JP2003274178A - Image processing method and image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform image processing such as gamma correction by effectively utilizing the computer resources such as a memory and a CPU. <P>SOLUTION: When gamma correction is instructed, whether a gamma correction table corresponding to a designated gamma value is registered in an effective gamma correction table is determined (S1 and 2). If a gamma correction table already prepared can be utilized, the registered gamma correction table is used to perform gamma correction (S3 and 4). Unless the gamma correction table of the designated gamma value is registered, a correction table for the instructed gamma value is newly prepared and registered in the effective gamma correction table (S5 to S9). This can prevent the same gamma correction table from being overlappedly generated even in the case of continuously processing a plurality of images. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method and an image processing apparatus for performing gamma correction, for example.

[0002]

2. Description of the Related Art For example, digital cameras and scanners,
Image processing devices such as displays and printers each have a unique gamma value. The gamma value is a scale showing the response characteristic of the gradation of the image, and by performing the gamma correction, the relationship between the gradation of the input image and the gradation of the output image is directly proportional and is planned. Images can be output with gradation.

Since gamma correction involves complicated calculations, it is often performed using a gamma correction table that has been calculated and created in advance. Therefore, conventionally, for example, when performing initialization, a gamma correction table corresponding to each gamma value is created for each image to be processed.

Here, even if the products of the same type are different in model and manufacturer, the gamma values thereof are often different, but the images generated by the same model have a common gamma value. There are many. For example, taking a digital camera as an example, the gamma value differs for each camera maker, but in the case of images taken by digital cameras of the same model or of the same maker, the gamma value does not change.

[0005]

As described above, in the prior art, since the gamma correction table is generated for each image, a storage area is required to hold each table, and the memory consumption increases. . Further, since a plurality of the same gamma correction tables are generated, there is a problem that the table generation process is wasteful and the load on the CPU increases.

The present invention has been made in view of the above problems, and an object thereof is an image processing method and an image which can efficiently perform image processing by effectively utilizing limited computer resources. It is to provide a processing device.

[0007]

To achieve the above object, an image processing method according to the present invention processes an input image by using a predetermined table based on predetermined attribute information associated with the image. Yes, it includes the first to sixth steps.

In the first step, it is determined whether the table stored in the storage means can be used, based on the predetermined attribute information. In the second step, when the table stored in the storage means can be used, a pointer is set in the table. In the third step, if the table stored in the storage means cannot be used, a table is newly generated according to the predetermined attribute information and the pointer is set in the new table. The fourth step stores the generated table in the storage means. In the fifth step, predetermined image processing is performed using the table in which the pointer is set. Sixth
The step deletes the table stored in the storage unit to release the storage area at a predetermined timing.

Here, the "predetermined attribute information" can be, for example, a gamma value. Further, as the “predetermined table”, for example, a gamma correction table can be cited.

Predetermined attribute information is associated with the image, and the image is processed using a predetermined table based on the attribute information. If the table necessary for processing a certain image has not been created yet, a new table is created based on the attribute information and stored in the storage means.
In this way, a predetermined table is generated for each piece of attribute information and stored in the storage means. If the already created table can be used, the image is processed using the table stored in the storage means. Then, when a predetermined timing arrives, each table stored in the storage means is deleted and the storage area is released.

As a result, it is possible to prevent the same table from being duplicated, so that the memory resources can be used efficiently. Further, since the generated table can be used for processing other images, it is possible to save the trouble of newly generating the table and reduce the processing load on the CPU.

In one aspect of the present invention, the table stored in the storage means is deleted page by page to release the storage area.

That is, when a page contains a plurality of images, the images existing in the same page are
Instead of generating a table for each image, generate only one table for each attribute information and store it in the storage means.
When the page processing is completed, the table in the storage means is erased and the storage area is released.

In another aspect of the present invention, the storage area is released by deleting the table stored in the storage means for each recording medium in which an image is recorded.

That is, a table corresponding to the attribute information is generated and stored for each recording medium, and when the recording medium is replaced, the storage means is reset.

According to another aspect of the present invention, there is provided an image processing apparatus for processing an input image by using a predetermined table based on predetermined attribute information associated with the image, the storage means storing the table. And management means for managing the table stored in the storage means, and image processing means for performing predetermined image processing using the table designated by the management means. Based on the determination means, it is determined whether the table stored in the storage means can be used, and if the table stored in the storage means cannot be used, a table for newly generating a table according to predetermined attribute information is generated. When it is determined that the generation means and the table stored in the storage means can be used, a pointer is set in the table and the table stored in the storage means is set. If cannot be used, a specifying unit that sets a pointer to a new table and specifies it, a registering unit that stores the generated table in the storage unit, and a table that is stored in the storage unit are deleted at a predetermined timing. And a storage area releasing means for releasing the storage area.

Then, the storage area releasing means can release the storage area by deleting the table recorded in the storage means in page units or in recording medium units in which the input images are recorded.

According to another aspect of the present invention, there is provided a printing device for performing a predetermined image processing on an input image and printing the image, and a storage means for storing a table based on predetermined attribute information associated with the image. Management means for managing the table stored in the storage means, image processing means for performing predetermined image processing using the table designated by the management means, and printing for printing the image processed by the image processing means. And a management unit that determines whether or not the table stored in the storage unit can be used based on the predetermined attribute information, and a management unit in the case where the table stored in the storage unit cannot be used. , If it is determined that the table stored in the storage means and the table generating means for newly generating the table according to the predetermined attribute information can be used, the table is stored in the table. Setting table and the table stored in the storage means cannot be used, a specifying means for setting a pointer to a new table and designating, a registration means for storing the generated table in the storage means, and a predetermined timing The storage area releasing means for releasing the storage area by deleting the table stored in the storage means.

The present invention can be understood as a computer program. The program is, for example, a CD-ROM
It can be distributed by being recorded on various recording media such as a hard disk and a memory, and can be distributed via a communication network.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

1. First Embodiment FIGS. 1 to 4 are block diagrams showing a configuration in the case where the image processing apparatus according to the first embodiment of the present invention is applied to a printer.

This printer, as will be described later, respectively,
Image processing control unit 10, PC card 20, print control unit 30
And a print engine 40. This printer is capable of so-called direct printing, which enables printing without using a host computer such as a personal computer. However, the present invention is not limited to a printer capable of direct printing.

The image processing controller 10 comprises a CPU 11, a control ROM 12, a system RAM 13, an LCD controller 14, a PC card controller 16, a parallel interface (I / F) 19, etc., which are interconnected by an internal bus 18. There is. Image processing control unit 1
0 is for reading image data from the PC card 20, performing predetermined image processing on the read image data, and outputting the image data to the print control unit 30. Examples of the predetermined image processing include gamma correction, enlargement processing, reduction processing, and color conversion processing.

The PC card 20 is inserted into the PC card slot 17 so that data can be read and written by a contact method, but the present invention is not limited to this. For example, when the PC card 20 has a wireless communication function, it is possible to read and write data by wireless data communication. Also, the PC card 20
Is an example of an image recording medium, and the present invention is not limited to this. For example, image data may be transmitted to the image processing control unit 10 in a wired or wireless manner from a mobile phone or the like having a photographing function.

The CPU 11 performs various data processing based on the program stored in the control ROM 12. The image data being processed, the processing result, and the like are stored in a predetermined area of the system RAM 13. LCD (Liquid Crystal Displa
y) 15 is a man-machine interface, which displays the printer status such as the remaining amount of paper and the printing status, and displays a message to the user. Also, LC
It is also possible to provide an input means such as a touch panel on the D15 and receive an instruction or the like from the user.

The PC card 20 is a portable image data recording medium and can be removably attached to the PC card slot 17. The PC card 20 can be attached to, for example, an image input device such as a digital camera, a scanner device, a mobile phone with a photographing function or a portable information terminal, and stores image data captured by these image input devices. The user inserts the PC card 20 in which the image data to be printed is recorded into the PC card slot 1
Attach to 7. PC card controller 16 is a CPU
The command from 11 accesses the image data in the PC card 20 and transfers the image data to the system RAM 13.

The print control unit 30 controls the operation of the print engine 40 based on the print data input from the image processing control unit 10 to perform predetermined printing. The print control unit 30 and the image processing control unit 10 include a parallel communication cable 2 that connects the I / Fs 19 and 35.
They are connected by 1 and bidirectional data communication is possible. Here, the print control unit 30 and the image processing control unit 10 may be housed and provided inside, for example, a multi-function peripheral (for example, one having a print function and a scanner function) or a printer. It is also possible to store only the control unit 30 inside the printer and form the image processing control unit 10 inside an external device such as a host computer.

The print control unit 30 includes a CPU 31 and a control RO.
M32, system RAM33, engine controller 3
The CPU 31 and the like are connected to each other by an internal bus 36. The CPU 31 performs various data processing while utilizing the system RAM based on the program stored in the control ROM to generate image data for printing. The engine controller 34 controls the operation of the print engine 40 to perform printing based on the printing image data. As the print engine 40, for example, an inkjet print engine that has a large number of nozzles for each color (cyan, magenta, yellow, black) and can eject ink droplets from each nozzle can be adopted.

Next, the gamma correction process and the like will be described with reference to FIGS.

FIG. 2 is an explanatory view schematically showing a gamma correction table and a method of managing the table. As shown in FIG. 2A, the gamma correction table is used for the gradation x of the input image.
And the gradation y of the output image are corrected, and are created so that the gamma value of the output image becomes 1.

As shown in FIG. 2B, the gamma correction table 51 has, for example, γ = −1.4, γ = −1.8, γ = −2.
2, gamma = 1.4, gamma = 1.8, gamma = 2.2, etc. are created for each gamma value, and the created gamma correction tables 51 are managed by the effective gamma correction table 50. That is, the effective gamma correction table 50 is
The storage destination address and gamma value of each gamma correction table 51 already created are managed in association with each other. By referring to the effective gamma correction table 50, it is possible to know whether or not there is a gamma correction table corresponding to the gamma value of the image to be processed.

FIG. 3 is a flow chart showing a process for ensuring a gamma correction table in the gamma process of each image. Hereinafter, the step is abbreviated as “S”.

First, it is determined whether or not gamma correction has been designated for the image to be processed (S1). If it is instructed to perform gamma correction, by searching the effective gamma correction table 50 with the specified gamma value (S2), the gamma correction table 51 corresponding to the specified gamma value is already created. It is determined whether it has been done (S3).

Since the gamma correction table is not registered in the effective gamma correction table 50 at the time of initialization when the printer is powered on, it is determined to be "NO" in S3, and the table new creation processing in S5 to S9. Move on to. First, an area for creating a new gamma correction table corresponding to the specified gamma value is secured (S5), and if the area can be secured (S6: YES), the gamma correction table corresponding to the gamma value is set. Create (S7). Then, a pointer for specifying the table used for gamma correction is set to the address of this newly created gamma correction table (S8), and the address of the newly created gamma correction table and the effective gamma correction table 50 are set. Register the gamma value (S9). In this way, through S5 to S9, the gamma correction table 51 is generated for each gamma value without duplication, and is registered in the effective gamma correction table 50.

When processing an image having the same gamma value as the already gamma-corrected image, the pointer is set in the gamma correction table registered in the effective gamma correction table 50 and the correction table is used. (S3: Y
ES, S4). Therefore, if all the images are associated with the same gamma value, all the images are gamma-corrected using the gamma correction table created first. If the gamma correction is not specified (S1: NO) or the storage area for creating a new gamma correction table cannot be secured (S6: NO), the pointer is stored in the default table registered in advance. Set.

Next, FIG. 4 is a flow chart showing the processing for erasing the created and registered gamma correction table and releasing the storage area.

This processing is performed in page units. When printing of one page is completed (S21: YES), the effective gamma correction table 50 is searched (S22), and it is determined whether or not the gamma correction table is registered in the effective gamma correction table 50 (S23).

When the gamma correction table is registered in the effective gamma correction table 50 (S23: YES), the registered gamma correction table is erased to release the storage area (S24) and registered from the effective gamma correction table. Is erased (S25).

As described above, according to the present embodiment, a gamma correction table is not created mechanically for each image, but a correction table is created for each gamma value. Even in the case of correction, it is possible to prevent the same gamma correction table from being generated in duplicate, and it is possible to effectively use memory resources. Further, since the gamma correction table registered in the effective gamma correction table 50 is used for other images associated with the same gamma value, there is no need to generate the gamma correction table and the processing load on the CPU is reduced. can do.

2. Second Embodiment Next, a second embodiment of the present invention will be described based on FIG. FIG. 5 is a flowchart showing a process of releasing the gamma correction table registered in the effective gamma correction table.

The feature of this processing is that it is performed for each recording medium (S31). That is, when the PC card 20 is inserted into or removed from the PC card slot 17, the registered contents of the effective gamma correction table 50 are erased.

Since it is considered that there are few cases where the images taken by a plurality of digital cameras are recorded together in the same PC card 20, this embodiment can also obtain the same effect as that of the first embodiment. be able to.

Those skilled in the art can make various additions, changes, combinations and the like within the scope of the gist of the present invention described in each of the above embodiments. For example, it can be applied to image processing other than gamma correction. Further, instead of releasing the table for each page, the table may be released for each print job.

[0044]

As described above, according to the image processing method and the image processing apparatus of the present invention, it is possible to effectively utilize computer resources such as a memory and a CPU to perform image processing efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic structure of a printer to which an image processing apparatus according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram showing a gamma correction table and its management method.

FIG. 3 is a flowchart showing processing for securing a gamma correction table to be used for gamma correction.

FIG. 4 is a flowchart showing a process of erasing a gamma correction table registered in an effective gamma correction table to release a storage area.

FIG. 5 is a flowchart showing a gamma correction table releasing process according to the second embodiment of the present invention.

[Explanation of symbols]

1 Image processing controller 11 CPU 12 Control ROM 13 System RAM 16 PC card controller 17 PC card slot 20 PC card 30 Print control unit 31 CPU 32 control ROM 33 system RAM 34 Engine Controller 40 print engine 50 Effective gamma correction table 51 Gamma correction table

Continued front page    F term (reference) 2C187 BF42 FB12 GB04                 2C262 AB19 AB20 AC11 BA09 BA10                       BC01 CA13 CA15 CA16 GA14                       GA15                 5B057 CA02 CA08 CA12 CA16 CB02                       CB08 CB12 CB16 CC01 CE11                       CH07 CH08                 5C077 LL04 MP01 PP15 PQ12 PQ23                       TT02

Claims (8)

[Claims] 1. An image processing method for processing an input image by using a predetermined table based on predetermined attribute information associated with an image, which is stored in a storage means based on the predetermined attribute information. A first step of determining whether or not the table stored in the storage means can be used, a second step of setting a pointer in the table if the table stored in the storage means is available, and a table stored in the storage means. If not available, a third step of newly generating a table according to the predetermined attribute information and setting a pointer in the new table; and a fourth step of storing the generated table in the storage means. A fifth step of performing a predetermined image processing using the table in which the pointer is set, and a storage step at a predetermined timing. A sixth step of deleting a table stored in a row to release a storage area, and an image processing method. 2. The image processing method according to claim 1, wherein the sixth step deletes the storage area by deleting the table stored in the storage unit in page units. 3. The image according to claim 1, wherein in the sixth step, the storage area is released by deleting the table stored in the storage means in units of recording media on which the image is recorded. Processing method. 4. The image processing method according to claim 1, wherein the predetermined attribute information is a gamma value, and the predetermined table is a gamma correction table. 5. An image processing apparatus for processing an input image by using a predetermined table based on predetermined attribute information associated with an image, the storage means storing the table, and the storage means stored in the storage means. Management means for managing the table, and an image processing means for performing predetermined image processing using the table designated by the management means, wherein the management means stores the information based on the predetermined attribute information. Determination means for determining whether or not the table stored in the storage means can be used, and table generation means for newly generating a table according to the predetermined attribute information when the table stored in the storage means cannot be used When it is determined that the table stored in the storage means can be used, a pointer is set in the table and stored in the storage means. When the created table cannot be used, a specifying unit that sets and specifies a pointer in the new table, a registering unit that stores the created table in the storage unit, and a storage unit that stores the created table at a predetermined timing. An image processing apparatus comprising: a storage area releasing unit that deletes a stored table to release a storage area. 6. The storage area releasing means releases the storage area by deleting the table recorded in the storage means in page units or in recording medium units in which the input image is recorded. The image processing device according to item 1. 7. A printing device, which prints an input image by performing predetermined image processing, comprising: storage means for storing a table based on predetermined attribute information associated with the image; and storage means stored in the storage means. Management means for managing the table, an image processing means for performing a predetermined image processing using the table designated by the management means, and a printing means for printing the image processed by the image processing means. The managing means determines, based on the predetermined attribute information, whether or not the table stored in the storage means can be used, and if the table stored in the storage means cannot be used, If it is determined that the table stored in the storage unit and the table generation unit that newly generates the table according to the predetermined attribute information can be used, A pointer stored in the storage means and the table stored in the storage means cannot be used, a designating means for setting the pointer in the new table and designating, and a registration for storing the generated table in the storage means A printing apparatus comprising: a means and a storage area releasing means for releasing a storage area by deleting a table stored in the storage means at a predetermined timing. 8. A program for processing an input image by using a predetermined table based on predetermined attribute information associated with an image, the table stored in a storage means based on the predetermined attribute information. A function of determining whether or not the table stored in the storage unit can be used, a function of setting a pointer in the table, and a table stored in the storage unit when the table stored in the storage unit cannot be used. A function of newly generating a table according to predetermined attribute information and setting a pointer in the new table, a function of storing the generated table in the storage means, and a table in which the pointer is set are used. Function to perform predetermined image processing, and delete the table stored in the storage means at a predetermined timing to save the storage area. A program that realizes the function to be released on a computer.