CN1148970C - Digit image coding/decoding device and method using water mark - Google Patents
Digit image coding/decoding device and method using water mark Download PDFInfo
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- CN1148970C CN1148970C CNB991109651A CN99110965A CN1148970C CN 1148970 C CN1148970 C CN 1148970C CN B991109651 A CNB991109651 A CN B991109651A CN 99110965 A CN99110965 A CN 99110965A CN 1148970 C CN1148970 C CN 1148970C
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Abstract
Digital image coding/decoding apparatus using watermarking, and methods thereof are provided. The digital image coding apparatus includes a discrete wavelet transform portion for performing discrete wavelet transform on a host image to be transmitted thereon, thereby outputting MxM discrete wavelet coefficients where M is a predetermined positive integer, a significant coefficient extraction portion for extracting a predetermined percentile of upper significant coefficients among MxM wavelet coefficients, a pseudo-random number generator for generating pseudo-random numbers in accordance with a predetermined rule corresponding to an encryption code, and a coefficient replacement/combination portion for obtaining replacing location data representing the NxN replacing locations, where N is a predetermined positive integer smaller than M, replacing and combining coefficients corresponding to NxN replacing locations selected among MxM wavelet coefficients with NxN significant wavelet coefficients. Since a distorted host image transmitted from a severely noisy environment is corrected using the current image, the flow of information is continuous. Also, even when the image is abruptly changed, an error in correcting the image is not generated.
Description
The application relates to the temporary patent application in the U.S.'s sequence number 60/091,540 that is entitled as " using watermark (watermarking) evaluate image method for quality " of submission on July 1st, 1998 by applicant of the present invention.
Technical field
The present invention relates to use digital image coding device, decoding device and the Code And Decode method of watermark, more particularly, relate to when the distortion of master image is serious by using signature image (signa ture image) correcting distortion master image to make the continuous digital image coding device of information flow, decoding device and Code And Decode method.
Background technology
Watermark is a kind of technology for providing fail safe and the purpose of differentiating power that the image that will transmit is transmitted with encrypted image.Receiver side receives the image (hereinafter being referred to as master image) that transmits with the secret encrypted image (hereinafter being referred to as signature image) that transmits.Signature image is by specific decryption device decoding.
Fig. 1 is that explanation is used to produce image that adds watermark and the conceptual block diagram of extracting the conventional digit image coding/decoding device of signature image from this image that adds watermark.In the conventional digital image coding device that will describe, during encoding, master image and the secret signature image that transmits are carried out DCT (discrete cosine transform), thereby extract the DCT coefficient of respective image.By encoder to the DCT coefficient coding.At this, be used to encrypt the DCT coefficient composition coding of the separation scrambled device of control operation to signature image by one.By this way, can transmit the DCT coefficient of master image and be inserted into the DCT coefficient of the signature image in the DCT coefficient of the master image after being encoded.The DCT coefficient of master image and the DCT coefficient that is inserted into the signature image in the DCT coefficient of master image are carried out IDCT (inverse discrete cosine transformation), thereby obtain to see master image and the watermarking images that adds that can not see signature image.
By specific decryption device to the signature image decoding that adds watermark on the master image with its recovery.Between convalescence, the image that adds watermark is carried out DCT, thereby extract its DCT coefficient.Next, separate by original master image being carried out the extraction DCT coefficient that DCT obtains from the DCT coefficient of the image that adds watermark, thereby extract the DCT coefficient composition of coding signature image.Then, decoder is to the DCT coefficient composition decoding of coding signature image.At this, encrypt the control operation that decoder is carried out deciphering.DCT coefficient by the signature image of deciphering the control operation decoding is carried out IDCT once more, thereby recover signature image.
As mentioned above, in the conventional digital image coding device that uses watermark,, use the master image of front to proofread and correct present image by decoding unit if determine the current serious distortion of master image.Yet if use the image rather than the present image of front in correcting image is handled, it is discontinuous that information flow becomes.In addition, when the image flip-flop, in handling, correcting image may produce error.
Summary of the invention
An object of the present invention is to provide digital image coding/decoding device and method thereof, can utilize present image to proofread and correct the distortion master image that transmits from SANE.
For realizing above-mentioned purpose of the present invention, a kind of digital image coding device is provided, this device comprises: a discrete wavelet (wavelet) conversion fraction, be used for the master image that will transmit on it is carried out discrete wavelet transform, thereby M * M discrete wavelet coefficient of output, wherein M is a predetermined positive; A coefficient of efficiency extracts part, is used for extracting at M * M wavelet coefficient the upper limit coefficient of efficiency of predetermined percentage; A pseudorandom number generator is used for producing pseudo random number according to the pre-defined rule corresponding with encrypted code; A coefficient replacement/built-up section, be used for obtaining N * N replacement position data of replacing the position of expression, wherein N is the predetermined positive less than M, with N * N effectively wavelet coefficient replace and combination and N * N the corresponding coefficient of in M * M wavelet coefficient, selecting in replacement position; An anti-discrete wavelet transform part is used for M * M the wavelet coefficient that is replaced carried out anti-discrete wavelet transform, to produce the combination master image; With a compression section, be used for compression combination master image and encrypted code.
In addition, predetermined positive N preferably is less than or equal to 0.5M.
According to a further aspect in the invention, provide a kind of digital image decoding device that is used for the bit stream decoding that uses watermark encoder, this device comprises: a decompression part is used for the bit stream of compression is decompressed to recover master image and predetermined encrypted code; An image quality measure part, be used to assess the quality of the master image of recovery, if and if the master image quality of recovering be lower than predetermine level and produce the control signal that becomes first logic state and the master image quality of recovering and be not less than predetermine level and produce the control signal that becomes second logic state; A discrete wavelet transform part is used to respond the first logic state control signal master image of recovering is carried out discrete wavelet transform, and to obtain M * M wavelet coefficient, M is a predetermined positive; A pseudorandom number generator is used for producing pseudo random number according to the rule corresponding with recovering encrypted code; A coefficient separating part is used to use pseudo random number to obtain N * N separation point position data of replacing the position of expression, and N is another predetermined positive less than M, with N * N the wavelet coefficient that separates N * N separation point position from M * M wavelet coefficient; An anti-discrete wavelet transform part is used for N * N sub-wave number carried out anti-discrete wavelet transform, to produce the signature image that recovers; An image scale conversion portion, be used for the scale of the signature image that recovers is increased to the scale of master image, select part with an image, be used to respond (scale-increasing) signature image that the first logic state control signal selectivity scale increases, the master image of select recovering with the response second logic state control signal, the image of selecting with output is as master image.
According to a further aspect of the invention, a kind of digit image coding/decoding device that uses watermark is provided, this device comprises: one first discrete wavelet transform part, be used for the master image that will transmit on it is carried out discrete wavelet transform, thereby M * M discrete wavelet coefficient of output, wherein M is a predetermined positive; A coefficient of efficiency extracts part, is used for extracting at M * M wavelet coefficient the upper limit coefficient of efficiency of predetermined percentage; One first pseudorandom number generator is used for producing pseudo random number according to the pre-defined rule corresponding with encrypted code; A coefficient replacement/built-up section, be used for obtaining N * N replacement position data of replacing the position of expression, wherein N is the predetermined positive less than M, with N * N effectively wavelet coefficient replace and combination and N * N the corresponding coefficient of in M * M wavelet coefficient, selecting in replacement position; One first anti-discrete wavelet transform part is used for M * M the wavelet coefficient of replacing carried out anti-discrete wavelet transform, to produce the master image of combination; A compression section is used to compress the master image and the encrypted code of combination; A decompression part is used for the bit stream of compression is decompressed to recover master image and encrypted code; An image quality measure part, be used to assess the quality of the master image of recovery, if and the master image quality of recovering be lower than predetermine level then produce the control signal that becomes first logic state and if the master image quality of recovering is not less than predetermine level then produces the control signal that becomes second logic state; One second discrete wavelet transform part is used to respond the first logic state control signal master image of recovering is carried out discrete wavelet transform, and to obtain M * M wavelet coefficient, M is a predetermined positive; One second pseudorandom number generator is used for producing pseudo random number according to the rule corresponding with the encrypted code that recovers; A coefficient separating part is used to use pseudo random number to obtain the separation point position data of N * N replacement of expression position, and N is another predetermined positive less than M, and separates from M * M wavelet coefficient and N * N N * N the wavelet coefficient that the separation point position is corresponding; One second anti-discrete wavelet transform part is used for N * N wavelet coefficient carried out anti-discrete wavelet transform, to produce the signature image that recovers; An image scale conversion portion is used for the scale that a scale of the signature image that recovers is increased to master image; Select part with an image, be used to respond the signature image of first logic state control signal selectivity scale increase and respond the master image that the second logic state control signal is selected recovery, with the output master image.
According to a further aspect of the invention, a kind of digital picture coding method that uses watermark is provided, the method comprising the steps of: (a) master image that will transmit on it is carried out discrete wavelet transform, thus M * M discrete wavelet coefficient of output, wherein M is a predetermined positive; (b) upper limit coefficient of efficiency of extraction predetermined percentage in M * M wavelet coefficient; (c) produce pseudo random number according to the rule corresponding with predetermined encrypted code; (d) the replacement position data of the replacement position of N * N pixel of acquisition expression, wherein N is the predetermined positive less than M; (e) replace and be combined in N * N the coefficient of selecting in M * M the wavelet coefficient of replacing the position with N * N effective wavelet coefficient; (f) M * M the wavelet coefficient that is replaced carried out anti-discrete wavelet transform, to produce the master image of combination; (g) master image and N * N pixel location data of compression combination.
According to a further aspect of the invention, a kind of digital image decoding method that is used for the bit stream decoding that uses watermark encoder is provided, and the method comprising the steps of: (a) whether the quality of the quality of assessment combination master image and definite combination master image is more than or equal to predetermine level; (b) if the quality of determining the combination master image in step (a), is then set the combination master image more than or equal to predetermine level as master image; (c), then be set in the signature image that embeds in the combination master image as master image if determine that in step (a) quality of combination master image is lower than predetermine level; (d) bit stream to compression decompresses to recover combination master image and predetermined encrypted code; Wherein step (c) further comprises following step: the master image of recovering is carried out discrete wavelet transform, and to obtain M * M wavelet coefficient, M is a predetermined positive; Produce pseudo random number according to the pre-defined rule corresponding with the encrypted code that recovers; Use pseudo random number to obtain N * N separation point position data of replacing the position of expression, N is another positive integer less than M; Separate and N * N N * N the wavelet coefficient that the separation point position is corresponding from M * M wavelet coefficient; N * N wavelet coefficient carried out anti-discrete wavelet transform, to produce the signature image that recovers; The scale of the signature image that recovers is converted to the scale of master image; With the signature image of setting the scale conversion as master image.
Description of drawings
To make above-mentioned purpose of the present invention and advantage become more apparent by preferred embodiments of the present invention will be described in detail with reference to the annexed drawings, wherein:
Fig. 1 is the conceptual block diagram that explanation is used to produce watermarking images and extracts the conventional digit image coding/decoding device of signature image from the image that adds watermark;
Fig. 2 is the block diagram of explanation according to digit image coding/decoding device of the present invention;
Fig. 3 is the flow chart that shows according to digital picture coding method step of the present invention; With
Fig. 4 is the flow chart that shows according to digital image decoding method step of the present invention.
Embodiment
With reference to figure 2, digit image coding/decoding device according to the present invention comprises a coding unit 20 and a decoding unit 22.Coding unit 20 comprises that a discrete wavelet transform part 202, coefficient of efficiency extract part 204, pseudorandom number generator 206, coefficient replacement/built-up section 208, an anti-discrete wavelet transform part 210 and a compression section 212.In addition, decoding unit 22 comprises that a decompression part 222, image quality measure part 224, discrete wavelet transform part 226, pseudorandom number generator 228, coefficient separating part 230, anti-discrete wavelet transform part 232, an image scale conversion portion 234 and an image select part 236.
The operation of coding unit 20 at first, is described with reference to figure 2 and 3.
Discrete wavelet transform part 202 receives the master image that will transmit, and carries out discrete wavelet transform (step 302), to obtain discrete wavelet coefficient.As known in the art, discrete wavelet coefficient is made up of a square matrix.In this embodiment, suppose that discrete wavelet coefficient is M * M, M is a predetermined positive.
Coefficient of efficiency extracts part 204 and extract 25% upper limit coefficient of efficiency (step 304) from M * M wavelet coefficient.
The 210 pairs of M * M that is replaced wavelet coefficients of anti-discrete wavelet transform part carry out anti-discrete wavelet transform to produce combination master image (step 310).Be included in wherein signature image because the combination master image has the watermark of utilizing, it and original master image do not have too big difference, with the naked eye can not see this signature image clearly.
As mentioned above, coding unit 20 rearranges to pseudorandom the effective wavelet coefficient of the upper limit of the master image that will transmit in self wavelet coefficient of master image.So the live part of master image is added into watermark in master image self.
By 22 pairs of master image decodings that add watermark by coding unit 20 of decoding unit.
With reference now to Fig. 2 and 4, the operation of decoding unit 22 is described.
The bit stream of 222 pairs of compressions of decompression part decompresses to recover master image and encrypted code (step 402).Encrypted code is used for determining that coding unit 20 is used for the generation rule of the pseudo random number of coefficient replacement and combination.In decoding unit 22, the pseudo random number generation rule that the coefficient that is identified for will be described later by encrypted code separates.
Whether the quality of the master image that 224 assessments of image quality measure part recover and the quality of definite master image of recovering be more than or equal to predetermine level (step 42).Therefore, if the master image quality of recovering is lower than predetermine level, image quality measure part 224 produces the control signal that becomes logic " height ", if the master image quality of recovering is not less than predetermine level, image quality measure part 224 produces the control signal that becomes logic " low ".For example, the available mode identical with the distortion assessment carried out the assessment of picture quality.
Discrete wavelet transform part 226 response logic " height " control signal is carried out discrete wavelet transform to the master image of recovering, and to obtain M * M wavelet coefficient, M is predetermined positive (step 460).
232 pairs of N * N wavelet coefficients of anti-discrete wavelet transform part carry out anti-discrete wavelet transform, to produce the signature image that recovers.
Image scale conversion portion 234 converts the scale of the signature image that recovers to the scale (step 470) of master image.The signature image of scale conversion is set at master image.
At last, image is selected the signature image of part 2 36 response logic " height " control signal selectivity scale conversion, and the master image of response logic " low " control signal selection recovery, to export selected image as master image.
Therefore, if the quality of recovering master image more than or equal to predetermine level, the master image that decoding unit 22 is selected combination is as master image (step 44), output then.On the other hand, if the master image quality of recovering is lower than predetermine level, decoding unit 22 recovers to embed the signature image in the master image, and the signature image of setting recovery is exported then as master image (step 46).
As mentioned above, according to the present invention, owing to use present image to proofread and correct the distortion master image that transmits from SANE, information flow is continuous.In addition, even when the image flip-flop, do not produce error in the processing of correcting image.
In addition, an available digital image coding device and a digital picture decoding device separate digital image coding and the decoding unit of realizing according to digit image coding/decoding device of the present invention.
In addition, can in computer program, work out digital image coding and coding/decoding method.In addition, the available general applications digital computer that is used for operating the program that adopts the medium that computer uses is realized digital image coding and coding/decoding method.Medium comprises magnetic recording media and the optical recording media such as CD-ROM or DVD such as floppy disk or hard disk.In addition, the programmer in field related to the present invention can easily derive this function program, code and code segment.
Claims (8)
1. digital image coding device that uses watermark comprises:
A discrete wavelet transform part is used for the master image that will transmit on it is carried out discrete wavelet transform, thus M * M discrete wavelet coefficient of output, and wherein M is a predetermined positive;
A coefficient of efficiency extracts part, is used for extracting at M * M wavelet coefficient the upper limit coefficient of efficiency of predetermined percentage;
A pseudorandom number generator, be used for producing N * N pseudo random number according to the pre-defined rule corresponding with encrypted code, wherein N is the predetermined positive less than M, and N * N pseudo random number represented the replacement position selected from M * M position corresponding to M * M wavelet coefficient;
A coefficient replacement/built-up section is used for obtaining N * N replacement position data of replacing the position of expression, with N * N effective wavelet coefficient N * N the corresponding coefficient in replacement position replacing and make up and select in M * M wavelet coefficient;
An anti-discrete wavelet transform part is used for M * M the wavelet coefficient that is replaced carried out anti-discrete wavelet transform, to produce the combination master image; With
A compression section is used for compression combination master image and encrypted code.
2. digital image coding device according to claim 1, wherein predetermined positive N is less than or equal to 0.5M.
3. digital image decoding device that is used for the bit stream decoding that uses watermark encoder comprises:
A decompression part is used for the bit stream of compression is decompressed to recover master image and predetermined encrypted code;
An image quality measure part, be used to assess the quality of the master image of recovery, if and if the master image quality of recovering be lower than predetermine level and produce the control signal that becomes first logic state and the master image quality of recovering and be not less than predetermine level and produce the control signal that becomes second logic state;
A discrete wavelet transform part is used to respond the first logic state control signal master image of recovering is carried out discrete wavelet transform, and to obtain M * M wavelet coefficient, M is a predetermined positive;
A pseudorandom number generator is used for producing pseudo random number according to the rule corresponding with recovering encrypted code;
A coefficient separating part is used to use pseudo random number to obtain N * N separation point position data of replacing the position of expression, and N is another predetermined positive less than M, with N * N the wavelet coefficient that separates N * N separation point position from M * M wavelet coefficient;
An anti-discrete wavelet transform part is used for N * N wavelet coefficient carried out anti-discrete wavelet transform, to produce the signature image that recovers;
An image scale conversion portion is used for the scale that a scale of the signature image that recovers is increased to master image; With
Image is selected part, is used to respond the signature image that the first logic state control signal selectivity scale increases and responds the second logic state control signal select the master image recovered, and the image of selecting with output is as master image.
4. digital image decoding device according to claim 3, wherein predetermined positive N is less than or equal to 0.5M.
5. digit image coding/decoding device that uses watermark comprises:
One first discrete wavelet transform part is used for the master image that will transmit on it is carried out discrete wavelet transform, thus M * M discrete wavelet coefficient of output, and wherein M is a predetermined positive;
A coefficient of efficiency extracts part, is used for extracting at M * M wavelet coefficient the upper limit coefficient of efficiency of predetermined percentage;
One first pseudorandom number generator, be used for producing N * N pseudo random number according to the pre-defined rule corresponding with encrypted code, wherein N is the predetermined positive less than M, and N * N pseudo random number represented the replacement position selected from M * M position corresponding to M * M wavelet coefficient;
A coefficient replacement/built-up section is used for obtaining N * N replacement position data of replacing the position of expression, with N * N effective wavelet coefficient N * N the corresponding coefficient in replacement position replacing and make up and select in M * M wavelet coefficient;
One first anti-discrete wavelet transform part is used for M * M the wavelet coefficient of replacing carried out anti-discrete wavelet transform, to produce the master image of combination;
A compression section is used to compress the master image and the encrypted code of combination;
A decompression part is used for the bit stream of compression is decompressed to recover master image and encrypted code;
An image quality measure part, be used to assess the quality of the master image of recovery, if and the master image quality of recovering be lower than predetermine level then produce the control signal that becomes first logic state and if the master image quality of recovering is not less than predetermine level then produces the control signal that becomes second logic state;
One second discrete wavelet transform part is used to respond the first logic state control signal master image of recovering is carried out discrete wavelet transform, and to obtain M * M wavelet coefficient, M is a predetermined positive;
One second pseudorandom number generator is used for producing pseudo random number according to the rule corresponding with the encrypted code that recovers;
A coefficient separating part is used to use pseudo random number to obtain the separation point position data of N * N replacement of expression position, and N is another predetermined positive less than M, and separates from M * M wavelet coefficient and N * N N * N the wavelet coefficient that the separation point position is corresponding;
One second anti-discrete wavelet transform part is used for N * N wavelet coefficient carried out anti-discrete wavelet transform, to produce the signature image that recovers;
An image scale conversion portion is used for the scale that a scale of the signature image that recovers is increased to master image; With
An image is selected part, is used to respond the signature image of first logic state control signal selectivity scale increase and responds the master image that the second logic state control signal is selected recovery, with the output master image.
6. digital picture coding method that uses watermark comprises step:
(a) master image that will transmit on it is carried out discrete wavelet transform, thus M * M discrete wavelet coefficient of output, and wherein M is a predetermined positive;
(b) upper limit coefficient of efficiency of extraction predetermined percentage in M * M wavelet coefficient;
(c) produce N * N pseudo random number according to the rule corresponding with predetermined encrypted code, wherein N is the predetermined positive less than M, and N * N pseudo random number represented the replacement position selected from M * M position corresponding to M * M wavelet coefficient;
(d) the replacement position data of the replacement position of N * N pixel of acquisition expression;
(e) replace and be combined in N * N the coefficient of selecting in M * M the wavelet coefficient of replacing the position with N * N effective wavelet coefficient;
(f) M * M the wavelet coefficient that is replaced carried out anti-discrete wavelet transform, to produce the master image of combination; With
(g) master image and N * N pixel location data of compression combination.
7. digital picture coding method according to claim 6, wherein predetermined positive N is less than or equal to 0.5M.
8. digital image decoding method that is used for the bit stream decoding that uses watermark encoder comprises step:
(a) bit stream to compression decompresses to recover combination master image and predetermined encrypted code;
(b) whether the quality of the quality of assessment combination master image and definite combination master image is more than or equal to predetermine level;
(c) if the quality of determining the combination master image in step (a), is then set the combination master image more than or equal to predetermine level as master image;
(d), then be set in the signature image that embeds in the combination master image as master image if determine that in step (a) quality of combination master image is lower than predetermine level; With
Wherein step (d) further comprises following step:
The master image of recovering is carried out discrete wavelet transform, and to obtain M * M wavelet coefficient, M is a predetermined positive;
Produce pseudo random number according to the pre-defined rule corresponding with the encrypted code that recovers;
Use pseudo random number to obtain N * N separation point position data of replacing the position of expression, N is another positive integer less than M;
Separate and N * N N * N the wavelet coefficient that the separation point position is corresponding from M * M wavelet coefficient;
N * N wavelet coefficient carried out anti-discrete wavelet transform, to produce the signature image that recovers;
The scale of the signature image that recovers is converted to the scale of master image; With
The signature image of setting the scale conversion is as master image.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US9154098P | 1998-07-01 | 1998-07-01 | |
| US60/091,540 | 1998-07-01 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1252676A CN1252676A (en) | 2000-05-10 |
| CN1148970C true CN1148970C (en) | 2004-05-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB991109651A Expired - Fee Related CN1148970C (en) | 1998-07-01 | 1999-07-01 | Digit image coding/decoding device and method using water mark |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP3494923B2 (en) |
| KR (1) | KR100292359B1 (en) |
| CN (1) | CN1148970C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100333163B1 (en) * | 1999-03-29 | 2002-04-18 | 최종욱 | Digital watermarking method and apparatus |
| US6956903B2 (en) * | 2001-05-29 | 2005-10-18 | Intel Corporation | Method and apparatus for three-dimensional wavelet transform |
| GB2408873A (en) * | 2003-12-01 | 2005-06-08 | Sony Uk Ltd | Generating marked material by introducing code words |
| CN109344629B (en) * | 2018-09-19 | 2021-04-23 | 湖北工程学院 | Image encryption hiding method and device and image decryption method and device |
-
1999
- 1999-06-25 KR KR1019990024294A patent/KR100292359B1/en not_active IP Right Cessation
- 1999-06-30 JP JP18659399A patent/JP3494923B2/en not_active Expired - Fee Related
- 1999-07-01 CN CNB991109651A patent/CN1148970C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
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| KR100292359B1 (en) | 2001-06-01 |
| JP3494923B2 (en) | 2004-02-09 |
| KR20000011332A (en) | 2000-02-25 |
| CN1252676A (en) | 2000-05-10 |
| JP2000101827A (en) | 2000-04-07 |
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