JP2005026729A - Image coding device and program, and image decoding device and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfactorily improve compression efficiency compared with a conventional technique in encoding an image having low correlation in a vertical direction such as an interlaced image. <P>SOLUTION: An input image rotating/transposing means 11 rotates or transposes input image data from an image input means 1. A body data generation means 2 encodes input image data from the means 1 to generate first body data. The means 2 further encodes the rotated/transposed input image data from the means 11 to generate second body data. A code quantity comparing means 12 determines the relation of magnitude between a code quantity Q1 of the first body data with a code quantity Q2 of the second body data. A code data output means 10 outputs the second body data if Q2<Q1, and outputs the first body data if Q1<Q2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image encoding device that encodes image data, an image encoding program, an image decoding device that decodes code data obtained by the encoding, and an image decoding program. It is.
[0002]
[Prior art]
As an image compression method, various methods have been conventionally used, including the most common JPEG. Recently, there is JPEG2000 as an image compression method which has been internationally standardized and attracting attention. This JPEG2000 is a method using wavelet transform (DWT), whereas conventional JPEG is a method using discrete cosine transform (DCT). It has many advantages such as a higher compression rate than comparable image quality. Even in the image data encoding technique using the JPEG2000 standard, further improvement of the compression rate is pursued (see, for example, Patent Document 1 or Patent Document 2).
[0003]
FIG. 10 is a block diagram showing a configuration of a conventional image encoding apparatus using JPEG2000. This apparatus includes an image input unit 1, a body data generation unit (image encoded data generation unit) 2, a header generation unit 9, and a code data output unit 10. The body data generation unit 2 includes a DC level shift unit 3, a color conversion unit 4, a wavelet conversion unit 5, a scalar quantization unit 6, a coefficient bit modeling unit 7, and an entropy encoding unit 8.
[0004]
Among the above-described components, the DC level shift means 3, the color conversion means 4, and the scalar quantization means 6 are provided as options in JPEG2000. In JPEG2000, there are other options as an option, but the explanation is omitted because they are not directly related to the technology of the present invention or are less important. In JPEG2000, an image is divided into a plurality of tile areas, and high-speed parallel processing is possible by eliminating the correlation between the tile areas. It is assumed that the processing is in the area. Therefore, in FIG. 10, illustration of components such as tiling means is omitted.
[0005]
Next, the operation of the apparatus according to FIG. 10 will be described. First, input image data from the image input means 1 is input to the DC level shift means 3, and the DC level is shifted. The shift of the DC level is to shift the level of the input image data with reference to a DC (direct current) component, that is, a zero component, in order to increase the encoding efficiency.
[0006]
Input image data from the DC level shift means 3 is input to the color conversion means 4, where conversion from values in the RGB color space to values in the YUV color space is performed. This conversion is also performed to increase the encoding efficiency.
[0007]
The image data color-converted by the color conversion means 4 is input to the wavelet conversion means 5 and wavelet conversion is performed. The wavelet transform is a transform used when analyzing a complex vibration waveform and the like, and is a waveform data analysis method that can simultaneously capture temporal or spatial fluctuations while taking advantage of the Fourier analysis.
[0008]
The scalar quantization means 6 quantizes the converted data into scalar values by dividing the converted data from the wavelet transform means 5 by a certain value. However, this quantization is not always necessary.
[0009]
The coefficient bit modeling unit 7 converts the wavelet coefficients quantized by the scalar quantization unit 6 into bit planes, and further, three predetermined paths (Significant Propagation Pass, Magnitude Refinement Pass, and Cleanup Pass) for each bit plane. (Process called three passes).
[0010]
The bit plane data processed by the coefficient bit modeling means 7 is input to the entropy encoding means 8 where entropy encoding is performed to generate body data (image encoded data). Then, necessary header information generated by the header generation unit 9 (for example, the number of bits of the wavelet coefficient, the number of zero bit planes, the number of processing paths, etc.) is added to the generated body data. The code data output means 10 outputs the body data and header information as code data.
[0011]
[Patent Document 1]
JP 2002-135594 A
[Patent Document 2]
JP 2002-165098 A
[0012]
[Problems to be solved by the invention]
By the way, FIG. 11 is explanatory drawing about the interlace image in a certain one code block CB. The interlaced image is an image obtained by alternately interleaving the top field and the bottom field, and in the example of FIG. 11, a certain object image P is interleaved with the top field side line L1 interleaved. The state formed by the bottom field side line L2 is clearly shown. In such an interlaced image of the object image P, it is clear that the correlation between the pixel data appears strongly in the horizontal direction, and the correlation in the vertical direction is extremely sparse.
[0013]
Here, the coefficient bit modeling and encoding performed by the coefficient bit modeling means 7 and the entropy encoding means 8 are based on a method specific to JPEG2000 called EBCOT, and the scanning direction is based on the vertical direction. FIG. 12A is an explanatory diagram of the scanning direction of such JPEG2000. As indicated by the arrows in this figure, within the region where the stripe height is 4 pixels and the stripe width is 10 pixels, the image is first lowered vertically by 4 pixels from the upper left position of the screen, and then the highest position in the next column. Then, the scanning of descending in the vertical direction by four pixels again is sequentially repeated.
[0014]
However, when encoding an image with very little correlation in the vertical direction as shown in FIG. 11, the scanning direction of JPEG 2000 in FIG. 12A based on the vertical direction is not a very suitable scanning direction. On the other hand, the preferred scanning direction is another scanning direction as shown in FIG. In other words, within the region where the stripe height is 1 pixel and the stripe width is 4 pixels, the image is first moved horizontally by 4 pixels from the upper left position on the screen, and then moved to the position one row below and again horizontally by 4 pixels. It is a scan like moving to.
[0015]
However, in the JPEG2000 standard, the scanning direction as shown in FIG. 12B is not allowed, so the scanning direction as shown in FIG. Therefore, conventionally, when encoding an image having low correlation in the vertical direction, such as an interlaced image, based on the JPEG2000 standard, it has been difficult to improve the compression efficiency beyond a certain level.
[0016]
The present invention has been made in view of the above circumstances, and it is possible to improve the compression efficiency by a certain level or more when encoding an image having low correlation in the vertical direction such as an interlaced image based on the JPEG2000 standard. It is an object of the present invention to provide a possible image encoding device, an image encoding program, and an image decoding device and an image decoding program for decoding code data obtained by the encoding.
[0017]
[Means for Solving the Problems]
As means for solving the above problems, the invention according to claim 1 is characterized in that input image rotation / transposition means for rotating or transposing 90 ° or −90 ° with respect to input image data, the input image data, Image encoded data generating means for performing the same encoding on both the rotated and transposed input image data that has been rotated or transposed by the input image rotating / transposing means, and generating image encoded data; A code amount of the first image encoded data generated by the image encoded data generation means by encoding the input image data, and the image encoded data generation means encodes the input image data after the rotation / transposition. A code amount comparison unit that compares the code amount of the second image encoded data generated by the first image encoded data and the first image encoded data according to the comparison result in the code amount comparison unit. Code data output means for outputting the image encoded data having the smaller code amount of the second image encoded data.
[0018]
According to the second aspect of the present invention, there is provided an input image rotation / transposition means for rotating or transposing a computer by 90 ° or −90 ° with respect to input image data, the input image data, and the input image rotation / transposition means. The encoded image data generating means for generating the image encoded data by performing the same encoding on both the rotated and transposed input image data subjected to the rotation or transposition in the above, and the image encoded data generation A code amount of the first image encoded data generated by the means for encoding the input image data, and a second image generated by the image encoded data generating means for encoding the input image data after rotation and transposition. Code amount comparison means for comparing the code amount of the encoded data, and the first image encoded data and the second image encoded data according to the comparison result of the code amount comparison means. Data code output means for outputting the encoded image data having the smaller code amount of the data.
[0019]
According to the third aspect of the present invention, the first encoded image data generated by predetermined encoding of the input image data, or the input image data after rotation / transposition after the input image data is rotated or transposed. The second image encoded data generated by the predetermined encoding is input, and the output image data by predetermined decoding with respect to the image encoded data from the code data input unit Output image data generation means for generating, rotation / transposition determination means for determining whether or not the image encoded data input by the code data input means has been rotated or transposed, and the rotation / transposition determination means When the transposition determination means determines that the rotation or transposition has been performed, the output image data generated by the output image data generation means is the rotation or transposition. Perform reverse rotation or re-transposition to return to the state before being performed, output image data after reverse rotation or re-transposition processing, and determine that the rotation / transposition discrimination means has not been rotated or transposed In this case, image output means for outputting the output image data generated by the output image data generation means as it is is provided.
[0020]
The invention according to claim 4 is the first image encoded data generated by predetermined encoding of the input image data, or the input image after rotation / transposition after rotating or transposing the input image data. The second image encoded data generated by the predetermined encoding is input to the data, the code data input means, and the image encoded data from the code data input means by the predetermined decoding Output image data generation means for generating output image data, rotation / transposition determination means for determining whether or not the image encoded data input by the code data input means has been subjected to the rotation or transposition, The output image data generated by the output image data generation means when the rotation / transposition determination means determines that the rotation or transposition has been performed. Reverse rotation or re-transposition for returning to the state before the rotation or transposition is performed, image data after reverse rotation or re-transposition processing is output, and the rotation / transposition discrimination means is rotated or transposed. When it is determined that the output image data is not, the image output unit is configured to function as an image output unit that outputs the output image data generated by the output image data generation unit as it is.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a configuration of an image encoding device according to an embodiment of the present invention, in which an image input means 1, body data generation means 2, header generation means 9, code data output means 10, input image rotation / A transposing means 11 and a code amount comparing means 12 are provided. The configuration of FIG. 1 is obtained by adding an input image rotation / transposition means 11 and a code amount comparison means 12 to the configuration of the conventional apparatus of FIG.
[0022]
That is, the input image rotation / transposition means 11 performs 90 ° or −90 ° rotation or transposition on the input image data from the image input means 1, and the input image data ( In this specification, this is referred to as “input image data after rotation / transposition”) and is output to the body data generation means 2 which is an image encoded data generation means.
[0023]
The body data generation unit 2 performs encoding based on JPEG2000 on the input image data directly input from the image input unit 1 to generate first body data (image encoded data). The input image data after rotation / transposition input via the input image rotation / transposition means 11 is encoded based on JPEG2000 to generate second body data (image encoded data).
[0024]
The code amount comparison unit 12 compares the code amount of the first body data generated by the body data generation unit 2 and the code amount of the second body data, and determines which is the smaller code amount. To do. The code data output means 10 outputs code data having the body data determined by the code amount comparison means 12 to be the smaller code amount of the first body data or the second body data. It has become.
[0025]
Here, the concept of “rotation” and “transposition” performed by the input image rotation / transposition means 11 will be described with reference to FIGS. FIGS. 2A and 2B are diagrams for explaining the rotation of the image data having the number of pixels of 3 × 3. FIG. 2A shows a state before the rotation, and FIG. 2B shows the image data from the state of FIG. A state after being rotated by 90 ° in the rotation direction is shown. Now, assuming that (a) is an image having low correlation in the vertical direction and high correlation in the horizontal direction like an interlaced image, the pixel data D1, D2 arranged in the first row (that is, in the horizontal direction). , D3 are highly correlated data. In (b), pixel data D3, D2, and D1 having high correlation with each other are arranged in the first column (that is, in the vertical direction) by rotation of −90 °. As described above with reference to FIG. 12A, since the scanning direction of JPEG 2000 is based on the vertical direction, efficient coding cannot be performed in the state of FIG. In the state (b), scanning is performed in accordance with the arrangement order of the pixel data D3, D2, and D1 having high correlation with each other, so that efficient encoding can be performed.
[0026]
FIG. 3 is an explanatory diagram of transposition of image data with 3 × 3 pixels. (A) is a state before transposition, and (b) is a transposition of image data from the state of (a) (for each pixel data). This shows the state after swapping rows and columns. Now, assuming that (a) is an image having low correlation in the vertical direction and high correlation in the horizontal direction like an interlaced image, the pixel data D1, D2 arranged in the first row (that is, in the horizontal direction). , D3 are highly correlated data. In (b), pixel data D1, D2, and D3 having high correlation with each other are arranged in the first column (that is, in the vertical direction) by transposition. Accordingly, in this case as well as in the case of FIG. 2B, scanning is performed according to the arrangement order of the pixel data D1, D2, and D3 having high correlation with each other, so that efficient encoding can be performed. .
[0027]
FIGS. 4A and 4B are diagrams for explaining the rotation of the image data having the number of pixels of 3 × 4. FIG. 4A is a state before the rotation, and FIG. It shows the state after. Assuming that (a) is an image having low correlation in the vertical direction and high correlation in the horizontal direction, such as an interlaced image, the pixel data D1, D2, D3, and D4 arranged in the first row are as follows. The data is highly correlated with each other. In (b), pixel data D4, D3, D2, and D1 having high correlation with each other are arranged in the first column by rotation of −90 °. Therefore, efficient coding cannot be performed in the state of FIG. 4A, but in the state of FIG. 4B, the arrangement of pixel data D4, D3, D2, and D1 that are highly correlated with each other. Since scanning is performed in accordance with the order, efficient encoding can be performed.
[0028]
FIG. 5 is an explanatory diagram of transposition of image data with 3 × 4 pixels. (A) is a state before transposition, and (b) is a state after transposing image data from the state of (a). Show. Assuming that (a) is an image having low correlation in the vertical direction and high correlation in the horizontal direction, such as an interlaced image, the pixel data D1, D2, D3, and D4 arranged in the first row are as follows. The data is highly correlated with each other. In (b), pixel data D1, D2, D3, and D4 having high correlation with each other are arranged in the first column by transposition. Therefore, in this case as well as in the case of FIG. 4B, scanning is performed according to the arrangement order of the pixel data D1, D2, D3, and D4 having high correlation with each other, so that efficient encoding can be performed. become.
[0029]
Further, as already described in FIG. 10, the header generation unit 9 generates header information such as the number of bits of the wavelet coefficient, the number of zero bit planes, the number of processing paths, etc. In this embodiment, Information on whether or not the input image data has been rotated or transposed, that is, image rotation / transposition information is also generated as the header information.
[0030]
FIG. 6 is an explanatory diagram showing the data storage position of the image rotation / transposition information. The header generation means 9 stores the image rotation / transposition information 16 together with the other header information generated in the main header 14, and stores the main header in the body data (image encoded data) 15 generated by the body data generation means 2. 14 is added. The code data output means 10 outputs the main header 14 and body data 15 as code data 13.
[0031]
The image rotation / transposition information 16 is generated because it may be necessary when decoding the body data 15 to obtain a reproduced image. In other words, if the input image data was rotated or transposed at the time of encoding, the reproduced image data obtained at the time of decoding is now rotated or re-transposed in the reverse direction to display the screen of the reproduced image data. Must be the same as the screen orientation of the original image. In this case, since the screen size of the input image data is usually different in horizontal and vertical dimensions (for example, 480 × 720), whether the image was rotated or transposed at the time of encoding when decoding was performed. Whether or not it can be determined by determining whether or not the horizontal and vertical dimensions of the screen size are switched. Therefore, on the decoding device side, whether or not reverse rotation or re-transposition is usually required for the reproduced image obtained by decoding, even if image rotation / transposition information is not added to the body data. Easy to know. However, if the screen of the input image data is square or if the screen size of the input image data has become a special size as a result of enlargement or reduction, the horizontal and vertical dimensions are switched. It is impossible to know whether or not rotation or transposition has been performed at the time of encoding only by discriminating. In the present embodiment, in consideration of such a case, the header generation unit 9 is configured to generate the image rotation / transposition information 16.
[0032]
Next, the operation of FIG. 1 will be described based on the flowchart of FIG. The image input means 1 inputs the original image data (step 71) and outputs it to the body data generation means 2 and the input image rotation / transposition means 11. The input image rotation / transposition means 11 rotates or transposes the input image data from the image input means 1 and outputs the input image data after the rotation / transposition to the body data generation means 2.
[0033]
The body data generation unit 2 performs encoding based on the JPEG2000 standard on the input image data input from the image input unit 1, generates first body data, and calculates the code amount Q1 (step 72). . The body data generation means 2 further performs encoding based on the JPEG 2000 standard on the rotated / transposed input image data input from the input image rotation / transposition means 11 to generate second body data and The code amount Q2 is calculated (step 73).
[0034]
The header generation means 9 adds header information not including image rotation / transposition information to the first body data, and adds header information including image rotation / transposition information to the second body data. In addition, these are output to the code data output means 10.
[0035]
The code amount comparison unit 12 determines the magnitude relationship between the code amounts Q1 and Q2 (step 74), and outputs the determination result to the code data output unit 10. When the code amount Q2 is smaller than the code amount Q1, the code data output means 10 outputs the code data having the second body data (step 75), while the code amount Q1 If is smaller than or equal to the code amount Q2, the code data having the first body data is output (step 76).
[0036]
In the above-described embodiment, both the first body data obtained by encoding the input image data as it is and the second body data encoded after rotating or transposing the input image data are generated. It is configured to output the smaller one. Therefore, even if the input image is an image having low correlation in the vertical direction such as an interlaced image, the compression efficiency at the time of encoding can be sufficiently improved.
[0037]
FIG. 8 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention, which is suitable for decoding code data obtained by the above-described image encoding apparatus of FIG. . This apparatus includes an image output means 27 having a code data input means 17, a header analysis means 18, an output image data generation means 19, a rotation / transposition determination means 25, and an image reverse rotation / reposition means 26. Based on the analysis result of the header analysis unit 18, the rotation / transposition determination unit 25 determines whether the body data of the code data input by the code data input unit 17 has been rotated or transposed at the time of encoding. Alternatively, the determination is made based on detection of whether the horizontal and vertical dimensions of the screen size of the input image data are switched. The image reverse rotation / retransposition means 26 rotates the output image data generated by the output image data generation means 19 when the rotation / transposition determination means 25 determines that the rotation or transposition has been performed at the time of encoding. Alternatively, reverse rotation or re-transposition for returning to the state before transposition is performed. The image output means 27 outputs an output image that has been reverse-rotated or re-transposed by the function of the image reverse-rotation / re-transposition means 26 or an output image that has not been reverse-rotated or re-transposed.
[0038]
The output image data generation unit 19 includes an entropy decoding unit, a scalar inverse quantization unit 21, an inverse wavelet transform unit 22, a color conversion unit 23, and a DC level shift unit 24. Among these, the scalar inverse quantization means 21, the color conversion means 23, and the DC level shift means 24 are provided as options in JPEG2000. In JPEG2000, there are other options as an option, but the explanation is omitted because they are not directly related to the technology of the present invention or are less important.
[0039]
The entropy decoding means 20 performs entropy decoding of the compression-encoded image data using the analysis result of the header analysis means 18, and creates a scalar quantized coefficient sequence from the output bit sequence.
[0040]
The scalar inverse quantization means 21 converts the coefficient sequence created by the entropy decoding means 20 based on the quantization style specified by the main header analyzed by the header analysis means 18 with a predetermined calculation formula in the JPEG2000 standard. Inverse quantization is used to generate wavelet coefficients. Note that the wavelet coefficients generated by the wavelet transform at the time of encoding are not necessarily scalar quantized, and in this case, the inverse quantization by the scalar inverse quantization means 21 is not performed.
[0041]
The inverse wavelet transform unit 22 performs inverse wavelet transform on the wavelet coefficient obtained by the scalar dequantization unit 21 based on the number of decompositions of the coding style specified by the main header, and creates image data in the YUV color space. It is.
[0042]
The color conversion means 23 converts the image data obtained by the inverse wavelet conversion means 22 from YUV components to RGB components according to the analysis result of the header analysis means 18. However, the color conversion means 237 does not operate when code data of a monochrome image or color conversion is not performed at the time of encoding.
[0043]
The DC level shift unit 24 shifts the DC level of each value of the RGB components obtained by the color conversion unit 23. The DC level shift is a shift so that the dynamic range is centered on the value 0 at the time of encoding, and is returned to the original at the time of decoding. The reason for performing the DC level shift is that the coefficient after frequency conversion is encoded by being divided into positive and negative signs and absolute values, and therefore the coding efficiency is higher when the data is arranged with reference to the zero value. It is.
[0044]
Next, the operation of FIG. 8 will be described based on the flowchart of FIG. Image data, that is, body data compressed and encoded in accordance with the JPEG 2000 standard by the image encoding apparatus of FIG. 1 is input by the code data input means 17 using a file system or network means (step 91). As described above with reference to FIG. 1, the input body data includes first body data obtained by encoding input image data as it is, or second body data obtained by encoding input image data after rotation / transposition. The code amount is smaller.
[0045]
A main header is attached to the body data, and the header analysis means 18 reads and analyzes these headers. Here, the main header stores information about the size of the image, the size of the tile, the offset of the image position, the offset of the tile position, the number of sample bits per pixel, the number of components such as RGB, and the like. The image rotation / transposition information described above is also stored.
[0046]
The output image data generation means 19 performs decoding based on the JPEG2000 standard on the body data of the code data from the code data input means 17 while referring to the analysis result of the header analysis means 18 (Step 92) The output image data is output to the image reverse rotation / retransposition means 26.
[0047]
Based on the analysis result of the header analysis unit 18, the rotation / transposition determination unit 25 determines whether the body data of the code data input by the code data input unit 17 has been rotated or transposed at the time of encoding. Alternatively, a determination is made based on whether or not the horizontal and vertical dimensions of the screen size of the input image data are switched (step 93), and the determination result is output to the image reverse rotation / retransposition means 26.
[0048]
When the rotation / transposition determination unit 25 determines that rotation or transposition has been performed at the time of encoding, the image reverse rotation / retransposition unit 26 rotates the output image data generated by the output image data generation unit 19. Alternatively, reverse rotation or re-transposition for returning to the state before the transposition is performed (step 94), and the output image data subjected to the reverse rotation or re-transposition is output to the image output means 27. On the other hand, when the rotation / transposition determination unit 25 determines that the rotation or transposition has not been performed at the time of encoding, the image reverse rotation / retransposition unit 26 outputs the output generated by the output image data generation unit 19. The image data is output to the image output means 27 as it is without doing anything.
[0049]
Then, the image output means 27 outputs an output image that has been reversely rotated or retransposed by the image reverse rotation / retransposition means 26, or an output image that has not been reversely rotated or retransposed (step 95). .
[0050]
The present invention includes a program for causing a computer to realize the functions of the above-described image encoding device and image decoding device. These programs may be read from a recording medium and loaded into a computer, or may be transmitted via a communication network and loaded into a computer.
[0051]
In the above embodiment, the encoding based on the JPEG2000 standard has been described. However, the present invention is not limited to the encoding method in which the compression efficiency can be improved by rotating or transposing the input image. Of course, the present invention can also be applied to those that use.
[0052]
【The invention's effect】
As described above, according to the present invention, when encoding an image having low correlation in the vertical direction, such as an interlaced image, the image encoding capable of sufficiently improving the compression efficiency as compared with the prior art. An apparatus and an image encoding program can be provided, and an image decoding program suitable for decoding the code data generated thereby can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an image encoding device according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram of the concept of “rotation” of image data with 3 × 3 pixels performed by the input image rotation / transposition means 11 in FIG. 1, where (a) is a state before rotation; ) Shows the state after rotation.
FIG. 3 is an explanatory diagram about the concept of “transposition” of image data with 3 × 3 pixels performed by the input image rotation / transposition means 11 in FIG. 1, wherein (a) is a state before transposition; ) Shows the state after transposition.
FIG. 4 is an explanatory diagram of the concept of “rotation” of image data with 3 × 4 pixels performed by the input image rotation / transposition means 11 in FIG. 1, where (a) is a state before rotation; ) Shows the state after rotation.
FIG. 5 is an explanatory diagram of the concept of “transposition” of image data with 3 × 4 pixels performed by the input image rotation / transposition means 11 in FIG. 1; (a) is a state before transposition; ) Shows the state after transposition.
6 is an explanatory diagram showing a data storage position of image rotation / transposition information generated by the header generation unit 9 in FIG. 1. FIG.
7 is a flowchart for explaining the operation of FIG. 1;
FIG. 8 is a block diagram showing a configuration of an image decoding apparatus according to an embodiment of the present invention.
FIG. 9 is a flowchart for explaining the operation of FIG. 8;
FIG. 10 is a block diagram showing a configuration of a conventional image encoding device.
FIG. 11 is an explanatory diagram of an interlaced image.
FIGS. 12A and 12B are explanatory diagrams of a scanning direction at the time of encoding, where FIG. 12A shows a scanning direction peculiar to JPEG 2000, and FIG. 12B shows another scanning direction.
[Explanation of symbols]
1 Image input means
2 Body data generation means (image encoded data generation means)
3 DC level shift means
4 Color conversion means
5 Wavelet transform means
6 scalar quantization means
7 Coefficient bit modeling means
8 Entropy encoding means
9 Header generation means
10 Code data output means
11 Input image rotation / transposition means
12 Code amount comparison means
13 Code data
14 Main header
15 Body data (image encoded data)
16 Image rotation / transposition information
17 Code data input means
18 Header analysis means
19 Output image data generation means
20 Entropy decoding means
21 Scalar inverse quantization means
22 Inverse wavelet transform means
23 Color conversion means
24 DC level shift means
25 Rotation / transposition discrimination means
26 Image reverse rotation / re-transposition means
27 Image output means
CB code block
P Object image
L1 Top field side line
L2 Bottom field side line
D1-D12 pixel data

Claims (4)

An input image rotation / transposition means for performing rotation or transposition of 90 ° or −90 ° with respect to the input image data;
An image that generates the encoded image data by performing the same encoding on both the input image data and the input image data that has been rotated or transposed by the input image rotation / transposition means. Encoded data generating means;
The code amount of the first image encoded data generated by the image encoded data generating means by encoding the input image data, and the image encoded data generating means by the encoding of the input image data after rotation / transposition. Code amount comparison means for comparing the code amount of the generated second image encoded data;
Code data output for outputting image encoded data having a smaller code amount of the first image encoded data and the second image encoded data according to the comparison result in the code amount comparing means Means,
An image encoding apparatus comprising: Computer
An input image rotation / transposition means for performing rotation or transposition of 90 ° or −90 ° with respect to the input image data;
An image that generates the encoded image data by performing the same encoding on both the input image data and the input image data that has been rotated or transposed by the input image rotation / transposition means. Encoded data generating means;
The code amount of the first image encoded data generated by the image encoded data generating means by encoding the input image data, and the image encoded data generating means by the encoding of the input image data after rotation / transposition. Code amount comparison means for comparing the code amount of the generated second image encoded data;
Code data output for outputting image encoded data having a smaller code amount of the first image encoded data and the second image encoded data according to the comparison result in the code amount comparing means Means,
An image coding program characterized in that the image coding program is for making it function. First image encoded data generated by predetermined encoding for input image data, or input image data after rotation / transposition after rotation or transposition of input image data, generated by the predetermined encoding Code data input means for inputting the encoded second image encoded data;
Output image data generation means for generating output image data by predetermined decoding with respect to the image encoded data from the code data input means;
Rotation / transposition discrimination means for discriminating whether or not the image encoded data input by the code data input means has been subjected to the rotation or transposition;
When the rotation / transposition determination means determines that the rotation or transposition has been performed, the output image data generated by the output image data generation means is returned to the state before the rotation or transposition. If the rotation / transposition determining means determines that the rotation or transposition has not been performed, the output is performed. Image output means for directly outputting the output image data generated by the image data generation means;
An image decoding apparatus comprising: Computer
First image encoded data generated by predetermined encoding for input image data, or input image data after rotation / transposition after rotation or transposition of input image data, generated by the predetermined encoding Code data input means for inputting the encoded second image encoded data;
Output image data generation means for generating output image data by predetermined decoding with respect to the image encoded data from the code data input means;
Rotation / transposition discrimination means for discriminating whether or not the image encoded data input by the code data input means has been subjected to the rotation or transposition;
When the rotation / transposition determination means determines that the rotation or transposition has been performed, the output image data generated by the output image data generation means is returned to the state before the rotation or transposition. If the rotation / transposition determining means determines that the rotation or transposition has not been performed, the output is performed. Image output means for directly outputting the output image data generated by the image data generation means;
An image decoding program characterized in that the program is made to function as an image.

Images