner that its contents can be surely grasped.

[Brief description of the drawings]

FIG. 1 is a systematic connection diagram for describing an embodiment of a digital compression encoding image signal encryption method and apparatus according to the present invention.

[Explanation of symbols]

1 means for extracting a frame or field 2 means for generating a frame or field 3 means for generating an encrypted digital compression-encoded image signal

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Noboru Sonehara 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo F-term within Nippon Telegraph and Telephone Corporation (reference) 5C059 KK43 MA00 ME01 PP04 SS11 SS13 UA02 5C064 CA14 CA18 CB08 CC04

Claims (4)

[Claims] A digital image signal is generated as a digital image signal from an image signal in the form of an analog signal by a digitizing process, and the digital image signal is subjected to redundancy in units of frames or fields. The digital image signal subjected to the redundancy reduction processing in units of frames or fields by the degree reduction processing is generated as a digital redundancy reduced image signal, and the digital redundancy reduced image signal is quantized by the quantization processing. The reduced digital redundancy reduced image signal is generated as a digital quantized redundancy reduced image signal, and from the digital quantized redundancy reduced image signal, an encoded digital quantized redundancy reduced image Signal as digital compression coded image signal A method of encrypting the digitally compressed and encoded image signal, which is generated by an image signal compression and encoding method of generating, for a part of frames or fields of the digitally compressed and encoded image signal, A digital compression-encoded image signal encryption method characterized by replacing the image with a frame or a field having a different image content. 2. The digital compression-encoded image signal encryption method according to claim 1, wherein said image signal compression-encoding method is an image signal compression-encoding method based on MPEG, and one of said digital compression-encoded image signals. I or P pictures or B frames constituting the digital redundancy reduced image signal generated by the means for generating the digital redundancy reduced image signal in the image signal compression coding method according to the MPEG.
The digital signal in the image signal compression coding method according to MPEG, wherein the frame or field having a different content has a different image content from the frame or field according to the I picture, P picture or B picture. Digital compression-encoded image signal encryption comprising a frame or a field of pictures corresponding to I-pictures constituting a digital redundancy-reduced image signal generated by a means for generating a redundancy-reduced image signal. Chemical method. 3. A digitized image signal is generated as a digital image signal from an image signal in the form of an analog signal by a digitizing process, and the digital image signal is subjected to redundancy in units of frames or fields. The digital image signal subjected to the redundancy reduction processing in units of frames or fields by the degree reduction processing is generated as a digital redundancy reduced image signal, and the digital redundancy reduced image signal is quantized by the quantization processing. The reduced digital redundancy reduced image signal is generated as a digital quantized redundancy reduced image signal, and from the digital quantized redundancy reduced image signal, an encoded digital quantized redundancy reduced image Signal as digital compression coded image signal A device for encrypting the digitally compressed and encoded image signal generated by an image signal compression and encoding method, comprising extracting a part of frames or fields from the digitally compressed and encoded image signal. Means for generating a frame or field having a different content from the frame or field extracted by the frame or field extracting means; and the part of the frame from the digital compression encoded image signal Or means for generating an encrypted digitally compressed image signal by replacing a field with a frame or field generated by the frame or field generating means. Image signal encryption device. 4. A digital compression-encoded image signal encryption apparatus according to claim 3, wherein said image signal compression-encoding method is an image signal compression-encoding method based on MPEG, and said means for extracting said frame or field. The extracted frame or field is the MPEG
A frame or field of I-pictures, P-pictures, or B-pictures constituting the digital redundancy-reduced image signal generated by the means for generating the digital redundancy-reduced image signal in the image signal compression encoding method according to The frame or field generated by the means for generating a frame or a field is the digital redundancy generated by the means for generating the digital redundancy reduced image signal in the image signal compression / encoding digital compression / encoding image signal encryption method according to MPEG. A digital compression-encoded image signal encrypting apparatus comprising a frame or a field of pictures corresponding to I-pictures constituting a reduced image signal.