Image data processor

Details Image data processor Image data processor

1997-10-31

2001-06-12

Couso, Jose L. (Department: 2621)

Image analysis

Image transformation or preprocessing

Reexamination Certificate

active

06246802

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a device for processing digital image data, in particular a device for encoding and decoding image data.
In recent years, devices have been developed for compressing image data based on standards such as JPEG, MPEG-1, MPEG-2, H261, H263, and reproducing the image data. Image encoding devices based on these standards offer a high data compression ratio while maintaining high image quality, and are therefore expected to become more widespread.
As this compressed data is digital data, there is almost no deterioration of quality even if the data is repeatedly duplicated, or copied. It is therefore possible, instead of expending the effort required to produce original data, to illegally duplicate data which is already commercially available and release any part of it onto the market as if it was original data. To counter this trend, producers of the original data are for example scrambling their data in order to prevent unauthorized duplication or partial misappropriation.
FIG. 8
is a block diagram showing an example of a conventional encoder/decoder of digital image data comprising an illegal duplication protection mechanism. In an encoder
201
, an original image is passed through a Discrete Cosine Transformation (DCT) unit
20
, quantizer (Q)
50
and variable word length coder (VWL)
60
to be converted into the compressed digital image data based on MPEG, for example, and is then scrambled in a scrambler
210
. The scrambled digital image data can be reproduced only by a descrambler corresponding to the scrambler. The scrambled data is transmitted to a recording/transmission means
70
.
The digital data inputted to a decoder
202
is therefore scrambled. In the descrambler
220
, the scrambled data is descrambled, and the original compressed digital image data based on MPEG, etc., is re-constructed. The re-constructed data passes through a variable word length decoder
80
, reverse quantizer
90
and inverse discrete consine transformation (IDCT) unit
100
so as to give a reproduced image. In this way, in the prior art, illegal duplication was prevented by scrambling data. JP-A-6-121313 (1994) discloses an example where a scrambling technique is applied to an analog picture signal.
Hence, it was previously possible to prevent illegal duplication by scrambling, but due to technical advances, protection of illegal duplication by this method has become ineffective. Specifically, a person who intends to illegally duplicate data analyzes the scrambling algorithm, and is then able to descramble the scrambled data. As a result, a cycle has been created where producers of original data continually develop new scrambling algorithms, and illegal duplicators continually analyze the new algorithms to descramble the scrambled data. Consequently, it has become fundamentally impossible to eradicate illegal duplication. After a scrambling algorithm is analyzed and the data has been descrambled, it may then be duplicated in the usual way. It is also extremely easy to duplicate data which has been duplicated once. Therefore, conventional techniques could not prevent the increasing spread of illegal duplication.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide an image data processor which can distinguish illegally duplicated data.
One aspect of this invention therefore provides an encoder for producing compressed, digital image data, this encoder comprising a DCT unit for subjecting DCT to an original image, electronic water mark embedding means for embedding an electronic water mark containing predetermined specific information in the data transformed by the DCT unit, a quantizer for quantizing data output by the electronic water mark embedding means, and a variable length encoder for performing variable length coding on the data quantized by the quantizer. The electronic water mark will be also called “electronic mark” hereinafter in the specification.
It is a further object of this invention to provide a decoder for decoding the compressed, digital image data, variable length decoder for performing variable length decoding on the variable length coded image data, an inverse quantizer for performing inverse quantization on the variable length decoded data, means for detecting an electronic mark in the inverse quantized data, means for notifying the result detected by the detecting means to an operator, or controlling the state of a device according to this result, means for performing an inverse discrete consine transformation on the inverse quantized data, and means for obtaining a reproduced image.
In the encoder, electronic mark data is embedded by electronic water mark embedding means in a characteristic part of the image represented by a spatial frequency area. In practice, the human eye cannot perceive the embedded electronic mark data, so the information can be incorporated in the image without affecting image quality.
Also, as the embedded electronic mark data cannot be deleted or modified, it is not eliminated by duplication. Hence, by first embedding electronic mark data having a specific meaning in the image data when it is produced, and detecting this mark in the decoding process, it may be used to verify the owner's rights to illegally duplicated data and to suppress unauthorized duplication by controlling the playback device.
One example of this is when the embedded electronic mark in the image data has the significance of prohibiting duplication. When the decoder on the playback side detects that such a mark has been embedded in the data, a warning may be given to the user in the form of sound or characters informing him that duplication is prohibited, and appealing to his moral sense to avoid illegal duplication.
Another example is when the electronic mark bears the electronic signature of the data's copyright owner. If data is found which is though to have been illegally copied, the decoder shows that the electronic mark is embedded in the image data. The user is then requested to stop using the data, or the mark may be used as evidence in a legal action to claim damages for the unauthorized use of the data.


REFERENCES:
patent: 4807029 (1989-02-01), Tanaka
patent: 5014198 (1991-05-01), Umemura
patent: 5046121 (1991-09-01), Yonekawa et al.
patent: 5548336 (1996-08-01), Ueda
patent: 5625714 (1997-04-01), Fukuda
patent: 5657399 (1997-08-01), Iwabuchi et al.
patent: 5848155 (1998-12-01), Cox
patent: 0 766 468 (1997-04-01), None
patent: 0 851 679 (1998-07-01), None
patent: 6-121313 (1994-04-01), None
“A Secure Robust Watermark for Multimedia”. Igemar J. Cox, Joe Kiliant, Tom Leighton and Tala J. Shamoon, Workshop on Information Hiding, Newton Institute, Univ. of Cambridge, May 1996.
“A Structural Method for Document Image Data Having a Copy Prevention Function”, Technical Report of IEICE IT93-65, ISEC93-67, SST93-60 (1993-12), pp. 13-18.
“NEC Data Hiding Proposal”, Response to Call for Proposal Issued by the Data Hiding SubGroup Copy Protection Technical Working Group, Version 1.0, Jul. 1, 1997.
“A WWW Service to Embeded And Prove Digital Copyright Watermarks,” Jian Zaho [sic], Prof. Of the European Converence on Multimedia Applications, Services and Technologies, Louvain-La-Neuve Belgium, May 1996.
Cox I J et al: “A Secure, Imperceptable Yet Perceptually Salient, Spread Spectrum Watermark for Multimedia”SOUTHCON, US, New York, IEEE, 1996, pp. 192-197, XP000613940 ISBN: 0-7803-83269-5.

Affiliated with

Also associated with

Rating

Image data processor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Image data processor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image data processor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2514302