Image analysis – Applications
Reexamination Certificate
2001-08-31
2004-12-14
Boudreau, Leo (Department: 2621)
Image analysis
Applications
Reexamination Certificate
active
06831992
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data processing apparatus and data processing method, and to a recording medium, and particularly relates to a data processing apparatus and data processing method and recording medium enabling data embedding with high decoding precision, for example.
2. Description of the Related Art
FIG. 1
illustrates the configuration of an example of a conventional embedded coding apparatus which embeds data in pixels (pixel values) configuring an image, by performing bit-swapping, wherein bits making up bit strings representing pixels are swapped.
Art relating to bit-swapping has already been filed with the United States Patent and Trademark Office (USPTO) on Jun. 6, 2000, by the present Assignee, as Ser. No. 09/587,838.
Image data is supplied to image data memory
1
, and the image data memory
1
temporarily stores the image data supplied thereto. Also, data to be embedded in the image data (hereafter also referred to as “embedding data”) is supplied to embedding data memory
2
, and the embedding data memory
2
temporarily stores the data to be embedded, supplied thereto.
A bit-swap embedding unit
3
sequentially, e.g., in raster scan order, takes pixels making up the image data stored in the image data memory
1
, as pixels of interest, and reads out the pixel value thereof, and also reads out the data to be embedded which is stored in the embedding data memory
2
. Further, the bit-swap embedding unit
3
performs bit-swapping of the bits making up the bit string representing the pixel value of the pixel of interest according to the data to be embedded, thereby embedding the data to be embedded in the pixel value of the pixel of interest, and supplies the pixel value obtained as the result of the embedding (hereafter also referred to as “post-embedding pixel value”) to post-embedding image data memory
4
.
The post-embedding image data memory
4
stores the post-embedding pixel value supplied from the bit-swap embedding unit
3
at an address corresponding to the position of the pixel of interest, and in the event that post-embedding pixel values for one frame are stored, for example, outputs image data made up of the one frame of post-embedding pixel values (hereafter also referred to as “post-embedding image data”).
Next, the processing of the embedding coding apparatus (embedding coding processing) shown in
FIG. 1
will be described with reference to the flowchart shown in FIG.
2
.
In the event that the embedding coding apparatus is provided with, for example, one frame (or field) of image data and data to be embedded in that one frame of image data, the image data memory
1
stores the image data and the embedding data memory
2
stores the data to be embedded in step S
1
.
The flow then proceeds to step S
2
, where, in raster scan order, the bit-swap embedding unit
3
takes, of the pixels making up the image data stored in the image data memory
1
, as pixel of interest, pixels that have not yet been made pixel of interest. The bit-swap embedding unit
3
reads out the pixel value thereof, and also reads out the data to be embedded from the embedding data memory
2
, of an amount equivalent to the number of bits which can be embedded in the pixel value. Further, in step S
2
, the bit-swap embedding unit
3
performs bit-swapping of the bits making up the bit string representing the pixel value of the pixel of interest, according to the data to be embedded, thereby embedding the data to be embedded in the pixel value of the pixel of interest, and supplies the post-embedding pixel value obtained as a result of this embedding to the post-embedding image data memory
4
, where it is stored.
Subsequently, the flow proceeds to step S
3
, the bit-swap embedding unit
3
judges whether or not all pixels making up the image data stored in the image data memory
1
have been subjected to processing as pixel of interest, and in the event that judgment is made that not all pixels have been processed as pixel of interest, the flow returns to step S
2
.
Also, in step S
3
, in the event that that judgment is made that all pixels making up the image data stored in the image data memory
1
have been processed as pixel of interest, i.e., in the event that the image data made up of the post-embedding pixel values for one frame (post-embedding image data) has been stored in the post-embedding image data memory
4
, the flow proceeds to step S
4
, and the post-embedding image data memory
4
outputs the post-embedding image data stored therein, thereby ending the processing thereof.
The processing of the flowchart shown in
FIG. 2
is preformed for one frame of image data each time one frame of image data is supplied to the embedded coding apparatus.
According to such embedded coding processing, data to be embedded is embedded in pixel values, as shown in
FIG. 3
, for example.
That is,
FIG. 3
illustrates a case wherein the pixel value of the pixel of interest is 16, and data to be embedded with a value of 3 is to be embedded in the pixel of interest.
For example, saying that 8 bits are appropriated to the pixel value (the same holding true for the following description as well), the pixel value “16”, is generally represented as “00010000” in binary code. Accordingly, the bit string obtained by bit-swapping the binary code “00010000” can only be one of the eight patterns shown in FIG.
3
. With regard to the bit strings making up the binary code corresponding to the pixel value, the bit-swap embedding unit
3
correlates and stores the swapping pattern of the bits making up the bit string (the bit-swap pattern) with the data to be embedded, and the binary code representing the pixel value of the pixel of interest is subjected to bit-swapping according to the pattern correlated with the embedding data which is to be embedded in the pixel of interest.
In
FIG. 3
, the eight bit-swap patterns obtained by performing bit-swapping of the binary code “00010000” representing the pixel value “16”, i.e., “00010000”, “00100000”, “01000000”, “10000000”, “00000001”, “00000010”, “00000100”, and “00001000”, are each correlated with the data to be embedded “0”, “1”, “2”, “3”, “4”, “5”, “6”, and “7”, and accordingly, in the event that the data to be embedded is “3”, the bit-swap embedding unit
3
performs bit-swapping of the binary code “00010000” representing the pixel value “16” with the binary code “10000000” correlated with “3”, and the pixel value “128” represented by the binary code “10000000” as the result of bit-swapping is output as the post-embedding pixel value.
According to the above, in the event of embedding data to be embedded in a pixel value by bit-swapping, how much data to be embedded that can be embedded in a pixel value is governed by the number of 0s or 1s in the bit string making up the binary code representing the pixel value.
That is to say, the amount of information which can be embedded in the pixel value is governed by the total number of bit-swap patterns of the binary code representing the pixel value, and with the total number of bit-swap patterns represented by N, the amount of information which can be embedded in the pixel value is log
2
N bits. Now,
FIG. 4
illustrates the relation between the number of 0s or 1s and the amount of information which can be embedded, with regard to 8-bit binary code.
Next,
FIG. 5
illustrates the configuration of an example of a decoding apparatus for decoding the original pixel value and embedded data, from the post-embedding image data which is output from the embedded coding apparatus shown in FIG.
1
.
The post-embedding image data is supplied to post-embedding image data memory
11
, and the post-embedding image data memory
11
temporarily stores the post-embedding image data supplied thereto.
A bit-swap reverting unit
12
sequentially, e.g., in raster scan order, takes pixels making up the post-embedding image data stored in the post-embedding image data memory
11
, as pixels of interest, reads out the post-embedding pixel value of the pixel
Kobayashi Naoki
Kondo Tetsujiro
Boudreau Leo
Frommer William S.
Frommer & Lawrence & Haug LLP
Lavin Chris
LandOfFree
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