JPH11187261A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processor which is capable of attaining a configuration that compresses both the image data and tag data and stores them on an identical memory, without causing the fall of an extending speed. SOLUTION: This image processor which interprets a file described in the known format, expands it into image data and further produces tag data that shows attributes of a pixel element included in the image data in a pixel unit contains compressing means 113 and 114 which perform the encoding compression of image data and tag data respectively, a common storing means 15 which stores both the compressed image and tag data and an extending means 16 which reads image data and a tag data in time division from the means 15, extends them respectively, associates them in a pixel unit, and outputs them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus, and more particularly, to generating attribute information (tag data) indicating the attribute of an image element included in image data for each pixel. And an image processing apparatus for supplying the image processing apparatus to an output device.

[0002]

2. Description of the Related Art In recent years, various input devices (scanners, video still cameras, etc.) and document editors have appeared with the advancement of hardware / software of DTP (Desk Top Publishing), and various spatial resolutions or gradations have been developed. It is now possible to capture image elements with resolution in one document (one page). As a result, documents have been created that combine more complex and sophisticated image elements with various spatial or gradation resolutions.

Here, an image element refers to an image block classified by data having similar properties, and can be classified into, for example, a character / line drawing area, a graphic area, and a natural image area. Documents that are complicated and sophisticated and have various spatial resolutions or gradation resolutions can be easily expressed by using PDL, and can be generated as simple files.

When a PDL file is generated, various spatial resolutions or gradation resolutions included in the document are described in a unique logical coordinate space independent of an input / output device. On the other hand, the image processing apparatus interprets these PDLs and performs expansion processing in accordance with the spatial resolution or the gradation resolution of the memory for both images included in its own image processing apparatus. Usually, the spatial resolution or the gradation resolution at the time of performing the expansion processing is the same as the spatial resolution or the gradation resolution of the target image forming apparatus such as a printer.

However, in such a conventional image processing apparatus,
When the PDL interpretation process is performed to perform the development process, basically, the image can be developed only at the unique spatial resolution and gradation resolution of the image processing apparatus or image forming apparatus. The image data developed at the spatial resolution and the gradation resolution specific to the image processing apparatus are all supplied to a target image forming apparatus such as a printer as a single spatial resolution and a gradation resolution. Various image processing is performed on the side, or image formation is performed without performing anything.

As described above, the image elements constituting a document can be classified into a character / line drawing area, a graphic area, and a natural image area. The spatial resolution and gradation required for each image element are described. The resolution is different.
For example, a high spatial resolution is required in a character / line drawing area, but in most cases, each pixel is expressed in a binary manner, so a low gradation resolution may be used. In the graphic region, since the same value is likely to appear continuously, it can be expressed with a low spatial resolution. The spatial resolution is higher than the spatial resolution of an image forming apparatus such as an image processing apparatus or a printer. Is very low, and can be expressed in binary in most cases, so that a low gradation resolution is sufficient. On the other hand, a high gradation resolution is required for a halftone image such as a natural image, but a high spatial resolution is not required.In addition, high resolution becomes oversampling and deteriorates image quality. Preferably, there is.

Originally, in order to form a true high-quality image for image elements having different spatial resolutions and gradation resolutions which are required respectively, an image processing apparatus must perform image formation. With the attributes of each image element stored up to the stage, data is sent to the target image forming apparatus such as a printer, and the image depending on each image forming apparatus in a format suited to each characteristic. Formation should take place.

In response to such a request, for example, Japanese Patent Application Laid-Open
In the publication No. 123939, a file (PD
When interpreting and developing an L file), attribute information corresponding to the type of image element (character / line drawing area, graphic area, natural image area) is generated as tag data. The image quality is improved by performing image processing according to the tag data.

[0009]

Since the tag data is generated for each pixel and temporarily stored together with the image data, the tag data is encoded and compressed like the image data in order to save the memory capacity. It is desirable to memorize it. Also, to save more memory space,
It is desirable to store the compressed image data and tag data in different areas on the same memory instead of storing them in separate memories.

However, since each data is stored in the same memory and cannot be read at the same time,
When decompressing, it is necessary to read out each data from the memory in a time division manner and transfer it to the decompressor.

On the other hand, comparing the data amount per pixel, the image data is about 8 bits, whereas the tag data is mostly about 2 bits, and the data amounts of both are greatly different. Furthermore, since tag data must be completely restored after decompression, it is necessary to perform reversible coding and compression, whereas image data has no necessity and irreversible coding with a high compression rate Compression is often performed.

As described above, the image data and the tag data differ in various conditions relating to compression / expansion. In order to output each data in pixel units after decompression, the image data and the tag data are stored in the same memory. , The expansion speed of each expander, and the like must be controlled. For this reason, no attempt has been made to compress the image data and the tag data together and store them on the same memory.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an image processing apparatus capable of compressing image data and tag data together and storing them in the same memory.

[0014]

In order to achieve the above-mentioned object, the present invention provides compression means for encoding and compressing image data and attribute data obtained by interpreting a file described in a known format. A common storage means for storing both the compressed image data and the tag data, and reading out the stored image data and the tag data in a time-division manner,
A decompression means for decompressing each of them and outputting them in association with each other on a pixel-by-pixel basis.

According to the above arrangement, the compressed data of the image data and the tag data stored on the common storage means are read out in a time division manner and decompressed, respectively, and the decompressed image data and the tag data are decompressed in pixel units. Since the image data and the tag data are output in association with each other, the image data and the tag data can be compressed and stored in the same memory.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. The image processing apparatus according to the present embodiment includes an image data processing apparatus 1 that expands a file input from an external device 2 such as a host computer into image data and tag data, an image data provided from the image data processing apparatus 1, It is roughly classified into an image forming processing apparatus 3 that executes printing based on tag data. Hereinafter, the image data processing apparatus 1 will be described first, and then the image forming processing apparatus 3 will be described.

FIG. 1 is a block diagram showing the configuration of an image data processing apparatus 1 according to one embodiment of the present invention. The data communication unit 14 inputs a document file described in a certain known PDL (hereinafter, simply referred to as “PDL file”). This PDL file has been created by the host computer 2. Various control programs executed by the CPU 11 are stored in the ROM 13. The RAM 12 functions as a work area when executing the control program. CPU11
Executes the overall control processing of the image data processing apparatus 1, and in the present embodiment, in particular, executes the image expansion unit 111, the image data conversion unit 112, and the first and second compression units 1.
13 and 114 function.

The image developing unit 111 performs an image developing process, interprets the PDL file, and creates an object list of each image element. Here, the object list refers to a position in the image coordinate space of the image data processing apparatus 1 where each object (image element) exists, what kind of configuration the image element is, and how. It has a structure that indicates whether the image element has an appropriate attribute or what color the object has.

The position in the image coordinate space is, for example, (x1
_min, y1 _min), can be expressed as a diagonal can be expressed by the coordinates, the character configuration, rectangular shapes, circles, lines, and other image elements as (x2 _max, y2 _max). In addition, attributes can be distinguished into characters, line drawings, natural images, graphic elements, and the like, and colors (colors) can be specified by instructing a color palette internally provided in the image development unit 111. Can be expressed.

The image data conversion unit 112 includes the image development unit 1
The image data described in the object list is expanded into byte map data by 11 and tag data indicating the attribute of the image element represented by the pixel is generated for each pixel of the byte map data. The tag data in the present embodiment classifies image elements into the following four types with 2 bits as shown in FIG. That is, image elements are classified into a natural image area, a graphic area, a character / line drawing area, and other areas, and tag data “11”, “10”, “01”, and “00” (binary notation) are respectively provided. Have been assigned. In the common storage unit 15, a tag memory area 151 and an image memory area 152 are secured.

The first compression unit 113 of the CPU 11 encodes and compresses the byte map data expanded by the image data conversion unit 112, and if the byte map data corresponds to black, the image data is transferred to the image memory 152 (K). , The image data is stored in the image memory 152 (Y) if the image data corresponds to yellow, the image memory 152 (M) if the image data corresponds to magenta, and the image memory 152 (C) if the image corresponds to cyan. In the image data according to the present embodiment, each pixel is 8 bits, the resolution is 400 dpi, and the size is A3.
The size (4 megapixels) is assumed. For this reason,
The total capacity of each image memory 152 is 128 megabytes. The second compression unit 114 encodes and compresses the tag data and stores it in the tag memory 151.

The decompression unit 16 is a first FIFO for temporarily storing compressed data relating to image data read from the image memory 152 of the common storage unit 15 in a first-in first-out manner.
162; a second FIFO 163 for temporarily storing compressed data relating to tag data read from the tag memory 151 of the common storage unit 15 in a first-in first-out manner;
A first decompressor 164 that decompresses and outputs the compressed data output from the FIFO 162; and a decompressed data supplied from the second FIFO 163 and temporarily stores the decompressed data in the buffer 165a. A second decompressor 165 for decompressing and outputting the byte map data and the tag data stored in the common storage unit 15.

The IF controller 17 is provided with the first decompressor 164
And the tag data output from the second decompressor 165 are synchronized and output in pixel units.
The input control unit 161 variably controls an opportunity to read the image data and the tag data from the common storage unit 15 in a time-sharing manner according to the free space of the second FIFO 163.

FIG. 2 is a block diagram showing the configuration of the image forming processing apparatus 3. The image interface 31 exchanges data with the image data processing apparatus 1 shown in FIG. 1, interprets tag data, and selects data. gamma correction unit 32, color space conversion unit 33,
The image processing units of the filter processing unit 34, the UCR / black generation unit 35, the gradation generation unit 36, and the screen processing unit 37 perform image processing functions that perform different image processing in accordance with respective tag data instructions. It has an LUT (Look Up Table) for performing processing. The laser drive circuit 38 forms an image according to the data. Note that the image forming method may be an electrophotographic method, an ink jet method, a thermal transfer method, or any other method. In this case, the laser drive circuit 38 is appropriately changed.

The control section 39 performs various controls such as synchronization control, system control, UI control, image processing control, and communication control in the image forming processing apparatus 3, and determines what kind of image is generated when what tag data is used. Instructions such as whether or not to perform processing are also instructed by software before the operation starts.

The image forming apparatus 3 may be of a copier type having an image input device 40.
In this case, the original is read in three colors of R (red), G (green), and B (blue) by the CCDs 41a to 41c, and these read signals are read by the A / D converters 42a to 42c.
c, the signal is converted into a digital signal. Next, the shading correction unit 43 corrects the sensitivity variation for each pixel and corrects the illumination unevenness, and finally outputs the output signal lines 44a to 44a.
44c, R.A. G. FIG. It is supplied to the image interface 31 as data having a B color space.
In this case, the image interface 31 selects the data from the image input device 40 instead of the image data from the image data processing device 1, and performs the image forming process.

FIG. 3 is a flowchart for explaining the operation of the present embodiment. First, the image data processing device 1
Will be described.

In the image data processing apparatus 1, step S1
, The PD created by the host computer 2
The L file is received by the data communication unit 14 and the CPU
The image is interpreted by the eleventh image development unit 111. Step S
In 2, an object list is generated for each line of one page by the interpretation of the image developing unit 111. The image data that has become the object list is transferred to the image data conversion unit 112, and is virtually rasterized (developed) in step S3. In step S4, K, Y, M, and C are applied to all scan lines of one page.
Is converted as a byte map rasterized for each color, and after being encoded and compressed by the first compression unit 113 in step S5, K, Y, and M are processed in the next step S6.
And C are temporarily stored in the respective image memories 152.

On the other hand, at the same time as performing the above processing,
The eleventh image data converter 112 generates an object tag in step S7. In other words, the characteristics of each image element and the position where the image element exists are interpreted by the object list passed to the image data conversion unit 112, and the two-bit data is determined based on the tag data function table shown in FIG. Generate tag data for configuration. The tag data obtained one after another is stored in step S9.
Are encoded and compressed by the second compression unit 114 in step S10, and are stored in the tag memory 151 in step S10.

When the generation, compression, and storage processing of the byte map data and the tag data is completed in this manner, communication is performed between the IF control unit 17 and the image forming processing apparatus 3 at a predetermined timing, and An output synchronization signal is supplied via the communication / synchronization signal line 23. Step S
In 11 and 12, each compressed data is decompressed by the decompressor 16, respectively.

Here, the block diagram of FIG.
The operation of the decompressor 16 will be described in detail with reference to the timing chart of FIG.

In FIG. 1, the input control unit 1 of the decompressor 16
61 receives the start address and size of the image data and the start address, size and cycle start command of the tag data from the CPU 11, and reads out the image data and the tag data from the common image memory 15 in a time-division manner in the DMA cycle.

Each of the FIFOs 162 and 163 is a general-purpose memory having a read port and a write port, and outputting data input from the write port from the read port in the input order. Each FIFO
The operations of 162 and 163 may be synchronous or asynchronous with the clock, but in the present embodiment, the operations are described as operating in synchronization with the clock. FIFOs 162, 16
The data width of 3 is the data width of the system bus 10 for writing, and 8 data for reading.

Each FIFO 162, 163 outputs an empty signal E if it is empty. If the read signal F output from the IF control unit 17 is valid, the data is output, and if the data is still present in itself, the data is continuously output thereafter.

The first decompressor 164 includes a first FIFO 162
The compressed image data output from the IF controller 17 is expanded and supplied to the IF controller 17 as long as the read signal F output from the IF controller 17 is valid. That is, the first expander 164 performs the expansion operation independently of the second expander 165. The second decompressor 165 includes a second FIFO1
The compressed tag data output from 63 is decompressed and stored in its own buffer 165a. The tag data stored in the buffer 165a is output in synchronization with the output timing of the image data from the first decompressor 164.

The IF controller 17 sets the size of the data to be printed in the main scanning direction and the sub-scanning direction from the CPU 11 and, upon receiving a data request signal from the image forming processing apparatus 3, sets the requested transfer speed at the requested transfer speed. The image data and the tag data are transferred synchronously in pixel units for each line.
The IF control unit 17 has a buffer corresponding to the line, and makes the data read signal F valid as long as its own buffer is not full and data exists in the first decompressor 164.

The second decompressor 165 continues the decompression operation as long as its own buffer 165a has a free space, but suppresses the decompression operation when the buffer 165a is full. Then, this suppression operation is reflected on the free space of the second FIFO 163. The free space of the second FIFO 163 is monitored by the input control unit 161. The input control unit 161
If there is free space in the second FIFO 163, the tag data and the image data are alternately read from the respective memory areas 151 and 152 of the common image memory 15 in a time-division manner, and supplied to the second FIFO 163 and the first FIFO 162, respectively. On the other hand, when the free space of the second FIFO 163 is exhausted, in other words, when the buffer 165a of the second decompressor 165 is exhausted, the reading of the tag data will be described in detail later with reference to the timing chart of FIG. At the opportunity, the image data is read and supplied to the first FIFO 162.

FIG. 4A shows the timing at which compressed data of image data and tag data are read out from the common storage unit 15 in a time-division manner. At the timing of the output “image”, the image data is read. FIG. 13B shows the timing at which the compressed data of the tag data is input to the second decompressor 165. FIG. 11C shows the timing at which the tag data is expanded by the second expander 165. Two squares correspond to one pixel (two bits in this embodiment).
Is represented. FIG. 11D shows a negative logic buffer full signal output when the number of empty buffers in the buffer 165a becomes "0". FIG. 11E shows the number of empty buffers in the buffer 165a. FIG.
The timing at which tag data is output from the second decompressor 165 is shown. FIG. 9G shows the timing at which the compressed data of the image data is input to the first decompressor 164. FIG. 11H shows the timing at which the image data is expanded by the first expander 164, and each square represents one pixel (1 byte in this embodiment). Same figure
(i) shows the timing at which image data is output from the first decompressor 164.

In such a configuration, for example, during the period from time t1 to time t2 in FIG. 4, the second decompressor 165 outputs one pixel in synchronization with the output of one pixel of image data from the first decompressor 164. The tag data for one pixel is expanded, and the tag data for one pixel is output from the buffer 165a. Therefore, the number of empty buffers remains at “9” without change. On the other hand, during the period from time t2 to time t3, while the tag data for two pixels is expanded by the second expander 165, only the tag data for one pixel is output from the buffer 165a. The number is reduced by "1" to "8".

As described above, in the present embodiment, the amount of data processing per pixel is twice as large as that of the first decompressor in the second decompressor 165. Therefore, in the second decompressor 165, the number of free buffers in the buffer 165a is gradually reduced. To decrease. Then, when the number of empty buffers becomes “0”, the second decompressor 165 temporarily suspends the decompression processing, and thus the reading of the tag data becomes unnecessary.

On the other hand, the time T1 required by the second decompressor 165 for one decompression is sufficiently shorter than the period T in which image data is supplied in a time-division manner. The decompression process will be interrupted in the medium term.

Therefore, in the present embodiment, when the reading of the tag data becomes unnecessary, this opportunity is allocated to the reading of the image data, so that the opportunity of inputting the image data to the first FIFO 162 is increased. That is, at the time t4 in FIG. 4, when the DMA cycle of the tag data arrives with the number of free buffers being “0”, the input control unit 161 accesses the image memory 152 instead of the original tag memory 151 to transfer the image data to the system. The data is sent out onto the bus 10 and a write signal is output to the first FIFO 162. As a result, at time t5, the decompression process by the first decompressor 164 is performed continuously without interruption, so that the decompression process of the entire apparatus is performed efficiently. At time t6, D related to the next tag data
At the end of the MA cycle, the tag memory 151 is accessed as usual because the number of empty buffers is "2".

Returning to FIG. 3, in step S13, the expanded image data and the tag data are processed by the IF control unit 17 via the image data output signal line 21 and the tag data output line 22 to form the image of the communication partner. Device 3
Are transmitted in synchronization with each other for the same coordinate data.

On the other hand, in the image forming processing device 3, when the data from the image input device 40 is not used, the image interface 31 selects the image data from the image data processing device 1 and, together with the tag data supplied at the same time, in the subsequent stage. It is supplied to each image processing unit. Thus, in step S14, image processing is performed for each image element based on the tag data. As shown in FIG. 5, the tag data is classified into a natural image area, a graphic area, a character / line drawing area, and another territory. It can be determined by the tag data supplied at that time.

Accordingly, the screen processing unit 37 determines whether the image element corresponding to the image data is classified into the character / line drawing area by the tag data supplied at the same time.
Processing is performed so as to be output on line 0, and to be output on line 200 when classified into other areas.

Similarly, the γ correction section 32 switches the γ correction coefficient in accordance with the tag data, and
3 switches the LUT during the color space conversion process according to the tag data, the filter processing unit 34 switches the filter coefficient during the filter process according to the tag data,
The CR / black generation unit 35 switches the coefficient at the time of UCR / black generation according to the tag data, and the gradation control unit 36 switches the gradation control LUT at the time of gradation control according to the tag data.

That is, in each of the image processing units 32-37,
Optimal processing is performed on the supplied image data for the image element indicated by the tag data. In step S15, the processing results are sent to the laser drive circuit 38, and image formation is performed.

[0048]

According to the present invention, the following effects are achieved. (1) Since the compressed data of the image data and the tag data stored on the same memory are read out in a time-division manner and decompressed respectively, and the decompressed image data and the tag data are output in association with each pixel, Image data and tag data can be compressed and stored on the same memory. (2) When the compressed image data and tag data are supplied to each decompressor in a time-division manner and decompressed, more decompressors are required for the decompressor for image data with a long decompression time per pixel. Since the data reading opportunity from the common memory is controlled so as to be distributed, the standby time can be effectively used, and the decompression process can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of an image forming processing apparatus.

FIG. 3 is a flowchart showing the operation of the embodiment.

FIG. 4 is a timing chart showing the operation of the present embodiment.

FIG. 5 is a diagram showing a configuration example of a tag bit function table.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image data processing apparatus, 2 ... Host computer, 3
... Image formation processing device, 11 CPU, 14 Data communication unit, 15 Common storage unit, 16 Decompressor

Continued on the front page (72) Inventor Yuji Yoshino 3-1-1, Honcho, Iwatsuki-shi, Saitama WAT SU Building West Building 4F Fuji Xerox Co., Ltd. In-house (72) Inventor Jun Fukui 3-1-1, Honcho, Iwatsuki-shi, Saitama WAT SU Building West Building 4F Fuji Xerox Co., Ltd. In-house (72) Inventor Kei Hatano 3-1-1 Honcho, Iwatsuki-shi, Saitama Prefecture WAT SU Building West Building 4F Fuji Xerox Co., Ltd.

Claims (6)

[Claims] 1. An image processing apparatus which interprets a file described in a known format and develops it into image data, and further generates tag data indicating an attribute of an image element included in the image data on a pixel basis. Compression means for encoding and compressing the image data and tag data respectively; common storage means for storing both the compressed image data and tag data; reading out the image data and tag data from the common storage means in a time-division manner; An image processing apparatus, comprising: a decompression means for decompressing and outputting in a pixel-by-pixel correspondence. 2. The decompressing means includes: first buffer storage means for temporarily storing compressed data of image data read from the common storage means in a first-in first-out manner; and tag data read from the common storage means. Second buffer storage means for temporarily storing the compressed data in a first-in first-out manner, first expansion means for expanding and outputting the compressed data output from the first buffer storage means, and second buffer storage Second decompression means for decompressing and temporarily storing compressed data output from the means, and outputting the decompressed data at the output timing of the first decompression means; and image data and tag data stored in the common storage means in time division. Input control means for reading and inputting the data to each buffer storage means. The input control means reads the image data and the image data according to the free space of the second buffer storage means. 2. The image processing apparatus according to claim 1, wherein an opportunity for reading tag data and tag data in a time-division manner is variably controlled. 3. The input control means reads the image data and the tag data alternately in a time-division manner if the second buffer storage means has a free space, and if the free space is insufficient, the image control means reads the image data and the tag data at an opportunity to read the tag data. 3. The image processing apparatus according to claim 2, wherein data is read. 4. The image processing apparatus further comprises a common bus interconnecting at least the common storage means and the decompression means, and the image data and the tag data read from the common storage means are transferred on the common bus in a time-division manner. The image processing apparatus according to claim 1, wherein: 5. The image processing apparatus according to claim 1, wherein the file has a plurality of different types of spatial resolution and gradation resolution. 6. The image processing apparatus according to claim 1, wherein the file is described in a page description language.