JP2004236003A - Image processing unit, program and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing unit which can accelerate the output of an image at an output unit side not corresponding to a multi-valued image without necessity of forming a binary image at the output unit side not corresponding to the multi-valued image. <P>SOLUTION: When image data are compression coded, an LL component divided to sub-band by a discrete wavelet transformation at each hierarchy is transformed from the multi-valued image into the binary image and is stored (binarizing means 34, binary image storage means 35), and a desired hierarchical LL component of the LL component transformed to the stored binary image is allowed to be acquired (image acquirement allowing means 36). Thus, when the desired hierarchical LL component is requested to be transmitted from the output unit 4 not corresponding to the multi-valued image, the desired hierarchical LL component transformed to the binary image is acquired in the output unit 4. Accordingly, the outputting of the image can be accelerated without necessity of forming the binary image at the output unit 4 side. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image processing device, a program, and a storage medium.
[0002]
[Prior art]
2. Description of the Related Art Due to advances in image input technology and output technology thereof, demands for higher definition of images have been extremely increased in recent years. For example, taking a digital camera (Digital Camera) as an example of an image input device, the price of a high-performance charge coupled device (CCD: Charge Coupled Device) having more than 3 million pixels has been reduced, and the price range has become widespread. Products have come to be widely used. It is said that this increasing tendency of 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 and sublimation printers, and flat devices such as CRTs, LCDs (liquid crystal display devices), and PDPs (plasma display devices). The high definition and low price of products in the field of soft copy of panel displays are remarkable.
[0004]
Due to the effect of bringing high-performance, low-cost image input / output products to the market, the popularization of high-definition images has begun, and it is expected that demand for high-definition images will increase in all scenes in the future. Indeed, 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 to transmit or receive high-definition images from any point using communication means have been rapidly increasing.
[0005]
Against this background, the demand for higher performance or multifunctional image compression / decompression technology that facilitates the handling of high-definition images will inevitably increase in the future.
[0006]
Therefore, in recent years, a new method called JPEG2000, which can restore a high-quality image even at a high compression ratio, is being standardized as one of the image compression methods satisfying such demands. In JPEG2000, by dividing an image into rectangular areas (tiles), it is possible to perform compression / expansion processing in a small memory environment. That is, each tile is a basic unit when 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 as to be able to output the data in a prescribed format when decoding the compression-encoded image data has been disclosed (for example, see Patent Document 1). )).
[0008]
[Patent Document 1]
JP 2001-105679 A
[Problems to be solved by the invention]
However, when image data is compression-encoded by the JPEG2000 algorithm, the LL component, which is one of the features of JPEG2000, becomes multi-valued even when a binary image is input. For this reason, when the output device does not support multi-value, it is necessary to create a binary image on the output device side. There is a problem that can not be processed.
[0010]
An object of the present invention is to eliminate the need to create a binary image on an output device that does not support multi-valued images, and to speed up image output on an output device that does not support multi-valued images. An image processing device, a program, and a storage medium are provided.
[0011]
[Means for Solving the Problems]
The image processing apparatus according to the first aspect of the present invention is an image processing apparatus that performs discrete wavelet transform of pixel values for each rectangular area obtained by dividing image data into one or a plurality of pieces, hierarchically compresses and encodes the values, and stores and holds the data to provide data. In the apparatus, binarizing means for converting an LL component band-decomposed by discrete wavelet transform for each layer at the time of compression encoding of image data from a multivalued image to a binary image, and a multivalued image by the binarizing means. A LL component converted from a binary image into a binary image for each layer, and a desired layer among the LL components converted into a binary image stored by the binary image storage means. Image acquisition permitting means for permitting the acquisition of the LL component.
[0012]
Therefore, the LL component band-decomposed by the discrete wavelet transform for each layer is converted from a multi-valued image to a binary image and stored, and of the LL components converted to the stored binary image, Acquisition of the LL component is allowed. Accordingly, when a request for transmitting the LL component of the desired layer is issued from the output device that does not support the multi-valued image, the LL component of the desired layer converted into the binary image is obtained in the output device. Therefore, there is no need 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, an LL component passed from an upper layer to a lower layer is converted from a multi-valued image to a binary image upon compression encoding of image data. Passed from upper layer to lower layer.
[0014]
Therefore, it is possible to suppress image quality deterioration, and it is possible to reproduce a good binary image close to the original at any hierarchical level.
[0015]
According to a third aspect of the present invention, there is provided a program for an image processing apparatus which performs discrete wavelet transform on pixel values for each rectangular area obtained by dividing image data into one or a plurality of pieces, performs hierarchical compression encoding, and stores and holds the data for data provision. A computer installed or interpreted and executed by the computer having the LL component band-decomposed by the discrete wavelet transform for each layer when compressing and encoding the image data, from the multi-valued image. A binarizing function for converting a binary image into a binary image, a binary image storing function for storing the LL component converted from a multi-valued image to a binary image by the binarizing function for each layer, and a binary image storing function And executing an image acquisition permitting function of permitting acquisition of an LL component of a desired layer among LL components converted into a binary image stored by the function. .
[0016]
Therefore, the LL component band-decomposed by the discrete wavelet transform for each layer is converted from a multi-valued image to a binary image and stored, and of the LL components converted to the stored binary image, Acquisition of the LL component is allowed. Accordingly, when a request for transmitting the LL component of the desired layer is issued from the output device that does not support the multi-valued image, the LL component of the desired layer converted into the binary image is obtained in the output device. Therefore, there is no need 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 when compressing and encoding the image data is converted from a multivalued image to a binary image, and then converted to an upper layer. To pass to lower hierarchy.
[0018]
Therefore, it is possible to suppress image quality deterioration, and it is possible to reproduce a good binary image close to the original at any hierarchical level.
[0019]
An image processing apparatus according to a fifth aspect of the present invention, wherein a pixel value is discretely wavelet-transformed for each rectangular area obtained by dividing image data into one or a plurality of pieces, hierarchically compression-coded, and stored and provided for providing data. Is a program installed or interpreted and executed on a computer having a LL component band-decomposed by a discrete wavelet transform for each layer when compressing and encoding image data. And a binary image storage function of storing the LL component converted from a multi-valued image to a binary image by this binary function for each layer, and a binary image storage function. And executing an image acquisition permitting function of permitting acquisition of an LL component of a desired layer among the LL components converted into the binary image stored by the storage function. Storing the program.
[0020]
Therefore, the LL component band-decomposed by the discrete wavelet transform for each layer is converted from a multi-valued image to a binary image and stored, and of the LL components converted to the stored binary image, Acquisition of the LL component is allowed. Accordingly, when a request for transmitting the LL component of the desired layer is issued from the output device that does not support the multi-valued image, the LL component of the desired layer converted into the binary image is obtained in the output device. Therefore, there is no need 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, an LL component passed from an upper layer to a lower layer upon compression encoding of image data is converted from a multi-valued image to a binary image, The program that passed from the hierarchy to the lower hierarchy was stored.
[0022]
Therefore, it is possible to suppress image quality deterioration, and it is possible to reproduce a good binary image close to the original at any hierarchical level.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0024]
First, the outlines 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 for realizing a hierarchical coding algorithm which is a basic of the JPEG2000 system. This system includes a color space conversion / inverse transformation unit 101, a two-dimensional wavelet transformation / inverse transformation unit 102, a quantization / inverse quantization unit 103, an entropy coding / decoding unit 104, and a 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: Discrete Cosine Transform) is used, whereas in the hierarchical coding algorithm, a two-dimensional wavelet transform / inverse transform unit 102 uses discrete wavelet transform (DWT: Discrete Wavelet Transform). ing. DWT has an advantage that the image quality in a high compression area is better than DCT, and this is one of the main reasons why DWT was adopted in JPEG2000 which is a successor algorithm of JPEG.
[0027]
Another major difference is that in the hierarchical coding algorithm, a functional block of the tag processing unit 105 is added in order to form a code at the last stage of the system. The tag processing unit 105 generates compressed data as code string data at the time of image compression operation, and interprets code string data required for decompression at the time of decompression operation. The JPEG2000 can realize various convenient functions by using the code string data. For example, the compression / expansion operation of a still image can be freely stopped at an arbitrary layer (decomposition level) corresponding to octave division in a DWT on a block basis (see FIG. 3 described later).
[0028]
In many cases, a color space conversion / inverse conversion 101 is connected to the input / output portion of the original image. For example, an RGB color system composed of R (red) / G (green) / B (blue) components of a primary color system, and Y (yellow) / M (magenta) / C (cyan) components of a complementary color system The conversion or inverse conversion from the YMC color system to the YUV or YCbCr color system corresponds to this.
[0029]
Next, the JPEG2000 algorithm will be described.
[0030]
Generally, in a color image, as shown in FIG. 2, each component 111 (here, the RGB primary color system) of the original image is divided by a rectangular area. The divided rectangular area is generally called a block or a tile. In JPEG2000, it is generally called a tile. Hereinafter, such a divided rectangular area is 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 vertically and horizontally.) When such individual tiles 112 (in the example of FIG. 2, R00, R01,..., R15 / G00, G01,..., G15 / B00, B01,. Is the basic unit of 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 of FIG. 1 and subjected to color space conversion. A dimensional wavelet transform (forward transform) is performed, and spatial division into frequency bands is performed.
[0032]
FIG. 3 shows subbands at each decomposition level when the number of decomposition levels is three. That is, a two-dimensional wavelet transform is performed on the tile original image (0LL) (decomposition level 0) obtained by dividing the original image into tiles, and the subbands (1LL, 1HL, 1LH) indicated by the decomposition level 1 are obtained. , 1HH). Subsequently, two-dimensional wavelet transform is performed on the low-frequency component 1LL in this layer to separate the subbands (2LL, 2HL, 2LH, 2HH) shown in the decomposition level 2. Similarly, two-dimensional wavelet transform is performed on the low-frequency component 2LL in the same manner to separate the sub-bands (3LL, 3HL, 3LH, 3HH) shown in the decomposition level 3. In FIG. 3, the subbands to be coded at each decomposition level are shaded. 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 subbands are encoded. Is not converted.
[0033]
Next, bits to be encoded are determined in the designated order of encoding, and the quantization / inverse quantization unit 103 shown in FIG. 1 generates a context from bits around the target bits.
[0034]
The wavelet coefficients after the quantization process are divided into non-overlapping rectangles called “precincts” for each subband. This was introduced to make efficient use of memory in the implementation. As shown in FIG. 4, one precinct is formed of three spatially coincident rectangular areas. Further, each precinct is divided into non-overlapping rectangular "code blocks". This is a basic unit when performing entropy coding.
[0035]
The coefficient value after wavelet transform can be quantized and encoded as it is. However, in JPEG2000, in order to increase the encoding efficiency, the coefficient value is decomposed into “bit plane” units, and each pixel or code block is decomposed. "Bit planes" can be ranked.
[0036]
Here, FIG. 5 is an explanatory diagram showing an example of a procedure for prioritizing bit planes. As shown in FIG. 5, in this example, the original image (32 × 32 pixels) is divided into four 16 × 16 pixel tiles, and the size of the precinct of the decomposition level 1 and the size of the code block are as follows. Each has 8 × 8 pixels and 4 × 4 pixels. The numbers of precincts and code blocks are assigned in raster order. In this example, the precincts are assigned numbers 0 to 3, and the code blocks are assigned numbers 0 to 3. The pixel expansion outside the tile boundary is performed by using a mirroring method, performing a wavelet transform using a reversible (5, 3) filter, and obtaining a wavelet coefficient value of decomposition level 1.
[0037]
FIG. 5 also shows an explanatory diagram showing an example of a typical “layer” configuration concept of tile 0 / precinct 3 / code block 3. The converted code block is divided into subbands (1LL, 1HL, 1LH, 1HH), and each subband is assigned a wavelet coefficient value.
[0038]
The layer structure is easy to understand when the wavelet coefficient value is 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 1, 3, 1, and 3 bit planes, respectively. A layer including a bit plane closer to LSB (Least Significant Bit: Least Significant Bit) is subject to quantization first, and conversely, a layer closer to MSB (Most Significant Bit: 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 it is possible to finely control the quantization rate.
[0039]
The entropy encoding / decoding unit 104 shown 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, the encoding process is performed on all the components 111 of the original image in tile 112 units. Finally, the tag processing unit 105 performs a process of combining all the encoded data from the entropy encoding / decoding unit 104 into one piece of code string data and adding a tag thereto.
[0040]
FIG. 6 shows a schematic configuration of one frame of the code string data. At the head of the code string data and the head of the code data (bit stream) of each tile, tag information called a header (main header, tile part header as tile boundary position information, etc.) is provided. This is followed by coded data for each tile. Note that the main header (Main header) describes coding parameters and quantization parameters. Then, 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 a packet containing encoded wavelet coefficient values is represented for each subband. As shown in FIG. 7, the same packet sequence structure is obtained even if the division processing using tiles is performed or the division processing is not performed using tiles.
[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 encoding of the image data. In this case, the tag processing unit 105 interprets the 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 A decoding process (decompression process) is performed for each code string data of each tile 112. At this time, the positions of the bits to be decoded are determined in the order based on the tag information in the code string data, and the quantization / dequantization unit 103 sets the peripheral bits of the target bit position (the A context is generated from the sequence of (finished). The entropy coding / decoding unit 104 performs decoding by probability estimation from the context and the code string data, generates a target bit, and writes it to 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 an inverse two-dimensional wavelet transform on the data to obtain each component of the image data. The tile is restored. The restored data is converted by the color space conversion / inverse conversion unit 101 into the original color system image data.
[0042]
The above is the outline of the “JPEG2000 algorithm”.
[0043]
Hereinafter, an embodiment of the present invention will be described. Here, an example relating to an image compression / decompression technique represented by JPEG2000 will be described, but needless to say, the present invention is not limited to the content 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 for inputting an image, an image processing device 3 for performing predetermined image processing on image data of the input image, and a predetermined image processing. And an output device 4 for outputting image data.
[0045]
The input device 2 is, specifically, various communication interfaces for transmitting image data to the image processing device 3, a storage device for storing image data, an image input device such as an image scanner for inputting an image, and a digital camera.
[0046]
The output device 4 includes, specifically, various communication interfaces for receiving image data from the image processing device 3, a storage device for storing image data, a display such as an LCD or CRT for displaying images, and various printing methods for printing images. Printer.
[0047]
Next, the image processing device 3 will be described in detail. FIG. 9 is a module configuration diagram of the image processing device 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 for performing information processing, a ROM (Read Only Memory) 12 for storing 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, and 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 transmitting information by communication with the input device 2 or the output device 4, a CRT (Cathode Ray Tube) or an LCD (Liquid) for displaying the progress and results of processing to the operator. It comprises a display device 19 such as an id Crystal Display, a keyboard 20 for the operator to input commands and information to the CPU 11, a pointing device 21 such as a mouse, and the like, and data transmitted and received between these units. Are operated by the bus controller 22.
[0048]
In such an image processing apparatus 3, when the user turns on the power, the CPU 11 starts a program called a loader in the ROM 12, reads a program called an operating system, which manages computer hardware and software, from the HDD 15 into the RAM 13, and Start the system. Such an operating system starts a program, reads information, and saves information in response to a user operation. As typical operating systems, Windows (registered trademark), UNIX (registered trademark), and the like are known. The operation programs running on these operating systems are called application programs.
[0049]
Here, the image processing device 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]
Generally, an 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 a DVD-ROM, or a magnetic medium such as an FD. Then, the recorded operation program is installed in the secondary storage device 16 such as the HDD 15. Therefore, a portable storage medium such as an optical information recording medium such as a CD-ROM or a magnetic medium such as an FD can be a storage medium for storing the image processing program. Further, the image processing program may be fetched from outside via, for example, the network interface 18 and installed in the secondary storage device 16 such as the HDD 15.
[0051]
When the image processing program running on the operating system is activated, the CPU 11 executes various arithmetic processes in accordance with the image processing program to centrally control each unit. Among 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 device 3, the first layer compression code generation unit 31, the second layer compression code generation unit 32, the third layer compression code generation unit 33, the binarization unit 34, and the binary image Each function of the storage unit 35 and the image acquisition permitting unit 36 is realized by various arithmetic processes executed by the CPU 11. When real-time performance is 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-layer compression code creation unit 31, the second-layer compression code creation unit 32, and the third-layer compression code creation unit 33 roughly compress and encode image data input from the input device 2 according to the JPEG2000 algorithm. Things. For 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 quantize unit 103, the entropy encoding / decode unit 104 shown in FIG. Since the description of the tag processing unit 105 has been described above, the description here is omitted. According to the compression processing according to the JPEG2000 algorithm, a compression code is created for each layer corresponding to the octave division in the DWT. In the present embodiment, a three-layer compression code is created.
[0054]
The first layer compression code creating means 31 creates a compression code of the highest layer (first layer), and creates a compression code of a lower layer of the multi-valued image of the LL component band-decomposed by the discrete wavelet transform. It is passed to the two-layer compression code creating means 32. The second-layer compression code creating means 32 creates a second-layer compression code, and creates a lower-layer compression code of the LL component multi-value image band-decomposed by the discrete wavelet transform. The code is passed to the sign creating means 33. Then, the third hierarchical compression code creating means 33 creates a third hierarchical compression code.
[0055]
In addition, the first layer compression code generation unit 31, the second layer compression code generation unit 32, and the third layer compression code generation unit 33 convert the multi-valued image of the LL component band-decomposed by the discrete wavelet transform into a binarization unit. 34, and performs binarization processing. The binarizing means 34 converts the passed LL component of each layer from a multivalued image to a binary image. The LL component converted from the multi-valued image to the binary image in this manner is stored and held in the binary image storage means 35 for each layer.
[0056]
The image acquisition permitting unit 36 has a function of permitting acquisition of an LL component of a desired layer among LL components converted into a binary image stored and held in the binary image storage unit 35.
[0057]
Therefore, the output device 4 accesses the LL component of a desired hierarchy stored and held in the binary image storage unit 35 via the image acquisition permitting unit 36, or accesses the LL component stored and held in the binary image storage unit 35. By transmitting the LL component of a desired hierarchy, a binary image having a required resolution can be displayed.
[0058]
According to such an image processing device 3, the LL component band-decomposed by the discrete wavelet transform for each layer is converted from a multi-valued image into a binary image, stored, and converted into the stored binary image. Of the LL components, acquisition of the LL component of a desired layer is allowed. Accordingly, when a request for transmitting the LL component of the desired layer is issued from the output device that does not support the multi-valued image, the LL component of the desired layer converted into the binary image is obtained in the output device. Therefore, there is no need 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 layer compression code generation unit 31 to the second layer compression code generation unit 32, and the LL component from the second layer compression code generation unit 32 to the third layer compression code generation unit The LL component passed to 33 remained a multi-valued image. However, when the multivalued image LL component is passed to the lower hierarchy, the thin line or the like may gradually be rubbed and become invisible. Therefore, the LL component passed to the lower layer may be subjected to the binarization processing. As a result, it is possible to suppress image quality deterioration, and it is possible to reproduce a good binary image close to the original in any layer.
[0060]
【The invention's effect】
According to the image processing apparatus of the first aspect of the present invention, pixel values are discretely wavelet-transformed for each rectangular region obtained by dividing image data into one or a plurality of regions, hierarchically compression-coded, and stored and provided for providing data. In the image processing apparatus, at the time of compression encoding of image data, the LL component band-decomposed by the discrete wavelet transform for each layer is converted from a multivalued image to a binary image by a binarizing unit. A binary image storage unit that stores the LL component converted from the value image into the binary image for each layer, and a desired one of the LL components converted into the binary image stored by the binary image storage unit. Image acquisition permitting means for permitting the acquisition of the LL component of the hierarchical level. The LL component band-decomposed by the discrete wavelet transform for each hierarchical level is converted from a multivalued image into a binary image and stored. By allowing the acquisition of the LL component of the desired hierarchy among the LL components converted into the stored binary image, a transmission request of the LL component of the desired hierarchy from an output device that is not compatible with the multi-level image is made. In this case, the output device can acquire the LL component of the desired layer converted into the binary image, so that it is not necessary to create the binary image on the output device side, and the output of the image can be performed. 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 upon compression encoding of image data is converted from a multi-valued image to a binary image. By passing the data from the upper layer to the lower layer after that, deterioration in image quality can be suppressed, so that a good binary image close to the original can be reproduced at any layer.
[0062]
According to a third aspect of the present invention, there is provided an image processing apparatus which performs discrete wavelet transform of pixel values for each of rectangular areas obtained by dividing image data into one or a plurality of pieces, hierarchically compresses and encodes them, and stores and holds the data for data provision. A program installed or interpreted and executed on a computer of the apparatus, wherein the LL component band-decomposed by the discrete wavelet transform for each layer at the time of compression encoding of image data is multi-valued. A binary function for converting an image to a binary image, a binary image storage function for storing the LL component converted from a multi-level image to a binary image by the binary function for each layer, and a binary image storage function. An image acquisition permitting function for permitting acquisition of an LL component of a desired layer among LL components converted into a binary image stored by the image storage function. Then, the LL component band-decomposed by the discrete wavelet transform for each layer is converted from a multi-valued image to a binary image and stored, and among the LL components converted into the stored binary image, By allowing the acquisition of the LL component, when an output device that does not support the multi-level image requests transmission of the LL component of a desired layer, the output device converts the desired LL component into a binary image. Since the LL component of the hierarchy can be obtained, 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 upon compression encoding of image data is converted from a multi-valued image to a binary image. By passing the image from the upper layer to the lower layer, the deterioration of the image quality can be suppressed. Therefore, a good binary image close to the original can be reproduced at any layer.
[0064]
According to the storage medium of the fifth aspect of the present invention, an image to be subjected to discrete wavelet transform of pixel values for each rectangular area obtained by dividing image data into one or a plurality of pieces, hierarchically compression-coded, and stored and provided for providing data. A program installed or interpreted and executed on a computer of the processing apparatus, the computer comprising: a plurality of LL components subjected to discrete wavelet transform for each layer when compressing and encoding image data; A binary function for converting a value image into a binary image, a binary image storing function for storing the LL component converted from a multi-valued image to a binary image by the binary function for each layer, Executing an image acquisition permitting function of permitting acquisition of an LL component of a desired layer among LL components converted into a binary image stored by the value image storage function. The LL component band-decomposed by the discrete wavelet transform for each layer is converted from a multi-valued image to a binary image and stored. Of the LL components converted to the stored binary image, By permitting the acquisition of the LL component of the desired layer, if the output device that does not support the multi-level image requests transmission of the LL component of the desired layer, the output device converts the LL component into a binary image. Since it is possible to obtain 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 present 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-valued image to a binary image. By storing a program that is passed from the upper layer to the lower layer, image quality degradation can be suppressed, so that a good binary image close to the original can be reproduced at any layer.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a system for realizing a hierarchical coding algorithm which is a basis of the JPEG2000 system on which the present invention is based.
FIG. 2 is an explanatory diagram showing a divided rectangular area of each component of an original image.
FIG. 3 is an explanatory diagram showing subbands at each decomposition level when the number of decomposition levels is three.
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 showing a schematic configuration of one frame of code string data.
FIG. 7 is an explanatory diagram showing a code stream structure in which packets containing encoded wavelet coefficient values are represented for each subband.
FIG. 8 is a block diagram illustrating 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 permitting means

Claims (6)

In an image processing apparatus, a pixel value is discrete wavelet transformed for each rectangular area obtained by dividing image data into one or a plurality of pieces, hierarchically compression-coded, and stored and provided for data provision.
Binarizing means for converting the LL component band-decomposed by the discrete wavelet transform for each layer at the time of compression encoding of image data from a multi-valued image to a binary image;
A binary image storage unit for storing, for each layer, the LL component converted from the multi-valued image to the binary image by the binarization unit;
Image acquisition permitting means for permitting acquisition of an LL component of a desired hierarchy among LL components converted into a binary image stored by the binary image storage means;
An image processing apparatus comprising: The LL component passed from an upper layer to a lower layer upon compression encoding of image data is converted from a multi-level image to a binary image, and then passed from the upper layer to a lower layer. 2. The image processing device according to 1. Pixel value is discrete wavelet transformed for each rectangular region obtained by dividing image data into one or a plurality of regions, compression-encoded hierarchically, and installed in a computer having an image processing device for storing and holding for providing data, or interpreted A program to be executed by the computer,
A binarizing function of converting the LL component band-decomposed by the discrete wavelet transform for each layer at the time of compression encoding of image data from a multi-valued image to a binary image;
A binary image storage function of storing the LL component converted from the multi-valued image to the binary image by the binarization function for each layer;
An image acquisition permitting function for permitting acquisition of an LL component of a desired hierarchy among LL components converted into a binary image stored by the binary image storage function;
A program characterized by executing The LL component passed from an upper layer to a lower layer upon compression encoding of image data is converted from a multi-level image to a binary image, and then passed from the upper layer to a lower layer. 3. The program according to 3. Pixel data is discretely wavelet transformed for each rectangular region obtained by dividing image data into one or a plurality of regions, compression-coded hierarchically, and installed in a computer having an image processing apparatus that stores and holds data for providing, or interprets A program to be executed by the computer,
A binarizing function of converting the LL component band-decomposed by the discrete wavelet transform for each layer at the time of compression encoding of image data from a multi-valued image to a binary image;
A binary image storage function of storing the LL component converted from the multi-valued image to the binary image by the binarization function for each layer;
An image acquisition permitting function for permitting acquisition of an LL component of a desired hierarchy among LL components converted into a binary image stored by the binary image storage function;
A storage medium characterized by storing a program for executing the program. A program is stored which converts an LL component passed from an upper layer to a lower layer upon compression encoding of image data from a multilevel image to a binary image, and then passes the LL component from the upper layer to the lower layer. The storage medium according to claim 5, wherein

Images