JP5046090B2 - Image data agitation device and its restoration device - Google Patents

Description

  The present invention relates to an agitation device for image data including encoded data and a restoration device thereof, and more particularly to an agitation device for image data capable of agitation of image data at an arbitrary intensity without depending on the characteristics of an image and the restoration device thereof.

As a conventional example of an image data stirring device, that is, a scramble device, there is one described in Patent Document 1 below. This document discloses that the last bit of the motion vector of the image and the last bit of the sign of the DCT coefficient are inverted so that the positive and negative of the motion vector and the DCT coefficient are switched and scrambled.
JP-A-6-90451

  However, in the above-described prior art, when the last bit of the motion vector of the image is inverted, when the motion amount is large, it changes greatly in the opposite direction, but when the motion vector is 0, there is no change even when scrambled. There is a problem that a scramble effect cannot be obtained in a scene where there is no motion, and there is a problem that the scramble effect is reduced because the amount of motion scrambled decreases as the scene moves more slowly. In addition, when the last bit of the sign of the DCT coefficient is inverted, the scrambling effect is large in a region where the spatial change such as an edge in the image is large, but the DCT coefficient value is small in a flat portion, so the scrambling effect is There was a problem of becoming smaller.

  As described above, the conventional technique has a problem that a stable scrambling effect cannot be obtained because the scrambling strength depends on the characteristics of the image.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art, and to provide an image data stirring device that can be stirred at an arbitrary intensity without depending on the movement of the image and the complexity of the scene, and a restoration device therefor There is.

To achieve the above objects, the present invention includes: a coded image data input means for inputting the encoded image data, a conversion coefficient extracting means for extracting a conversion coefficient of the stirring object from the coded image data, the stirring With respect to the means for designating the stirring intensity of the object and the extracted conversion coefficient of the stirring object , the absolute value of the non-zero DC coefficient value of the specific coding layer or the non-zero AC coefficient value of the specific coding layer is absolute. Agitation means for changing the coefficient value within the range of the agitation intensity using at least one of the maximum value, the lowest frequency, and the one determined using a key sequence; Means for generating and outputting encoded image data after stirring from the conversion coefficient and the conversion coefficient for the non-stirring object, and the change of the conversion coefficient value for the stirring target is within the range of the stirring intensity. To the complement value Further there is a first feature in that provided a stirring device of the image data, characterized by.

Further, the invention includes an image data input means for inputting image data, converting means for converting the image data into transform coefficients, a conversion coefficient extracting means for extracting a conversion coefficient of the stirring object from said transform coefficients, the stirring With respect to the means for designating the stirring intensity of the object and the extracted conversion coefficient of the stirring object , the absolute value of the non-zero DC coefficient value of the specific coding layer or the non-zero AC coefficient value of the specific coding layer is absolute. Agitation means for changing the coefficient value within the range of the agitation intensity using at least one of the maximum value, the lowest frequency, and the one determined using a key sequence; transform coefficients after stirring consisting of a transform coefficient and unstirred target transform coefficients to inverse transform was and a restoring means for restoring the image data, change of transform coefficient values to be the stirring object, the stirring In the range of intensity There is a second feature in that provided a stirring device of the image data and changes in value that is a number.

Further, the image data input means for inputting the image data stirred by the stirring device, the means for converting the image data into a conversion coefficient, the conversion coefficient of the stirring object is extracted, and the extracted conversion coefficient value is A stirring / restoring device for image data, comprising: restoring means for restoring the conversion coefficient value before stirring according to the specified stirring intensity; and means for reversely converting the restored conversion coefficient to restore image data before stirring. There is a third feature in the point provided.

  Also, image data input means for inputting image data, conversion means for converting the image data into a conversion coefficient that is a frequency space, means for designating the stirring intensity, and a conversion coefficient designated according to the designated stirring intensity. Fourthly, the present invention provides a stirring device for image data, comprising stirring means for changing the value and stirring the conversion coefficient, and means for encoding an image using the converted conversion coefficient after stirring and other encoding information. There are features.

  Furthermore, a fifth feature is that an apparatus for restoring encoded image data after stirring obtained by the stirring apparatus is provided.

  According to the present invention, since the screen can be stably stirred at the specified stirring (scramble) intensity, the stirring can be performed without being influenced by the movement of the image data or the complexity of the scene. Further, the stirring process can be performed so that the content of the image cannot be predicted.

  Furthermore, not only encoded image data compressed by MPEG or the like, but also unencoded image data can be stirred.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention.

  In FIG. 1, encoded image data a is input to the encoded image information extraction unit 1, and encoded data a <b> 1 used for agitation out of encoded data belonging to the agitation image region is extracted. The stirring target code data a1 is input to the data stirring unit 2. On the other hand, the encoded data a <b> 3 that is not subject to stirring is input to the encoded data generation unit 3. The data agitation unit 2 performs the agitation process with the agitation intensity specified for the agitation target code data a1. The agitation method can be realized by agitating DCT coefficients, motion vector amounts, and the like included in the encoded image data.

  Further, the data a <b> 2 after the stirring process is input to the encoded data generation unit 3. In the code data generation unit 3, the agitated data a2 and the encoded data a3 that has not been agitated are combined to generate encoded image data a4 after agitation.

  The coded image information extraction unit 1 can extract coding information of a coding block in a specific image area, a specific coding hierarchy, a specific coding mode, and the like of the input coded image data a.

  Next, the configuration and function of the present embodiment will be described with more specific examples. FIG. 2 is a block diagram showing a specific example.

  In the figure, the encoded image data a is input to the partial decoding unit 4, and the partially decoded partial decoded image data b is input to the encoded data extraction unit 5. Partial decoded data g other than the image data is sent to the partial encoding unit 8. The encoded data extraction unit 5 extracts encoded data c to be agitation processing target in accordance with the agitation target data information q and sends it to the data agitation unit 6. On the other hand, the encoded data d that is not subject to the stirring process is sent to the encoded data generation unit 7. The partial decoding unit 4 may be given the agitation target area information p to partially decode only the agitation target area, or may partially decode the entire area of the encoded data a.

  The data agitation unit 6 agitates (scrambles) the encoded data c according to the given agitation intensity S or according to the agitation intensity preset inside. In the encoded data generation unit 7, the data e that has been agitated by the data agitation unit 6 and the encoded data d that has not been subjected to the agitation process are synthesized, and the synthesized encoded data f is sent to the partial encoding unit 8. Sent. The partial encoding unit 8 combines the combined encoded data f and the partial decoded data g other than the image data, partially encodes them, and outputs the encoded image data h after stirring.

  In the encoded data extraction unit 5, for example, in the case of MPEG encoded data, a DCT coefficient or the like can be used as the agitation processing target encoded data c. The data agitation unit 6 performs an agitation process on the agitation process target encoded data c. As an agitation method, the DCT coefficient can be agitated according to the agitation intensity by using a key sequence that generates pseudo-random numbers.

  The encoded data generation unit 7 generates the encoded data f by combining the encoded data e that has been agitated by the data agitation unit 6 and the encoded data d that has not been subjected to the agitation process. For example, in MPEG data, the DCT coefficient data of each block is located in each 8 × 8 block layer. For this reason, when the DCT coefficient is agitated, GOP (Group of Pictures) and macroblock information can be used as they are before agitation, and the agitated DCT coefficient information can be stored for the block information layer.

  The stirring target area information p can be limited to a specific image area, a specific encoding layer, and a specific encoding mode as described in Japanese Patent Application No. 2006-187924, which is a patent application filed by the present applicant. is there.

  As shown in FIG. 3A, in the case of the specific image region, the coded data related to the specific image region is agitated. For example, for the 8 × 8 block group in the specific image area 10 in the image 9, it is possible to agitate the block layer information from which the encoded information regarding the block is obtained. Thereby, only a specific image area can be stirred.

  Also, as shown in FIG. 5B, in the case of the specific coding layer, for example, only a specific GOP in the GOP layer is targeted for mixing, or a specific picture (for example, only an I picture) in the picture layer. Etc.) can be targeted for stirring. As a result, the entire image of a specific picture can be agitated, and the encoded image using the image as a reference image can be agitated automatically.

  Furthermore, as shown in FIG. 5C, in the case of the specific coding mode, for example, only the block in the intra coding mode can be set as a stirring target. In this case as well, the block using the encoding mode that is the target of the stirring process is stirred, and all the blocks that refer to this block are also stirred automatically. For example, since only the intra-coded block is targeted for stirring, a stirring effect can be obtained for all subsequent forward prediction and bidirectional prediction blocks. It is possible to obtain an equivalent effect. Moreover, when the inter coding block using the forward prediction is also set as a stirring target, a stronger stirring effect can be obtained.

  Further, as the stirring target area information p, it is possible to set only a temporally specified image as a stirring process target, or to combine the specific image area, a specific encoding layer, a specific encoding mode, and the like.

  For the agitation method and the agitation area, a method determined in advance can be used, but as other methods, it is possible to store by using a technique such as encryption in the user data area of MPEG data, for example. It is. Furthermore, it is also possible to use a plurality of agitation methods and key sequences, and to change these pieces of information at the encoding layer (eg, GOP layer, macroblock layer, etc.). For example, in MPEG encoding, changing the key sequence between an I picture and a P picture corresponds to this. Thereby, the intensity | strength of stirring can be strengthened more. The key sequence can be changed according to the encoded image area. For example, a technique of changing the key sequence between the upper half and the lower half of the screen can be used.

  Furthermore, it is also possible to embed the agitation method and agitation area information as confidential information in the image data using a digital watermark. As a result, unless the watermark information can be read, the agitation method and the agitation area information cannot be obtained, so that very strong agitation is possible.

Next, specific examples of the present embodiment will be described below.
(Example 1) DC component stirring

  FIG. 4 shows an embodiment in which an image is stirred using a DC component for compressed image data.

  The encoded moving image data and the stirring target region information p are input to the partial decoding unit 11 configured by VLD (variable length decoding) or the like, and the conversion coefficient i of the stirring target region obtained from the partial decoding unit 11 is a DC component. Input to the extraction unit 12. Only the DC component j in the stirring target region indicated by the stirring target region information p is extracted to the DC component extraction unit 12, and information k outside the stirring target region, that is, the AC component is input to the partial encoding unit 14. Is done. The DC component j to be stirred extracted by the DC component extraction unit 12 is input to the DC component stirring unit 13 and stirred according to the stirring method q. The partial encoding unit 14 partially encodes the agitated DC component j ′ and other information k and m (AC component k, encoding information m outside the stirring target area, etc.) and encodes after stirring. Output as image data h.

As the stirring method q in the DC component stirring unit 13, several methods are conceivable.
In order to stir the DC component according to the stirring strength, the DC coefficient is changed with respect to the stirring strength S as follows. In this case, the DC coefficient value can be changed within the range of the stirring intensity. For example, assuming that the DC coefficient is Cd and the stirring intensity is S, the DC coefficient Cd ′ after stirring can be changed to a range of Cd ± S / 2.

The following methods can be used as the change method. In this case, the stirring intensity S is a multiple of 8 from 8 to 128,
Cd '= (2 * [Cd / S] +1) * S-Cd (1)
Can be obtained as Here, [X] indicates an integer operation.

For example, when S = 16 and Cd = 34, Cd ′ = 46. This is because the DC coefficient is divided into bands of 1-16, 17-32, 33-48,... By stirring intensity S = 16, and the coefficient after stirring is calculated by complement calculation in the band corresponding to the DC coefficient. Is equivalent to In the above example, since Cd = 34, the complement is 46 in the band of 33-48 (see FIG. 5). By converting in this way, it can be changed uniquely.
Conversely, to restore Cd from Cd ',
Cd = (2 * [Cd '/ S] +1) * S-Cd' (2)
Can be obtained as
For example, in the above example, when S = 16, Cd ′ = 46 and the process returns to Cd = 34.

  For the stirring, any of the luminance component Y and the color difference components Cb and Cr can be applied, and any one or a combination thereof can be used.

  When S is large, the conversion range becomes large, so that the value is converted to a significantly different value. Conversely, when S is small, the conversion range is limited, so the conversion amount is small. Thereby, the magnitude of the stirring effect can be controlled by the magnitude of the stirring strength S. For example, as shown in FIG. 6, when S is 32, the band is divided into 1-32, 33-64, 65-96,..., For example, Cd = 2 is 1-32 band. In FIG. On the other hand, when S is small 4, it is divided into bands of 1-4, 4-8, 9-12,..., For example, Cd = 2 is converted to complement 3 in the band of 1-4. The

  Next, a case where this technique is applied to MPEG encoded data will be described. For example, when encoded with MPEG-1, the DC component of the encoded data corresponds to the DC component on the DCT coefficient. In addition, when stirring is performed in the macroblock layer of MPEG-1, since stirring can be performed in units of macroblocks, stirring can be performed in a specific small region. In addition, when stirring is performed in the slice layer, stirring can be performed in units of slices, and therefore, stirring can be performed in units that are more organized than in units of blocks.

  In the above method, the agitated DC component is also within the same encoding specifications as before the agitation, so even if encoded data compliant with international standards such as MPEG-1 is input, the MPEG- It is possible to comply with one standard, and the encoded data after stirring can be reproduced by a reproducing means compliant with the MPEG-1 standard.

By stirring only the DC component by the method of this embodiment, it is possible to stir without depending on the movement or the complexity of the scene. Further, by stirring the most important DC component by human vision, even when the AC component is not stirred as it is, the stirring region can be stirred to an extent that the contents cannot be predicted.
(Example 2) AC component stirring

  FIG. 7 shows an embodiment in which an image is agitated using an AC component with respect to compressed image data.

The encoded image data is input to the partial decoding unit 21, and the quantized transform coefficient obtained from the partial decoding unit 21 is input to the AC component extraction unit 22. Other information is input to the partial encoding unit 25. In the AC component extraction unit 22, only the AC component is extracted from the quantized transform coefficients, the AC component to be stirred is inversely quantized and input to the AC component stirring unit 23, and the AC component is stirred. Other information is input to the partial encoding unit 25. The AC component stirred by the AC component stirring unit 23 is synthesized by the AC component encoded data generation unit 24 together with the information not to be stirred. In the partial encoding unit 25, the synthesized AC component and other information are partially encoded and output as encoded data after stirring.

  As a method for stirring the AC component, a method similar to the stirring of the DC component described in (Example 1) can be used.

That is, for a specific AC coefficient Ca, a value that is a complement in the band to which Ca belongs according to the stirring intensity S is used as the coefficient Ca ′ after conversion by a method such as the expression (1).
Ca '= (2 * [Ca / S] +1) * S-Ca (3)
Since the AC coefficient may be a negative number, in this case, the absolute value may be calculated in the same manner and then replaced with a negative number. Further, when restoring, the AC coefficient can be restored by a method such as equation (2).
Ca = (2 * [Ca '/ S] +1) * S-Ca' (4)

  Regarding AC coefficients, which AC coefficient is targeted can be determined by various methods. As a first method, there is a method using the AC coefficient of the lowest frequency among the non-zero AC coefficients. This is because the low frequency component has a large visual influence. As a second method, there is a method using a coefficient having the largest absolute value among non-zero AC coefficients. Also in this case, the same effect as the first method can be obtained by using a coefficient having a visually large influence. As a third method, a non-zero AC coefficient determined using a key sequence capable of generating a pseudorandom number can be used. In this case, the AC coefficient is selected at random. When similar images are continuous, a specific coefficient is selected in the first and second methods, which may reduce the stirring effect. However, in the case of the third method, randomness may be reduced. Since it can be ensured, the stirring effect can be improved. FIG. 8 shows an example of stirring by the third method. In this case, with the stirring intensity S = 32, the coefficient Ca = −2, which is present at the position (x, y) = (3, 1), is selected from the non-zero AC coefficients by the key sequence. Therefore, since the absolute value becomes 30 when converted using the equation (3), it becomes -30 as a negative number.

  In addition, about AC coefficient, it is also possible to stir several AC coefficients combining the said method. For example, it is possible to target two coefficients by combining the first and second methods, or to sequentially target two coefficients from a low frequency in the first method.

  As a modification, it is also possible to set both the AC coefficient and the DC coefficient as stirring targets. In this case, it is possible to enhance the effect as compared with the case of a single case.

  Furthermore, this stirring method can be combined with another stirring method. For example, as described in Japanese Patent Application No. 2006-187924, it is possible to combine a conversion coefficient between blocks using a key sequence, or a method of mixing conversion coefficients in a block using a key sequence. . For example, when the conversion coefficient is stirred between blocks, first, the DC component and AC component described in the first and second embodiments are changed to different values according to the stirring strength, and the conversion coefficients of all the blocks are further changed to a key sequence. It is possible to exchange with another block specified by. As for stirring in the block, first, the DC component and AC component described in Example 1 and Example 2 are changed to different values according to the stirring intensity, and the AC component in the block is further stirred according to the key sequence. be able to. By such a combination of stirring methods, stirring that is more difficult to decipher becomes possible.

  In addition, since the stirred AC component is within the same encoding specifications as before mixing, even if encoded data that conforms to international standards such as MPEG-1 is input, it will also comply with the MPEG-1 standard even after mixing. It is possible to reproduce the encoded data after stirring by a reproducing means compliant with the MPEG-1 standard.

  Next, a second embodiment of the present invention will be described. This embodiment is characterized in that a stirring process is performed during encoding.

  FIG. 9 shows a method in which the stirring process is also performed when the input image data is encoded. The image data is input to the first encoding unit 121 typified by DCT, quantizer, VLC and the like. Among the encoded outputs, the stirring target data and the stirring intensity are input to the data stirring unit 122. Further, the data not subject to stirring is input to the second encoding unit 123. In the data agitation unit 122, the encoded data is agitated and input to the second encoding unit 123. The second encoding unit 123 re-encodes the encoded data that has been agitated and the encoded data that has not been agitated, and outputs the encoded data. For example, when an I picture is an object to be stirred and a P picture located later in time is not an object to be stirred, the encoded output is performed so that the P picture data that is not stirred is followed by the stirred I picture data.

  In this case as well, as described with reference to FIGS. 4 and 8 of the first embodiment, by using an appropriate agitation method, the standards such as MPEG and JPEG are observed even after agitation with and without agitation. Is possible.

  Next, a third embodiment of the present invention will be described. In this embodiment, the agitated encoded data is restored to the encoded data before agitation using the reverse method during agitation.

  This will be described with reference to FIG. The stirred encoded data is input to the partial decoding unit 131 configured by VLD or the like. The data after partial decoding is input to the agitation restoration unit 132 for the encoded information belonging to the agitation target region. Also, the encoded information that is not subject to stirring is directly input to the partial encoding unit 133. The agitation restoration unit 132 restores the agitated encoded information to the original encoded information using equation (2) or the like. The returned encoded information is output as encoded data before mixing by the partial encoding unit 133 together with encoded information that is not subject to stirring.

  For example, if the I picture is being stirred and the subsequent P picture is not subject to stirring, the stirred I picture is input to the stirring restoration unit 132 and restored, and the I picture information before stirring is output. Is done. The partial encoding unit 133 encodes and outputs the P picture information that has not been mixed after the I picture before mixing.

  When an appropriate agitation method is selected, the encoded data restored by the above method can be restored to the same encoded data as the encoded data before being agitated. For example, in the case of the I picture described in the above example, it is possible to restore the encoded data before mixing by completely restoring the I picture encoded data before mixing.

  Next, a fourth embodiment of the present invention will be described. In this embodiment, the agitated encoded data is restored to the image data before agitation using the reverse method at the time of agitation.

  This will be described with reference to FIG. The stirred encoded data is input to the first decoding unit 141. The encoded data decoded by the first decoding unit 141 is input to the agitation restoration unit 142 for the encoded information belonging to the agitation target region. The encoded information that is not subject to stirring is input to the second decoding unit 143 as it is. In the agitation restoration unit 142, for example, the encoded information that has been agitated by a method such as Equation (2) is restored to the original encoded information. The returned encoded information is output as image data before mixing by the second decoding unit 143 configured by inverse quantization or inverse DCT together with the encoding information that is not to be mixed.

  For example, when an I picture is being stirred and the subsequent P picture is not subject to stirring, the stirred I picture is input to the stirring restoration unit 142, and the I picture encoded data before stirring is output. Is done. The second decoding unit 143 outputs an image obtained by sequentially decoding and restoring P picture information that has not been mixed after the I picture before mixing.

  Next, a fifth embodiment of the present invention will be described. In this embodiment, image data is agitated to obtain agitated image data.

  This will be described with reference to FIG. The image data is input to the image data extraction unit 151, and the image data of the stirring target area is extracted. If the target is the entire screen, all image data will be the target. Further, the non-target image data is input to the transform coefficient inverse transform unit 154. The stirring target image data is input to the image data converter 152. In the image data conversion unit, the target image data is frequency-converted. For example, DCT or Wavelet conversion that can be converted in block units can be used. The frequency-converted conversion coefficient is stirred by the data stirring unit 153. In the data stirring unit 153, the conversion coefficient of each block is stirred according to the stirring strength. As the stirring method, as described in Example 1 and Example 2, it is possible to stir the DC component and AC component of the conversion coefficient using the equations (1) and (3), respectively. For the method of specifying the AC coefficient, the method described in the second embodiment (the non-zero AC coefficient with the lowest frequency, the non-zero AC coefficient with the maximum absolute value, the non-zero AC coefficient specified with the key sequence), etc. is used. Can be specified. It is also possible to stir a plurality of coefficients by combining a DC component and an AC component. Furthermore, it is possible to target a plurality of AC coefficients such as using two non-zero AC coefficients from the lowest frequency to the higher frequency. The data-mixed conversion coefficient is input to the conversion coefficient inverse conversion unit 154. Here, the data-stirred conversion coefficient is inversely converted back to image data, and is output as image data after stirring together with the image data excluded by the image data extraction unit 151.

  When the output image data is stored in, for example, a storage device and saved, the image cannot be obtained even if another person reads the image data from the storage device and the image can be understood or predicted. can do.

  A method of restoring the image data stirred as described above to the image data before stirring will be described with reference to FIG. The stirred image data is input to the image data extraction unit 161, and the image data of the stirred region is extracted. If the target is the entire screen, all image data will be the target. Further, the non-target image data is input to the transform coefficient inverse transform unit 164. The stirring target image data is input to the image data converter 162. In the image data conversion unit, the target image data is frequency-converted. For example, DCT or Wavelet conversion that can be converted in block units can be used. The frequency-converted conversion coefficient is stirred by the stirring restoration unit 163. The stirring restoration unit 163 returns the conversion coefficient designated in each block before stirring. As the stirring restoration method, as described in the first and second embodiments, the DC component and the AC component of the conversion coefficient can be restored using the equations (2) and (4), respectively. The conversion coefficient whose stirring has been restored is input to the conversion coefficient inverse conversion unit 164. Here, the conversion coefficient is inversely converted to return to image data, and is output as image data after stirring together with the image data excluded by the image data extraction unit 161.

  Next, a sixth embodiment of the present invention will be described. In this embodiment, the amount of motion vector of encoded image data is agitated to obtain agitated encoded image data.

  FIG. 14 shows an embodiment in which an image is stirred using a motion vector for compressed image data.

The encoded image data is input to the partial decoding unit 171, and motion vector information obtained from the partial decoding unit 171 is input to the motion vector extraction unit 172. The other information is input to the partial encoding unit 174. The motion vector extraction unit 1 7 2, motion vector of the stirring object is input to the vector stirring section 173 motion, the motion vector is agitated. The other information is input to the partial encoding unit 174. The partial encoding unit 174 outputs the agitated motion vector component and other information together as encoded data after agitation.

  As a motion vector stirring method, a method similar to the DC component stirring described in the first embodiment can be used.

That is, for the motion vector MV, a value that is a complement of the motion vector MV in the band to which the MV belongs according to the stirring intensity S ′ is used as the coefficient MV ′ after the conversion by a method such as the equation (1).
MV '= (2 * [MV / S'] + 1) * S'-MV (5)
For example, when the motion vector range is ± 32 and the stirring intensity S ′ = 8, MV ′ = (9, −31 s) when MV = (15, −25). Since the motion vector may be a negative number, in this case, the absolute value is calculated in the same manner and then replaced with a negative number. Further, when restoring, the motion vector MV before stirring can be restored by a method such as the equation (6).
MV = (2 * [MV '/ S'] + 1) * S'-MV '(6)

  Further, as a modification, in addition to the motion vector, stirring can be performed in combination with the AC coefficient and the DC coefficient described in the first and second embodiments. In this case, it is possible to enhance the effect as compared with the case of a single case.

  In addition, since the agitated motion vector is within the same encoding specifications as before the agitation, even if encoded data that conforms to international standards such as MPEG-1 is input, it will also comply with the MPEG-1 standard after agitation. It is possible to reproduce the encoded data after stirring by a reproducing means compliant with the MPEG-1 standard.

1 is a block diagram showing a schematic configuration of a first embodiment of the present invention. It is a block diagram which shows the structure of one specific example of this invention. It is explanatory drawing of the specific example of stirring object area | region information. It is a block diagram which shows the structure of the outline of 1st Example. It is a figure explaining the relationship between a band and a complement in case of stirring intensity S = 16. It is a figure explaining the relationship between a band and a complement in case stirring intensity | strength S = 32 and S = 4. It is a block diagram which shows the structure of the outline of 2nd Example. It is explanatory drawing of an example of the stirring of AC component according to stirring intensity. It is a block diagram which shows the structure of the outline of 2nd Embodiment of this invention. It is a block diagram which shows the structure of the outline of 3rd Embodiment of this invention. It is a block diagram which shows the structure of the outline of 4th Embodiment of this invention. It is a block diagram which shows the structure (stirring apparatus) of the outline of 5th Embodiment of this invention. It is a block diagram which shows the structure (restoration apparatus) of the outline of 5th Embodiment of this invention. It is a block diagram which shows the structure of the outline of 6th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coded image information extraction part, 2 ... Data stirring part, 3 ... Code data generation part, 11, 21 ... VLD, 12 ... DC component extraction part, 13 ... DC Component stirrer, 14, 25 ... VLC, 22 ... AC component extractor, 23 ... AC component stirrer, 24 ... AC component encoded data generator, 121 ... first sign , 122... Data agitation unit, 123... Second encoding unit, 131... Partial decoding unit, 132. -1st decoding part, 142 ... Agitation restoration part, 143 ... 2nd decoding part, 151 ... Image data extraction part, 152 ... Image data conversion part, 153 ... Data stirring part 154 ... Conversion coefficient inverse transform unit, 161 ... Image data extraction unit, 162 ... Image data Conversion unit, 163... Stirring restoration unit, 164... Conversion coefficient inverse conversion unit, 171... Partial decoding unit, 172... Motion vector extraction unit, 173. -Partial encoding part.

Claims (8)

Encoded image data input means for inputting encoded image data;
Conversion coefficient extraction means for extracting a conversion coefficient to be agitated from the encoded image data;
Means for designating the stirring intensity of the stirring target ;
Regarding the extracted conversion coefficient to be agitated, the non-zero DC coefficient value of a specific coding layer or the non-zero AC coefficient value of the specific coding layer has the largest absolute value and the lowest frequency And a stirring means for changing the coefficient value within the range of the stirring intensity using at least one of those determined using a key sequence, and
Means for generating and outputting encoded image data after stirring, from the conversion coefficient subjected to the stirring process and the conversion coefficient to be unstirred,
The change of the conversion coefficient value to be agitated is changed to a value that is a complement within the range of the agitation intensity . Image data input means for inputting image data;
Conversion means for converting the image data into conversion coefficients;
Conversion coefficient extraction means for extracting the conversion coefficient to be stirred from the conversion coefficient;
Means for designating the stirring intensity of the stirring target ;
Regarding the extracted conversion coefficient to be agitated, the non-zero DC coefficient value of a specific coding layer or the non-zero AC coefficient value of the specific coding layer has the largest absolute value and the lowest frequency And a stirring means for changing the coefficient value within the range of the stirring intensity using at least one of those determined using a key sequence, and
; And a restoring means for restoring the image data by inverse transforming the transform coefficients after stirring consisting of the stirring process transform coefficients and unstirred target transform coefficients,
The change of the conversion coefficient value to be agitated is changed to a value that is a complement within the range of the agitation intensity . In the stirring device for image data according to claim 1 or 2,
The agitation means further uses at least one of the one having the maximum absolute value, the one having the lowest frequency, and the one determined using a key sequence, and a non-zero DC coefficient value. Stirring device. In the stirring restoration device for restoring the image data stirred by the image data stirring device according to claim 2 or 3 to the image data before stirring,
Image data input means for inputting the image data stirred by the stirring device;
Means for converting the image data into conversion coefficients;
A restoring means for extracting the conversion coefficient of the stirring target, and restoring the extracted conversion coefficient value to the conversion coefficient value before stirring according to the specified stirring intensity ;
A stirring / restoring apparatus for image data, comprising: means for inversely converting the restored conversion coefficient to restore the image data before stirring. Image data input means for inputting image data;
Conversion means for converting the image data into conversion coefficients;
Conversion coefficient extraction means for extracting the conversion coefficient to be stirred from the conversion coefficient;
Means for designating the stirring intensity of the stirring target ;
Regarding the extracted conversion coefficient to be agitated, the non-zero DC coefficient value of a specific coding layer or the non-zero AC coefficient value of the specific coding layer has the largest absolute value and the lowest frequency And a stirring means for changing the coefficient value within the range of the stirring intensity using at least one of those determined using a key sequence, and
And means for encoding an image by using the transformation coefficient value after stirring consisting of the stirring process transform coefficients and unstirred target transform coefficients, and other coded information,
The change of the conversion coefficient value to be agitated is changed to a value that is a complement within the range of the agitation intensity . In the stirring restoration device for restoring the image data stirred by the image data stirring device according to claim 5 to the image data before stirring,
Encoded image data input means for inputting encoded image data stirred by the stirring device;
Encoded information extracting means for partially decoding the encoded image data and extracting encoded information;
A stirring / restoring device for image data, comprising: restoring means for restoring the extracted coded information to coded information before stirring according to a designated restoration method. In the stirring restoration device for restoring the image data stirred by the image data stirring device according to claim 5 to the image data before stirring,
Encoded image data input means for inputting encoded image data stirred by the stirring device;
Encoded information extracting means for partially decoding the encoded image data and extracting encoded information;
Restoring means for restoring the extracted encoded information to the encoded information before stirring according to the specified restoration method;
A stirring / restoring apparatus for image data, comprising: decoding means for decoding the restored encoded information into image data before stirring. Encoded image data input means for inputting encoded image data;
Motion vector extraction means for extracting a motion vector from the partially decoded encoded image data;
Means for specifying the stirring intensity;
With respect to the motion vector, stirring means for changing the value of the motion vector to a motion vector using a complement expression in the range of the stirring intensity ;
Stirrer image data, characterized by comprising a means for outputting the encoded image data after stirring generated together with the stirring motion vectors and other coded picture information.

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