JPH11196279A - Image processing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing unit where the compression rate of image data is controlled and the processing efficiency of the compressed data is enhanced. SOLUTION: The processing unit is provided with a control information management section 50 that manages system control information such as a data transfer speed and an idle capacity of a disk or the like, and it is also provided with a compression control section 14 that controls a compression factor of image data by a data compression section 17, based on the control information managed by the control information management section 50. A compression rate of the image data is set in response to a transfer speed of a compression data transfer path 30 that is a transfer path of data after compression.

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 more particularly, to an image processing apparatus which controls a compression ratio of image data to improve processing efficiency of compressed data.

[0002]

2. Description of the Related Art In image processing apparatuses such as printers and copiers, processing efficiency is improved by compressing image data according to the characteristics of the image data. For example, in the technique disclosed in Japanese Patent Application Laid-Open No. 9-247419, a compression method is selected according to whether image data is a color image or a monochrome image, and compression is performed by the selected compression method.

FIG. 7 is a block diagram showing a configuration of a conventional image processing apparatus. Conventional image processing apparatus 2 shown in FIG.
Is composed of blocks surrounded by a dotted line in the figure, and is connected to the external terminal 1.

As shown in FIG. 1, a conventional image processing apparatus 2
Is a print data receiving unit 11 for receiving print data from the external terminal 1, and an image data expanding unit 1 for expanding the print data received by the print data receiving unit 11 into image data.
2, an image data storage unit 13 for storing image data expanded by the image data expansion unit 12, an image characteristic detection unit 15 for detecting characteristics of the image data stored in the image data storage unit 13, and an image characteristic detection unit. A compression ratio setting unit 16 for setting the compression ratio of the image data based on the characteristics detected by the unit 15; a data compression unit 17 for compressing the image data at the compression ratio set by the compression ratio setting unit 16; A compression control unit 14 for controlling the unit 15, the compression ratio setting unit 16 and the data compression unit 17; an auxiliary storage unit 18 for storing the compressed data compressed by the data compression unit 17; A compressed data transfer path 30 serving as a transfer path between the output buffer 19 and an output buffer 19 for temporarily storing compressed data at a high speed; A data decompression unit 20 for decompressing data and restoring image data, an image output unit 21 for outputting an image to the paper 3 based on the image data decompressed by the data decompression unit 20, and a main unit for controlling operations of these blocks. It comprises a control unit 10.

Here, the conventional image processing apparatus 2 also has a mode in which image data is directly output to the auxiliary storage unit 18, the output buffer 19, and the image output unit 21 without compressing the data. .

FIG. 8 is a time chart showing the timing at which the conventional image processing apparatus shown in FIG. 7 processes an image. The time chart shown in the figure shows the time required for each of the blocks to perform processing.

The timing shown in FIG. 1 is based on an image processing apparatus capable of outputting 15 images per minute, and this apparatus requires an image output time of 4 seconds per image.

The operation timing of the conventional image processing apparatus 2 shown in FIG. 7 will be described with reference to FIG. 8. First, the print data of the first page is expanded by the image data expansion unit 12, and then the data compression unit 17 Data compression is performed, and the compressed data is output to the output buffer 19. The processing up to this point is a serial processing, and the next processing cannot be executed unless each of the above-described processings is completed.

After the compressed data is output to the output buffer 19, the function of the data compression unit 17 becomes free, so that the compressed data is transmitted via the compressed data transfer path 30.
The data is transferred to the auxiliary storage unit 18.

Here, since the data transfer to the auxiliary storage unit 18, the data expansion by the data expansion unit 20 and the image output by the image output unit 21 can be executed in parallel, the auxiliary storage unit Simultaneously with the data transfer to the section 18, expansion of the compressed data stored in the output buffer 19 and output of an image by the image output section 21 are performed.

When the transfer to the auxiliary storage unit 18 is completed, 2
Image data development for the page is started, and thereafter, the above-described series of processing is repeatedly executed for the third page and the fourth page.

[0012]

However, in the above-described conventional image processing apparatus 2, as shown at T1 in FIG. 8, the transfer time to the auxiliary storage unit does not affect the image output time of the next page. In this case, it is possible to continuously execute the image output without any loss time. However, as shown in T2 in FIG. 8, if the transfer time to the auxiliary storage unit becomes long, the loss of the image output by the next page starts. Time occurs.

Further, as a result of the compression of the image data by the data compression section 17, there is a possibility that the capacity of the auxiliary storage section 18 will be exceeded and storage will be impossible. In particular, when an electronic sort function for outputting a plurality of pages in an arbitrary order is executed, the image data of all pages needs to be stored in the auxiliary storage unit 18, and the problem of free space becomes serious.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image processing apparatus which controls the compression ratio of image data and improves the processing efficiency of the compressed data.

[0015]

According to one aspect of the present invention, there is provided an image data generating means for generating image data, and an image for compressing image data generated by the image data generating means. Data compression means; transfer means for transferring data compressed by the image data compression means; image data restoration means for expanding data compressed by the image data compression means to restore image data; An image processing apparatus comprising: an image output unit that outputs an image to a sheet based on the image data restored by the unit; a transfer speed obtaining unit that obtains a transfer speed of the transfer unit; A compression rate for determining a compression rate by the compression means based on a transfer rate; Characterized by comprising a constant section.

According to a second aspect of the present invention, there is provided image data generating means for generating image data, image data compressing means for compressing image data generated by the image data generating means, and image data compressing means for generating image data. Storage means for storing the compressed data; image data restoring means for decompressing the data compressed by the image data compressing means to restore the image data; and an image on a sheet based on the image data restored by the image data restoring means. An image processing apparatus comprising: an image output unit that outputs a free space; a free space obtaining unit that obtains a free space of the storage unit; and a compression ratio by the compression unit based on the free space obtained by the free space obtaining unit. Compression ratio determining means for determining .

[0017]

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

First, an outline of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus according to the present invention.

As shown in FIG. 1, the present invention is based on a control information management unit 50 for managing system control information such as a data transfer speed and a free disk space, and a control information managed by the control information management unit 50. A compression control unit 14 for controlling the compression of the image data by the data compression unit 17;
The above-mentioned problem is solved by setting the compression ratio of the image data according to the transfer speed of the compressed data transfer path 30, which is the transfer path of the compressed data.

Hereinafter, the contents of the present invention will be described in more detail.

The image processing apparatus 4 according to the present invention shown in FIG. 1 has the configuration of the conventional image processing apparatus 2 shown in FIG.
A control information management unit 50 that manages system control information such as a data transfer speed and a free disk space is provided. The control information management unit 50 includes a main control unit 10 and a compression control unit 1.
4 is connected.

The operation of the image processing apparatus 4 according to the present invention thus configured will be described with reference to FIG.

FIG. 2 is a flowchart showing a procedure for executing the printing process of the image processing apparatus according to the present invention shown in FIG.

First, the print data receiving unit 11 is connected to the external terminal 1.
(Step 100), the main control unit 10 instructs the print data receiving unit 11 to output the print data, and causes the image data expanding unit to output the print data.

The image data developing unit develops the print data into image data (step 101), and stores the image data in the image data storage unit 13 (step 102).

When the image processing apparatus 4 according to the present invention is in the compression mode (step 10)
In 3), image data is compressed by a compression control process described later (step 104). The compressed data is transferred to the output buffer 19 (step 105), the compressed data is expanded by the data expansion unit 20 (step 106), and the compressed data is transferred to the auxiliary storage unit 18 by the data compression unit 17. (Step 111) at the same time. After the data decompression by the data decompression unit 20 is completed, the image output unit 21 outputs an image (step 107).

On the other hand, when the image processing apparatus 4 according to the present invention is not in the compression mode (N in step 103)
o), the image data is directly transferred to the output buffer 19 (step 110), the image output is sent to the image output unit 21 (step 107), and the compressed data is transferred to the auxiliary storage unit 18 by the data compression unit 17. (Step 111) Execute simultaneously.

Thereafter, it is determined whether a jam has occurred on the printed sheet (step 108). If no jam has occurred, the process is terminated.

If a jam has occurred on the printed sheet (Yes in step 108), the auxiliary storage unit 18 is instructed to output the data transferred in step 111, and is output to the output buffer (step 109). ). Thereafter, the printing process is executed again based on the data stored in the output buffer (step 107).

FIG. 3 is a flowchart showing a first example of the compression control process shown in FIG. The process shown in FIG. 7 shows a detailed execution procedure of the compression control process in step 104 of FIG.

First, the main controller 10 causes the image characteristic detector 15 to execute the characteristic detection of the image data via the compression controller 14 (step 200). This characteristic detection may be such as to discriminate between black and white and color, as described in the above-mentioned JP-A-9-247219, and may be based on resolution, gradation, data size, etc. It may be something.

The compression control unit 14 causes the compression ratio setting unit 16 to set a compression ratio based on the detected characteristics of the image data (step 201). Thereafter, the transfer rate of the compressed data transfer path 30 is obtained from the control information management unit 50 (step 202), and the amount of compressed data is calculated based on the following equation 1 (step 203).

Compressed data amount = compression rate × data amount of image data [Equation 1] Subsequently, based on the following equation 2, the compressed data amount is calculated from the compressed data amount calculated by the above equation and the transfer rate acquired in step 202. Calculate the transfer time.

Compressed data transfer time = compressed data amount × transfer rate [Expression 2] Thereafter, the transfer time of the compressed data calculated by the above expression is compared with a preset maximum transfer time (step 204). A method of setting the maximum transfer time will be described with reference to FIG.

FIG. 5 is a time chart showing the operation of the image processing apparatus according to the present invention shown in FIG. The time chart shown in the figure is described on the same time scale as that shown in FIG.

As shown in the figure, the maximum transfer time means the time required to transfer the compressed data to the auxiliary storage unit 18, and this maximum transfer time is determined so as to satisfy the following equation (3).

Image data expansion time + image data compression time + output buffer transfer time + maximum transfer time ≦ compressed data decompression time + image output time [Equation 3] FIG. 5 shows the maximum transfer when the equality of the above equation holds. The state when the transfer to the auxiliary storage unit 18 is performed at a time is shown. As described above, if the maximum transfer time that satisfies Equation 3 is set in advance, image output can be executed without loss.

If the transfer time of the compressed data has not exceeded the maximum transfer time in step 204 in FIG. 3 (Yes in step 204), the data compression unit 17 is caused to execute compression of the image data (step 206).

When the transfer time of the compressed data exceeds the maximum transfer time (No in step 204), when the compression rate set in step 201 is equal to or less than the maximum compression rate that can be set in the compression rate setting unit 16 Is (Step 205
No), the compression control unit 14 instructs the compression ratio setting unit 16 to increase the compression ratio and resets the compression ratio (step 207), and then returns to step 203 again to calculate the compressed data amount. Then, the processing after step 204 is executed.

If the compression rate is not equal to or less than the maximum compression rate in step 205 (Yes in step 205), the data compression section 17 is caused to execute the compression of the image data at the compression rate (step 206).

FIG. 4 is a flowchart showing a second example of the compression control process shown in FIG. In the process shown in FIG.
Unlike the one shown in FIG. 3, the compression ratio is set in consideration of the data transfer rate.

First, the compression control unit 14 calculates the data amount of the image data stored in the image data storage unit 13 (Step 300). Subsequently, the control information management unit 5
The data transfer rate of the compressed data transfer path 30 is obtained from 0 (step 301), and the amount of compressed data is calculated based on the following equation (step 302).

Compression rate = image data amount / (maximum transfer time × data transfer rate) [Equation 4] Then, the compression rate setting unit 16 is caused to set the compression rate obtained by the above equation, and the data compression unit 17 is set at the compression rate. To compress the image data (step 303).

By the series of processes described above, it is possible to execute the printing process at the timing shown in FIG.

As described above, according to the present invention, the processing efficiency can be improved by providing the means for setting the compression ratio according to the transfer speed of the compressed data.

Next, a third example of the compression control process shown in FIG. 2 will be described with reference to FIG.

FIG. 6 is a flowchart showing an execution procedure of the compression control process when the compression ratio is controlled in consideration of the free space of the auxiliary storage unit 18 shown in FIG. In the processing shown in the figure, first, the main control unit 10 causes the image characteristic detection unit 15 to execute the characteristic detection of the image data via the compression control unit 14 (step 400).

Subsequently, the compression control section 14 causes the compression rate setting section 16 to set a compression rate based on the detected characteristics of the image data (step 401). After that, the free space of the auxiliary storage unit 18 is obtained from the control information management unit 50 (step 402), and the amount of compressed data is calculated based on the above-described formula 1 (step 403).

Then, the compressed data amount and step 40
2 is compared with the free space obtained in the auxiliary storage unit 18 (step 404). If the amount of compressed data is smaller than the free space (Yes in step 404), the image data is compressed at the compression ratio set in step 401. Then, if the compressed data amount is larger than the free space (No in Step 404), the compression rate is increased and output to the compression rate setting unit 16 to execute the compression of the image data at the increased compression rate (Step 406). (Step 406).

As described above, in the present invention, in particular, by providing the means for setting the compression ratio according to the free space of the auxiliary storage unit, it is possible to prevent the capacity from being exceeded.

In the above embodiment, the description has been made with a focus on the improvement of the processing for the auxiliary storage unit. However, the present invention is not limited to the above-described auxiliary storage unit. When a means for storing compressed data is provided by controlling the compression rate based on the transfer speed of the transfer means, the same effect can be obtained by controlling the compression rate based on the capacity of the storage means. Obtainable.

[0052]

As described above, according to the present invention,
It is possible to provide an image processing apparatus that controls the compression ratio of image data and improves the processing efficiency of compressed data.

Further, in the present invention, the processing efficiency can be improved by providing a means for setting the compression ratio according to the transfer speed of the compressed data.

Further, in the present invention, the provision of a means for setting the compression ratio in accordance with the free space of the auxiliary storage unit can prevent the capacity from being exceeded.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing an execution procedure of a printing process of the image processing apparatus according to the present invention shown in FIG.

FIG. 3 is a flowchart showing a first example of the compression control process shown in FIG. 2;

FIG. 4 is a flowchart showing a second example of the compression control process shown in FIG. 2;

FIG. 5 is a time chart showing the operation of the image processing apparatus according to the present invention shown in FIG. 1;

6 is a flowchart showing an execution procedure of a compression control process when a compression ratio is controlled in consideration of a free space of an auxiliary storage unit 18 shown in FIG.

FIG. 7 is a block diagram illustrating a configuration of a conventional image processing apparatus.

FIG. 8 is a time chart showing a timing at which the conventional image processing apparatus shown in FIG. 7 processes an image.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 external terminal 2 conventional image processing device 3 paper 4
... the image processing apparatus according to the present invention, 10 ... main control unit, 11 ...
Print data receiving unit, 12 ... image data developing unit, 13
... Image data storage unit, 14 compression control unit, 15 image characteristic detection unit, 16 compression ratio setting unit, 17 data compression unit, 18 auxiliary storage unit, 19 output buffer, 2
0: data decompression unit, 21: image output unit, 30: compressed data transfer path, 50: control information management unit.

Claims (2)

[Claims] 1. An image data generating means for generating image data, an image data compressing means for compressing the image data generated by the image data generating means, and a transfer for transferring the data compressed by the image data compressing means. Means, image data restoring means for expanding the data compressed by the image data compressing means and restoring the image data, and image output means for outputting an image on a sheet based on the image data restored by the image data restoring means. An image processing apparatus comprising: a transfer rate obtaining unit that obtains a transfer speed of the transfer unit; and a compression ratio determining unit that determines a compression ratio of the compression unit based on the transfer speed obtained by the transfer speed obtaining unit. An image processing apparatus comprising: 2. An image data generating means for generating image data, an image data compressing means for compressing the image data generated by the image data generating means, and a storage for storing the data compressed by the image data compressing means. Means, image data restoring means for expanding the data compressed by the image data compressing means and restoring the image data, and image output means for outputting an image on a sheet based on the image data restored by the image data restoring means. An image processing apparatus comprising: a free space obtaining unit that obtains a free space of the storage unit; and a compression ratio determining unit that determines a compression ratio by the compression unit based on the free space obtained by the free space obtaining unit. An image processing apparatus comprising: