KR101669854B1 - Data concealment apparatus and method based on continuous integer transform - Google Patents
Data concealment apparatus and method based on continuous integer transform Download PDFInfo
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- KR101669854B1 KR101669854B1 KR1020160044262A KR20160044262A KR101669854B1 KR 101669854 B1 KR101669854 B1 KR 101669854B1 KR 1020160044262 A KR1020160044262 A KR 1020160044262A KR 20160044262 A KR20160044262 A KR 20160044262A KR 101669854 B1 KR101669854 B1 KR 101669854B1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T1/00—General purpose image data processing
- G06T1/0021—Image watermarking
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
- H04N21/83—Generation or processing of protective or descriptive data associated with content; Content structuring
- H04N21/835—Generation of protective data, e.g. certificates
- H04N21/8358—Generation of protective data, e.g. certificates involving watermark
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2201/00—General purpose image data processing
- G06T2201/005—Image watermarking
- G06T2201/0051—Embedding of the watermark in the spatial domain
Abstract
A data concealment apparatus and method based on continuous integer transform is disclosed. The data concealment apparatus and method based on the continuous integer conversion according to the present invention differs from the conventional method of concealing data of 1 bit on a pair of existing pixel values when concealing data on an image, N-1 bits of data can be concealed by successively performing integer conversion based on Difference Expansion for a pixel group composed of pixels of a predetermined number of pixels It is possible to conceal more data than techniques that conceal the data on the basis of the data, thereby increasing the efficiency of data concealment.
Description
Embodiments of the present invention are directed to techniques that can prevent sensitive information from being exposed by hiding data on an image.
Recently, as various types of information are generated and circulated, important information is exposed to a third party due to hacking or transmission of information to a wrong path.
Particularly, in case that important information such as military information or personal information is not applied in the process of transmitting information, and if such important information is accidentally transmitted to a third party, a third party can easily access important information , Can cause great damage.
In recent years, in order to prevent such important information from being exposed, a technique of inserting and transmitting important information in the form of a watermark has been introduced.
A watermark is a technique for inserting a mark originally known only to the owner into the original data such as text, image, video, and audio so that the mark can not be distinguished from the naked eye or the ear by a person. Recently, A data hiding technique has been introduced in which only a limited user can extract important information inserted in the image from the image.
There are various techniques for concealing data on an image, but a technique of concealing data in an image using Difference Expansion will be described as follows.
The data concealment based on the differential expansion method changes the pixel values of a pair of pixels located adjacent to each other in an image to be subjected to data concealment to another pixel value through a predetermined integer conversion, It is a technique of concealing original data by 1 bit for pixels.
In this regard, a specific process of concealing original data by one bit for a pair of pixels is as follows.
First, when a pixel value for a pair of pixels existing in the image is (x, y), an operation according to the following expression (1) is performed based on the pixel value (x, y) h).
here, "
When (l, h) is calculated based on the above-mentioned equation (1), h 'is calculated by performing the following equation (2) or (3) on h as the next process.
Here, b is 1-bit data having a value of "0" or "1 " to be hidden in the pair of pixels, and h used in computing h ' ) Is called a difference value, and h used in calculating h 'according to Equation (3) is referred to as a changeable difference value.
When the operation of h 'is completed, the operation according to Equation (4) is performed using l calculated in Equation (1) and h' calculated in Equation (2) or Equation (3) (X ', y'), which is a final converted pixel value for the pair of pixels, is concealed as 1-bit data of b is hidden in the pixel of the pixel.
The calculation of (x ', y') using h 'calculated through Equation (2) is called an integer transformation based on the extensible difference value h, and h' calculated through Equation (X ', y') is referred to as an integer conversion based on the exchangeable difference value h.
The data concealment technique based on the differential expansion in this manner combines a plurality of pixels existing in the image with one pair of pixels and performs an operation according to Equations 1, 2, 3, and 4 on each pair of pixels , The pixel values of each pair of pixels are changed, and the data is concealed by one bit for each pair of pixels.
In general, when a pixel value of a pixel included in an image is a grayscale, a data value having an 8-bit size has a value between 0 and 255. [ In this case, when the data is concealed on the image according to Equations 1, 2, 3 and 4, the pixel values of each pair of pixels are changed to (x ', y') as in Equation (4) When the image is assumed to be a gray scale image, the changed pixel values (x ', y') for each pixel pair must have a value between 0 and 255. However, even if the data is hidden on the image, The concealed hidden image may remain in the format of one image.
Therefore, when the pixel value (x, y) of a pair of pixels is changed to (x ', y') as the integer conversion is performed based on the expandable differential value through the above Equation 2, , y ') have values between 0 and 255, h' must satisfy the condition of the following equation (5).
In this case, since h 'can be expressed by Equation (2), Equation (5) can be expressed by Equation (6) below.
At this time, in the data concealment technique based on the differential expansion, the pixel value (x, y) of one pair of pixels is (x ', y') as integer conversions are performed based on the expandable differential value through the above- (X, y) has a value of 0 to 255, that is, when the expandable difference value h satisfies the condition of Equation (6), "(x, y) h is extensible for "h.
Further, when the pixel value (x, y) of a pair of pixels is changed to (x ', y') as the integer conversion is performed based on the exchangeable difference value through Equation (3) , y ') have values between 0 and 255, h must satisfy the condition of the following Equation (7).
At this time, in the data concealment technique based on differential expansion, the pixel value (x, y) of a pair of pixels is (x ', y') as the integer conversion is performed based on the exchangeable difference value through Equation (3) (X, y) has a value of 0 to 255, that is, when the exchangeable difference value h satisfies the condition of Equation (5), "(x, y) quot; is interchangeable with respect to "h. "
The nature of such extensibility and interchangeability in the data concealment technique based on differential extension can be summarized as shown in Table 1 below.
2. If a pair of pixel values (x, y) is expandable with respect to h, then the pair of pixel values (x, y) is interchangeable for h.
3. Change (x ', y') as a pair of pixel values (x, y) has been subjected to integer conversion based on an extensible difference value h, or an integer conversion is performed based on an interchangeable differential value h (X ', y') can also be exchanged for h 'inversely computed from (x', y ').
Under such a characteristic, the data concealment based on the differential expansion performs integer conversion on the expandable pixel pairs among the pair of pixels included in the image using the extensible difference value as shown in Equation (2) Bit interleaved and the interleavable pixel pairs are subjected to integer conversion using the interchangeable difference value as shown in Equation (3), thereby hiding the data bit by bit.
However, when the data is later restored from the image after hiding the data on the image in this manner, it is possible to determine which pixel pair has undergone the integer conversion based on the expandable difference value, The data concealment technique based on the differential expansion can not determine whether any pixel pair among the pixel pairs included in the image is subjected to integer conversion based on the expandable differential value Or an integer value indicating whether integer conversion has been performed based on the exchangeable difference value.
Then, the data for the location map is concealed on the image together with the original data to be concealed in the image.
(X ', y') as a result of the integer conversion being performed based on the extensible difference value for the pixel value (x, y) of a pair of pixels, The method of extracting data is a method of extracting the LSB of h 'after inversely calculating the expandable difference value h' from (x ', y') to (x ', y' Data can be extracted and the pixel value (x, y) of the original image can be easily restored by performing an inverse operation on Equation (2) and Equation (1) with respect to h '.
However, if the pixel value (x, y) of the pair of pixels is converted into (x ', y') as the integer conversion is performed based on the exchangeable difference value, As a method of extracting data, the LSB of h 'is extracted after inverse operation of the exchangeable difference value h' from (x ', y') to (x ', y' Data can be extracted. However, since the LSB of the exchangeable difference value h for (x, y) is lost in the course of data hiding, the inverse operation of Equation (3) and Equation , The pixel value (x, y) of the original image is not restored.
Therefore, when integer conversion is performed on the pixel value (x, y) of a pair of pixels based on the exchangeable difference value, the LSB of the exchangeable difference value h for the pixel value (x, y) The image can be accurately restored to the original image when the hidden data is extracted from the image at a later time.
Therefore, the data concealment technique based on the differential expansion can be applied to pixel pairs whose integer conversions have been performed based on the convertible differential value among the pixel pairs of the image, the original data to hide the LSB of the convertible differential value h on the image and And is concealed along with the data for the location map.
In this way, when a hidden image is generated as the data is concealed on the image, a method of restoring the data from the hidden image is as follows.
First, interchangeable pixel pairs are extracted from each pixel pair constituting the hidden image.
Then, an inverse operation according to Equation (4) is performed on the pixel value (x ', y') of the interchangeable pixel pairs to calculate the interchangeable difference value h ', and the LSB of the interchangeable difference value h' Extracts the original data, the data for the location map, and the data for the original LSB that are hidden in the exchangeable pixel pairs.
When the original data is separated from the extracted data, the original data can be recovered from the hidden image.
In addition, in order to restore the original image from the hidden image, when the data is concealed on the original image among the replaceable pixel pairs with reference to the location map, it is exchangeable with the pixel pairs subjected to the integer conversion based on the extensible difference value And separates the pixel pairs subjected to the integer conversion based on the difference value.
Then, the original pixel value (x, y) can be restored by performing an inverse operation on the expression (2) and the expression (1) on the pixel pairs whose integer conversions have been performed based on the expandable difference value, For the pixel pairs subjected to the integer conversion based on the interchangeable difference value, the interchangeable difference value h is restored using the original LSB, and then the inverse operation is performed on the expression (1) ) Can be restored.
The data hiding technique based on the existing differential extension has been briefly described. The data concealment technique based on the differential expansion described above is a technique of bundling a plurality of pixels included in an image into a pair of pixels and then concealing one bit of data for a pair of pixels, There was a limit to the size of the data.
In addition, since it is necessary to generate a location map indicating whether integer conversion has been performed based on the extensible difference value for each pair of pixels or whether integer conversion has been performed based on the exchangeable difference value, the data size of the location map is increased, There is a problem that the size of the actual data that can be concealed on the screen becomes small.
Therefore, in relation to the technique of concealing data based on differential expansion, there is a need for research on a method for increasing the efficiency of data concealment by hiding more data on the image than existing data concealment techniques.
The data concealment apparatus and method based on the continuous integer conversion according to the present invention differs from the conventional method of concealing data of 1 bit on a pair of existing pixel values when concealing data on an image, N-1 bits of data can be concealed by successively performing integer conversion based on Difference Expansion for a pixel group composed of pixels of a predetermined number of pixels It is possible to conceal more data than a technique of concealing data based on it, thereby increasing the efficiency of data concealment.
The data concealment apparatus based on continuous integer transformation according to an embodiment of the present invention includes n (n is a natural number of 3 or more) pixels arranged in a line in the image adjacent to each other in a plurality of pixels constituting an image, A grouping unit for generating a plurality of pixel groups by performing grouping for the n pixels included in each of the plurality of pixel groups, and a grouping unit for grouping the n pixels included in each of the plurality of pixel groups, And a data concealment unit for successively performing integer conversions based on a difference expansion for a pixel value between a pair of pixels to conceal the original data on the image.
According to still another aspect of the present invention, there is provided a data concealment method based on continuous integer conversion, comprising the steps of: storing n (n is a natural number of 3 or more) adjacent to each other in a row in the image, Generating a plurality of pixel groups by grouping the pixels of each of the plurality of pixel groups in accordance with the order of arrangement of the n pixels in the image with respect to the n pixels included in each of the plurality of pixel groups, And successively performing an integer conversion based on differential expansion of pixel values between a pair of adjacent pixels to conceal the original data on the image.
The data concealment apparatus and method based on the continuous integer conversion according to the present invention differs from the conventional method of concealing data of 1 bit on a pair of existing pixel values when concealing data on an image, N-1 bits of data can be concealed by successively performing integer conversion based on Difference Expansion for a pixel group composed of pixels of a predetermined number of pixels It is possible to conceal more data than techniques that conceal the data on the basis of the data, thereby increasing the efficiency of data concealment.
1 is a diagram illustrating a structure of a data concealment apparatus based on continuous integer conversion according to an embodiment of the present invention.
FIG. 2 and FIG. 3 are views for explaining a data concealment apparatus based on continuous integer conversion according to an embodiment of the present invention.
4 is a flowchart illustrating a data concealment method based on continuous integer conversion according to an embodiment of the present invention.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.
It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.
The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.
Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.
Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.
1 is a diagram illustrating a structure of a data concealment apparatus based on continuous integer conversion according to an embodiment of the present invention.
Referring to FIG. 1, a
Hereinafter, the operation of the
First, when a target image to be concealed with predetermined original data is input to a
In this regard, when the image to which the original data is to be concealed is an image composed of 64 pixels as shown in Fig. 2, and the n is assumed to be 4, the
The
In this regard, the
For example, when the pixel values of the four pixels included in the pixel group 1 (211) are arranged in the left-to-right direction (u 1 , u 2 , u 3 , u 4 ) The
That is, the
In this manner, the
As a result, the
When the
For example, if the image is a grayscale image as described above in the background, all pixel values included in the image must have a value between 0 and 255. [ Also, even if the image is changed as the data is concealed in the image, the pixel values included in the changed image must also have a value between 0 and 255. [
Accordingly, the
In this regard, according to an embodiment of the present invention, the
The first identifying
The unshrouded pixel
The first identifying
In this case, according to an embodiment of the present invention, the integer conversion based on the exchangeable difference value may be performed through an operation process of Equations (8) to (10).
For example, when the original pixel value of a pair of pixels is (x, y), an integer conversion based on the exchangeable difference value is first performed on the basis of the pixel value (x, y) (L, h) is calculated on the basis of Equation (8), and then by performing the operation according to Equation (9) on h in the next process, h '.
here, "
When the operation of h 'is completed, an integer conversion based on the exchangeable difference value performs an operation according to Equation (10) using the calculated h' so that a 1-bit And calculating (x ', y'), which is the final converted pixel value for the pair of pixels, as the data is concealed.
At this time, when the pixel value (x, y) of the pair of pixels is changed to (x ', y') as the integer conversion is performed based on the exchangeable difference value, any b, that is, b In both "0" and "1", if the modified (x ', y') has a value of 0 to 255, it is defined that "(x, y) can be exchanged for h".
In this regard, the first identifying
The unshrouded pixel
In this way, when the at least one first pixel group is determined, the
In this case, the
The second identifying
For each of at least one third pixel group in which it is determined that the predetermined pixel value range for the n pixels among the at least one second pixel group is within the predetermined pixel value range, And performs an integer conversion based on the extensible difference value to sequentially hide the original data by n-2 bits.
In this regard, the second confirming
In this case, according to an embodiment of the present invention, integer conversion based on the extensible difference value can be performed through the calculation process of Equations (11) to (13).
For example, when the original pixel value of a pair of pixels is (x, y), the integer conversion based on the extensible difference value is first performed on the basis of the pixel value (x, y) (L, h) is calculated on the basis of Equation (11), and by performing an operation according to Equation (12) on h in the next process, h '.
Here, b denotes 1-bit data having a value of "0" or "1 " to be hidden in the pair of pixels, h used in calculating h ' It is called differential value.
When the operation of h 'is completed, an integer conversion based on the scalable differential value performs an operation according to Equation (13) using the calculated h' to obtain a 1-bit And calculating (x ', y'), which is the final converted pixel value for the pair of pixels, as the data is concealed.
At this time, when the pixel value (x, y) of the pair of pixels is changed to (x ', y') as the integer conversion is performed based on the expandable difference value, any b, that is, b In both "0" and "1", if the modified (x ', y') has a value from 0 to 255, it is defined that "(x, y) is scalable for h".
Here, the properties related to the interchangeable and expandable with respect to the pixel value (x, y) of the pair of pixels have the features of Table 1 described in the Background of the Invention.
In this regard, the second confirming
At this time, for each of at least one third pixel group identified as being within the range of 0 to 255, the hidden pixel value for the four pixels among the at least one second pixel group, An integer conversion based on the scalable differential value according to the operations of Equations (11) to (13) may be sequentially performed to conceal the original data by two bits.
In this case, according to an embodiment of the present invention, the
The location
In this case, for each of the at least one third pixel group, the
For each of the at least one fourth pixel group, the
In this regard, the plurality of
At this time, the
At this time, the
When the generation of the location map is completed, the
That is, for each of the at least one third pixel group, the
In this case, when the integer conversion based on the extensible difference value is performed chained between the pixel having the third enumeration order in the image and the pixel having the fourth enumeration order, the
In this regard, when the concealment of b 1 and b 2 is completed, the
That is, if the partial data corresponding to a specific part of the bit string of the data constituting the location map is the first partial data, the
Accordingly, the
For each of the at least one fourth pixel group, the second concealing
In relation to the bit string of the data constituting the at least one fourth pixel group called, and the location of the pixel values of the four pixels (u 1, u 2, u 3, u 4) included in each map by said first speaking the data of a bit string specified one bit of the L p2 of the second section data other than the first partial data, the input to the b value in the second
As a result, the
As a result, the data concealment apparatus 110 based on continuous integer conversion according to the present invention groups a plurality of pixels constituting an image by n pixels to generate a plurality of pixel groups, and then, for each of the plurality of pixel groups Wherein the first pixel group includes at least one first pixel group that is not capable of data hiding and at least one second pixel group that is capable of data hiding for the plurality of pixel groups, And performing integer conversion based on the expandable difference value for the at least one second pixel group to form at least one third pixel group capable of data hiding and at least one fourth pixel group not capable of hiding And extracting original data for the at least one third pixel group based on the expandable difference value Number conversion of the at least one third pixel group and the at least one fourth pixel group to the at least one third pixel group and the at least one fourth pixel group, A technique of concealing data based on the existing difference expansion by further dividing and hiding the pixel data into four pixel groups hides the original data and the location map data for one pair of pixels, If the number of the at least one third pixel group is large, n-1 pieces of original data and a location map of n pixels belonging to the at least one third pixel group, Data can be concealed so that more data can be concealed in the same image. In addition, Because when you create a location map for each pixel groups grouped by the advantage which can reduce the data volume of the map location than the technique of each pixel of the original pair of creating a location map.
According to the present invention, an integer conversion is performed based on an interchangeable difference value between an n-1th pixel and an nth pixel among n pixels included in each of the at least one fourth pixel group, The original LSB of the interchangeable difference value h for the n-1th pixel and the n-th pixel out of the n pixels included in each of the at least one fourth pixel group is lost do.
Accordingly, in order to recover the hidden image from the hidden image after extracting the hidden data from the hidden image in which the data is later hidden, the n-1th pixel among the n pixels included in each of the at least one fourth pixel group And the original LSB of the interchangeable difference value h for the n-th pixel need to be additionally hidden on the image.
If only the data is concealed on the image and only the concealed data is extracted from the concealed image, it is sufficient to hide only the data on the original data and the location map on the image, It is not necessary to additionally include the original LSB of the interchangeable difference value h for the n-1th pixel and the n-th pixel among the n pixels included in the pixel.
However, the
The process of hiding the predetermined data on the image by the
According to an embodiment of the present invention, the
The reconstructed
2, when the plurality of pixels constituting the image are grouped into four pixels and the original data is concealed on the image, the reconstructed
The
In this regard, when the hidden image is a gray-scale image, the
That is, the
(X, y) of a pair of pixels have properties as shown in Table 1, and the pixel value (x, y) of the pair of pixels is If the pixel value (x ', y') of the converted pixel pair is expandable or interchangeable with respect to the extensible difference value or the interchangeable difference value h, it is always exchangeable with respect to the inverse. At this time, when the data is hidden on the image, since the data is hidden in the extension or exchange manner for the (n-1) th pixel and the (n) th pixel pair for each of the at least one second pixel group, Of the plurality of reconstructed pixel groups can be exchanged between the (n-1) -th hidden pixel and the (n-1) -th hidden pixel with respect to each of the plurality of reconstructed pixel groups, Can be found as a pixel group that is hidden.
The first reconstructed pixel
That is, the first restoration pixel
Thereafter, the location
In this case, when integer conversion is performed on the pixel value (x, y) of a pair of pixels in an extension or exchange manner and is converted into (x ', y'), The bit value b of the data concealed through the operation is equal to the LSB of the interchangeable difference value h 'for (x', y ') as shown in Table 1 above.
In this regard, when the data is concealed in the image, an integer conversion is performed on the third pixel and the fourth pixel among the four pixels included in each of the at least one second pixel group in an expansion or exchange manner, Since the data for the location map is hidden, the location
When the location map is restored, the second restoration pixel
In this regard, an index "1" is assigned to the at least one third pixel group as the division data on the location map, and an index "0" The second restoration pixel
Then, for each of the at least one second reconstructed pixel group, the
In this regard, the
That is, the
In this regard, since the LSB of the h 'in the computation characteristic of Equation (12) is b, the
The process of restoring the original data from the hidden image by the
The data concealment
Also, according to another embodiment of the present invention, a data concealment apparatus based on continuous integer conversion can transmit a concealed image to a predetermined information receiving terminal after concealing data on a predetermined image, And to receive the image and to recover the data from the hidden image.
4 is a flowchart illustrating a data concealment method based on continuous integer conversion according to an embodiment of the present invention.
In step S410, the plurality of pixels constituting the image are grouped by n (n is a natural number of 3 or more) pixels arranged in a line adjacent to each other in the image to generate a plurality of pixel groups do.
In step S420, for the n number of pixels included in each of the plurality of pixel groups, the pixel value of a pixel value between a pair of pixels adjacent to each other according to the enumeration order of the n number of pixels in the image And performs integer conversion based on the differential extension to chain the original data on the image.
According to an embodiment of the present invention, in step S420, for each of the plurality of pixel groups, among the n pixels included in each of the plurality of pixel groups, 1) -th pixel and the n-th pixel are subjected to integer conversion based on the exchangeable difference value among the integer conversions based on the differential expansion, Determining whether or not a pixel value belongs to a predetermined pixel value range; and determining whether a pixel value of a pixel to be changed for the n-1th pixel and the nth pixel among the plurality of pixel groups is within a predetermined pixel value range Determining at least one first pixel group as a pixel group not to be subjected to data hiding if there is at least one first pixel group identified as not belonging thereto It may contain.
According to an embodiment of the present invention, in step S420, for each of at least one second pixel group excluding the at least one first pixel group among the plurality of pixel groups, an integer based on the differential expansion When an integer conversion based on an extensible difference value during conversion is performed chained, it is determined whether or not the predetermined pixel value range for the n pixels in the at least one second pixel group falls within the predetermined pixel value range And for each of at least one third pixel group in which it is determined that the predetermined pixel value range for the n pixels among the at least one second pixel group falls within the predetermined pixel value range, And successively performing an integer conversion based on the difference value to hide the original data by n-2 bits.
According to an embodiment of the present invention, in step S420, the at least one third pixel group from the at least one second pixel group and at least one fourth pixel group excluding the at least one third pixel group, And generating a location map into which the classification data for identifying the pixel group is inserted.
Wherein the step of masking the original data by n-2 bits comprises, for each of the at least one third pixel group, selecting, within each of the n pixels included in each of the at least one third pixel group, And an integer-based conversion from the first pixel to the (n-1) -th pixel in order of the expandable difference value to hide the original data by n-2 bits, And hiding the first partial data for the data constituting the location map by one bit when an integer conversion based on the expandable differential value is cascade-executed between a pixel having an order n-1 and an n-th pixel, And for each of the at least one fourth pixel group, within each of the n pixels included in each of the at least one fourth pixel group, Performing an integer conversion based on the exchangeable difference value only for the pixel having the (n-1) -th order and the n-th order for the second order partial data and excluding the first partial data from the data constituting the location map, And a step of concealing the data.
According to an embodiment of the present invention, in the integer conversion based on the expandable difference value, when the pixel value of a pair of pixels to be converted is "(x, y) Quot; b "of the 1-bit data is calculated according to Equations (11) to (13) above with respect to the pixel value" (x, y) (x ', y') ", and the integer conversion based on the exchangeable difference value is performed on the pixel value" (x, y) "of the pair of pixels to be converted (X ', y') ", which is calculated according to Equations (8) to (10) above with the interchangeable difference value" h " Value. ≪ / RTI >
According to still another aspect of the present invention, there is provided a data concealment method based on continuous integer conversion, wherein a restoration command for the original data from the hidden image is generated after a hidden image is generated as the original data is concealed on the image Generating a plurality of restored pixel groups by grouping the plurality of hidden pixels constituting the hidden image into n hidden pixels arranged in a line adjacent to each other in the hidden image, For each of the plurality of restored pixel groups, the n-th hidden pixel and the n-th hidden pixel in the hidden image, which are included in each of the plurality of restored pixel groups, When integer conversion based on the exchangeable difference value is performed between pixels, the (n-1) -th hidden pixel and the (n-1) Determining whether or not a pixel value to be changed for a hidden pixel belongs to the predetermined pixel value range; changing the n-1th hidden pixel and the n-th hidden pixel among the plurality of restored pixel groups, Selecting at least one first reconstructed pixel group in which a predetermined pixel value is determined to fall within the predetermined pixel value range, and for each of the at least one first reconstructed pixel group, Calculating an interchangeable difference value based on an n-th hidden pixel and an n-th hidden pixel in the hidden image among the n hidden pixels included in the hidden image, Extracting the LSB of the difference value and restoring the location map based on the LSB extracted from each of the at least one first restoration pixel group, The at least one second reconstructed pixel group corresponding to the at least one third pixel group among the at least one first reconstructed pixel group is selected by referring to the division data inserted in the reconstructed location map, And for each of the at least one second reconstructed pixel group, the order of the n hidden pixels included in each of the at least one second reconstructed pixel group in the hidden image is n Wherein the step of performing an inverse transformation on an integer transformation based on the extensible difference value from a hidden pixel to a first hidden pixel is performed so that the order of enumeration in the hidden image is n-1th hidden pixel, From the n-1 hidden pixels existing between the pixels, the extensible difference value between a pair of hidden pixels adjacent to each other The step of restoring by n-2 bits of the original data by extracting from the LSB, wherein the at least one second decoding pixel groups each may further include.
The data concealment method based on continuous integer conversion according to an embodiment of the present invention has been described above with reference to FIG. Here, the data concealment method based on the continuous integer conversion according to the embodiment of the present invention can correspond to the configuration for the operation of the
The data concealment method based on continuous integer conversion according to an embodiment of the present invention can be implemented by a computer program stored in a storage medium for execution via a combination with a computer.
In addition, the data concealment method based on the sequential integer conversion according to an embodiment of the present invention may be implemented in the form of a program command which can be executed through various computer means and recorded in a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.
As described above, the present invention has been described with reference to particular embodiments, such as specific elements, and specific embodiments and drawings. However, it should be understood that the present invention is not limited to the above- And various modifications and changes may be made thereto by those skilled in the art to which the present invention pertains.
Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .
110: Data concealment device based on continuous integer conversion
111: grouping unit 112: data hiding unit
113: first verification unit 114: unconfigured pixel group determination unit
115: second confirmation unit 116:
117: Location map generation unit
118: first concealment unit 119: second concealment unit
120: Restoration pixel grouping unit 121: Restoration confirmation unit
122: first restoration pixel group selection unit 123: location map restoration unit
124: second restoration pixel group selection unit 125:
Claims (14)
A difference expansion unit for performing a difference expansion on a pixel value between a pair of pixels adjacent to each other in accordance with the order of arrangement of the n pixels in the image for each of the n pixels included in each of the plurality of pixel groups, ) For sequentially performing integer conversions based on the input data and concealing original data on the image,
Lt; / RTI >
The data hiding unit
For each of the plurality of pixel groups, among the n pixels included in each of the plurality of pixel groups, between the pixel whose order is n-1 and the pixel that is n-th in the image, (N-1) -th pixel and the (n-1) -th pixel are converted into a predetermined pixel value by a predetermined pixel value, A first checking unit for checking whether or not the value is in a range of values;
When there is at least one first pixel group in which it is determined that the predetermined pixel value range for the (n-1) -th pixel and the n-th pixel among the plurality of pixel groups is not within the predetermined pixel value range, An unshrouded pixel group determination unit for determining the at least one first pixel group as a pixel group not to perform data hiding;
For each of the at least one second pixel group excluding the at least one first pixel group among the plurality of pixel groups, an integer conversion based on an expandable difference value among integer conversions based on the differential expansion is cascade- A second confirming unit for confirming whether or not the predetermined pixel value range for the n pixels in the at least one second pixel group falls within the predetermined pixel value range;
If at least one third pixel group is identified as a pixel group in which the predetermined pixel value range for the n pixels among the at least one second pixel group is determined to be within the predetermined pixel value range, A location map in which the division data for distinguishing the at least one third pixel group from the second pixel group and at least one fourth pixel group excluding the at least one third pixel group is inserted is generated A location map generator; And
For each of the at least one third pixel group in which it is determined that the predetermined pixel value range for the n pixels among the at least one second pixel group is within the predetermined pixel value range, Based on a predetermined number of consecutive integers, and conceals the original data by n-2 bits,
/ RTI >
The concealing unit
And for each of the at least one third pixel group, among the n pixels included in each of the at least one third pixel group, an n-1th pixel from the first pixel, Wherein the step of sequentially hiding the original data by n-2 bits and performing the integer transform based on the scalable differential value between the n-1th pixel and the n- A first concealment unit for concealing the first partial data for the data constituting the location map bit by bit when the integer conversion based on the extensible difference value is performed chained; And
And for each of the at least one fourth pixel group, among the n pixels included in each of the at least one fourth pixel group, a pixel having an order of n-1th order in the image and an n- Of the first partial data except for the first partial data by performing an integer conversion on the basis of the exchangeable differential value,
Based on the continuous integer transform.
The integer transform based on the extensible difference value
(X, y) " of the pixel pair "(x, y)" of the pair of pixels to be converted, when the pixel value of a pair of pixels to be converted is "Quot; is converted into a new pixel value of "(x ', y')" while being hidden according to the following equation (1)
The integer conversion based on the exchangeable difference value
(2) with respect to the pixel value "(x, y)" of the pair of pixels to be converted via the exchangeable difference value "h " is transformed into a new pixel value of "(x ', y') ",while" b "is hidden.
[Equation 1]
here,
At this time,
&Quot; (2) "
here,
At this time,
When a restoration command for the original data is input from the hidden image after the hidden image is generated as the original data is hidden on the image, a restoration command for the original data is input to the hidden image, A reconstructed pixel grouping unit for generating a plurality of reconstructed pixel groups by performing grouping for n hidden pixels arranged in a line adjacent to each other;
Wherein, for each of the plurality of restored pixel groups, among the n hidden pixels included in each of the plurality of restored pixel groups, the hidden pixel whose enumeration order in the hidden image is the (n-1) When the integer conversion based on the exchangeable difference value is performed between the hidden pixels, it is determined whether or not the expected pixel value for the (n-1) -th hidden pixel and the n-th hidden pixel fall within the predetermined pixel value range A restoration confirmation unit;
Selecting at least one first reconstructed pixel group in which it is determined that the predetermined pixel value range for the (n-1) -th hidden pixel and the n-th hidden pixel among the plurality of reconstructed pixel groups falls within the predetermined pixel value range A first restoration pixel group selection unit that selects a first restoration pixel group;
For each of the at least one first reconstructed pixel group, among the n hidden pixels included in each of the at least one first reconstructed pixel group, (LSB) of the calculated interchangeable difference value and extracts LSB (Least Significant Bit) of the calculated interchangeable difference value from the LSB extracted from each of the at least one first reconstructed pixel group A location map reconstruction unit for reconstructing the location map;
The at least one second reconstructed pixel group corresponding to the at least one third pixel group among the at least one first reconstructed pixel group is selected by referring to the division data inserted in the reconstructed location map, A second restoration pixel group selection unit for selecting the second restoration pixel group; And
For each of the at least one second reconstructed pixel group, among the n hidden pixels included in each of the at least one second reconstructed pixel group, the order in the hidden image is n Th hidden pixel and the hidden pixel in the hidden image, while sequentially performing an inverse transformation on an integer transformation based on the expandable difference value to the hidden pixel in the hidden image, extracts the LSBs of the expandable difference values between a pair of hidden pixels adjacent to each other from n-1 hidden pixels, and restores the original data from each of the at least one second restored pixel group by n-2 bits The data restoring unit
Based on the continuous integer transform.
A difference expansion unit for performing a difference expansion on a pixel value between a pair of pixels adjacent to each other in accordance with the order of arrangement of the n pixels in the image for each of the n pixels included in each of the plurality of pixel groups, ) To perform an integer transformation on the image to conceal the original data on the image
Lt; / RTI >
Wherein hiding the original data on the image comprises:
For each of the plurality of pixel groups, among the n pixels included in each of the plurality of pixel groups, between the pixel whose order is n-1 and the pixel that is n-th in the image, (N-1) -th pixel and the (n-1) -th pixel are converted into a predetermined pixel value by a predetermined pixel value, Determining whether the value falls within a range of values;
When there is at least one first pixel group in which it is determined that the predetermined pixel value range for the (n-1) -th pixel and the n-th pixel among the plurality of pixel groups is not within the predetermined pixel value range, Determining the at least one first pixel group as a pixel group not to perform data concealment;
For each of the at least one second pixel group excluding the at least one first pixel group among the plurality of pixel groups, an integer conversion based on an expandable difference value among integer conversions based on the differential expansion is cascade- Determining whether a predetermined pixel value range for the n pixels in the at least one second pixel group belongs to the predetermined pixel value range;
If at least one third pixel group is identified as a pixel group in which the predetermined pixel value range for the n pixels among the at least one second pixel group is determined to be within the predetermined pixel value range, A location map in which the division data for distinguishing the at least one third pixel group from the second pixel group and at least one fourth pixel group excluding the at least one third pixel group is inserted is generated step; And
For each of the at least one third pixel group in which it is determined that the predetermined pixel value range for the n pixels among the at least one second pixel group is within the predetermined pixel value range, Performing a series of integer transform based on the original data to hide the original data by n-2 bits
/ RTI >
The step of concealing the original data by n-2 bits comprises:
And for each of the at least one third pixel group, among the n pixels included in each of the at least one third pixel group, an n-1th pixel from the first pixel, Wherein the step of sequentially hiding the original data by n-2 bits and performing the integer transform based on the scalable differential value between the n-1th pixel and the n- Hiding the first partial data for the data constituting the location map bit by bit when an integer conversion based on an extensible difference value is performed chained; And
And for each of the at least one fourth pixel group, among the n pixels included in each of the at least one fourth pixel group, a pixel having an order of n-1th order in the image and an n- Performing an integer conversion based on the exchangeable difference value to hide the second partial data excluding the first partial data of the data constituting the location map by one bit
/ RTI > The method of concealing data based on continuous integer transform comprising:
The integer transform based on the extensible difference value
(X, y) " of the pixel pair "(x, y)" of the pair of pixels to be converted, when the pixel value of a pair of pixels to be converted is " (X ', y') "as the data bit value" b "of one bit is concealed,
The integer conversion based on the exchangeable difference value
(X, y) "of the pair of pixels to be converted is calculated according to the following equation (4) through the exchangeable difference value" h " wherein a new pixel value of "(x ', y')" is changed while "b" is hidden.
&Quot; (3) "
here,
At this time,
&Quot; (4) "
here,
At this time,
When a restoration command for the original data is input from the hidden image after the hidden image is generated as the original data is hidden on the image, a restoration command for the original data is input to the hidden image, Generating a plurality of restored pixel groups by performing grouping for n hidden pixels arranged in a line adjacent to each other;
Wherein, for each of the plurality of restored pixel groups, among the n hidden pixels included in each of the plurality of restored pixel groups, the hidden pixel whose enumeration order in the hidden image is the (n-1) When the integer conversion based on the exchangeable difference value is performed between the hidden pixels, it is determined whether or not the expected pixel value for the (n-1) -th hidden pixel and the n-th hidden pixel fall within the predetermined pixel value range ;
Selecting at least one first reconstructed pixel group in which it is determined that the predetermined pixel value range for the (n-1) -th hidden pixel and the n-th hidden pixel among the plurality of reconstructed pixel groups falls within the predetermined pixel value range ;
For each of the at least one first reconstructed pixel group, among the n hidden pixels included in each of the at least one first reconstructed pixel group, (LSB) of the calculated interchangeable difference value and extracts LSB (Least Significant Bit) of the calculated interchangeable difference value from the LSB extracted from each of the at least one first reconstructed pixel group Restoring the location map to the location map;
The at least one second reconstructed pixel group corresponding to the at least one third pixel group among the at least one first reconstructed pixel group is selected by referring to the division data inserted in the reconstructed location map, ; And
For each of the at least one second reconstructed pixel group, among the n hidden pixels included in each of the at least one second reconstructed pixel group, the order in the hidden image is n Th hidden pixel and the hidden pixel in the hidden image, while sequentially performing an inverse transformation on an integer transformation based on the expandable difference value to the hidden pixel in the hidden image, extracts the LSBs of the expandable difference values between a pair of hidden pixels adjacent to each other from n-1 hidden pixels, and restores the original data from each of the at least one second restored pixel group by n-2 bits step
Based on the continuous integer transform.
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