JP2008271193A - Image processing apparatus and program - Google Patents

Abstract

An image processing apparatus and a program capable of improving the processing time of a program when executing a plurality of types of image processing for each classified unit data that can be processed independently.
First area securing means (S1) for securing a first area for sequentially storing classified unit data that can be independently processed in a storage unit, and a plurality of types to be executed for the unit data Second area securing means (S2) for securing a second area necessary for image processing in the storage unit, storage means (S3) for storing one unit data in the first area, and storage in the first area The processing by the image processing means (S4 to S7) for sequentially executing a plurality of types of image processing using the second area for the single unit data, and the processing by the image processing means for all the unit data are completed. (Yes in S8), an opening means (S9, 10) for opening the first area and the second area is provided.
[Selection] Figure 10

Description

  The present invention relates to an image processing apparatus and a program.

  In Patent Document 1, in order to save the amount of memory used for printing, image information is separated into multi-value data and binary data, the binary data is stored in a bitmap memory, and the multi-value data is grayscale. The invention of the content to be stored in the information memory is described.

  On the other hand, in an apparatus that performs image compression / decompression processing, a method for pre-allocating a memory space of the maximum size expected from the size of image data to be processed, or a memory space of a certain size in advance, A general method is to add a memory space when the memory space is insufficient.

  Further, in the compression / decompression algorithm such as JPEG2000 (IS15444-1), the compression process or the decompression process consists of a plurality of processing steps. When the same processing step is repeatedly executed, before and after the execution of the processing step. In general, the method of repeatedly securing / releasing the memory space is used.

JP-A-8-130645

  By the way, the memory space required for image compression / decompression processing is large in size, and the memory is generally shared with other applications. Compared with the arithmetic processing performed at the time of processing, it takes much time.

  Therefore, in a compression / decompression algorithm such as JPEG2000, if the number of repetitions of the same processing step is large, the ratio of the time taken to secure / release the memory space to the processing time becomes very large. The result affects the processing time.

  According to the technique described in Patent Document 1, it is possible to increase the program speed by improving the amount of memory used. However, in a compression / decompression algorithm such as JPEG2000, the number of repetitions of the same processing step Processing when there are many is not considered.

  The present invention has been made in view of the above, and is capable of improving the processing time of a program when executing a plurality of types of image processing for each classified unit data that can be processed independently An object is to provide an apparatus and a program.

  In order to solve the above-described problems and achieve the object, the invention according to claim 1 is to secure a first area in the storage unit for sequentially storing classified unit data that can be processed independently. Area securing means, second area securing means for securing a second area necessary for the plurality of types of image processing to be executed for the unit data in the storage unit, and the unit data that is one in the first area Storage means for storing, image processing means for sequentially executing the plurality of types of image processing using the second area for one unit data stored in the first area, and all the An opening unit that opens the first area and the second area when it is determined that the processing by the image processing unit has been completed for the unit data;

  According to a second aspect of the present invention, there is provided a first area securing means for securing a first area in the storage unit for sequentially storing classified unit data that can be processed independently, and the unit data is executed on the unit data. Second area securing means for sequentially securing a second area necessary for a plurality of types of image processing in the storage unit for each unit data; storage means for storing one unit data in the first area; Image processing means for sequentially executing the plurality of types of image processing on the one unit data stored in the first region using the second region, and the image for all the unit data An opening unit that opens the first area and the second area when it is determined that the processing by the processing unit has been completed;

  According to a third aspect of the present invention, in the image processing apparatus according to the second aspect, the second area securing means includes the size of the second area that has already been secured and the unit data to be processed. Compare the required size of the second area, and if the required size of the second area is smaller, use the already secured size of the second area as it is. When the size of the second area is larger, the second area is opened and re-secured to secure a sufficient size of the second area.

  According to a fourth aspect of the present invention, in the image processing apparatus according to the third aspect, the second area securing means is configured such that the size of the second area required for the unit data to be processed is already greater. If it is larger than the size of the reserved second area, the second area required for the unit data to be processed after partially releasing the already reserved second area Ensure the size of the.

  According to a fifth aspect of the present invention, in the image processing apparatus according to the third or fourth aspect, the second area securing means opens when the second area that has already been secured is partially opened. Initialize only the part to be used.

  According to a sixth aspect of the present invention, in the image processing device according to any one of the first to fifth aspects, the unit data is any one of a color component, a divided region, a frequency band, and an effective bit plane of the image data. is there.

  According to a seventh aspect of the present invention, in the image processing apparatus according to any one of the first to fifth aspects, the unit data is any one of a color component, a divided region, a frequency band, and an effective bit plane of the image data. Such code string data.

  According to an eighth aspect of the present invention, in the image processing apparatus according to any one of the first to seventh aspects, the plurality of types of image processing for the unit data is performed by a JPEG2000 (IS15444-1) compression or expansion algorithm. It is compliant.

  According to a ninth aspect of the present invention, there is provided a first area securing function for securing a first area in the storage unit for sequentially storing classified unit data that can be independently processed, and the unit data being executed. A second area securing function that secures a second area necessary for a plurality of types of image processing in the storage unit, a storage function that stores one unit data in the first area, and a storage function that stores the unit data in the first area. An image processing function for sequentially executing the plurality of types of image processing using the second area for the stored unit data, and processing by the image processing function for all the unit data is completed. If it is determined that the first area and the second area are opened, the computer is caused to execute an opening function for opening the first area and the second area.

  According to a tenth aspect of the present invention, there is provided a first area securing function for securing a first area in the storage unit for sequentially storing classified unit data that can be independently processed, and the unit data being executed. A second area securing function for sequentially securing a second area necessary for a plurality of types of image processing in the storage unit for each unit data, and a storage function for storing one unit data in the first area; An image processing function for sequentially executing the plurality of types of image processing using the second area for one unit data stored in the first area, and the image for all the unit data If it is determined that the processing by the processing function has been completed, the computer is caused to execute an opening function for opening the first area and the second area.

  According to the present invention, the first area for sequentially storing the unit data and the execution for the unit data in the case of a plurality of types of image processing executed for the classified unit data that can be processed independently The processing time of the program can be improved by reducing the frequency of securing and releasing the second areas necessary for the plurality of types of image processing.

  Furthermore, since the usage amount of the storage unit can be controlled by the classified unit data (color component, region, frequency band, effective bit plane, etc.) that can be processed independently, the first region and the second region can be efficiently The time required for securing and releasing the area memory can be omitted, and image processing can be executed at high speed.

  First, an outline of the “hierarchical encoding algorithm” and the “encoding / decoding algorithm based on discrete wavelet transform” which are the premise of the present invention will be described. A representative example of “encoding / decoding algorithm based on discrete wavelet transform” is “JPEG2000 algorithm”.

  FIG. 1 is a functional block diagram of an image processing unit 100 that realizes a hierarchical encoding algorithm that is the basis of an encoding method based on discrete wavelet transform. The image processing unit 100 functions as an image compression unit, and includes a color space conversion / inverse conversion unit 101, a two-dimensional wavelet transform / inverse conversion unit 102, a quantization / inverse quantization unit 103, an entropy encoding / The functional block includes a decoding unit 104 and a tag processing unit 105.

  One of the biggest differences between the image processing unit 100 and the conventional JPEG algorithm is the conversion method. While JPEG uses discrete cosine transform (DCT), this hierarchical coding algorithm uses discrete wavelet transform (DWT) in the two-dimensional wavelet transform / inverse transform unit 102. ing. DWT has the advantage that the image quality in the high compression region is better than DCT, and this is one of the main reasons why DWT is adopted in JPEG2000, which is a successor algorithm of JPEG.

  Another major difference is that in this hierarchical encoding algorithm, a functional block of the tag processing unit 105 is added in order to perform code formation at the final stage of the system. The tag processing unit 105 generates compressed data as code string data during an image compression operation, and interprets code string data necessary for decompression during the decompression operation. With the code string data, JPEG2000 can realize various convenient functions. For example, the compression / decompression operation of a still image can be freely stopped at an arbitrary hierarchy (decomposition level) corresponding to octave division in block-based DWT (see FIG. 3 described later). Further, a low resolution image (reduced image) can be extracted from one file, or a part of the image (tiling image) can be extracted.

  In many cases, a color space conversion / inverse conversion unit 101 is connected to an input / output portion of an original image. For example, the RGB color system composed of R (red) / G (green) / B (blue) components of the primary color system and the Y (yellow) / M (magenta) / C (cyan) components of the complementary color system This corresponds to the part that performs conversion or reverse conversion from the YMC color system consisting of the above to the YUV or YCbCr color system. Further, when the original image data is RGB data or the like, a DC level shift for reducing the dynamic range in half is also performed.

  Next, the JPEG2000 algorithm will be described. As shown in FIG. 2, in the color image, each component 111 (in this case, the RGB primary color system) of the original image is generally divided by a rectangular area (division number ≧ 1). This divided rectangular area is generally called a block or a tile, but in JPEG2000, it is generally called a tile. Therefore, such a divided rectangular area is hereinafter referred to as a tile. (In the example of FIG. 2, each component 111 is divided into a total of 16 rectangular tiles 112, 4 × 4 in length and breadth). When such individual tiles 112 (R00, R01,..., R15 / G00, G01,..., G15 / B00, B01,..., B15 in the example of FIG. 2) execute the image data compression / decompression process. It becomes the basic unit. Therefore, the compression / decompression operation of the image data is performed independently for each component and for each tile 112.

  At the time of encoding image data, the data of each tile 112 of each component 111 is input to the color space conversion / inverse conversion unit 101 of FIG. 1 and subjected to color space conversion, and then the two-dimensional wavelet conversion / inverse conversion unit. A two-dimensional wavelet transform (forward transform) is applied at 102 to divide the space into frequency bands.

  FIG. 3 shows subbands at each decomposition level when the number of decomposition levels is three. That is, the tile original image (0LL) (decomposition level 0) obtained by the tile division of the original image is subjected to two-dimensional wavelet transform, and subbands (1LL, 1HL, 1LH, 1HH shown in the composition level 1). ). Subsequently, the low-frequency component 1LL in this hierarchy is subjected to two-dimensional wavelet transform to separate subbands (2LL, 2HL, 2LH, 2HH) shown in the decomposition level 2. Similarly, the low-frequency component 2LL is also subjected to two-dimensional wavelet transform, and the subbands (3LL, 3HL, 3LH, 3HH) indicated by the decomposition level 3 are separated. In FIG. 3, subbands to be encoded at each decomposition level are indicated by shading. For example, when the number of decomposition levels is 3, the subbands (3HL, 3LH, 3HH, 2HL, 2LH, 2HH, 1HL, 1LH, 1HH) indicated by shading are to be encoded, and the 3LL subband is encoded. Not.

  Next, the bits to be encoded are determined in the specified encoding order, and the context is generated from the bits around the target bits by the quantization / inverse quantization unit 103 shown in FIG.

  The wavelet coefficients that have undergone this quantization process are divided into non-overlapping rectangles called precincts for each subband. This was introduced to use memory efficiently in implementation. As shown in FIG. 4, one precinct is composed of three rectangular regions that are spatially matched. More specifically, a set of three regions at the same spatial position of the HL, LH, and HH subbands having the same decomposition level in the rectangular region of the subband is treated as one precinct. However, in the LL subband, one area is treated as one precinct. It is also possible to make the size of the precinct the same as that of the subband. Furthermore, each precinct is divided into non-overlapping rectangular code blocks. The code block is a basic unit for entropy coding. FIG. 4 shows an example of a precinct and its code block at decomposition level 1. A set of three regions located at the same spatial position as a precinct in FIG. 4 is treated as one precinct.

That is, between images, tiles, subbands, precincts, code blocks,
There is a size relationship of image ≧ tile> subband ≧ precinct ≧ code block.

  The coefficient values after the wavelet transform can be quantized and encoded as they are, but in JPEG2000, in order to increase the encoding efficiency, the coefficient values are decomposed into “bit plane” units, and each pixel or code block is divided. Ranking can be performed on “bitplanes”.

  Here, FIG. 5 is an explanatory diagram showing an example of a procedure for ranking the bit planes. As shown in FIG. 5, this example is a case where the original image (32 × 32 pixels) is divided into four 16 × 16 pixel tiles, and the size of the precinct and code block at the composition level 1 are respectively 8 × 8 pixels and 4 × 4 pixels. Precincts and code block numbers are assigned in raster order. In this example, precincts are assigned numbers 0 to 3, and code blocks are assigned numbers 0 to 3. A mirroring method is used for pixel expansion outside the tile boundary, wavelet transform is performed with a reversible (5, 3) filter, and a wavelet coefficient value of decomposition level 1 is obtained.

  An explanatory diagram showing an example of the concept of a typical “layer” configuration for tile 0 / precinct 3 / code block 3 is also shown in FIG. The converted code block is divided into subbands (1LL, 1HL, 1LH, 1HH), and wavelet coefficient values are assigned to the subbands.

  The layer structure is easy to understand when the wavelet coefficient values are viewed from the horizontal direction (bit plane direction). One layer is composed of an arbitrary number of bit planes. In this example, layers 0, 1, 2, and 3 are made up of bit planes of 1, 3, 1, and 3, respectively. A layer including a bit plane close to LSB (Least Significant Bit) is subject to quantization first. Conversely, a layer close to MSB (Most Significant Bit) is quantized to the end. It will remain without being. A method of discarding from a layer close to the LSB is called truncation, and the quantization rate can be finely controlled.

  The entropy encoding / decoding unit 104 illustrated in FIG. 1 performs encoding on the tile 112 of each component 111 by probability estimation from the context and the target bit. In this way, encoding processing is performed in units of tiles 112 for all components 111 of the original image.

  Finally, the tag processing unit 105 performs a process of combining all the encoded data from the entropy encoding / decoding unit 104 into one code string data and adding a tag thereto. More specifically, the tag processing unit 105 discards unnecessary entropy codes, generates packets by collecting necessary entropy codes, arranges packets in a predetermined order, and adds necessary tags and tag information. The code string data (code stream) is generated. A packet is a collection of a part of codes of all code blocks included in the precinct (for example, codes of three bit planes from the most significant bit to the third bit). Packets with an empty code are allowed. A group of codes in a code block and packets arranged in a predetermined order is called a “bit stream”.

  FIG. 6 shows a schematic configuration for one frame of the code string data. Tag information called a header (main header, tile part header which is tile boundary position information, etc.) is provided at the head of the code string data and the head of the code data (bit stream) of each tile. Appended, followed by the encoded data for each tile. In the main header, coding parameters and quantization parameters are described. A tag (end of codestream) is placed again at the end of the code string data.

  FIG. 7 shows a code stream structure in which packets containing encoded wavelet coefficient values are represented for each subband. As shown in FIG. 7, the same packet string structure is obtained regardless of whether the tile division process is performed or the tile division process is not performed.

  On the other hand, when the encoded data is decoded, the image data is generated from the code string data of each tile 112 of each component 111, contrary to the case of encoding the image data. In this case, the tag processing unit 105 interprets tag information added to the code string data input from the outside, decomposes the code string data into code string data of each tile 112 of each component 111, and Decoding processing (decompression processing) is performed for each code string data of each tile 112. At this time, the position of the bit to be decoded is determined in the order based on the tag information in the code string data, and the quantization / inverse quantization unit 103 determines the peripheral bits (that have already been decoded) of the target bit position. Context is generated from the sequence of The entropy encoding / decoding unit 104 performs decoding by probability estimation from the context and code string data, generates a target bit, and writes it in the position of the target bit. Since the data decoded in this way is spatially divided for each frequency band, the two-dimensional wavelet transform / inverse transform unit 102 performs two-dimensional wavelet inverse transform on each of the components of the image data. The tile is restored. The restored data is converted to original color system image data by the color space conversion / inverse conversion unit 101.

  The above is the outline of the “encoding / decoding algorithm based on discrete wavelet transform”.

[First Embodiment]
Next, the first embodiment of the present invention will be described in detail. Here, FIG. 8 is a block diagram showing a hardware configuration of the image processing apparatus 1 of the present embodiment. The image processing apparatus 1 is mainly configured by a personal computer or a workstation, for example. As shown in FIG. 8, such an image processing apparatus 1 includes a CPU (Central Processing Unit) 2 that is a main part of a computer and controls each part centrally. The CPU 2 is connected by a bus 5 to a ROM (Read Only Memory) 3 that is a read-only memory storing BIOS and a RAM (Random Access Memory) 4 that is a storage unit that stores various data in a rewritable manner. ing.

  Further, the bus 5 has an HDD (Hard Disk Drive) 6 that stores various programs and the like, and a CD-ROM drive 8 that reads a CD (Compact Disc) -ROM 7 as a mechanism for reading computer software that is a distributed program. A communication control device 10 for communicating information with other external computers via the network 9, an input device 11 such as a keyboard and mouse for inputting various commands and information to the CPU 2, and processing progress And a display device 12 such as a CRT (Cathode Ray Tube) or an LCD (Liquid Crystal Display) for displaying results and the like are connected via an I / O (not shown).

  Since the RAM 4 has the property of storing various data in a rewritable manner, it functions as a work area for the CPU 2 and functions as a buffer.

  A CD-ROM 7 shown in FIG. 8 implements the storage medium of the present invention, and stores an OS (Operating System) and various programs. The CPU 2 reads the program stored in the CD-ROM 7 with the CD-ROM drive 8 and installs it in the HDD 6.

  As the storage medium, not only the CD-ROM 7 but also various types of media such as semiconductor memories such as various optical disks such as DVD, various magnetic disks such as various magneto-optical disks and flexible disks, and the like can be used. Further, a program may be downloaded from the Internet or the like via the communication control device 10 and installed in the HDD 6. In this case, the storage device storing the program in the server on the transmission side is also a storage medium of the present invention. Note that the program may operate on a predetermined OS (Operating System), and in that case, the OS may take over the execution of some of the various processes described later, It may be included as a part of a group of program files constituting the application software or OS.

  The CPU 2 that controls the operation of the entire system executes various processes based on a program loaded on the HDD 6 used as the main storage of the system.

  Next, among the functions that the various programs installed in the HDD 6 of the image processing apparatus 1 cause the CPU 2 to execute, the characteristic functions provided in the image processing apparatus 1 of the present embodiment will be described.

  FIG. 9 is a block diagram illustrating a functional configuration of the image processing apparatus 1. As illustrated in FIG. 9, the image processing apparatus 1 includes a memory management unit 31 that manages the memory space of the image processing unit 100 described in FIG. 1 and the RAM 4 that executes a plurality of types of image processing for JPEG2000 compression / decompression. , A data input unit 32, a data output unit 33, and a control unit 34 for controlling a processing sequence in the image processing apparatus 1.

  The memory management unit 31 secures a memory space in the RAM 4 that is necessary for the image compression / decompression process of the image processing unit 100.

  The data input unit 32 inputs image data to be compressed or encoded data to be decompressed.

  The data output unit 33 outputs compressed encoded data or decompressed image data.

  The control unit 34 controls a processing sequence in the image processing apparatus 1. Specifically, the control unit 34 records processing results in various processing steps in the image processing unit 100 in the RAM 4.

  Next, the operation at the time of compression processing under the control of the control unit 34 will be described with reference to the flowchart of FIG.

As shown in FIG. 10, the control unit 34 controls the memory management unit 31 to sequentially store classified unit data (here, tile data) that can be independently processed. Are reserved on the RAM 4 (step S1: first area securing means). The compression conditions such as the tile size (number of pixels), the bit depth, and the number of components necessary for calculating the size of the memory space are notified from, for example, an application program operating on a computer in which the image processing apparatus 1 is constructed. Is done. For example, when the tile size notified from the application program is (Tx × Ty), the bit depth is 8 bits (1 byte), and the number of components is C, the required memory space (MSIZE) is
MSIZE = (Tx × Ty) × 2 × C
And calculated. Here, when calculating the required memory space, the bit depth is set to “2” because, when the image data is 1 byte, the calculation such as wavelet transform requires several extra bits.

Subsequently, the control unit 34 controls the memory management unit 31 to secure on the RAM 4 a tile processing memory space (second region) necessary for a plurality of types of image processing to be executed on tile data. (Step S2: Second area securing means). The compression conditions (component, decomposition level, precinct, layer, code block size, etc.) necessary for calculating the size of the memory space are also notified from the application program in the same manner as in step S1. For example, when the number of components notified from the application program is C, the decomposition level is D, the precinct size is (Px, Py), the layer is L, and the code block size is (Cx, Cy), each decomposition For each level, a precinct size (PxD, PyD) and a code block size (CxD, CyD) are calculated. The amount of memory M required for the calculation is as follows:
M = (CxD × CyD) × 2 × C
And calculated. When processing in units of precincts, the memory amount M required for calculation is
M = (PxD × PyD) × 2 × C
And calculated. Here, when calculating the necessary memory amount, the bit depth is set to “2” because, when the image data is 1 byte, the calculation such as wavelet transform requires several extra bits.

  Subsequently, the control unit 34 controls the data input unit 32 to input data of one tile from the HDD 6 or the like, for example, and inputs the input data to the RAM 4 in the memory space (the first space allocated in step S1). (Step S3: storage means).

  In subsequent step S4, the control unit 34 performs color space conversion (ICT) on the tile data by controlling the image processing unit 100 (color space conversion / inverse conversion unit 101), and generates the generated Y, Cb. , Cr are stored in the memory space allocated to each component. Specifically, the control unit 34 reads tile data from the RAM 4, and outputs the color conversion result or DC level shift result in the color space conversion / inverse conversion unit 101 of the image processing unit 100 for the tile data read from the RAM 4. , Recorded in the RAM 4. In this case, the memory management unit 31 may manage the recording position for each color component.

  In subsequent step S5, the control unit 34 controls the image processing unit 100 (two-dimensional wavelet transform / inverse transform unit 102) to perform two-dimensional wavelet transform on each of the Y, Cb, and Cr components to generate them. Each of the subband coefficients thus stored is stored in a memory space allocated thereto. Specifically, the control unit 34 reads data after color space conversion from the RAM 4, and generates the data after color space conversion read from the RAM 4 by wavelet conversion in the two-dimensional wavelet transform / inverse conversion unit 102. Each subband coefficient is recorded in the RAM 4. In this case, the memory management unit 31 may manage the recording position of each subband.

  In subsequent step S6, the control unit 34 performs linear quantization for each subband by controlling the image processing unit 100 (quantization / inverse quantization unit 103), and sets each subband coefficient after quantization. Store in the memory space allocated to. Specifically, the control unit 34 reads the data after wavelet transform from the RAM 4, and each quantized and quantized linear quantized data by the quantization / inverse quantization unit 103 for the data after wavelet transform read from the RAM 4. The subband coefficient is recorded in the RAM 4.

  In subsequent step S7, the control unit 34 controls the image processing unit 100 (entropy encoding / decoding unit 104) to perform entropy encoding on each quantized subband coefficient, thereby entropy encoding. The encoded results are stored in the memory space allocated to each. Specifically, the control unit 34 reads each quantized subband coefficient from the RAM 4, and entropy coding / decoding unit 104 performs entropy coding on each quantized subband coefficient read from the RAM 4. The encoded result is recorded in the RAM 4. In this case, the memory management unit 31 may manage the recording position of each packet.

  The processes in steps S3 to S7 (image processing means) described above are repeated until the compression process for all tile data is completed (No in step S8).

  When the compression processing in steps S3 to S7 is completed for all tile data (No in step S8), the control unit 34 controls the memory management unit 31 to allocate the memory space allocated to the RAM 4 for tile data. Is released (step S9: release means) and the memory space allocated to the RAM 4 for tile processing is released (step S10: release means).

  Next, the control unit 34 controls the image processing unit 100 (tag processing unit 105) to perform a code forming process for generating code string data (code stream), and the generated code string data (code stream). It memorize | stores in RAM4 (step S11).

  Finally, the control unit 34 controls the data output unit 33 to read out and output the generated code string data (code stream) from the RAM 4 (step S12).

  Next, the operation at the time of decompression processing under the control of the control unit 34 will be described with reference to the flowchart of FIG.

  As shown in FIG. 11, the control unit 34 controls the memory management unit 31 to reduce the memory space for storing the code string data (code stream) that is the unit data that can be processed independently. Secured on the RAM 4 (step S21: first area securing means). The size of the memory space may be determined in advance, or may be specified from an application program, for example.

  Subsequently, the control unit 34 controls the data input unit 32 to input code string data (code stream), and the input code string data (code stream) is allocated to the RAM 4 in step S21. It memorize | stores in a space (1st area | region) (step S22: memory | storage means). At this time, the control unit 34 analyzes the header information of the code string data (code stream) by controlling the image processing unit 100 (tag processing unit 105) (step S23). More specifically, the tag processing unit 105 includes information necessary for allocating memory space, such as the type and number of two-dimensional wavelet transformations, the type of color space transformation, the number of components of the original image, size, bit depth, and tile size. And the analysis information is passed to the memory management unit 31.

  Subsequently, the control unit 34 controls the memory management unit 31, and based on the analysis information analyzed in step S <b> 23, the memory space (the second space required for a plurality of types of image processing executed on the code string data). 2 area) is secured on the RAM 4 (step S24: second area securing means).

  In subsequent step S25, the control unit 34 controls the image processing unit 100 (entropy encoding / decoding unit 104) to perform entropy decoding on the code string data (code stream) input in step S22. And the entropy-decoded decoding result is stored in the allocated memory space.

  In subsequent step S26, the control unit 34 controls the image processing unit 100 (quantization / inverse quantization unit 103) to perform inverse quantization on each subband coefficient after decoding, and after the inverse quantization, Each subband coefficient is stored in a memory space assigned to it.

  In subsequent step S27, the control unit 34 controls the image processing unit 100 (two-dimensional wavelet transform / inverse transform unit 102) to perform two-dimensional inverse wavelet transform on each subband coefficient after inverse quantization. The generated Y, Cb, and Cr components are stored in the memory space allocated to each component.

  In subsequent step S28, the control unit 34 performs reverse color space conversion (and reverse DC level shift) on the 0LL data by controlling the image processing unit 100 (color space conversion / inverse conversion unit 101). The color system tile data is generated and stored in the allocated memory space.

  The processes in steps S25 to S28 (image processing means) described above are repeated until the expansion process for all tile data is completed (No in step S29).

  When the decompression processing in steps S25 to S28 is completed for all tile data (No in step S29), the control unit 34 controls the data output unit 33 to output decompressed image data (step S30). .

  Finally, the control unit 34 controls the memory management unit 31 to release the memory space allocated to the RAM 4 for encoding (step S31: release means) and to allocate the memory space allocated to the RAM 4 for tile processing. Release (step S32: release means).

  As described above, according to the present embodiment, the first area for sequentially storing the unit data and the unit for the plurality of types of image processing to be executed on the classified unit data that can be processed independently The processing time of the program can be improved by reducing the frequency of securing and releasing the second area necessary for a plurality of types of image processing to be performed on the data.

  Furthermore, since the amount of use of the storage unit can be controlled by the classified unit data that can be processed independently (for example, color components, divided regions, frequency bands, effective bit planes, etc.), the memory space (first Time and the second area) can be saved, and image processing can be executed at high speed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is also omitted.

  The operation at the time of compression processing by the control of the control unit 34 of the present embodiment will be described with reference to the flowchart of FIG.

  As shown in FIG. 12, the control unit 34 controls the memory management unit 31 to sequentially store classified unit data (here, tile data) that can be processed independently. Are reserved on the RAM 4 (step S41: first area securing means). Note that the tile size (number of pixels), the bit depth, the number of components, and the like necessary for calculating the size of the memory space are notified from, for example, an application program operating on a computer in which the image processing apparatus 1 is constructed.

  Subsequently, the control unit 34 controls the memory management unit 31 to secure on the RAM 4 a tile processing memory space (second region) necessary for a plurality of types of image processing to be executed on tile data. (Step S42: second area securing means). The compression conditions (component, decomposition level, precinct, layer, code block size, etc.) necessary for calculating the memory space size are also notified from the application program in the same manner as in step S41.

  Here, in the memory space securing process in step S42, in the case of the second and subsequent tile data, the memory space size already secured is compared with the memory size required for the data to be processed. When the required memory size is smaller, the memory size is used as it is, and when the required memory size is larger, additional memory space is reserved, released or re-allocated.

  In releasing and reallocating the memory space, a method of partially releasing and reallocating the memory space that is insufficient for the processing of the processing tile can be considered. For example, the amount of memory space already secured (for example, the amount of memory space for component Y, composition level 1, precinct 0, layer 0) and the amount of memory space required for the tile to be processed (for example, component Y, (Decomposition level 1, precinct 0, layer 0 required memory space amount) are compared, and if it is insufficient, the memory space may be re-secured or the shortage may be re-secured. Further, when reusing the memory space, data is written in the memory space in the previous tile processing, but it is necessary to initialize as necessary. In this initialization process, overwriting always occurs, and if the recorded data is not used, initialization is not required. If it is not certain that overwriting will occur, it is necessary to perform initialization. In this case as well, only a specific memory space (for example, the memory space of component Y, composition level 1, precinct 0, layer 0) may be initialized.

  Subsequently, the control unit 34 controls the data input unit 32 to input data of one tile from, for example, the HDD 6 or the like, and the input data is stored in the memory space (the first space allocated in step S41 on the RAM 4). (Step S43: storage means).

  In subsequent step S44, the control unit 34 performs color space conversion (ICT) on the tile data by controlling the image processing unit 100 (color space conversion / inverse conversion unit 101), and the generated Y, Cb , Cr are stored in the memory space allocated to each component. Specifically, the control unit 34 reads tile data from the RAM 4, and outputs the color conversion result or DC level shift result in the color space conversion / inverse conversion unit 101 of the image processing unit 100 for the tile data read from the RAM 4. , Recorded in the RAM 4. In this case, the memory management unit 31 may manage the recording position for each color component.

  In subsequent step S45, the control unit 34 controls the image processing unit 100 (two-dimensional wavelet transform / inverse transform unit 102) to perform a two-dimensional wavelet transform on each of the Y, Cb, and Cr components to generate them. Each of the subband coefficients thus stored is stored in a memory space allocated thereto. Specifically, the control unit 34 reads data after color space conversion from the RAM 4, and generates the data after color space conversion read from the RAM 4 by wavelet conversion in the two-dimensional wavelet transform / inverse conversion unit 102. Each subband coefficient is recorded in the RAM 4. In this case, the memory management unit 31 may manage the recording position of each subband.

  In subsequent step S46, the control unit 34 performs linear quantization for each subband by controlling the image processing unit 100 (quantization / inverse quantization unit 103), and each subband coefficient after the quantization is obtained. Store in the memory space allocated to. Specifically, the control unit 34 reads the data after wavelet transform from the RAM 4, and each quantized and quantized linear quantized data by the quantization / inverse quantization unit 103 for the data after wavelet transform read from the RAM 4. The subband coefficient is recorded in the RAM 4.

  In subsequent step S47, the control unit 34 controls the image processing unit 100 (entropy encoding / decoding unit 104) to perform entropy encoding on each quantized subband coefficient, thereby entropy encoding. The encoded results are stored in the memory space allocated to each. Specifically, the control unit 34 reads each quantized subband coefficient from the RAM 4, and entropy coding / decoding unit 104 performs entropy coding on each quantized subband coefficient read from the RAM 4. The encoded result is recorded in the RAM 4. In this case, the memory management unit 31 may manage the recording position of each packet.

  The processing in steps S42 to S47 (image processing means) described above is repeated until the compression processing for all tile data is completed (No in step S48).

  When the compression processing of steps S42 to S47 is completed for all tile data (No in step S48), the control unit 34 controls the memory management unit 31 to allocate the memory space allocated to the RAM 4 for tile data. Is released (step S49: release means) and the memory space allocated to the RAM 4 for tile processing is released (step S50: release means).

  Next, the control unit 34 controls the image processing unit 100 (tag processing unit 105) to perform a code forming process for generating code string data (code stream), and the generated code string data (code stream). It memorize | stores in RAM4 (step S51).

  Finally, the control unit 34 controls the data output unit 33 to read out and output the generated code string data (code stream) from the RAM 4 (step S52).

  Next, the operation during the decompression process under the control of the control unit 34 will be described with reference to the flowchart of FIG.

  As shown in FIG. 13, the control unit 34 controls the memory management unit 31 to secure a memory space on the RAM 4 for storing code string data (code stream) (step S61: first area). Securing means). The size of the memory space may be determined in advance, or may be specified from an application program, for example.

  Subsequently, the control unit 34 controls the data input unit 32 to input code string data (code stream), and the input code string data (code stream) is allocated to the RAM 4 in step S21. It memorize | stores in a space (1st area | region) (step S62: memory | storage means). At this time, the control unit 34 controls the image processing unit 100 (tag processing unit 105) to analyze the header information of the code string data (code stream) (step S63). More specifically, the tag processing unit 105 includes information necessary for allocating memory space such as the type and number of two-dimensional wavelet transformations, the type of color space transformation, the number of components of the original image, the size, the bit depth, and the tile size. And the analysis information is passed to the memory management unit 31.

  Subsequently, the control unit 34 controls the memory management unit 31, and based on the analysis information analyzed in step S 63, the memory space (second number) required for a plurality of types of image processing executed on the code string data. 2 area) is secured on the RAM 4 (step S64: second area securing means). Decompression conditions (component, decomposition level, precinct, layer, code block size, etc.) necessary for calculating the size of the memory space are obtained in step S63.

  Here, in the memory space securing process in step S64, in the case of the second and subsequent code string data, the memory space size already secured is compared with the memory size required for the data to be processed. When the required memory size is smaller, the memory size is used as it is, and when the required memory size is larger, additional memory space is reserved, released or re-allocated.

  In releasing and reallocating the memory space, a method of partially releasing and reallocating the memory space that is insufficient for the processing of the processing tile can be considered. For example, the amount of memory space already secured (for example, the amount of memory space for component Y, composition level 1, precinct 0, layer 0) and the amount of memory space required for the tile to be processed (for example, component Y, (Decomposition level 1, precinct 0, layer 0 required memory space amount) are compared, and if it is insufficient, the memory space may be re-secured or the shortage may be re-secured. Further, when reusing the memory space, data is written in the memory space in the previous tile processing, but it is necessary to initialize as necessary. In this initialization process, overwriting always occurs, and if the recorded data is not used, initialization is not required. If it is not certain that overwriting will occur, it is necessary to perform initialization. In this case as well, only a specific memory space (for example, the memory space of component Y, composition level 1, precinct 0, layer 0) may be initialized.

  In subsequent step S65, the control unit 34 controls the image processing unit 100 (entropy encoding / decoding unit 104) to perform entropy decoding on the code string data (code stream) input in step S62. And the entropy-decoded decoding result is stored in the allocated memory space.

  In subsequent step S66, the control unit 34 controls the image processing unit 100 (quantization / inverse quantization unit 103) to perform inverse quantization on each subband coefficient after decoding, and after the inverse quantization, Each subband coefficient is stored in a memory space assigned to it.

  In subsequent step S67, the control unit 34 controls the image processing unit 100 (two-dimensional wavelet transform / inverse transform unit 102) to perform two-dimensional inverse wavelet transform on each subband coefficient after inverse quantization. The generated Y, Cb, and Cr components are stored in the memory space allocated to each component.

  In subsequent step S68, the control unit 34 performs reverse color space conversion (and reverse DC level shift) on the 0LL data by controlling the image processing unit 100 (color space conversion / inverse conversion unit 101). The color system tile data is generated and stored in the allocated memory space.

  The processes (image processing means) in steps S64 to S68 described above are repeated until the expansion process for all tile data is completed (No in step S69).

  When the decompression processing in steps S64 to S68 is completed for all tile data (No in step S69), the control unit 34 controls the data output unit 33 to output decompressed image data (step S70). .

  Finally, the control unit 34 controls the memory management unit 31 to release the memory space allocated to the RAM 4 for encoding (step S71: release means) and to allocate the memory space allocated to the RAM 4 for tile processing. Release (step S72: release means).

  As described above, according to the present embodiment, the first area for sequentially storing the unit data and the unit for the plurality of types of image processing to be executed on the classified unit data that can be processed independently The processing time of the program can be improved by reducing the frequency of securing and releasing the second area necessary for a plurality of types of image processing to be performed on the data.

  Furthermore, since the amount of use of the storage unit can be controlled by the classified unit data that can be processed independently (for example, color components, divided regions, frequency bands, effective bit planes, etc.), the memory space (first Time and the second area) can be saved, and image processing can be executed at high speed.

  In each embodiment, image data compression or image encoded data decompression is performed according to the JPEG2000 basic method (IS154444-1). However, the present invention is not limited to this, and other encoding methods are used. It is obvious that the present invention can be similarly applied to an image processing apparatus that performs compression or decompression according to the above.

1 is a functional block diagram of a system that realizes a hierarchical encoding algorithm that is the basis of an encoding / decoding scheme based on a discrete wavelet transform that is a premise of the present invention. It is explanatory drawing which shows the rectangular area | region where each component of the original image was divided | segmented. It is explanatory drawing which shows the subband in each decomposition level when the number of decomposition levels is three. It is explanatory drawing which shows a precinct. It is explanatory drawing which shows an example of the procedure which ranks a bit plane. It is explanatory drawing which shows schematic structure for 1 frame of code sequence data. It is explanatory drawing which shows the code stream structure which represented the packet in which the encoded wavelet coefficient value was accommodated for every subband. It is a block diagram which shows the hardware constitutions of the image processing apparatus concerning the 1st Embodiment of this invention. It is a block diagram which shows the function structure of an image processing apparatus. It is a flowchart which shows the flow of a compression process. It is a flowchart which shows the flow of an expansion | extension process. It is a flowchart which shows the flow of the compression process concerning the 2nd Embodiment of this invention. It is a flowchart which shows the flow of an expansion | extension process.

Explanation of symbols

1 Image processing device 4 Storage unit

Claims (10)

First area securing means for securing in the storage unit a first area for sequentially storing classified unit data that can be processed independently;
A second area securing means for securing a second area necessary for a plurality of types of image processing to be executed for the unit data in a storage unit;
Storage means for storing one unit data in the first area;
Image processing means for sequentially executing the plurality of types of image processing using the second area for the unit data stored in the first area;
When it is determined that the processing by the image processing unit has been completed for all the unit data, an opening unit that opens the first region and the second region;
An image processing apparatus comprising: First area securing means for securing in the storage unit a first area for sequentially storing classified unit data that can be processed independently;
Second area securing means for sequentially securing a second area necessary for a plurality of types of image processing to be executed for the unit data in the storage unit for each unit data;
Storage means for storing one unit data in the first area;
Image processing means for sequentially executing the plurality of types of image processing using the second area for the unit data stored in the first area;
When it is determined that the processing by the image processing unit has been completed for all the unit data, an opening unit that opens the first region and the second region;
An image processing apparatus comprising: The second area securing means compares the size of the second area that is already secured with the size of the second area that is necessary for the unit data to be processed, and When the size of the second area is smaller, the already secured size of the second area is used as it is, and when the required size of the second area is larger, the second area is used. Ensuring the size of the second region of sufficient size by opening and re-reserving,
The image processing apparatus according to claim 2. The second area securing means is already secured if the size of the second area required for the unit data to be processed is larger than the size of the second area already secured. Securing the size of the second area necessary for the unit data to be processed after partially releasing the second area.
The image processing apparatus according to claim 3. The second area securing means initializes only the part to be opened when partially releasing the second area that has already been secured,
The image processing apparatus according to claim 3, wherein the image processing apparatus is an image processing apparatus. The unit data is any one of a color component of image data, a divided region, a frequency band, and an effective bit plane.
The image processing apparatus according to claim 1, wherein the image processing apparatus is an image processing apparatus. The unit data is code string data according to any of color components, divided regions, frequency bands, and effective bit planes of image data.
The image processing apparatus according to claim 1, wherein the image processing apparatus is an image processing apparatus. The plurality of types of image processing for the unit data are compliant with JPEG2000 (IS154444-1) compression or decompression algorithm.
The image processing apparatus according to claim 1, wherein the image processing apparatus is an image processing apparatus. A first area securing function for securing a first area in the storage unit for sequentially storing classified unit data that can be processed independently;
A second area securing function for securing a second area necessary for a plurality of types of image processing to be executed for the unit data in a storage unit;
A storage function for storing one unit data in the first area;
An image processing function for sequentially executing the plurality of types of image processing using the second area for one unit data stored in the first area;
When it is determined that the processing by the image processing function has been completed for all the unit data, an opening function for opening the first area and the second area;
A program that causes a computer to execute. A first area securing function for securing a first area in the storage unit for sequentially storing classified unit data that can be processed independently;
A second area securing function that sequentially secures a second area necessary for a plurality of types of image processing to be executed for the unit data in the storage unit for each unit data;
A storage function for storing one unit data in the first area;
An image processing function for sequentially executing the plurality of types of image processing using the second area for the unit data stored in the first area;
When it is determined that the processing by the image processing function has been completed for all the unit data, an opening function for opening the first area and the second area;
A program that causes a computer to execute.

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