JP4093870B2 - Image processing apparatus, program, and storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus, a program, and a storage medium.
[0002]
[Prior art]
Due to advances in image input technology and output technology, the demand for higher definition of images has increased greatly in recent years. For example, taking a digital camera as an example of an image input device, the price of a high-performance charge coupled device (CCD) having a number of pixels of 3 million or more has progressed, and the spread price range has increased. It has come to be widely used in products. And it is said that this increasing trend in the number of pixels will continue for a while.
[0003]
On the other hand, with regard to image output / display devices, for example, products in the hard copy field such as laser printers, ink jet printers, sublimation printers, and flats such as CRTs, LCDs (liquid crystal display devices), and PDPs (plasma display devices). The high definition and low price of products in the soft copy field of panel displays are remarkable.
[0004]
Due to the market launch of these high-performance, low-priced image input / output products, high-definition images have become popular, and it is expected that demand for high-definition images will increase in all situations. In fact, the development of technologies related to networks such as personal computers and the Internet is accelerating these trends. In particular, recently, mobile devices such as mobile phones and notebook personal computers have become very popular, and opportunities for transmitting or receiving high-definition images from any point using communication means are rapidly increasing.
[0005]
Against this background, it is inevitable that the demand for higher performance or higher functionality for image compression / decompression technology that facilitates the handling of high-definition images will become stronger in the future.
[0006]
Thus, in recent years, a new method called JPEG2000, which can restore high-quality images even at a high compression rate, is being standardized as one of image compression methods that satisfy these requirements. In JPEG2000, it is possible to perform compression / decompression processing in a small memory environment by dividing an image into rectangular regions (tiles). That is, each tile becomes a basic unit for executing the compression / decompression process, and the compression / decompression operation can be performed independently for each tile.
[0007]
In recent years, a technique for determining the size of a decoded image so that it can be output in a prescribed format when decoding compressed and encoded image data has been disclosed (see, for example, Patent Document 1). )).
[0008]
[Patent Document 1]
JP 2001-105679 A [0009]
[Problems to be solved by the invention]
However, when image data is compression-encoded with the JPEG2000 algorithm, the LL component, which is one of the JPEG2000 feature values, becomes multivalued even when a binary image is input. Therefore, when the output device does not support multi-value, it is necessary to create a binary image on the output device side. However, when the performance of the output device is low, the output device is burdened, and high speed is required. There is a problem that can not be processed.
[0010]
An object of the present invention is not to create a binary image on the output device side that does not support multi-valued images, and can speed up image output on the output device side that does not support multi-valued images. An image processing apparatus, a program, and a storage medium are provided.
[0011]
[Means for Solving the Problems]
The image processing apparatus according to claim 1 is an image processing in which pixel values are subjected to discrete wavelet transform for each rectangular area obtained by dividing image data into one or a plurality of blocks, hierarchically compressed and encoded, and stored for data provision. In the apparatus, binarization means for converting an LL component band-resolved by discrete wavelet transform for each layer at the time of compression coding of image data from a multi-value image to a binary image, and a multi-value image by this binarization means Binary image storage means for storing LL components converted from binary to binary images for each hierarchy, and a desired hierarchy among the LL components converted into binary images stored by the binary image storage means Image acquisition permitting means for permitting acquisition of the LL component.
[0012]
Therefore, the LL component band-resolved by the discrete wavelet transform for each layer is converted from the multi-valued image to the binary image and stored, and among the stored LL components converted to the binary image, Acquisition of the LL component is allowed. As a result, when there is a transmission request for an LL component of a desired layer from an output device that does not support multi-valued images, the LL component of the desired layer converted into a binary image is acquired in the output device. Therefore, it is not necessary to create a binary image on the output device side, and it is possible to speed up image output.
[0013]
According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the LL component passed from the upper layer to the lower layer at the time of compression encoding of the image data is converted from a multi-value image to a binary image. Passed from upper hierarchy to lower hierarchy.
[0014]
Therefore, since it is possible to suppress image quality deterioration, it is possible to reproduce a good binary image close to the original in any hierarchy.
[0015]
According to a third aspect of the present invention, there is provided a program for an image processing apparatus that stores and holds data for providing data by discretely compressing and encoding pixel values for each rectangular area obtained by dividing image data into one or a plurality of rectangular areas. A computer program that is installed in a computer or that is interpreted and executed, and the computer converts the LL component that has been band-resolved by discrete wavelet transform for each layer when compressing and encoding image data from a multilevel image A binarization function for converting to a binary image, a binary image storage function for storing the LL component converted from a multi-value image into a binary image by the binarization function for each layer, and this binary image storage An image acquisition permission function that allows acquisition of an LL component of a desired hierarchy among LL components converted into a binary image stored by the function; .
[0016]
Therefore, the LL component band-resolved by the discrete wavelet transform for each layer is converted from the multi-valued image to the binary image and stored, and among the stored LL components converted to the binary image, Acquisition of the LL component is allowed. As a result, when there is a transmission request for an LL component of a desired layer from an output device that does not support multi-valued images, the LL component of the desired layer converted into a binary image is acquired in the output device. Therefore, it is not necessary to create a binary image on the output device side, and it is possible to speed up image output.
[0017]
According to a fourth aspect of the present invention, in the program according to the third aspect, the LL component passed from the upper layer to the lower layer upon compression encoding of the image data is converted from a multi-value image to a binary image and then the upper layer. Passed to the lower hierarchy from.
[0018]
Therefore, since it is possible to suppress image quality deterioration, it is possible to reproduce a good binary image close to the original in any hierarchy.
[0019]
According to a fifth aspect of the present invention, there is provided an image processing apparatus for storing and holding data for providing data by performing discrete wavelet transform and pixelally compressing pixel values for each rectangular area obtained by dividing image data into one or a plurality of rectangular areas. Installed in a computer included in, or interpreted and executed by the computer, the LL component subjected to band decomposition by discrete wavelet transform for each layer at the time of compression encoding of image data. A binarization function for converting from a binary image to a binary image, a binary image storage function for storing, for each hierarchy, an LL component converted from a multi-value image to a binary image by the binarization function, and the binary image An image acquisition permission function that allows acquisition of an LL component of a desired hierarchy among the LL components converted into a binary image stored by the storage function is executed. Storing the program.
[0020]
Therefore, the LL component band-resolved by the discrete wavelet transform for each layer is converted from the multi-valued image to the binary image and stored, and among the stored LL components converted to the binary image, Acquisition of the LL component is allowed. As a result, when there is a transmission request for an LL component of a desired layer from an output device that does not support multi-valued images, the LL component of the desired layer converted into a binary image is acquired in the output device. Therefore, it is not necessary to create a binary image on the output device side, and it is possible to speed up image output.
[0021]
According to a sixth aspect of the present invention, in the storage medium according to the fifth aspect, the LL component passed from the upper layer to the lower layer at the time of compression encoding of the image data is converted from a multi-value image to a binary image and then the upper layer A program that was passed from the hierarchy to the lower hierarchy was stored.
[0022]
Therefore, since it is possible to suppress image quality deterioration, it is possible to reproduce a good binary image close to the original in any hierarchy.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0024]
First, an outline of the “hierarchical encoding algorithm” and the “JPEG2000 algorithm” which are the premise of the present invention will be described.
[0025]
FIG. 1 is a functional block diagram of a system that implements a hierarchical encoding algorithm that is the basis of the JPEG2000 system. This system includes color space transform / inverse transform unit 101, two-dimensional wavelet transform / inverse transform unit 102, quantization / inverse quantization unit 103, entropy encoding / decoding unit 104, and tag processing unit 105. It is configured.
[0026]
One of the biggest differences between this system and the conventional JPEG algorithm is the conversion method. In JPEG, discrete cosine transform (DCT) is used. In this hierarchical coding algorithm, the two-dimensional wavelet transform / inverse transform unit 102 uses discrete wavelet transform (DWT). ing. DWT has the advantage of better image quality in the high compression region than DCT, and this is one of the main reasons why DWT is adopted in JPEG2000, which is a successor algorithm of JPEG.
[0027]
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. And JPEG2000 can realize various convenient functions by code string data. For example, the compression / decompression operation of a still image can be freely stopped at an arbitrary layer (decomposition level) corresponding to octave division in block-based DWT (see FIG. 3 described later).
[0028]
In many cases, color space conversion / inverse conversion 101 is connected to the input / output portion of the 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.
[0029]
Next, the JPEG2000 algorithm will be described.
[0030]
As shown in FIG. 2, in a color image, each component 111 (RGB primary color system here) of an original image is generally divided by a rectangular area. This divided rectangular area is generally called a block or a tile. 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.
[0031]
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 in FIG. A dimensional wavelet transform (forward transform) is applied to divide the space into frequency bands.
[0032]
FIG. 3 shows subbands at each decomposition level when the number of decomposition levels is three. In other words, the tile original image (0LL) (decomposition level 0) obtained by tile division of the original image is subjected to two-dimensional wavelet transform, and the subbands (1LL, 1HL, 1LH shown in the decomposition level 1) , 1HH). Subsequently, the low-frequency component 1LL in this hierarchy is subjected to two-dimensional wavelet transformation to separate the subbands (2LL, 2HL, 2LH, 2HH) indicated by the decomposition level 2. Similarly, the low-frequency component 2LL is also subjected to two-dimensional wavelet transform to separate subbands (3LL, 3HL, 3LH, 3HH) shown in the decomposition level 3. In FIG. 3, the 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 the encoding targets, and the 3LL subband is encoded. It is not converted.
[0033]
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.
[0034]
The wavelet coefficients that have undergone the 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 consists of three rectangular regions that are spatially coincident. Further, each precinct is divided into non-overlapping rectangular “code blocks”. This is the basic unit for entropy coding.
[0035]
The coefficient values after 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”.
[0036]
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 is Each is 8 × 8 pixels and 4 × 4 pixels. The numbers of the precinct and the code block are assigned in raster order. In this example, the number of assigns is assigned from numbers 0 to 3, and the code block is assigned from 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.
[0037]
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.
[0038]
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 closer to LSB (Least Significant Bit) is subject to quantization first. Conversely, a layer closer 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.
[0039]
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.
[0040]
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.
[0041]
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.
[0042]
The above is the outline of the “JPEG2000 algorithm”.
[0043]
Hereinafter, an embodiment of the present invention will be described. Although an example relating to an image compression / decompression technique represented by JPEG2000 will be described here, it goes without saying that the present invention is not limited to the contents of the following description.
[0044]
FIG. 8 is a block diagram showing the overall configuration of the image output system 1 according to the present embodiment. As shown in FIG. 8, the image output system 1 includes an input device 2 that inputs an image, an image processing device 3 that performs predetermined image processing on image data of the input image, and predetermined image processing. And an output device 4 for outputting the image data.
[0045]
Specifically, the input device 2 includes various communication interfaces for transmitting image data to the image processing device 3, a storage device for storing image data, an image input device for inputting an image, an image input device such as a digital camera, and the like.
[0046]
Specifically, the output device 4 includes various communication interfaces that receive image data from the image processing device 3, a storage device that stores image data, a display such as an LCD or CRT that displays images, and various printing methods that print images. Such as a printer.
[0047]
Next, the image processing apparatus 3 will be described in detail. FIG. 9 is a module configuration diagram of the image processing apparatus 3 according to the present embodiment. The image processing device 3 is a so-called personal computer, and a primary storage device 14 such as a CPU (Central Processing Unit) 11 that performs information processing, a ROM (Read Only Memory) 12 that stores information, and a RAM (Random Access Memory) 13. , A secondary storage device 16 such as an HDD (Hard Disk Drive) 15 which is a storage unit for storing a compression code to be described later, a CD-ROM for storing information, distributing information to the outside, and obtaining information from the outside A removable disk device 17 such as a drive, a network interface 18 for communicating information with the input device 2 and the output device 4, a CRT (Cathode Ray Tube) or LCD (Liquid Crystal) for displaying processing progress and results to the operator Display) 19, a keyboard 20 for an operator to input commands and information to the CPU 11, a mouse, etc. It consists of a pointing device 21 and the like, and the bus controller 22 operates by arbitrating data transmitted and received between these units.
[0048]
In such an image processing device 3, when the user turns on the power, the CPU 11 activates a program called a loader in the ROM 12, loads a program for managing the computer hardware and software called the operating system from the HDD 15 into the RAM 13, and Start the system. Such an operating system starts a program, reads information, and performs storage according to a user operation. As typical operating systems, Windows (registered trademark), UNIX (registered trademark), and the like are known. An operation program running on these operating systems is called an application program.
[0049]
Here, the image processing apparatus 3 stores an image processing program in the HDD 15 as an application program. In this sense, the HDD 15 functions as a storage medium that stores the image processing program.
[0050]
In general, the operation program installed in the secondary storage device 16 such as the HDD 15 of the image processing apparatus 3 is recorded on an optical information recording medium such as a CD-ROM or DVD-ROM, a magnetic medium such as an FD, or the like. The recorded operation program is installed in the secondary storage device 16 such as the HDD 15. For this reason, portable storage media such as optical information recording media such as CD-ROM and magnetic media such as FD can also be storage media for storing image processing programs. Furthermore, the image processing program may be imported from the outside via, for example, the network interface 18 and installed in the secondary storage device 16 such as the HDD 15.
[0051]
In the image processing apparatus 3, when an image processing program that operates on an operating system is started, the CPU 11 executes various arithmetic processes according to the image processing program and controls each unit intensively. Of the various types of arithmetic processing executed by the CPU 11 of the image processing apparatus 3, the characteristic processing of the present embodiment will be described below.
[0052]
Here, functions realized by various arithmetic processes executed by the CPU 11 of the image processing apparatus 3 will be described. As shown in FIG. 10, in the image processing apparatus 3, the first hierarchy compression code creation means 31, the second hierarchy compression code creation means 32, the third hierarchy compression code creation means 33, the binarization means 34, and the binary image The functions of the storage unit 35 and the image acquisition permission unit 36 are realized by various arithmetic processes executed by the CPU 11. In addition, when real-time property is regarded as important, it is necessary to speed up the processing. For this purpose, it is desirable to separately provide a logic circuit (not shown) and realize various functions by the operation of the logic circuit.
[0053]
The first hierarchy compression code creation means 31, the second hierarchy compression code creation means 32, and the third hierarchy compression code creation means 33 roughly compress and encode image data input from the input device 2 according to the JPEG2000 algorithm. Is. Regarding the compression processing according to the JPEG2000 algorithm, the spatial transform / inverse transform unit 101, the two-dimensional wavelet transform / inverse transform unit 102, the quantization / inverse quantization unit 103, and the entropy encoding / decoding unit 104 shown in FIG. Since the tag processing unit 105 has been described above, the description thereof is omitted here. According to the compression processing according to the JPEG2000 algorithm, a compression code is created for each layer corresponding to octave division in DWT. In the present embodiment, a three-level compression code is created.
[0054]
The first hierarchy compression code creating means 31 creates a compression code of the highest hierarchy (first hierarchy) and creates a compression code of the lower hierarchy from the multi-level image of the LL component band-resolved by the discrete wavelet transform. The data is passed to the two-layer compression code creation means 32. The second layer compression code creating means 32 creates a second layer compression code and a third layer compression for creating a lower layer compression code from the multi-valued image of the LL component band-resolved by discrete wavelet transform. It passes to the code creation means 33. Then, the third layer compression code creating means 33 creates a third layer compression code.
[0055]
In addition, the first hierarchy compression code creation means 31, the second hierarchy compression code creation means 32, and the third hierarchy compression code creation means 33 binarize the multilevel image of the LL component that has been band-resolved by discrete wavelet transform. 34 to perform binarization processing. The binarization means 34 converts the passed LL component of each layer from a multi-value image to a binary image. The LL component converted from the multi-value image to the binary image in this way is stored and held for each hierarchy in the binary image storage means 35.
[0056]
The image acquisition permitting unit 36 has a function of permitting acquisition of an LL component in a desired hierarchy among LL components converted into binary images stored and held in the binary image storage unit 35.
[0057]
Therefore, the output device 4 accesses the LL component of the desired hierarchy stored in the binary image storage unit 35 via the image acquisition permission unit 36 or is stored in the binary image storage unit 35. By transmitting the LL component of a desired layer, a binary image having a necessary resolution can be displayed.
[0058]
According to such an image processing device 3, the LL component band-resolved by the discrete wavelet transform for each layer is converted from a multi-value image into a binary image, stored, and converted into a stored binary image. Of the LL components, acquisition of the LL component of a desired hierarchy is allowed. As a result, when there is a transmission request for an LL component of a desired layer from an output device that does not support multi-valued images, the LL component of the desired layer converted into a binary image is acquired in the output device. Therefore, it is not necessary to create a binary image on the output device side, and it is possible to speed up image output.
[0059]
In the present embodiment, the LL component passed from the first hierarchy compression code creation means 31 to the second hierarchy compression code creation means 32, and the second hierarchy compression code creation means 32 to the third hierarchy compression code creation means. The LL component passed to 33 remained a multi-valued image. However, when the multi-valued image LL component is transferred to a lower layer, there are cases where fine lines and the like are gradually rubbed and become invisible. Therefore, binarization processing may be performed on the LL component passed to the lower layer. As a result, image quality deterioration can be suppressed, and a good binary image close to the original can be reproduced at any level.
[0060]
【The invention's effect】
According to the image processing apparatus of the first aspect of the invention, pixel values are discretely wavelet transformed and hierarchically compressed and encoded for each rectangular area obtained by dividing image data into one or a plurality, and stored for data provision. In the image processing apparatus, binarization means for converting a band-resolved LL component by discrete wavelet transform for each layer at the time of compression coding of image data from a multi-valued image to a binary image, and the binarization means The binary image storage means for storing the LL component converted from the binary image into the binary image for each layer, and the desired LL component among the LL components converted into the binary image stored by the binary image storage means Image acquisition permitting means for allowing acquisition of LL components in a layer of the image, and storing the LL component band-resolved by discrete wavelet transform for each layer from a multi-value image to a binary image A request to transmit an LL component of a desired hierarchy from an output device that does not support a multi-valued image by allowing acquisition of the LL component of a desired hierarchy among the LL components converted into a stored binary image If there is, the output device can acquire the LL component of the desired hierarchy converted into a binary image, so there is no need to create a binary image on the output device side, and the output of the image The speed can be increased.
[0061]
According to the second aspect of the present invention, in the image processing apparatus according to the first aspect, the LL component passed from the upper layer to the lower layer when compressing and encoding the image data is converted from a multilevel image to a binary image. Since image quality deterioration can be suppressed by passing from the upper hierarchy to the lower hierarchy after that, a good binary image close to the original can be reproduced in any hierarchy.
[0062]
According to the program of the third aspect of the present invention, image processing is performed in which pixel values are discretely wavelet transformed and hierarchically compressed and encoded for each rectangular area obtained by dividing image data into one or a plurality, and stored for data provision. A program that is installed in a computer included in the apparatus, or that is interpreted and executed, and the computer stores multiple values of LL components that have been band-resolved by discrete wavelet transform for each layer when compressing and encoding image data. A binarization function for converting an image into a binary image, a binary image storage function for storing the LL component converted from a multi-value image into a binary image by the binarization function for each layer, and the binary An image acquisition permission function that allows acquisition of an LL component of a desired hierarchy among LL components converted into a binary image stored by the image storage function; The LL component band-resolved by discrete wavelet transform for each layer is converted from a multi-valued image to a binary image and stored, and among the stored LL components converted to a binary image, a desired layer By allowing the acquisition of the LL component, if there is a transmission request for the LL component of the desired hierarchy from the output device that does not support the multi-valued image, the output device converts the desired image converted into a binary image. Since the LL component of the hierarchy can be acquired, there is no need to create a binary image on the output device side, and the output of the image can be speeded up.
[0063]
According to a fourth aspect of the present invention, in the program according to the third aspect, the LL component passed from the upper layer to the lower layer at the time of compression encoding of the image data is converted from a multi-value image to a binary image. Since image quality deterioration can be suppressed by passing from the upper layer to the lower layer, a good binary image close to the original can be reproduced in any layer.
[0064]
According to the storage medium of the fifth aspect of the present invention, an image to be stored and held for data provision is provided by hierarchically compressing and encoding the pixel values for each rectangular area obtained by dividing the image data into one or a plurality of discrete wavelet transforms. A program that is installed in a computer included in a processing device, or that is interpreted and executed. The computer includes a plurality of LL components that are band-resolved by discrete wavelet transform for each layer in compression encoding of image data. A binarization function for converting a binary image into a binary image, a binary image storage function for storing, for each hierarchy, an LL component converted from a multi-value image into a binary image by the binarization function; An image acquisition permission function that allows acquisition of an LL component of a desired hierarchy among LL components converted into a binary image stored by a value image storage function; A program for storing the LL component band-resolved by discrete wavelet transform for each layer, converting the multi-value image into a binary image and storing it, and among the LL components converted into the stored binary image, By allowing the acquisition of the LL component of the desired hierarchy, if there is a transmission request for the LL component of the desired hierarchy from an output device that does not support multilevel images, the output device converts it to a binary image Since it is possible to acquire the LL component of the desired hierarchy, it is not necessary to create a binary image on the output device side, and the output of the image can be speeded up.
[0065]
According to the sixth aspect of the invention, in the storage medium according to the fifth aspect, the LL component passed from the upper layer to the lower layer when compressing and encoding the image data is converted from a multi-value image to a binary image. By storing the program that is passed from the upper layer to the lower layer, image quality deterioration can be suppressed, and a good binary image close to the original can be reproduced in any layer.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a system that realizes a hierarchical encoding algorithm that is the basis of the JPEG2000 system that is a premise of the present invention.
FIG. 2 is an explanatory diagram showing a divided rectangular area of each component of the original image.
FIG. 3 is an explanatory diagram showing subbands at each decomposition level when the number of decomposition levels is 3. FIG.
FIG. 4 is an explanatory diagram showing a precinct.
FIG. 5 is an explanatory diagram showing an example of a procedure for ranking bit planes;
FIG. 6 is an explanatory diagram illustrating a schematic configuration of one frame of code string data.
FIG. 7 is an explanatory diagram showing a code stream structure representing a packet containing encoded wavelet coefficient values for each subband.
FIG. 8 is a block diagram showing an overall configuration of an image output system according to an embodiment of the present invention.
FIG. 9 is a module configuration diagram of the image processing apparatus.
FIG. 10 is a functional block diagram illustrating functions realized by processing executed by a CPU based on an image processing program.
[Explanation of symbols]
3 image processing device 15 storage medium 34 binarization means 35 binary image storage means 36 image acquisition permission means

Claims (3)

In an image processing apparatus that performs discrete wavelet transform and hierarchically compresses and encodes pixel values for each rectangular area obtained by dividing image data into one or more, and stores and holds the data for data provision.
Binarizing means for converting the LL component band-resolved by discrete wavelet transform for each layer in compression encoding of image data from a multi-value image to a binary image;
Binary image storage means for storing the LL component converted from a multi-value image into a binary image by the binarization means for each layer;
Image acquisition means for acquiring an LL component of a predetermined hierarchy among LL components converted into a binary image stored by the binary image storage means ;
The LL component passed from the upper layer to the lower layer when compressing and encoding image data is converted from a multi-valued image to a binary image and then passed from the upper layer to the lower layer;
The image processing apparatus according to feature a. Installed or interpreted on a computer that has an image processing device that stores and holds the pixel data for data provision in a hierarchical manner by discrete wavelet transform for each rectangular area obtained by dividing image data into one or more Executed on the computer.
A binarization function for converting an LL component band-resolved by discrete wavelet transform for each layer when compressing and encoding image data from a multi-value image to a binary image;
A binary image storage function for storing the LL component converted from a multi-value image into a binary image by this binarization function for each layer;
Among the LL components converted into the binary image stored by the binary image storage function, the image acquisition function for acquiring the acquisition of the LL component of a predetermined hierarchy is executed.
Further, the LL component passed from the upper layer to the lower layer when compressing and encoding the image data is converted from a multi-value image to a binary image and then passed from the upper layer to the lower layer.
Program for causing runs. A computer-readable recording medium on which the program according to claim 2 is recorded.

Images