JP2002152506A - Image processor and processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the size of an input image contained in an intermediate code buffer as much as possible when an intermediate coding system is employed and to prevent the image quality from lowering even in the case of irreversible compression. SOLUTION: If an input image has a resolution lower than the output resolution at the time of image data processing, an image processor 4 stores input image data as it is, in an intermediate code buffer 41-5 and generates an output image from the stored input image at the end of a page based on the information of enlarging or reducing rate. It is composited with other object before being delivered to an output unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and a processing method thereof, and more particularly to a case where the size of an input image stored in an intermediate code buffer when an intermediate code system is used is minimized and lossy compression is performed. However, the present invention relates to an image processing apparatus and a processing method for preventing image quality from being lowered.

[0002]

2. Description of the Related Art Conventionally, when an intermediate code system is used, image data is converted to a normal output size, and the data is compressed or held as it is until the end of a page, and output to an output device while expanding the intermediate code. are doing.

[0003] Conventionally, when image data is compressed, a trade-off is made between size and image quality by switching to an optimal compression method according to the input image.

However, in the conventional method, when the input image has a low resolution and outputs a high resolution, the intermediate code size can often be larger than the input image size.

[0005] When the compression method is irreversible compression, it is possible to reduce the intermediate code size by increasing the compression rate, but the image quality also decreases as the compression rate increases.

FIG. 11 shows a configuration of a conventional image data processing section, and FIG. 12 shows a conventional processing procedure using the configuration shown in FIG. Further, FIG. 13 is a conceptual diagram showing the ratio relationship between the input image and the data size of the compressed data stored in the intermediate code buffer according to the conventional processing procedure.
Shown in In FIG. 13, FIG. 13A shows a state in which binary output is performed, and FIG. 13B shows a state in which multi-value output is performed.

[0007]

As described above, conventionally, when the input image has a low resolution and outputs a high resolution, the intermediate code size is often larger than the input image size. When the compression method is irreversible compression, it is possible to reduce the intermediate code size by increasing the compression rate, but there is a disadvantage that the image quality decreases as the compression rate increases.

Therefore, the present invention solves the above-mentioned disadvantages, minimizes the size of the input image stored in the intermediate code buffer when using the intermediate code system, and reduces the image quality even when performing irreversible compression. It is an object of the present invention to provide an image processing apparatus and a processing method for preventing such an event.

[0009]

According to a first aspect of the present invention, there is provided an image processing apparatus for performing image processing using an intermediate code system, wherein image data input in a page unit is output resolution. Determining means for determining whether or not the input image data has a low resolution with respect to the output resolution, as a result of determination by the determining means, The image processing apparatus further comprises control means for directly storing the data in the intermediate code buffer without conversion to the output size, and converting the input image of the stored page to the output size when the storage of one page is completed.

According to a second aspect of the present invention, in the processing method of the image processing apparatus for performing image processing using the intermediate code system, it is determined whether or not the image data input on a page basis has a lower resolution than the output resolution. If the result of the determination is that the input image data is determined to be lower resolution than the output resolution, the input image is stored in the intermediate code buffer without conversion to the output size, When the storage of one page is completed, the input image of the stored page is converted into an output size.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a functional block diagram showing a functional configuration of an image processing apparatus 4 according to the present invention. In particular, FIG. 1 shows a page description language interpreter (decomposer) 41 together with a data flow.

As shown in FIG. 1, the image processing apparatus 4 inputs print data transmitted from the scanner 2 or the client terminal 3 and interprets the data to obtain three images, graphics, and characters. And an image data processing unit 41 for generating an intermediate code of the image data output from the input data interpreting unit 41-1.
-2, a character data processing unit 41-3 for generating intermediate codes of the character data output from the input data interpreting unit 41-1, and an input data interpreting unit 41-
Graphics data processing unit 41-4 that performs a process of generating an intermediate code of the graphics data output from 1
And an intermediate code buffer 41-5 for storing intermediate code data generated by each of the data processing units (41-2 to 41-4), and an intermediate code stored in the intermediate code buffer 41-5. Decoding processing, that is, an intermediate code processing unit 41-6 that converts the data into raster data, combines three objects of images, graphics, and characters and outputs the resultant to the image forming unit.

Here, the intermediate code is a set having a specific property.
It has information such as the size, print position, and the compressed / uncompressed data body.

FIG. 2 shows in detail the functional configuration of the image data processing section 41-2 shown in FIG. 1 and a compression processing section 41-7 and a decompression processing section 41-not shown in FIG. FIG.

As shown in FIG. 2, the image data processing section 41-2 converts the input image into a gradation suitable for performing color conversion according to the output device (for example, (Convert 1 bit to 8 bits)
A tone conversion processing unit 41-2a converts the color space of the image subjected to the tone conversion processing by the tone conversion processing unit 41-2a into the color space of the output device (for example, converting RGB into C
MYK), a rotation processing unit 41-2c that performs a rotation process on the image subjected to the color space conversion processing by the color conversion processing unit 41-2b, and a rotation processing unit 41-2. A sequence switching section 41-2d for switching the subsequent processing flow (sequence) of the image rotated in 2c, and a sequence switching section 41-2d
The enlargement / reduction processing unit 41-2e for performing the enlargement or reduction processing of the image output from the above, and the binary image by using the pseudo gradation for the multi-valued image similarly output from the sequence switching unit 41-2d. And a sequence switching unit 41-2g for switching the sequence of the subsequent processing of the image halftoned by the halftone processing unit 41-2f. It is comprised including.

The compression processing section 41-7 is a section for performing compression at a predetermined compression ratio, and a decompression processing section 41-8.
Is a part for expanding the data compressed by the compression processing unit 41-7.

That is, in the present invention, when an image having a low resolution with respect to the output resolution is input, the input image data is stored together with the information on the enlargement ratio, and the information on the enlargement ratio and the input image are generated at the end of the page. Other objects are combined and output by the image forming unit.

The operation of the present invention with this configuration will be described.

FIG. 3 is a flowchart showing a procedure for processing image data when the intermediate code system is used in the image processing apparatus 4 shown in FIGS. 1 and 2. In this example, binary output, image division The processing procedure in the case where there is no data is shown.

As shown in FIG. 3, when this processing is started, first, a gradation conversion processing is performed in a gradation conversion processing section 41-2a (step S101), and then a color conversion processing section 41-2b is performed. Performs a color conversion process (step S10).
2).

Thereafter, after the rotation processing section 41-2c performs the rotation processing (step S103), the sequence switching section 41-2d determines whether the input image has a lower resolution than the output resolution. (Step S1
04).

If it is determined that the input image has a lower resolution than the output resolution (step S104: YES), the sequence switching section 41-2d transfers the input image to the intermediate code buffer 41-5. .

Thus, the intermediate code buffer 41-6
To store the input image data (step S10).
5).

Thereafter, the sequence switching section 41-2d reads the stored input image data from the intermediate code buffer 41-5, and executes the enlargement / reduction processing section 41-d.
2e.

Then, predetermined enlargement or reduction processing is performed in the enlargement / reduction processing section 41-2e (step S10).
6) Then, halftone processing is performed in the halftone processing unit 41-2f (step S107).

Thereafter, the sequence switching section 41-2g performs switching control so as to transfer the input image data to the intermediate code processing section 41-6. The process is performed (Step S108).

After the intermediate code processing, the input image data is transferred to the image forming unit (step S109),
The process here ends.

On the other hand, as a result of the determination in step S104, when the sequence switching section 41-2d determines that the input image data is not low resolution (step S1).
04NO), the input image data is transferred to the enlargement / reduction processing unit 41-2e, and predetermined enlargement or reduction processing is performed (step S110), and then the halftone processing is performed by the halftone processing unit 41-2f. This is performed (step S111).

Thereafter, the input image data is supplied to the compression processing unit 41 by the switching control of the sequence switching unit 41-2g.
-7, a predetermined compression process is performed by the compression processing unit 41-7 (step S112), and then transferred to the intermediate code buffer 41-5 and stored (step S112).
113).

Next, the stored input image data is input to the decompression processing unit 41-8, and is subjected to a predetermined decompression process (step S114).
The process proceeds to 108 and the same processing is performed.

FIG. 4 is a conceptual diagram of an input image stored in the intermediate code buffer 41-5 when the processing procedure shown in FIG. 3 is used. As shown in FIG. 4, in the present invention, when binary output is performed and the input image data has a lower resolution than the output resolution, the input image data is not subjected to enlargement or halftone processing. Is directly stored in the intermediate code buffer 41-5. Then, in the present invention, after the image data is stored in the intermediate code buffer 41-5, the enlargement / halftone processing is performed.

According to this configuration, when the input image has a lower resolution than the output resolution, the intermediate code amount can be reduced, and the processing can be performed at a higher speed because the compression / expansion processing is omitted. .

FIG. 5 is a flow chart showing a procedure for processing image data when the intermediate code system is used in the image processing apparatus 4 shown in FIGS. 1 and 2. In this example, multi-value output, image division No, shows a processing procedure when irreversible compression processing is performed.

As shown in FIG. 5, when this processing is started, first, a gradation conversion processing is performed in a gradation conversion processing section 41-2a (step S201), and then a color conversion processing section 41-2b is performed. Performs a color conversion process (step S20).
2).

Thereafter, after the rotation processing is performed by the rotation processing section 41-2c (step S203), the sequence switching section 41-2d determines whether the input image has a lower resolution than the output resolution. (Step S2
04).

If it is determined that the input image has a lower resolution than the output resolution (step S204: YES), the sequence switching section 41-2d transfers the input image to the intermediate code buffer 41-5. .

Thus, the intermediate code buffer 41-5
To store the input image data (step S20).
5).

Thereafter, the sequence switching section 41-2d reads the stored input image data from the intermediate code buffer 41-5, and reads the input image data from the intermediate code buffer 41-5.
2e.

Then, predetermined enlargement processing is performed in the enlargement / reduction processing section 41-2e (step S206).

Thereafter, the sequence switching section 41-2g performs switching control so as to transfer the input image data to the intermediate code processing section 41-6, so that the intermediate code processing section 41-6 converts the predetermined intermediate code. The process is performed (Step S207).

After the intermediate code processing, the input image data is transferred to the image forming section (step S208),
The process here ends.

On the other hand, as a result of the determination in step S204, when the sequence switching section 41-2d determines that the input image data is not lower than the output resolution (NO in step S204), the input image data is enlarged / reduced. The data is transferred to the reduction processing unit 41-2e, and predetermined enlargement or reduction processing is performed (step S209). Then, the data is transferred to the compression processing unit 41-7 by the switching control of the sequence switching unit 41-2g, and the compression processing is performed. Part 41-
7, lossy compression is performed (step S210).

Thereafter, the data is transferred to and stored in the intermediate code buffer 41-6 (step S211).

Next, the stored input image data is input to the decompression processing unit 41-8, and a predetermined decompression process is performed (step S212).
07, the same processing is performed thereafter.

FIG. 6 is a conceptual diagram of an input image stored in the intermediate code buffer 41-5 in the case of the processing procedure shown in FIG. As shown in FIG. 6, according to the present invention, when multi-value output is performed and the input image data has a lower resolution than the output resolution, the input image is directly intermediately processed without performing enlargement processing. The data is stored in the code buffer 41-5. Then, in the present invention, the enlargement process is performed after the image data is stored in the intermediate code buffer 41-5.

According to this configuration, when the input image has a lower resolution than the output resolution, the intermediate code amount can be reduced, and the intermediate code amount is kept constant even when the output resolution becomes higher. In addition, since the compression / expansion processing is omitted, the processing can be performed at a higher speed, and further, since the lossy compression is not performed, the deterioration of the image quality is eliminated.

FIG. 7 is a flowchart showing a procedure for processing image data when the intermediate code system is used in the image processing apparatus 4 shown in FIGS. 1 and 2. In this example, binary output, image division The processing procedure in the case of performing the presence processing is shown.

As shown in FIG. 7, when this process is started, first, a tone conversion process is performed by a tone conversion processing unit 41-2a (step S301), and then a color conversion processing unit 41-2b is performed. Performs a color conversion process (step S30).
2).

Thereafter, after the rotation processing is performed by the rotation processing section 41-2c (step S303), the input image is divided (step S304), and then the sequence switching section 41-2d performs the processing. It is determined whether the input image has a lower resolution than the output resolution (step S305).

If it is determined that the input image has a lower resolution than the output resolution (step S305 YES), the sequence switching section 41-2d transfers the input image to the intermediate code buffer 41-6. .

Thus, the intermediate code buffer 41-5
To store the input image data (step S30).
6).

Thereafter, the sequence switching section 41-2d reads the stored input image data from the intermediate code buffer 41-5, and reads the stored input image data from the intermediate code buffer 41-5.
2e.

Then, predetermined enlargement processing is performed by the enlargement / reduction processing section 41-2e (step S307), and thereafter, halftone processing is performed by the halftone processing section 41-2f (step S308).

Thereafter, the sequence switching section 41-2g performs switching control so as to transfer the input image data to the intermediate code processing section 41-6. The processing is performed (step S309).

After the intermediate code processing, the input image data is transferred to the image forming unit (step S310),
The process here ends.

On the other hand, if the result of the determination in step S305 is that the sequence switching section 41-2d determines that the input image data is not lower in resolution than the output resolution (NO in step S305), the input image data is enlarged / reduced. The data is transferred to the reduction processing unit 41-2e, and predetermined enlargement or reduction processing is performed (step S311). Then, halftone processing is performed in the halftone processing unit 41-2f (step S312).

Thereafter, the input image data is supplied to the compression processing unit 41 by the switching control of the sequence switching unit 41-2g.
-5, a predetermined compression process is performed by the compression processing unit 41-8 (step S313), and then the data is transferred to the intermediate code buffer 41-5 and stored therein (step S313).
314).

Next, the stored input image data is input to the decompression processing unit 41-8, and is subjected to a predetermined decompression process (step S314).
The process shifts to 309, and the same processing is performed thereafter.

FIG. 8 is a flowchart showing a procedure for processing image data when the intermediate code system is used in the image processing apparatus 4 shown in FIGS. 1 and 2. In this example, multi-value output, image division Yes, shows a processing procedure when irreversible compression processing is performed.

As shown in FIG. 8, when this processing is started, first, the gradation conversion processing is performed by the gradation conversion processing section 41-2a (step S401), and then the color conversion processing section 41-2b is performed. Performs color conversion processing (step S40).
2).

Then, after the rotation processing section 41-2c performs the rotation processing (step S403), the input image is divided (step S404), and then the sequence switching section 41-2d performs the division processing. It is determined whether the input image has a lower resolution than the output resolution (step S405).

If it is determined that the input image has a lower resolution than the output resolution (step S305 YES), the sequence switching section 41-2d transfers the input image to the intermediate code buffer 41-6. .

Thus, the intermediate code buffer 41-5
To store the input image data (step S40).
6).

Thereafter, the sequence switching section 41-2d reads the stored input image data from the intermediate code buffer 41-5, and executes the enlargement / reduction processing section 41-d.
2e.

Then, predetermined enlargement processing is performed in the enlargement / reduction processing section 41-2e (step S407).

Thereafter, the sequence switching section 41-2g performs switching control so as to transfer the input image data to the intermediate code processing section 41-6. The process is performed (Step S408).

After the intermediate code processing, the input image data is transferred to the image forming section (step S409),
The process here ends.

On the other hand, if the result of the determination in step S405 is that the sequence switching section 41-2d determines that the input image data is not lower in resolution than the output resolution (step S405 NO), the input image data is enlarged / reduced. The data is transferred to the reduction processing section 41-2e, and predetermined enlargement or reduction processing is performed (step S410).

Thereafter, the input image data is subjected to the switching control of the sequence switching section 41-2g to control the compression processing section 41-g.
7 and lossy-compressed by the compression processing unit 41-7 (step S411), and then transferred to the intermediate code buffer 41-5 and stored therein (step S41).
2).

Next, the stored input image data is input to the decompression processing unit 41-8, and is subjected to a predetermined decompression process (step S413).
The process proceeds to 408, where the same processing is performed.

FIG. 9 is a conceptual diagram of an input image stored in the intermediate code buffer 41-5 when the processing procedure shown in FIGS. 7 and 8 is used. As shown in FIG. 9, in the present invention, when there is a band division,
If the input image data has a low resolution, the input image is band-divided and stored in the intermediate code buffer 41-5 without performing enlargement processing or the like. In the present invention, the intermediate code buffer 41
After storing in -5, enlargement processing is performed. FIG. 14 shows a case of the conventional method corresponding to the conceptual diagram of the input image stored in the intermediate code buffer when there is band division in the case of the present invention shown in FIG. As shown in FIG. 14, according to the conventional method, the data size in the intermediate code buffer is larger than the input image size because the data is enlarged and then compressed and then stored in the intermediate code buffer. On the other hand, in the present invention, the input image is divided into bands, stored in the intermediate code buffer as it is, and then enlarged, so that the data size on the intermediate code buffer is the same as the input image size. It's done in size.

In the above-described embodiment, the case where the image processing apparatus of the present invention is applied to an image forming apparatus such as a printer or a copying machine is shown. However, the present invention is not limited to this, and is shown in FIG. It can be applied to the server 4A of such a system. In this case, "image forming unit" in the description of the above embodiment is replaced with "output device" and "image processing device" is replaced with "server". Further, when the present invention is applied to the server 4A as described above, the present invention can be applied not only to a print request but also to a case where intermediate code data is stored in order to reuse the intermediate code data later.

[0074]

As described above, according to the present invention,
When performing image processing using the intermediate code method,
It is determined whether or not the image data input in page units has a lower resolution than the output resolution, and as a result of the determination, it is determined that the input image data has a lower resolution than the output resolution Since the input image is stored in the intermediate code buffer without conversion to the output size and the input image of the stored page is converted to the output size when the storage of one page is completed. If the resolution is lower than the output resolution, the amount of intermediate code can be reduced, and even if the output resolution becomes higher, the amount of intermediate code can be kept constant. Since it is omitted, processing can be performed at a higher speed, and further, since lossy compression is not performed, deterioration of image quality is eliminated.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a functional configuration of an image data processing unit shown in FIG. 1 in detail, and showing a compression processing unit and a decompression processing unit not shown in FIG. 2;

FIG. 3 is a flowchart showing a processing procedure of image data when the intermediate code method is used in the image processing apparatus shown in FIGS. 1 and 2;

FIG. 4 is a conceptual diagram of an input image stored in an intermediate code buffer when the processing procedure shown in FIG. 3 is used.

FIG. 5 is a flowchart showing a processing procedure of image data in the case where an intermediate code method is used in the image processing apparatus shown in FIGS. 1 and 2;

FIG. 6 is a conceptual diagram of an input image stored in an intermediate code buffer when the processing procedure shown in FIG. 5 is used.

FIG. 7 is a flowchart showing a processing procedure of image data in the case where the intermediate code method is used in the image processing apparatus shown in FIGS. 1 and 2;

FIG. 8 is a flowchart showing a processing procedure of image data in the case where an intermediate code method is used in the image processing apparatus shown in FIGS. 1 and 2;

FIG. 9 is a conceptual diagram of an input image stored in an intermediate code buffer according to the processing procedures shown in FIGS. 7 and 8;

FIG. 10 is a diagram illustrating a configuration example of an image processing system to which the image processing apparatus according to the invention is applied.

FIG. 11 is a diagram showing a configuration of a conventional image data processing unit.

FIG. 12 is a diagram showing a conventional processing procedure using the configuration shown in FIG. 11;

FIG. 13 is a conceptual diagram of a ratio relationship between an input image and a data size of compressed data stored in an intermediate code buffer according to a conventional processing procedure.

FIG. 14 is a conceptual diagram of an input image stored in an intermediate code buffer when there is a conventional band division.

[Explanation of symbols]

4 image processing apparatus 41 page description language interpreter 41
-1: Input data interpreter, 41-2: Image data processor, 41-3: Character data processor, 41-4: Graphics processor, 41-5: Intermediate code buffer, 41
-6: intermediate code processing unit, 41-2a: gradation conversion processing unit, 41-2b: color conversion processing unit, 41-2c: rotation processing unit, 41-2d: sequence switching unit, 41-2e: enlargement / reduction Processing unit, 41-2f... Halftone processing unit, 4
1-2g: Sequence switching unit, 41-7: Compression processing unit, 41-8: Decompression processing unit, 100: Image processing system, 1: Network, 2: Scanner, 3: Client terminal, 4A: Server, 5: Printer ,

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Claims (2)

[Claims] 1. An image processing apparatus for performing image processing using an intermediate code system, a determining unit for determining whether image data input in a page unit has a lower resolution than an output resolution, and the determining unit If it is determined that the input image data has a lower resolution than the output resolution, the input image is stored in the intermediate code buffer without conversion to the output size, An image processing apparatus, comprising: control means for converting an input image of the stored page into an output size when the storage is completed. 2. A processing method of an image processing apparatus for performing image processing using an intermediate code method, wherein it is determined whether image data input on a page basis is lower in resolution than an output resolution. As a result, when it is determined that the input image data has a lower resolution than the output resolution, the input image is stored in the intermediate code buffer without conversion to the output size, and the storage of one page is completed. Converting the input image of the stored page to an output size when the processing is performed.