CN102263879B - Image data processing system and related data hiding method thereof - Google Patents

Abstract

The invention discloses an image data processing system, which comprises an image input module, a bitmap generation module and a coding module, wherein the image input module receives an image and confidential information, and obtains at least one gray scale image according to the image; the bitmap generation module is coupled to the image input module, and is used for generating a bitmap image according to the gray scale image and generating an order dither block truncation coding image according to the bitmap image and the gray scale image; each pixel in the bitmap image is a black or white point; and the coding module is coupled to the image input module and the bitmap generation module to generate a coded gray scale image according to the bitmap image and the confidential information. The coding module divides the gray scale image into a plurality of image blocks, finds candidate blocks with proximate black point and white point numbers from the image blocks, screens high frequency blocks from the found candidate blocks and hides the confidential information into the high frequency blocks to generate the coded gray scale image with the hidden confidential information.

Description

Image data processing system and related data hidden method thereof

Technical field

The present invention relates to a kind of data hiding technique, relate in particular to a kind of moderately with computation complexity, and utilize gray scale image to come data-hiding method and the associated processing system thereof of hiding data.

Background technology

The digital halftone technology is a kind of technology that gray scale image is shown with two kinds of colors of black and white.Halftone technique is mainly used in print data, and magazine, newspaper and books that for example print etc. are because these output devices are only to export with black and white form.Halftone technique mainly is to utilize the human not high characteristic of eyes acuteness, so a uniform site, and we can control its density degree, utilizes monochrome pixels to demonstrate the GTG effect that originally will express.Halftone technique mainly can be divided into two large classes: standalone processes method and neighbor point facture.For the standalone processes method, the output of halftoning is normally passed through with certain mask (Mask) comparison by each pixel of original image and is got, and this kind method is take the method for trembling (DitherMethod) as representative.

The in recent years development of digital information and world-wide web is rapid, and the transmission opportunity of digital information file significantly increases, so that data are downloaded easily at world-wide web, alter and destruction, so the protection of intellectual property becomes more important.Most of multimedia in the storage area or the delivery time all store with the pattern of compressed-bit crossfire, therefore, the Information hiding subject under discussion just is subject to popular attention.By doing some processing in multimedia content, as: add digital relief watermark, digital signature, can protect the copyright of digital information and correctness and the ownership of authorization information.

A kind of common Stealth Modus is that data are hidden in the gray scale image, and data are hidden in the effect that gray scale image can also reach compression.In this field, a kind of common coding algorithm is that block blocks compiling method (Block Truncation coding, BTC).It is that an original image is divided into several nonoverlapping blocks that block blocks compiling method, and in the block that each is cut apart, replace the interior all pixel values of block with the maximum in the block (maximumvalue) and minimum value (minimum value), maximum, minimum value and the bitmap that therefore can only need transmit each block just can be rebuild original image before encoding in receiving terminal, calculates very quick.

Yet, because each block that uses block to block in the coded image that coding produces only has maximum and minimum value, cause easily irksome false limit and block effect, and block is cut apart more greatly, and block effect more obviously affects the quality of coded image.

Summary of the invention

In view of this, the invention provides a kind of data handling system of hiding for data with and data-hiding method, so that a confidential information is hidden in colour or the gray scale image, or hide the confidential information that enters and rebuild back original image by decoding in the image.

The embodiment of the invention provides a kind of image data processing system, and it comprises an image input module, a bitmap generation module and a coding module.Image input module receives an image and a confidential information, and obtains at least one gray scale image according to image.The bitmap generation module is coupled to image input module, produces a bitmap images and according to bitmap images and gray scale image, blocks coded image and produce an orderly shake block with the foundation gray scale image, and wherein each pixel in the bitmap images is black or white point.Coding module is coupled to image input module and bitmap generation module, with foundation bitmap images and confidential information, produces a coding gray scale image.Wherein, coding module is divided into a plurality of image block with gray scale image, and by finding out the stain candidate block close with the white point number in the image block, in the candidate block of finding out, filter out the high frequency block, again confidential information is hidden in the tremendously high frequency block at random, keep the coding gray scale image of confidential information with generation.

The embodiment of the invention provides a kind of data-hiding method in addition, and so that confidential information data are hidden in the image, it is applicable to a system, and this system comprises at least one image input module, a bitmap generation module and a coding module.The method comprises the following steps.At first, receive an image and confidential information, and obtain at least one gray scale image according to image.Then, bitmap module produces an orderly shake block and blocks coded image, and obtain shaking in order the bitmap images that block blocks coded image corresponding to this according to gray scale image and a halftoning array.Afterwards, coding module can be divided into bitmap images a plurality of image block, and by finding out the stain candidate block close with the white point number in the image block, by filtering out the high frequency block that belongs to HFS in the candidate block of finding out.Secondly, coding module can be hidden confidential information into the tremendously high frequency block at random, and obtains changing the plan of transposition image.At last, coding module can obtain maximum and the minimum value of each block in the gray scale image, and utilizes maximum and the minimum value of each block, replaces changing the corresponding block of bitmap images, keeps a coding gray scale image of confidential information with generation.

The embodiment of the invention more provides a kind of data-hiding method, decodes confidential information to comprise in the input coding gray scale image of a confidential information by one, and it is applicable to a system, and this system comprises at least one decoder module.The method comprises the following steps.At first, decoder module can utilize the input coding gray scale image, obtains a bitmap images.Then, this decoder module can be divided into bitmap images a plurality of image block, and by finding out the stain candidate block close with the white point number in the image block, by filtering out the high frequency block that belongs to HFS in the candidate block of finding out.Afterwards, decoder module utilizes the high frequency block in the bitmap images, and an average gray scale image of corresponding input coding gray scale image, decides to hide the place value into the high frequency block.At last, the Tibetan that the decoder module utilization determines enters the place value of high frequency block, obtains confidential information.

Said method of the present invention can see through the procedure code mode and include in tangible media.When procedure code was written into and carries out by a machine, this machine will become to carry out device of the present invention.

Description of drawings

Accompanying drawing described herein is used to provide a further understanding of the present invention, consists of the application's a part, does not consist of limitation of the invention.In the accompanying drawings:

Figure 1A is for showing a data handling system that data are hidden that is used for according to the embodiment of the invention;

Figure 1B is the thin section block diagram of demonstration one according to the bitmap generation module of the embodiment of the invention;

Fig. 2 A is for showing a schematic diagram according to halftoning array of the invention process;

Fig. 2 B is for showing the schematic diagram of a confidential information of demonstrating;

Fig. 3 is for the flow chart of demonstration one according to the data-hiding method of the embodiment of the invention, in order to a confidential information is hidden in the gray scale image;

Fig. 4 is for showing the schematic diagram in contiguous 3 * 3 zones on every side of a pixel B;

Fig. 5 is for showing another flow chart according to the data-hiding method of the embodiment of the invention;

Fig. 6 is the flow chart of demonstration one according to the data-hiding method of the embodiment of the invention, wherein comprises confidential information and rebuilds back gray scale image in order to enter the input coding image of confidential information from the Tibetan, to decode;

Fig. 7 is for showing another flow chart according to the data-hiding method of the embodiment of the invention;

Fig. 8 A is for showing the original gray scale image of a demonstration;

Fig. 8 B is for showing the data-hiding method according to the embodiment of the invention, and the orderly shake block that Fig. 8 A is produced blocks coded image;

Fig. 8 C is for showing the data-hiding method according to the embodiment of the invention, and the orderly shake block that keeps confidential information that Fig. 8 B is produced blocks coded image;

Fig. 8 D is for showing the data-hiding method according to the embodiment of the invention, by the bitmap images that decodes among Fig. 8 C.

Drawing reference numeral:

100～system;

110～image input module;

120～bitmap generation module;

122～extreme value judging unit;

124～halftoning array lookup unit;

126～in order shake block blocks coding unit;

130～coding module;

132～high frequency region block analysis unit;

134～information embedded unit;

140～decoder module;

142～high frequency region block analysis unit;

144～information reverting unit;

150～original gray scale image;

160～confidential information;

170～coding gray scale image;

180～decoded picture;

S310-S350～execution in step;

S610-S690～execution in step.

Embodiment

For above and other purpose of the present invention, feature and advantage can be become apparent, cited below particularlyly go out preferred embodiment, and cooperate accompanying drawing, be described in detail below.

The present invention relevant for a kind of data handling system of hiding for data with and data-hiding method, so that confidential information (a for example watermark of half tone image) is hidden in colour or the gray scale image, or by decode in the image Tibetan into confidential information, and rebuild GTG or coloured image.Method proposed by the invention is with data concealment and coding techniques, data are embedded (Tibetan enters) to gray scale image, block coding (Ordered Dither Block Truncation Coding at orderly shake block, hereinafter to be referred as ODBTC) but the bit plane elasticity of image embeds different data volumes, wherein shake is blocked coded image for the jitter quantisation block in order, avoids previous block to block irksome false limit and block effect that coded image causes.Compared to existing block method, under identical image quality efficient, the present invention not only can keep good image quality, also can make the decoding accuracy up to 100%.In addition; the Tibetan that foundation data-hiding method of the present invention produces enters the image of confidential information; under the observation of human eye, can't find out difference; and can utilize decoding and rebuilding to return original image; and therefore the correct confidential information of concealing of decoding can provide a good mechanism of copyright protection to verify action.

Below introduce the data handling system that data are hidden that is used for of the embodiment of the invention.What must remind is for convenience of description, be to describe as main take original image as a gray scale image in following examples, yet the present invention to be not limited to this.In other words, data handling system of the present invention and data-hiding method also can be used for processing the situation that original image is a coloured image.For instance, when original image is a coloured image, can first coloured image be converted to respectively different look planes, for example can be converted to respectively R, G, three look planes of B, the color separated image that each look plane is produced is considered as a gray scale image, again with data-hiding method of the present invention, apply mechanically to each corresponding gray scale image in look plane and can reach identical effect.Similarly, when when decoding, as long as a coding gray scale image corresponding to indivedual look planes overlapping the combining of decoding respectively again, just can obtain the color effect of former figure.For example, in certain embodiments, when original image is a coloured image, can adopt respectively data-hiding method of the present invention, each corresponding gray scale image in look plane is hidden into identical or different confidential information, therefore can hide into more information.For instance, can hide respectively R, G, three corresponding gray scale images in look plane of B and carry out data into three different watermark and hide, be decoded by three coding gray scale images corresponding to look plane respectively again during decoding and hide three watermark of entering.

Figure 1A shows the data handling system 100 that data are hidden that is used for according to the embodiment of the invention.Shown in Figure 1A, comprise at least an image input module 110, a bitmap generation module 120, a coding module 130 and a decoder module 140 in this system 100.Image input module 110 in order to receive an image and wish hide into a confidential information 160 (a for example watermark), and obtain at least one original gray scale image data 150 according to the image that receives.Wherein, image can be a coloured image or a gray scale image.What must remind is, in the present embodiment, image input module 110 can directly read a gray scale image with as original gray scale image data 150, and in another embodiment, image input module 110 can read a coloured image, be converted to respectively R, G, three look planes of B with the coloured image that will be read, and respectively with the corresponding color separated image in plane of the same colour wherein, as original gray scale image data 150.Wherein, confidential information 160 is a half tone image.Generally speaking, the size of confidential information 160 depends on the size of original gray scale image 150.For example, if original gray scale image 150 sizes be 1024 * 1024 and each cut section block size be 8 * 8, then confidential information is necessary for 128 * 128, shown in Fig. 2 B.Bitmap generation module 120 is coupled to image input module 110, and it can receive original gray scale image data 150 and confidential information 160, and original gray scale image 150 is carried out ODBTC coding of the present invention, is encoded to main bitmap to produce ODBTC.Wherein, the hybrid technology that ODBTC is encoded to orderly shake (OD) and block blocks coding (BTC), the account form of the corresponding value of every bit of its Bitmap is shown in following equation (1).

Please refer to Figure 1B, it is the thin section block diagram of demonstration one according to the bitmap generation module 120 of the embodiment of the invention.As shown in Figure 1B, bitmap generation module 120 can more comprise an extreme value judging unit 122, a halftoning array lookup unit 124 and is shaken in order block and blocked coding (ODBTC) unit 126.Wherein, extreme value judging unit 122 can be divided into a plurality of blocks with received original gray scale image 150, and to finding out its maximum and minimum value in each block of cutting apart, again with the maximum X that finds out _MaxWith minimum value X _MinBe sent to ODBTC unit 126.ODBTC unit 126 can receive the maximum X that extreme value judging unit 122 finds _MaxWith minimum value X _MinAnd utilize a halftoning array (shown in Fig. 2 A) that original gray scale image 150 is converted to a half tone image 150 ' (that is its pixel value is not that black (0) is exactly white (255)), interior stain or the white point of each block that again half tone image 150 ' is cut out is with the maximum X in the corresponding block in the original gray scale image 150 _MaxWith minimum value X _MinReplace, if stain then is substituted by minimum value X _MinOtherwise,, if white point then is substituted by maximum X _Max, and produce accordingly an ODBTC coded image.

In the present invention, it adopts orderly dithering (Order dithering) that gray scale image is converted to a half tone image.The correlation computations that about how the orderly dithering of gray scale image utilization is converted to a half tone image is existing technology, below only lists its result, and details is omitted at this.

In this embodiment, at first, extreme value judging unit 122 can be divided into a plurality of sub-block take n * n as the block size for the original gray scale image of M * N with the image block size.Suppose X _iThe GTG value unit that represents pixel in this block, calculate single order moment, second order moment and the variance of each block, then recycle the single order moment, second order moment and the variance that calculate the pixel value in the block is represented with maximum (highmean) and minimum value (low mean) and bitmap.

If maximizing and minimum value are respectively with x in the block of BTC _MaxWith x _MinExpression, the size of this halftoning array is identical with BTC cutting area block size, then shake in order block block coding (ODBTC) unit 126 can following equation generation ODBTC image:

$O_{i,j}=\left\{\begin{array}{cc}{x}_{\max },& \mathrm{if}{x}_{i,j}\&GreaterEqual;{\mathrm{DA}}_{i\mathrm{mod}M,j\mathrm{mod}N}^{\left(k\right)}+x_{\min }\\ x_{\min },& \mathrm{if}{x}_{i,j}<{\mathrm{DA}}_{i\mathrm{mod}M,j\mathrm{mod}N}^{\left(k\right)}+x_{\min }\end{array}\right.,---\left(1\right)$

Wherein, O _{I, j}Pixel value and the k=x of expression output _Max-x _Min, herein with two extreme values of the high mean value (high mean) of previous BTC and harmonic(-)mean value (low mean) with x _MaxWith x _MinThe reason of expression is that the threshold value for halftoning array (dither array) may be higher than high mean value or be lower than the harmonic(-)mean value.This phenomenon is so that reconstructed results feels partially dark.Therefore, more use a kind of look-up table based on the ODBTC image among the present invention, and utilize halftoning array lookup unit 124 via following equation (2), each halftoning array is adjusted for different sizes, so that its correction is adjusted to 255, wherein the halftoning array of each specific size all has 255 different adjusted values (scaling value) of its correspondence.These 255 different adjusted values can be resulting by following formula:

${\mathrm{DA}}_{m,n}^{\left(k\right)}=k\&times;\frac{{\mathrm{DA}}_{m,n}-{\mathrm{DA}}_{\min }}{{\mathrm{DA}}_{\max }-{\mathrm{DA}}_{\min }}---\left(2\right)$

1≤k≤255,1≤m≤M and 1≤n≤N wherein; DA _MinWith DA _MaxThen represent respectively maximum and minimum value in the halftoning array.

The dynamic area be k, its minimum value is 0, therefore

Value must add x _Min, so that the threshold value of the justice of all pixel values in the block to be provided.Because it is calculated off-line halftoning array in advance Value, be used as a table of comparisons and use, and can effectively reduce complexity.

Coding module 130 is coupled to image input module 110 and bitmap generation module 120, and bitmap images and confidential information that it can produce according to bitmap generation module 120 produce a coding gray scale image 170.Coding module 130 more comprises a high frequency region block analysis unit 132 and a data embedded unit 134, wherein high frequency region block analysis unit 132 is divided into a plurality of image block with bitmap images, and by finding out the stain block close with the white point number in these image block of cutting apart with as candidate block, by filtering out the high frequency block that belongs to HFS in the image in these candidate block of finding out.Data embedded unit 134 is hidden confidential information to these high frequency blocks more at random, and then produces the coding gray scale image 170 that keeps confidential information.The explanation of following Fig. 3 is asked for an interview in the detailed action of coding module 130.

Fig. 3 shows a flow chart according to the data-hiding method of the embodiment of the invention, and it is in order to be hidden in a confidential information in the gray scale image.Can be applicable in the system 100 shown in Figure 1A according to the data-hiding method of the embodiment of the invention.Similarly, the original gray scale image 150 in the present embodiment can directly get by the gray scale image of input or by the color separated image of the coloured image of inputting.At first, such as step S310, data input module 110 can receive original gray scale images 150 and a wish hide into confidential information 160, wherein confidential information 160 is a half tone image.Generally speaking, the size of confidential information 160 depends on the size of original gray scale image 150.For example, if original gray scale image 150 sizes be 1024 * 1024 and each block size be 8 * 8, then confidential information 160 is necessary for 128 * 128.

Then, such as step S312, bitmap generation module 120 can be with original gray scale image 150, (shown in Fig. 2 A) is converted to original half tone image via a halftoning array, again with stain and white point in the block of original half tone image, be made as respectively maximum and minimum value in the corresponding original image block, to obtain an ODBTC image.

Then, such as step S320, the high frequency region block analysis unit 132 in the coding module 130 can be divided into a plurality of image block with original half tone image (being the bitmap image), and by finding out the stain candidate block close with the white point number in the image block of telling.Wherein, the judgement of the candidate block that stain is close with the white point number in the image block can be judged by the formula of following equation (3).

Because the halftoning array that adopts is 16 * 16, it has symmetric property, therefore this halftoning array can be cut into 4 blocks.Each block is all 4 * 4.Fig. 2 A shows according to a halftoning array of the invention process.Therefore shown in Fig. 2 A, it is upper left identical with the bottom right, and is upper right identical with the lower-left, can all be divided into 4 * 4 to original half tone image, next, selects the stain number block the most close with the white point number in the half tone image block, with as candidate block.Wherein, the judgement of the candidate block that the stain in the image block is close with the white point number, can be judged by the formula of following equation (3):

|#black pixel-#white pixel|＜BW _Th (3)

Wherein #black pixel represents total number of stain in the block, and #white pixel represents total number of white point in the block, and BW _ThBe adjustable threshold parameter, it can be defined according to actual demand.Therefore, if wherein the block formula that satisfies equation (3) namely can be considered a candidate block.

After determining candidate block, such as step S330, filter out the high frequency block in the candidate block that high frequency region block analysis unit 132 is found out by step S320 again.Please refer to the explanation of following equation (4) about the mode that filters out the high frequency block.

The 132 pairs of candidate block that find in high frequency region block analysis unit judge whether to satisfy following equation (4):

CON _max≥#connect≥CON _min (4)

CON wherein _MaxWith CON _MinBe adjustable parameter.Generally speaking, larger parameters C ON _MaxWith less parameters C ON _MinCan obtain more block and enter more confidential information with the Tibetan, but excessive or too small parameter value also may can produce wrong judgement in decoding end.If wherein a candidate block satisfies equation (4), should belong to the HFS in the half tone image just represent this candidate block, it is defined as the high frequency block.Wherein, parameter #connect is defined as follows:

$\mathrm{con}(m,n)=\underset{i=0}{\overset{7}{\mathrm{\&Sigma;}}}w\left(i\right)h(P,P_i)$

And

$h(P,P_i)=\left\{\begin{array}{cc}1& P=P_i,\\ 0& P{\&NotEqual;P}_i,\end{array}\right.$

$w\left(i\right)=\left\{\begin{array}{ccc}1,& \mathrm{for}& i=\mathrm{1,3,4,6}\\ 0,& \mathrm{for}& i=\mathrm{0,2,5,7}\end{array}\right.$

See also Fig. 4, it shows the schematic diagram in contiguous 3 * 3 zones on every side of a pixel B.Then, the con (m, n) in the block is added up, just can obtain the value of parameter #connect, be expressed as follows formulation:

$\#\mathrm{connect}=\underset{m,n\&Element;\frac{M}{2}X\frac{N}{2}}{\mathrm{\&Sigma;}}\mathrm{\&Sigma;con}(m,n)---\left(5\right)$

Wherein M * the N in the equation (5) represents the size of halftoning array, for example 8 * 8 arrays shown in Fig. 2 A.Therefore, satisfy the block that the condition of aforesaid equation (4) searches and just can be considered the high frequency block.

Find out after the high frequency block, data embedded unit 134 just wish can be hidden into confidential information 160 be embedded in these high frequency blocks.So such as step S340, data embedded unit 134 can be hidden confidential information 10 to enter to these high frequency blocks at random.Because confidential information 160 is half tone image, therefore, only comprise 0 (being GTG value 0) and 1 (being GTG value 255) in the confidential information.In this step, if wish hide into the position for " 1 ", then with all pixel values counter-rotatings in corresponding this high frequency block, that is black bleaching, leucismus is black.On the contrary, if wish hide into the position for " 0 ", then all pixel values in corresponding this high frequency block are kept original values.Hiding one in the fashionable confidential information names a person for a particular job to be entered in the high frequency block by the Tibetan.

It should be noted that; the present invention also can utilize original confidential information first one default golden key (key) that it is broken up before hiding confidential information, with form wish hide into the confidential information figure; recycle formed confidential information figure execution in step S340, then further protected data.

Such as step S350, data embedded unit 134 can correspond to corresponding original gray scale image 150 with the half tone image of this change, insert maximum (high mean) and the minimum value (low mean) of each corresponding block in the gray scale image 150, and its corresponding block of difference substitution, to obtain keeping the coding gray scale image 170 of confidential information.It is worth mentioning that, in the present embodiment, block all is cut into the block of 8 * 8 sizes, when only the half tone image after the coil insertion device confidential information will be inserted maximum and minimum value, adopting the block size is 4 * 4 maximum and minimum values with corresponding block in the gray scale image, come backfill to hide half tone image into confidential information, therefore can make image seem more not have block effect.Through abovementioned steps S310 to S350, just confidential information can be hidden to image.

Fig. 5 shows another according to the flow chart of the data-hiding method of the embodiment of the invention, so that a confidential information is hidden in the gray scale image.Please be simultaneously with reference to Fig. 8 A to Fig. 8 C.Fig. 8 A shows one for the original gray scale image that illustrates.Fig. 8 B shows the data-hiding method according to the embodiment of the invention, and the orderly shake block that Fig. 8 A is produced blocks coded image.Fig. 8 C shows the data-hiding method according to the embodiment of the invention, the coding gray scale image that keeps confidential information that Fig. 8 B is produced.

At first, original gray scale image 50 (such as Fig. 8 A) is blocked coded system through orderly shake block of the present invention as the aforementioned, be encoded into orderly shake and block coding (ODBTC) image 51 (shown in Fig. 8 B), again by obtaining bitmap images 52 in the ODBTC image.Then, bitmap images is seen through formula (3), find out candidate block possible in the bitmap images block 53, again by utilizing formula (4) to filter out high frequency block 54 in the candidate block.The high frequency block 54 that these filter out will be used to hide confidential information.Afterwards, confidential information 55 utilizes first one at random behind the golden key beater confidential information, and the confidential information after breaing up is inserted corresponding high frequency block 54 again, wherein, if wish hide into the position for " 1 ", then with all pixel values counter-rotatings in corresponding this high frequency block, that is black bleaching, leucismus is black.On the contrary, if wish hide into the position for " 0 ", then all pixel values in corresponding this high frequency block are kept original values.Therefore, can produce the bitmap images of a change, the bitmap images of this change keeps confidential information.At last, recycling ODBTC 51 and the bitmap images that changes are added together 58, block coded image (shown in Fig. 8 C) with the orderly shake block that obtains containing confidential information, this ODBTC image that contains confidential information is the coding gray scale image, afterwards, the coding gray scale image can be sent to receiving terminal gets final product.

System 100 can more comprise a decoder module 140, to enter the input coding image of confidential information, to decode wherein to comprise confidential information 160 from the Tibetan and to rebuild back gray scale image or coloured image (being decoded picture 180).Decoder module 140 can more comprise a high frequency region block analysis unit 142 and a data reduction unit 144.Wherein, high frequency region block analysis unit 142 is in order to find out the high frequency block that belongs to HFS in the image, and its action is similar to high frequency region block analysis unit 132, so details is omitted at this.Data reduction unit 144 corresponds to relative position with the confidential information position of judging in the high frequency region block analysis unit 142 detected high frequency blocks, just can obtain half tone image data, and this half tone image is hides the confidential information of entering.It should be noted that, if before hiding confidential information, have and first original confidential information is utilized a default golden key that it is broken up, then in this step, resulting half tone image must utilize the golden key before broken up to break up detected image is counter, just can separate back the real confidential information of entering of hiding.The explanation of following Fig. 6 is asked for an interview in the detailed action of decoder module 140.

Fig. 6 shows a flow chart according to the data-hiding method of the embodiment of the invention, and it is in order to from the input coding image of hiding confidential information, decodes wherein to comprise confidential information and also rebuild back gray scale image or coloured image.Similarly, the data-hiding method according to the embodiment of the invention can be applicable to such as the system 100 among Figure 1A.At first, such as step S610, data input module 110 meeting receptions one keep the input coding image 170 of confidential information.In the present embodiment, the ODBTC coded image of input coding image for forming according to ODBTC coded system coding of the present invention.Such as step S620, utilize to receive the ODBTC coded image 170 of hiding confidential information, can produce the bitmap images that only has stain and white point.Wherein, when if the wherein pixel value in the ODBTC image is maximum (high mean), its corresponding bitmap pixels value just is 1, and if the wherein pixel value in the ODBTC image when being minimum value (low mean), just its corresponding bitmap pixels value is 0.Then, such as step S630, the bitmap images that high frequency region block analysis unit 142 will produce, and utilize aforementioned formula (3) to find the stain number block similar to the white point number in the block, just these blocks can be used as candidate block.Find out after the interior stain number of the block candidate block similar to the white point number, such as step S640, high frequency region block analysis unit 142 recycling formula (4) calculate the candidate block that finds, and judge the high frequency block.Afterwards, such as step S650, image restoring unit 144 will be with the block relative position that is found, and the half tone image obtained with average gray scale image calculates Hamming distance (Hamming distance) H _dWherein, image restoring unit 144 will be averaging after all the pixel value additions in the ODBTC coded image 170 first, to obtain an average pixel value, again each pixel value is made as average pixel value to form average gray scale image, recycle as the aforementioned halftoning array (shown in Fig. 2 A) average gray scale image is carried out in order shake (second round ordereddithering) computing second time, to obtain half tone image.Then, such as step S660, the Hamming distance H that calculates can be judged in image restoring unit 144 _dWhether more than or equal to half of number of pixels in the block.If H _dHalf ("Yes" of step S660) more than or equal to block size number of pixels, represent that then it is via counter-rotating (inverse) operation that the interior pixel value of this block has half, this block is via a large amount of counter-rotatings, can determine that therefore the confidential information value of hiding into this block is " 1 " (step S670).On the contrary, if H _dLess than half ("No" of step S660) of block size number of pixels, represent that the pixel value in this block does not pass through reverse turn operation, can determine that therefore the confidential information value of hiding into this block is " 0 " (step S680).

After all high frequency block execution of step S670-S680, such as step S690, the confidential information position that image restoring unit 144 can be judged the high frequency block that detects corresponds to relative position, just can obtain half tone image data, and this half tone image is hides the confidential information 160 of entering.It should be noted that, if before hiding confidential information, have and first original confidential information is utilized a default golden key that it is broken up, then in this step, resulting half tone image must utilize the golden key before broken up to break up detected image is counter, just can separate back the real confidential information of entering of hiding.Because confidential information utilization gold key is broken up, can prevent therefore that data in the data transfer procedure are stolen and the problem of leaking confidential information occurs.In addition, according to the data-hiding method of Fig. 6, can return hiding confidential information 100% decoding that enters, decoding rate is 100%.

Fig. 7 shows another according to the flow chart of the data-hiding method of the embodiment of the invention, and it is in order to from the input coding image of hiding confidential information, decodes wherein to comprise confidential information and rebuild back gray scale image or coloured image.Please be simultaneously with reference to Fig. 8 C to Fig. 8 D.Fig. 8 D is for showing the data-hiding method according to the embodiment of the invention, by decode among Fig. 8 C bitmap images.

At first, utilize the orderly shake block that contains confidential information that receives to block coding (ODBTC) image 70 (shown in Fig. 8 C), obtain a bitmap images 71.By the mode that obtains bitmap images 71 in the ODBTC image 70 that contains confidential information, for pixel value in the ODBTC image 70 that will receive is that the peaked of block just is made as 1, and pixel value be block minimum value just be made as 0, produce by this bitmap images 71.Note that bitmap images 71 still keeps confidential information.Then, bitmap images 71 via formula (3), is found the stain number candidate block 72 close with the white point number in the block.Again by in the candidate block 72 that finds via formula (4), filter out and belong to the subregional high frequency block 73 of radio-frequency head.Again these high frequency blocks 73 are carried out anti-halftoning computing, obtain the bitmap 74 of anti-halftone, again to the bitmap 74 of anti-halftone, utilize the halftoning array (as Fig. 2 A shown in) identical with coding side to carry out the in order shake computing second time afterwards, and the bitmap 75 that obtains changing.Afterwards, calculate again the bitmap 75 of change and the Hamming distance H between the ODBTC image 70 resulting bitmap images 71 _d, and judge the Hamming distance H that calculates _dWhether more than or equal to number of pixels in the block half 76.Therefore for instance, in the present embodiment, the block size is 4 * 4, so number of pixels is 16 in the block, judges that the Hamming distance that calculates whether more than or equal to number of pixels in the block half, is and judges the Hamming distance H that calculates _dWhether more than or equal to 8.If the Hamming distance H that calculates _dHalf ("Yes" of step S660) more than or equal to block size number of pixels, represent that it is via counter-rotating (inverse) operation that the interior pixel value of this block has half, this block is via a large amount of counter-rotatings, can determine that the confidential information value of hiding into this block is " 1 ", so can find all blocks 78 of hiding " 1 ".On the contrary, if H _dLess than block size number of pixels half, represent that the pixel value in this block does not pass through reverse turn operation, can determine that the confidential information value of hiding into this block is " 0 ", so can find all blocks 77 of hiding " 0 ".Afterwards, the block 78 that hides " 1 " is combined with the block 77 of hiding " 0 " obtain a temporary transient bitmap images (shown in Fig. 8 D) again.If confidential information is not broken up with random key first in compression end, then this temporary transient bitmap images is and hides the confidential information of entering.Yet, in the present embodiment, be compression end is broken up confidential information first with random key after, to be encoded to again example, therefore, need to detect in the temporary transient bitmap images hide the implantation site imagery exploitation at random golden key counter to break up running after 80s, the confidential information 81 that just can obtain rebuilding.In addition, if wish to get original gray scale image, can compare the ODBTC image 70 that contains confidential information and the block 78 of hiding " 1 ", all pixel values counter-rotatings in block corresponding to the block 78 that will contain in the ODBTC image 70 of confidential information and hide " 1 ", the orderly shake block that just can obtain reversing blocks coded image (decoded picture), and the orderly shake block that just can reverse thus blocks coded image and obtains original gray scale image.

Should be noted that although aforementioned modules of the present invention or unit are the independent assembly that is illustrated as this system, these two or more assemblies can be incorporated into together, thereby can reduce intrasystem package count.In like manner, one or above assembly can separately be used, thereby increase intrasystem package count.In addition, these modules or unit block can be implemented in the combination of any hardware, firmware and software.

Method of the present invention, or specific kenel or its part, can be contained in tangible media with the kenel of procedure code, get (such as readable in computer) Storage Media such as floppy disk, CD, hard disk or any other machine readable, wherein, when procedure code by machine, when being written into and carrying out such as computer, this machine becomes to participate in device of the present invention.Method and apparatus of the present invention also can see through some transfer mediums with the procedure code kenel, transmit such as electric wire or cable, optical fiber or any transmission kenel, wherein, when procedure code by machine, such as the computer reception, when being written into and carrying out, this machine becomes to participate in device of the present invention.When in general service processor implementation, the procedure code associative processor provides a class of operation to be similar to the unique apparatus of using particular logic circuit.

Although the present invention discloses as above with preferred embodiment; so it is not to limit the present invention, any those skilled in the art, without departing from the spirit and scope of the present invention; when can doing a little change and retouching, so protection scope of the present invention is as the criterion when looking the claim scope person of defining.

Claims (9)

1. an image data processing system is characterized in that, described image data processing system comprises:

One image input module receives an image and a confidential information, and obtains at least one gray scale image according to described image;

One bitmap generation module, couple described image input module, in order to original described gray scale image, be converted to an original half tone image via a halftoning array, and with stain and white point in the block of described original half tone image, be made as respectively maximum and minimum value in the corresponding described gray scale image block, block coded image to obtain an orderly shake block, each pixel in the wherein said original half tone image is black or white point; And

One coding module is coupled to described image input module and described bitmap generation module, according to described original half tone image and described confidential information, produces a coding gray scale image,

Wherein said coding module is divided into a plurality of image block with described original half tone image, and by finding out the stain candidate block close with the white point number in the described image block, by filtering out the high frequency block in the described candidate block of finding out, described confidential information is hidden at random to described high frequency block again, and this half tone image that changes corresponded to corresponding original described gray scale image, insert maximum and the minimum value of each corresponding block in the described gray scale image, and its corresponding block of difference substitution, to obtain keeping the described coding gray scale image of described confidential information.

2. image data processing system as claimed in claim 1, it is characterized in that, described coding module comprises a high frequency region block analysis unit, described oscillometry unit judges more whether in the described image block each satisfies following equation, with by finding out the stain candidate block close with the white point number in the described image block:

|#black pixel-#white pixel|<BW _Th，

Wherein #black pixel represents total number of stain in the block, and #white pixel represents total number of white point in the block, and BW _ThBe adjustable threshold parameter.

3. image data processing system as claimed in claim 1, it is characterized in that, described coding module more comprises a data embedded unit, in order to hide in wish into the place value of described confidential information be 1 o'clock, the place value counter-rotating of all pixels in the high frequency block that described wish is hidden, with the corresponding block in the mutagenic original half tone image, and wish hide into the place value of confidential information be 0 o'clock, the place value of described wish being hidden all pixels in the block keeps identical with the corresponding block in the original half tone image that produces this change, described confidential information is hidden at random into to described high frequency block.

4. image data processing system as claimed in claim 1, it is characterized in that, described image data processing system more comprises a decoder module, in order to be decoded described confidential information and to be rebuild back described gray scale image by the described coding gray scale image that keeps described confidential information.

5. image data processing system as claimed in claim 1 is characterized in that, described image comprises a coloured image, and described coloured image has plane of the same colour at least, and described image input module obtains described gray scale image according to described look plane.

6. a data-hiding method is characterized in that, described data-hiding method is applicable to a system in order to a confidential information is hidden in the image, and described system comprises at least one bitmap generation module and a coding module, comprises the following steps:

Receive an image and described confidential information and obtain at least one gray scale image according to described image;

Described bitmap generation module is with original described gray scale image, be converted to an original half tone image and with stain and white point in the block of described original half tone image via a halftoning array, be made as respectively maximum and minimum value in the corresponding described gray scale image block, block coded image to obtain an orderly shake block;

Described coding module is divided into a plurality of image block with described original half tone image, and by finding out the stain candidate block close with the white point number in the described image block;

Described coding module is by filtering out the high frequency block that belongs to HFS in the described candidate block of finding out;

Described coding module hides described confidential information at random into to described high frequency block, obtain an original half tone image that changes, if wherein wish hide into the place value of described confidential information be 1 o'clock, the place value counter-rotating of all pixels in the high frequency block that described wish is hidden, with the corresponding block in the original half tone image that produces described change, if and wish hide into the place value of confidential information be 0 o'clock, the place value of described wish being hidden all pixels in the block keeps identical with the corresponding block in the original half tone image that produces described change; And

Described coding module obtains maximum and the minimum value of each block in the described gray scale image, and the maximum of utilizing each block and minimum value replace the corresponding block of the original half tone image of described change, keeps a coding gray scale image of described confidential information with generation.

7. data-hiding method as claimed in claim 6 is characterized in that, it is to hide to described high frequency block again after utilizing one golden key being broken up described confidential information at random at random that described coding module hides described confidential information at random to the step of described high frequency block.

8. data-hiding method, it is characterized in that described data-hiding method decodes described confidential information in order to comprise in the input coding gray scale image of a confidential information by one, is applicable to a system, described system comprises at least one decoder module, comprises the following steps:

Described decoder module utilizes described input coding gray scale image, obtain a bitmap images, wherein, if in the described input coding gray scale image wherein a pixel value is maximum the time, its corresponding bitmap pixels value just is 1, if and in the described input coding gray scale image wherein a pixel value is minimum value the time, just its corresponding bitmap pixels value is 0;

Described decoder module is divided into a plurality of image block with described bitmap images, and by finding out the stain candidate block close with the white point number in the described image block;

Described decoder module is by filtering out the high frequency block that belongs to HFS in the described candidate block of finding out;

Described decoder module utilizes described high frequency block in the described bitmap images and an average gray scale image of corresponding described input coding gray scale image, determines the place value of hiding described high frequency block, more comprises:

Utilize the halftoning array that described average gray scale image is shaken computing in order, to obtain a half tone image;

Calculate the Hamming distance between the corresponding block of each described high frequency block and described half tone image;

If it is 1 that described Hamming distance, determines the place value of hiding described high frequency block more than or equal to a half of all number of pixels of a block;

If it is 0 that described Hamming distance, determines the place value of hiding described high frequency block less than a half of all number of pixels of a block; And

Described decoder module utilizes the described Tibetan that determines to enter the place value of described high frequency block, obtains described confidential information,

Wherein said decoder module is to judge whether in the described image block each satisfies following equation by the step of finding out the stain candidate block close with the white point number in the described image block:

|#black pixel-#white pixel|<BW _Th,

Wherein #black pixel represents total number of stain in the block, and #white pixel represents total number of white point in the block, and BW _ThBe adjustable threshold parameter.

9. data-hiding method as claimed in claim 8 is characterized in that, described data-hiding method more comprises:

Described decoder module utilizes the described Tibetan that determines to enter place value and the described input coding gray scale image of described high frequency block, rebuilds back a gray scale image,

When the place value that wherein enters a wherein block of described high frequency block when the described Tibetan that determines is 1, with in the described input coding gray scale image corresponding to the counter-rotating of the pixel value in the block of described block, to produce described gray scale image.

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