JPH0756639B2 - Virtual memory management method for images - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a virtual memory management method for images in a so-called virtual memory system in which a memory for processing an image can be used substantially virtually.

2. Description of the Related Art In the conventional image virtual memory management method of this type, as shown in FIG. 3, when an image expansion request is made on an image memory provided separately from the main memory (step: ST1), CPU
(Central processing unit) determines whether or not the image memory has a space (ST2), and if there is a space (ST2 YE
S), on the image memory, secure a new area for expanding the requested image (ST5), and perform processing to expand the image in the reserved area (ST6), If there is no space (NO in ST2),
Sends a message to the CPU to discard the part of the image currently being processed and free the storage area for that image (ST3)
Alternatively, based on the request of another application (ST4), the CPU erases a part of the image currently being processed to secure an area for storing a new image, and then stores the new image. An area is secured (ST5), and the requested image is developed in that area (ST6).

As shown in FIG. 4, the hardware configuration for carrying out the above-mentioned conventional method has a main memory 2 directly accessible by the CPU 1 and an image memory provided separately from the main memory 2 via the system bus 3. 4 and this image
It comprises a display device 6 for displaying the image A developed on the memory 4 through an image / memory display unit 5, and an input unit (keyboard, mouse, etc.) 7 for inputting an image processing command.

The main memory 2 includes an image processing unit 21 for processing an image and an image memory processing unit for processing an image on the image memory 4 based on a command input from the input unit 7.
22, an image memory area securing unit 23 that secures a storage area for one image on the image memory 4, and an image memory area release for erasing an image to be abandoned and releasing the storage area for the image. Consisting of part 24 and.

However, according to such a configuration, the number of images that can be processed is determined by the capacity of the main memory. Therefore, in order to process a plurality of different images, the number of images currently being processed is There was a problem that an area for storing the image could not be secured unless some of the images were discarded. In particular, when the program is multitasking, there is a serious problem that images cannot be processed in parallel.

The above problem occurs due to the limited capacity of the main memory.

Therefore, as a countermeasure, increase the capacity of the main memory,
Although it can be considered, it is not practical because the memory cost increases. In addition, by the virtual memory management program,
A method of managing while temporarily storing the image data area in a secondary storage medium (such as a floppy disk) is also possible, but the image data capacity is, for example, 8 dots / mm in A4 size.
It's as big as 12K bytes, and it's inefficient to store and store.
There is also a problem with the transfer speed to the next storage medium, which is not practical at all.

The present invention has been made in view of the above-mentioned circumstances, and is for an image with high usage efficiency that can process a plurality of different images in parallel without abandoning the image currently being processed as in the conventional art. An object is to provide a virtual memory management method.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention includes an image memory for storing a plurality of images in units of images of a predetermined capacity,
The image memory includes a compression / expansion circuit for compressing / expanding the image stored in the image memory, and a secondary storage medium for storing the image compressed by the compression / expansion circuit.
When the memory is full of images, the compression / expansion circuit compresses the image that has not been processed at that time, transfers the compressed image to the secondary storage medium, and stores the image.
A storage area for a new image is secured in the memory, the new image is expanded in the secured area, and when the compressed image in the secondary storage medium is required, the compressed image is expanded by the compression / expansion circuit. Is expanded and expanded in the image memory.

The present invention has the above-described configuration, and even when the image memory is full, the image to be processed can be compressed and stored by the capacity of the secondary storage medium.
The image is expanded from the next storage medium, expanded in the image memory and processed. As a result, even in a multi-task program, it is possible to efficiently process a plurality of different images in parallel in each program in parallel.

Embodiment FIG. 1 is a flow chart showing an embodiment of the processing operation of the image virtual memory management method according to the present invention. In FIG.
ST28 indicates the step of each processing operation.

The method of the present invention will be described with reference to FIG.

First, when there is a request to develop an image on the image memory (ST21), the CPU determines whether the image memory has a free space (ST22).

Therefore, if there is a free space (YES in ST22), an area for developing a newly requested image (hereinafter referred to as a requested image) is immediately secured in the image memory (ST25).
The capacity of one image of the requested image is, for example, 512 Kbytes in A8 size dots / mm as shown in the conventional example.

If there is no space (NO in ST22), compress the image that is not currently processed and transfer it to the secondary storage medium (ST23).
Then, the storage area for the image is released (ST24).

Then, a new storage area for the requested image is secured in the image memory (ST25).

When the storage area for one image is secured (ST25) in this way, the CPU checks whether or not the requested image is stored as a compressed image in the secondary storage medium (ST).
26).

If it is found that the requested image is stored and stored as a compressed image (YES in ST26), the compressed image is read from the secondary storage medium, decompressed, and then expanded / processed in the image memory ( ST27).

When it is determined that the requested image is not stored (NO in ST26), the requested image is directly expanded and processed in the image memory (ST28).

Next, FIG. 2 shows an example of a schematic configuration of hardware for carrying out the above-described method of the present invention.

In FIG. 2, 31 is a main memory that can be directly accessed by the CPU 32, 33 is an image memory provided separately from the main memory 31, and a storage area for one image is secured on this image memory 33, and the requested image is stored here. A is deployed. 34 is an image compression / expansion circuit, and 35 is a secondary storage medium.
A compressed image obtained by compressing an image not currently processed in the image memory 33 by the compression / expansion circuit 34 (the request image A shows the compressed image A compressed in the figure) is transferred and stored. . 36 is an image memory display processing unit that processes the image on the image memory 33 so as to display it; 37 is a display device that displays the image processed by the processing unit 36;
Is an input unit (comprising a keyboard or a mouse) for inputting image processing commands, 39 is a system bus, and 40 is an image bus.

The main memory 31 includes an image processing unit 311 for processing an image and an image memory processing unit 312 for developing / processing a requested image on the image memory 33 based on a command input from the input unit 38, and one image. Image memory request unit 313 for requesting a storage area of the image memory, virtual memory management means 314 for managing virtual memory based on this request, and image memory 3
Image memory management unit 315 that manages 3
An image that secures a storage area for one image on the memory 33.
The memory area reserving unit 316 and the image memory 33 for releasing the storage area of the image currently not processed in the image memory 33.
The memory area release unit 317, the compressed image management unit 318 that manages the compressed image in the secondary storage medium 35, and the image from the image memory 33 are compressed or secondary stored via the compression / expansion circuit 34. The image compression / decompression unit 319 is configured to decompress the compressed image from the medium 35.

Next, the operation will be described with reference to FIG.

First, the image processing means 311 secures an area for storing the requested image in the image memory 33 by the processing command of the requested image given from the input section 38, stores the requested image A in the area, and stores the requested image A. Is processed and edited.

Next, it is assumed that when the different requested images are to be processed, the image memory 33 has already stored the image in its full capacity. At this time, the virtual memory management means 314 detects this, compresses the image A that is not currently processed, transfers the compressed image A to the secondary storage medium 35 and stores it, and at the same time releases the storage area of the image. This secures an area on the image memory 33 for a new image.

Therefore, the virtual memory management unit 314 secures a new image storage area on the image memory 33 via the image memory area securing unit 316.

The image processing means 311 stores, processes and edits the different requested image in the secured new area.

After this processing / editing is completed, the image previously transferred and stored in the secondary storage medium 35 as the compressed image A is again processed by the image processing means 31.
When 1 requests the virtual memory management unit 314 via the image memory request unit 313, the virtual memory management unit 314 sends the compressed image A to the secondary storage medium 35 via the compressed image management unit 318.
Read from the image compression / expansion unit 319 and compression / expansion unit.
The expanded image A is expanded through the expansion circuit 34,
Again, it is expanded on the image memory 33 in the same manner as described above.

As described above, in the present invention, the image processing means 311 stores an image on the image memory 33 assuming that there is an infinite memory, without worrying about the remaining area on the image memory 33, the address, etc. be able to.

As the compression / expansion circuit 34, for example, a document having a compression speed of A4 size 8 dots / mm is 0.35 on average.
It is preferable that the second and the compression rate are about 1/6 on average, but it is preferable to select and use it appropriately depending on the image.

Further, the image processing means 311 and the virtual memory management means 3
14 are respectively executed by the management program.

EFFECTS OF THE INVENTION As is clear from the above description, according to the present invention, an image memory that stores a plurality of images in units of a predetermined capacity of images, and an image that is stored in the image memory are compressed and compressed.
A compression / expansion circuit for expanding and a secondary storage medium for storing the image compressed by the compression / expansion circuit are provided, and when the image memory is full of images, the compression / expansion circuit has not been processed at that time. The image is compressed, the compressed image is transferred and stored in the secondary storage medium, a storage area for a new image is secured in the image memory, the new image is expanded in the secured area, and the secondary image is stored. When the compressed image of the storage medium is required, the compressed image is expanded by the compression / expansion circuit and expanded in the image memory, so that the image to be processed can be processed even when the image memory is full. It can be compressed and stored as much as the capacity of the secondary storage medium,
In addition, when necessary, the image is expanded from the secondary storage medium and expanded into the image memory for processing.
It is possible to improve the usage efficiency of the image memory,
Also, without abandoning the images to be processed,
It has an effect that a plurality of different images can be processed in parallel.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of the processing operation of a virtual memory management method for images according to the present invention, and FIG. 2 is a block diagram showing an example of a schematic configuration of hardware for carrying out the method of the present invention. FIG. 3 is a flowchart of processing operations based on the conventional method, and FIG. 4 is a schematic block diagram of a hardware configuration for implementing the conventional method. 31 ... Main memory, 311 ... Image processing means, 314 ... Virtual memory management means, 32 ... CPU (central processing unit), 33 ... Image memory, 34 ... Compression / expansion circuit, 35 ... 2 Next storage medium, 38 …… Input section, 39 …… System bus, 40 ……
Image bus.

Claims (1)

[Claims] 1. An image memory for storing a plurality of images in units of a predetermined capacity of images, a compression / expansion circuit for compressing / expanding the images stored in the image memory, and a compression / expansion circuit for compressing / expanding the images. A secondary storage medium for storing an image, wherein when the image memory is full of images, the compression / expansion circuit compresses an image that has not been processed at that time, and the compressed image is stored in the secondary storage. When a transfer image is stored in a medium, a storage area for a new image is secured in the image memory, the new image is expanded in the secured area, and a compressed image in the secondary storage medium is required. A virtual memory management method for images, wherein the compressed image is expanded by the compression / expansion circuit and expanded in the image memory.