JP2000350005A - Image processing unit, image forming device and image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save memory capacity required to store print data and to substantially eliminate a loss in character/line drawing data in an image processing unit, that separately processes image data and character/line drawing data. SOLUTION: Character/line drawing data are generated for every pixel (step S503), after putting together expanded data and the character/line drawing data for each pixel (step S504), compression processing is conducted, until a compression rate is decreased to attain reversible compression (step S508). As a result, deterioration in the character/line drawing data is avoided, reversible compression is made applicable to the character/line drawing data and irreversible compression can also be made applicable to image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a page description language (P)
DL), which develops and outputs image information (hereinafter referred to as PDL data) described in PDL data.
An image processing apparatus, an image forming apparatus, and the like having a result of expanding the DL divided by character / line drawing data and image data;
The present invention relates to an image forming system using the image processing apparatus and / or the image forming apparatus.

[0002]

2. Description of the Related Art Recently, a PDL from a host computer has been used.
Data is received via a network, and the PDL data is converted into print data in an image processing apparatus (hereinafter, referred to as print data).
This is called image development. An image forming system that prints the data on paper, OHP, or the like using a high-quality color copying machine has already been proposed.

[0003] Further, with respect to the image data sent from the image processing apparatus, the character portion is recognized in the color copying machine to reproduce the output resolution high, and in the other portions, the gradation is higher than the resolution. It is also known that the emphasis reproduction is performed adaptively.

In developing an image in an image processing apparatus,
Recognize the character / line drawing part and generate image feature data (hereinafter referred to as character / line drawing data) representing the character / line drawing part,
Attempts are being made to send the data to a color copier together with the image data and to control printing in accordance with the data.

[0005]

However, the above-mentioned prior art has the following problems. For example, when a character / line drawing portion is recognized by the image processing device, the character / line drawing data must be stored in a memory in the image processing device like the image data. As a result, in addition to a memory for image data, a memory for character / line drawing data is required, which increases costs and complicates the structure.

Therefore, if image data and character / line drawing data formed by the image processing apparatus are grouped for each pixel and, for example, an image of each color of CMYK is represented by 8 bits per pixel, One bit of character / line drawing data is added to each pixel, and 9 bits are added to each CMYK image.
Currently, a configuration using a small-capacity memory by reconstructing the data into bits / pixels, compressing and encoding the result, and storing the result in a memory is being studied.

However, if the lossy encoding method used for efficiently compressing the image data is applied to the compression of the image data to which the character / line drawing data is added, the image Loss ( Loss) also affects the character / line drawing data, and as a result, the final printed matter for which printing control is performed based on the data.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and in an image processing apparatus that handles image data and character / line drawing data separately, it is possible to reduce the memory capacity necessary for storing print data and It is another object of the present invention to provide an image processing apparatus capable of substantially eliminating loss of character / line drawing data.

Another object of the present invention is to provide image data,
Provided is an image forming apparatus that handles character / line drawing data separately, which can save a memory capacity necessary for storing print data and can substantially eliminate loss of character / line drawing data. It is in.

[0010] Still another object of the present invention is to provide an image forming system using the image processing apparatus or the image forming apparatus of the present invention.

[0011]

That is, the gist of the present invention is an image processing apparatus which receives image forming data, converts the data into a format suitable for a predetermined image forming apparatus, and outputs the converted data. Separating means for separating the first image information having substantially no gradation and the second image information having the gradation from the application data, and a corresponding one of the first image information and the second image information. A data generating means for generating, for each pixel data, third image information having an information amount smaller than the sum of the first image information and the second image information; Data output means for restoring the second image information and outputting it as an output signal of the image processing apparatus, wherein the data generation means performs compression encoding on at least the second image information Exists in the device.

Another aspect of the present invention resides in an image forming apparatus that receives first image information and second image information from an image processing apparatus of the present invention, and forms and outputs a corresponding image.

Another aspect of the present invention is a storage medium for storing a program executable by an apparatus, wherein the apparatus executes the program and functions as an image processing apparatus of the present invention. Be in the medium.

Another aspect of the present invention is a storage medium for storing a program that can be executed by the apparatus, wherein the apparatus that executes the program functions as the image forming apparatus of the present invention. Be in the medium.

Another aspect of the present invention is a storage medium for storing a program that can be executed by an apparatus, wherein the apparatus that has executed the program functions as the image forming system of the present invention. Be in the medium.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] The present invention will be described in detail below based on preferred embodiments. In the following embodiments, an example of a system of a color copying machine and an image processing apparatus is shown as an application example of the present invention. However, the present invention is not limited to this and can be applied to other various apparatuses.

FIG. 1 is a system configuration diagram of an image processing system according to an embodiment of the present invention. In the present embodiment, as shown in FIG.
It is composed of a color copying machine (120) comprising a color image printing unit for printing and outputting a grayscale image, an image processing device (110) connected on a network, and a plurality of host computers (101 to 103). . First, the color copier will be described in detail.

<Structure of Color Copier> FIG. 2 is a sectional view of the main structure of a color copier (120 in FIG. 1) according to the present invention. In FIG. 2, reference numeral 201 denotes an image scanner unit, for example, 400 dpi (400 dots / inch).
Is a part that reads a document at a resolution of and performs digital signal processing. Reference numeral 202 denotes a printer unit which prints out an image corresponding to the document image read by the image scanner 201 in full color on paper at a resolution of, for example, 400 dpi. An operation unit 227 includes keys for giving an instruction from a user and a display device for displaying a message.

First, the image scanner unit 201 will be described. Reference numeral 200 denotes a mirror surface pressure plate, and a document 204 on a platen glass (hereinafter, platen) 203 is a lamp 20.
5, and the reflected images are reflected by mirrors 206, 207, and 208.
, An image is formed on a three-line sensor (hereinafter referred to as a CCD) 210 by a lens 209, and sent to a signal processing unit 211 as full-color information red (R), green (G), and blue (B) components. The speed of the lamp 205 and the mirror 206 is v, and the speed of the mirrors 207 and 208 is は.
The entire surface of the document is scanned (sub-scanning) by mechanically moving the line sensor in the direction perpendicular to the electrical scanning (main scanning) direction of the line sensor at v.

In the signal processing section 211, the read image signal is electrically processed, and magenta (M),
It is decomposed into cyan (C), yellow (Y), and black (Bk) components and sent to the printer unit 202.

Then, for one original scan in the image scanner unit 201, one component of M, C, Y, and Bk is sent to the printer unit 202, and one printout is performed by a total of four original scans. Is completed.

Each of the M, C, Y and Bk image signals sent from the image scanner unit 201 is sent to a laser driver 212. The laser driver 212 modulates and drives the semiconductor laser 213 according to the sent image signal. The laser light is applied to the polygon mirror 214, f
The photosensitive drum 2 via the −θ lens 215 and the mirror 216
17 is scanned.

Reference numeral 218 denotes a rotary developing unit, which includes a magenta developing unit 219, a cyan developing unit 220, and a yellow developing unit 22.
1. The black developing unit 222 includes four developing units that alternately come into contact with the photosensitive drum 217 and develop the electrostatic development formed on the photosensitive drum with toner.

Reference numeral 223 denotes a transfer drum, which winds a sheet supplied from the sheet cassette 224 or 225 around the transfer drum 223 and transfers an image developed on the photosensitive drum to the sheet. In this way, after the four colors of M, C, Y, and Bk are sequentially transferred, the sheet passes through the fixing unit 226, and is discharged after the toner is fixed on the sheet.

<Host Computer> FIG. 4 shows host computers 101, 102 and 103 on a network.
Is shown. It is not necessary that each host computer has the same configuration, and different host computers may be connected.

The host computer has a network controller 4 for controlling a protocol on the network.
09, a CPU 401 which performs central control of a host computer in accordance with a program stored in a ROM 406 or a hard disk 410, a hard disk 410 for temporarily registering image data and storing various data, a hard disk controller 408 for controlling the same, and a main memory. 407, a mouse 411 as a means for inputting instructions from an operator, a keyboard 413, a keyboard / mouse controller 405 for controlling them,
The display includes a color display 412 for displaying a layout / edit menu, a display memory 403, a display controller 404, and an image edit controller 402 for laying out and editing an image on the display memory.

<Image Processing Apparatus><Output to Color Copier> FIG.
It is an internal block diagram of. In the figure, 3011 is C
The PU controls the entire image processing apparatus based on a program stored in the ROM 3012. At the same time, this C
Since the PU 3011 has to perform the image development processing of the PDL data, a CPU having a high processing speed, for example, R
ISC (Reduced Instruction S)
et Computer) is preferably used.

First, PDL data is received from a host computer via a host I / F (parallel, LAN controller) 3015. At this time, the PDL data is sent from the host computer in parallel or / and L
Since the data is sent through the AN I / F, an interface cable is connected according to the intended use.
That is, when there is a request from the host computers 101 to 103, each interface is automatically switched.

Next, the received PDL data is temporarily stored in a partial area (PDL buffer) of the frame memory 3013 via the CPU bus. And the CPU 30
11 performs image development from the received PDL data to raster image data (red, green, blue) using font data stored in the ROM 3012, the internal HDD 3020, or the external HDD.

At the time of image development, image characteristic data is generated for a character / line drawing portion. The developed image data is subjected to color conversion processing by the color conversion processing unit 3014. That is, it converts the red, green, and blue raster image data into raster image data (cyan, magenta, yellow, and black) that can be printed by a color copying machine (see FIG. 2). Then, after the color-converted image data and character / line drawing data are grouped for each pixel, they are compression-encoded by a predetermined compression method.

Then, the address generation circuit 3016 writes the write address 30 to the frame memory 3013.
Step 18 is performed to store the compressed raster image data in the frame memory 3013.

At the same time as the PDL development processing, the operation states of the image processing apparatus and the color copier, the names of documents created by the host computer, and the like are also displayed using an operation panel controller and an operation panel (not shown).

The above-described color copier (see FIG. 2) is an electrophotographic color copier that sequentially forms images for a plurality of output color components cyan, magenta, yellow, and black.

When the color copier is ready to receive raster image data (Ready state), the compressed raster data stored in the frame memory 3013 is expanded,
The data is stored in the FIFO 3023. And the FIFO 302
3 is read out based on a synchronization signal (not shown) from a color copying machine (see FIG. 2) and sent to the color copying machine via an external I / F unit 3024.

The CPU 3011 performs the creation of image feature data, the compilation of data for each pixel, and the compression and decompression operations.
M3012, and can be realized by executing a control code stored in any of the internal HDD and the external HDD. Of course, it is also possible to adopt a configuration in which the additional compression and decompression operations are processed using dedicated hardware.

Also, compression (encoding) and decompression (decoding)
In this case, at least two methods, a reversible method (small compression rate) and an irreversible method (high compression rate), can be executed.
For example, a basic method (Baseline System) using DCT (Discrete Cosine Transform) and a DP (Digital Signaling) without DCT
CM (Differential Pulse Code Modulation) method (Indepedent Funct
ion) can be executed. Which coding method is used can be selected, for example, based on the value of a predetermined address of the frame memory 3013, and the coding method currently set can be known by this configuration. .

<Encoding Control> Next, based on the above description, the control flow of the image processing apparatus according to the present embodiment will be described in detail with reference to FIG. First, in step S501, it is checked whether or not PDL data has been received. If there is, in step S502, PDL data is received, and image development is started. In step S503, character / line drawing data is generated for each pixel, and in step S504, image conversion data (8 bits) and character / line drawing data (1 bit) color-converted for each pixel are combined into 9 bits. To

Next, in step S505, it is checked whether the compression method is lossless compression. If the compression method is lossless compression, in step S506, the data compiled in step S504 is compressed and stored in the memory. If the compression is not lossless, in step S507, the compression ratio is reduced (or the lossless compression method is selected) until the lossless compression method is selected, and step S50 is performed.
In step 8, compression is performed at the compression ratio determined in step S507.
Store in memory.

Next, in step S509, it is checked whether or not image development and generation of character / line drawing data have been completed. Until the processing is completed, steps S503 to S50 are performed.
Step 9 is repeated.

Then, in step S510, it is checked whether the color copying machine is in the Ready state. If it is not in the Ready state, it waits until it becomes Ready.

Then, in step S511, the compressed data (image expansion, character / line drawing data) is expanded, and the data is sent to the color copier. After that, the processing makes a transition to Step S501.

<Print Control> Next, the control operation of the color copying machine will be described with reference to FIG. First, step S601
To check whether an error has occurred in the color copier. If an error has occurred, step S
In step 602, the error content is notified to the image processing apparatus.

If no error has occurred, it is checked in step S603 whether there is a copy or print request. If there is no copy and print request, the process proceeds to step S601. At this time, if there is a copy request, a busy indication is displayed on the copier operation unit 227 in step S604, and key input from the operation unit is prohibited. Then, in step S605, local copying is started, and in step 606, local copying is executed.
After the local copy is completed, the process proceeds to step S601, and the subsequent processes are repeated.

On the other hand, if there is a print request from the image processing apparatus in step S603, a busy display is displayed on the copier operation unit 227 in step S607, and key input from the operation unit is prohibited. In step S608, printing is started. In steps S609 to 610, printing (printing) is controlled based on the character and line drawing data sent from the image processing apparatus, and the output resolution of the character portion is reproduced high. In other parts, reproduction that emphasizes gradation rather than resolution is adaptively performed. Then, after the printing operation is completed, the process proceeds to step S601.

[Second Embodiment] This embodiment is characterized in that when the compression method of image development data and character / line drawing data is irreversible, only the character / line drawing data is changed to a lossless compression method. . With such a configuration, the character / line drawing data to be subjected to the printing control is compressed by the image Loss.
s (loss)
The print control of the line drawing portion can be performed, and the optimum character / line drawing can be reproduced.

Next, the processing of the image processing apparatus according to this embodiment will be described in detail with reference to FIG. First, step S
At 701, it is checked whether or not PDL data has been received. If there is, in step S702, PDL data is received and image development is started. And step S
In step 703, character / line drawing data is generated for each pixel, and in step S704, the color-converted image development data (8 bits) and character / line drawing data (1 bit) are combined into 9 bits for each pixel.

Next, in step S705, it is checked whether the compression method is lossless compression. If the compression method is lossless compression, in step S706, the data compiled in step S704 is compressed and stored in the memory. If it is not lossless compression, the image development data is separated from the character / line drawing data in step S707, and the image development data is directly compressed in step S706 and stored in the memory.

On the other hand, the character / line drawing data is stored in step S7.
At 08, the compression method is changed to the lossless compression method. And
In step S709, the data is compressed by the compression method determined in step S708 and stored in the memory.

Next, in step S710, it is checked whether or not image development and generation of character / line drawing data have been completed. Until the processing is completed, steps S703 to S71 are performed.
0 is repeated.

Then, in step S711, it is checked whether the color copying machine is in the Ready state. If it is not in the Ready state, it waits until it becomes Ready.

Then, in step S 712, the compressed data (image expansion, character / line drawing data) is expanded, and the data is sent to the color copying machine 120. After that, the processing makes a transition to Step S701.

The color copying machine 120 performs image formation and output processing according to the received data in the same manner as in the first embodiment.

[Third Embodiment] In the present embodiment, the compression method of image expansion data and character / line drawing data is irreversible, and particularly when the image loss (loss) ratio is equal to or less than a certain value (image loss (loss When the loss is small), the data is compressed and stored as it is. With this configuration, the memory can be used effectively, and the image loss (loss) is so small that it can be ignored. Therefore, even if printing (printing) is controlled using the character / line drawing data, the final printed matter is hardly affected. There is an advantage of not receiving.

Next, the processing of the image processing apparatus according to this embodiment will be described in detail with reference to FIG. First, step S
At 801, it is checked whether or not PDL data has been received. If there is, in step S802, PDL data is received and image development is started. And step S
In step 803, character / line drawing data is generated for each pixel, and in step S804, image development data (8 bits) and character / line drawing data (1 bit) are collectively set to 9 bits for each pixel.

Next, in step S805, it is checked whether the compression method is lossless compression. If the compression method is lossless compression, in step S806, the data compiled in step S804 is compressed and stored in the memory. If it is not lossless compression, it is checked in step S807 whether the image loss (loss) rate is equal to or less than a certain value. At this time, if it is less than a certain value, it is compressed as it is in step S806 and stored in the memory.

On the other hand, if the picture loss (loss) is larger than the fixed value, the compression rate is reduced (or a coding scheme with a low loss rate is selected) in step S808 until the picture loss (loss) rate becomes equal to or less than the fixed value. Do). Then, in step S809, the data is compressed at the compression ratio determined in step S808, and stored in the memory. The image loss rate may be stored in advance for each selectable encoding method, or an average value of the loss rates obtained for a plurality of test data, or a part of the actual data may be actually encoded and decoded. Actual measurement may be performed by comparing with data.

Next, in step S810, it is checked whether or not image development and generation of character / line drawing data have been completed. Until the processing is completed, steps S803 to S81 are performed.
0 is repeated.

Then, in step S811, it is checked whether the color copying machine is in the Ready state. If it is not in the Ready state, it waits until it becomes Ready.

Then, in step S812, the compressed data (image expansion, character / line drawing data) is expanded, and the data is sent to the color copying machine. After that, the processing makes a transition to Step S801. The color copier 120 performs image formation and output processing according to the received data in the same manner as in the first embodiment.

[Fourth Embodiment] In this embodiment, characters /
It is characterized in that the line drawing data is not compressed at all times and is stored in the memory as it is. Of course, the image development data is compressed and stored in order to make effective use of the memory. With this configuration, the character / line drawing data to be printed is not affected by the compression, and the printing of the character / line drawing can be controlled optimally, and the optimal character / line drawing can be reproduced. Becomes

Next, the operation of the image processing apparatus according to this embodiment will be described in detail with reference to FIG. First, in step S901, it is checked whether or not PDL data has been received. If there is, in step S902, PDL data is received and image development is started. In step S903, character / line drawing data is generated for each pixel. In step S904, the image development data is compressed after color conversion, and the character / line drawing data is stored in a memory without compression.

Next, in step S905, it is checked whether or not image development and generation of character / line drawing data have been completed. Until the processing is completed, steps S903 to S90 are performed.
Step 5 is repeated. Then, in step S906, it is checked whether the color copying machine is in the Ready state. If it is not in the Ready state, it waits until it becomes Ready.

In step S907, the compressed image data is decompressed, and the character / line drawing data is read out and sent to the color copier. Then, step S
Transition to 901 The color copier 120 performs image formation and output processing according to the received data in the same manner as in the first embodiment.

[0064]

[Other Embodiments] In the above-described embodiment, the case where the image forming apparatus is a color copying machine has been described. However, not only a monochrome copying machine but also a laser printer (monochrome or color) having no scanner function. Is also good.

Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus including one device (for example, a copier, a facsimile) Device).

Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (a computer) of the system or the apparatus. It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. Also,
When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also the operating system (OS) running on the computer based on the instructions of the program code.
It is needless to say that a case in which the functions of the above-described embodiments are implemented by performing part or all of the actual processing.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the flowcharts (shown in FIGS. 5 to 9) described above.

[0069]

As described above, according to the present invention,
In an image processing apparatus that separates print data described in PDL into image data and character / line drawing data, and collectively compresses and stores the data for each pixel, the compression method for character / line drawing data is a method with no or little image loss. By doing so, the amount of memory in the image processing apparatus can be saved, and the image quality of the output image can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a computer network to which an image forming system according to the present invention is connected.

FIG. 2 is a cross-sectional view illustrating a main configuration of a color copying machine that forms the image forming system of the present invention.

FIG. 3 is an internal block diagram of an image processing apparatus constituting the image forming system of the present invention.

FIG. 4 is an internal block diagram of a host computer.

FIG. 5 is a flowchart illustrating control of the image processing apparatus according to the first embodiment.

FIG. 6 is a flowchart illustrating control of the color copying machine according to the first embodiment.

FIG. 7 is a flowchart illustrating control of an image processing apparatus according to a second embodiment.

FIG. 8 is a flowchart illustrating control of an image processing apparatus according to a third embodiment.

FIG. 9 is a flowchart illustrating control of an image processing apparatus according to a fourth embodiment.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 5C076 AA27 CA10 5C077 LL17 MP06 PP27 PP28 PQ08 RR21 5C078 AA01 AA04 BA21 BA32 BA57 CA02 CA27 DA01 DA02 DB01 DB11 9A001 BB06 DD15 EE04 HH25 HH27 HH31 JJ35 KK31 KK42 KK42

Claims (15)

[Claims] 1. An image processing apparatus for receiving image forming data, converting the data into a format suitable for a predetermined image forming apparatus, and outputting the converted data. Separating means for separating the first image information not to be used and the second image information having a gradation, and the first image information and the second image information, each of the corresponding pixel data of the first image information and the second image information, Data generating means for generating third image information having a smaller information amount than the sum of the image information and the second image information; and converting the third image information into the first image information and the second image. Data output means for restoring the information to output as an output signal of the image processing apparatus, wherein the data generation means performs compression coding on at least the second image information. 2. The data generating means generates the third image information by performing a compression encoding on the first image information at a compression rate lower than a compression encoding applied to the second image information. The image processing apparatus according to claim 1, wherein: 3. The image processing apparatus according to claim 1, wherein said data generating means performs lossless compression encoding on said first image information to generate said third image information. 4. The data generating means generates the third image information without performing irreversible compression encoding on the second image information and compression encoding on the first image information. The image processing apparatus according to claim 1, wherein: 5. The data generating means performs lossy compression encoding on the second image information and lossless compression encoding on the first image information to generate the third image information. The image processing apparatus according to claim 1, wherein: 6. The data generating means performs lossy compression encoding on the first and second image information so that an image loss does not substantially affect the first image information, and 3. The image processing apparatus according to claim 1, wherein the image processing apparatus generates three pieces of image information. 7. The image processing apparatus according to claim 1, wherein the image forming data is described in a page description language. 8. The image processing according to claim 1, wherein the first image information is character / line drawing information, and the second image information is image data. apparatus. 9. An image forming apparatus for receiving the first image information and the second image information from the image processing apparatus according to claim 1 and forming and outputting a corresponding image. apparatus. 10. The image forming apparatus according to claim 9, wherein an image is formed with a higher resolution for the first image information than for the second image information. 11. The image forming apparatus according to claim 9, wherein an image is formed such that the gradation of the second image information is higher than the gradation of the first image information. 12. An image forming system formed by the image processing apparatus according to claim 1 and the image forming apparatus according to claim 9. 13. A storage medium for storing a program that can be executed by an apparatus, wherein the apparatus that executes the program causes the apparatus to function as the image processing apparatus according to any one of claims 1 to 8. Storage medium. 14. A storage medium for storing a program that can be executed by an apparatus, wherein the apparatus that executes the program causes the apparatus to function as the image forming apparatus according to any one of claims 9 to 11. Storage medium. 15. A storage medium for storing a program executable by an apparatus, wherein the apparatus executes the program to function as the image forming system according to claim 12.