JPH10224580A - Picture storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of mismatch between a data transfer speed requested to a compressed picture data page and the transfer speed of a disk area to be written by writing compressed picture data in a storage area corresponding to the transfer speed. SOLUTION: Compressed picture data inputted through an input interface part 19 are temporarily stored in a picture input memory (CPU memory) 15. In the case of transferring the data from the memory 15 to a hard disk device 11, the functions of a transfer request speed operation part 141 for finding out a request transfer speed from the inputted compressed picture data volume and specified output size and a writing address determination part 142 for determining a writing block address from the request transfer speed and the transfer speeds of respective track parts of the hard disk device are used. The functions of the operation part 141 and the determination part 142 are attained by executing program control by a CPU 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage device for storing a large amount of compressed image data at high speed and efficiently in a disk type storage medium such as a hard disk device having a plurality of storage areas with different transfer speeds.

[0002]

2. Description of the Related Art In an electrophotographic printer or display device, a disk-type storage device such as a hard disk device has been used as a means for storing ripped image data (Japanese Patent Laid-Open Nos. 8-70425 and 8-70425). 2
-100679). Also, in the prior art,
At the read speed of the hard disk (10 MB / S or less), the data transfer speed (number + MB / S) required for a high-speed multi-valued printer cannot be met. Compression +
A method is used in which the worst compression ratio is guaranteed to be about 1/10 by the JPEG composite compression means, compressed, stored in a hard disk, and decompressed and output in real time. In this case, in consideration of frequent occurrence of disk errors, it is general to use a compressed image memory having a data amount (several MB) at the worst compression ratio. In such a general technology,
When the hard disk device is used not as a temporary buffer but as a storage device of an application for filing compressed image data and continuously outputting a large number of variable pages, one page of compressed image data is stored in a compressed image memory within a predetermined time. Is required over the entire surface of the disk.

[0003]

In a hard disk drive, however, a difference in data transfer speed (approximately 1.5 times) occurs between the outer circumference and the inner circumference of the disk. Can not be ignored. If the data transfer speed at the worst compression ratio exceeds the data transfer speed of the inner peripheral portion of the disk, problems arise, such as continuous printing being stopped and input performance to the disk being reduced. In the conventional technology, measures are taken such as increasing the data transfer speed by preparing a plurality of disks and increasing the size of the compressed image memory by using a disk that is one class faster.
There is a problem that these methods are costly. On the other hand, the compression ratio of the compressed image data changes depending on the image density of the page. In other words, the amount of compressed image data changes depending on each page, and the data transfer speed required for each page changes accordingly. According to past statistics, the average compression ratio for a general document using the composite compression means is about 1/20. However, if sequential address control is performed as usual, when image data with the worst compression ratio comes in, there is a mismatch between the data transfer speed required for the compressed image data page and the transfer speed of the disk area to be written. There is a problem that may occur.

An object of the present invention is to solve these problems. That is, the present invention provides an image storage device which does not cause a mismatch between the data transfer speed required for a compressed image data page and the transfer speed of a disk area to be written even when image data with the worst compression ratio comes. The task is to provide Another object of the present invention is to provide an image storage device capable of averaging the readout time per page even when image data with a low compression ratio is input, and performing stable output to an output device. is there. A further object of the present invention is to realize relatively high-speed transfer of compressed image data at low cost.

[0005]

According to the present invention, there is provided input means for inputting compressed image data, information relating to compression of the compressed image data, and output size designation information, and stores the compressed image data input by the input means. A disk-type storage unit having a plurality of storage areas with different transfer speeds, and the compressed data is input to the disk-type storage unit in real time based on the information on the compression input by the input unit and the designated output size. Request speed calculating means for calculating a required transfer speed required for transferring data by speed, speed information storing means for holding transfer speed information of each storage area of the disk type storage means, and request transfer calculated by the requested speed calculating means. By referring to the transfer speed information of each storage area held in the speed information storage means, a record satisfying the requested transfer speed is obtained based on the speed. Selection means for selecting an area, the storage area of the disk type storage means selected by the selection means, characterized in that a writing means for writing the compressed image data which has been the input.

[0006]

According to the present invention, in order to solve the above-mentioned problems, regarding the control of the disk of the disk type storage means, the point that the transfer speed decreases from the outer circumference to the inner circumference of the disk and the content of the compressed page data is reduced. From the information about the output size of the input compressed image data, or from information about compression such as the compression ratio. When the data amount is small (the compression ratio is high), When the data amount is large (the compression ratio is low), the compressed image data is written in a storage area corresponding to the transfer speed, such as on the outer periphery. That is, the speed calculating means calculates the requested transfer speed based on the information on the compression and the specified output size. The transfer rate information for each storage area of the disk-type storage device is stored in advance in the transfer rate information storage unit, and the selection unit compares the transfer speed information with the calculated requested transfer speed to satisfy the requested transfer speed. Select a storage area with a transfer rate that allows The writing means writes the compressed data to the storage area selected by the selection means.

As described above, in the present invention, an optimal disk area is selected and stored based on the required transfer speed required for the disk-type storage means in order to transfer compressed image data in real time. Even when image data with the worst compression ratio arrives, there is no mismatch between the transfer speed required for the data and the transfer speed of the disk area to be written. Therefore, even when reading data,
The reading time is averaged, stable output to the output device is possible, and the rate of parallel processing of input / output to the disk within a fixed time can be increased. Further, since the performance of the disk-type storage means can be utilized to the maximum, it is possible to cope with a high-speed output device with a cheaper device than the conventional technology. When storing a plurality of units of compressed image data continuously, the relative movement time of the head from the immediately preceding storage area, that is, the seek time, may affect the transfer speed. In order to reduce the influence of the child, the relative movement seek time from the storage area (cylinder) stored immediately before can be added to the factor of the area selection.

[0008]

FIG. 1 is a block diagram showing the configuration of an image storage device according to the present invention. This image storage device
A hard disk drive 11, a disk control unit 12, a system bus 13, a CPU 14, a CPU memory 15, a compressed image memory 16, a memory control unit 17, a decompressor 18, and an input interface unit 19 are provided.

The hard disk device 11 is connected to a system bus 13 via a disk control unit 12. The disk control unit 12 controls a sequence of a disk bus (for example, SCSI) and a data transfer between the CPU memory 15 and the hard disk device 11 according to a command from the CPU 14. The hard disk device 11 is connected to the disk bus 13 via an internal buffer memory (FIFO) 111 of about 512 KB. The compressed image memory 16 is connected to the system bus 13 via the memory control unit 163. In order to cause a disk error or perform input / output in parallel, the compressed image is temporarily held with a capacity of two data volumes at the worst compression ratio. The memory control unit 17 performs writing and reading from the disk control unit 12 and the decompressor 18 in parallel. The decompressor 18 controls the reading of data from the compressed image memory 16 in response to a command from the CPU 14, and performs real-time decompression and data transfer at a speed required for the operation of the printer.

The compressed image data input via the input interface unit 19 is temporarily held in an image input memory (using the CPU memory 15), and is temporarily stored in the image input memory 15.
In the transfer from the HDD to the hard disk drive 11, a transfer request speed calculation unit 141 for obtaining a requested transfer speed from the input compressed image data amount and the designated output size, and writing from the requested transfer speed and the transfer speed of each track of the hard disk device. The function of the write address determination unit 142 that determines the block address is used. The transfer request speed calculator 141 and the write address determiner 14
The function 2 is realized by program control by the CPU 14. The CPU memory 15 is used for work, and functions as a buffer (image input memory) for calculating the control and input image data. The transfer request speed calculation unit 141 obtains the number N of images that can be output per second by the printer from information previously stored in the CPU program by designating the input output size, and converts the page data into the data amount M (MB) of the input compressed image. Required transfer rate Si = M / N
(MB / S) is determined. Write address determination unit 14
2 functionally has the configuration shown in FIG.
It is processed by CPU program control based on i. An example will be described based on the processing using the table shown in FIG.

The division of the disk area may be performed by using the division for each transfer speed of the disk, or may be further divided to simplify the processing. For example, it is possible to divide the disc into six (in 0.5 MB / S steps).

[0012] As shown in FIG.
One disk generally has areas # Z0, # Z1,... #Zi,... #Zn where the data amount per cylinder is constant. For example, a certain disk is divided into 13 areas, and each area is approximately It consists of 500 cylinders. Transfer speed within the area (about 0.5 MB / S from the inner circumference to the outer circumference).
(2 MB / S increments) is almost constant.

The disk area comparison / selection unit 22 compares the requested transfer rate Si with the average transfer rate data si of the disk areas #Zo to #Zn (# 0 is the outer periphery) and determines an area Zi faster than Si. Therefore, disk space comparison /
The selecting unit 22 calculates the average transfer speed data si and the area #Zo to
3 has an area selection table 31 as shown in FIG. 3 associated with #Zn, and refers to the area selection table 31 based on the requested transfer rate Si to obtain a pointer (address) to the storage location of the block usage information of the corresponding area #Zi. ). The area selection table 31 associates an average transfer speed with an area corresponding thereto, and the corresponding area is an in-area use state management address table 24 (321, 322, 322, and 322 in FIG. 3) for managing the use state of blocks in the area. 32
Determined as the address of the storage position in 3).

Next, the in-area unused block selecting section 23 refers to the in-area block usage management table 24 to specify a unit transfer block size (for example, 32) in the area Zi.
The head address of an unused block for each (KB: 64 sectors) is obtained. The intra-region block use status management address table 24 includes a 1-bit flag indicating whether or not the block is usable and a head address of each block. The flag “1” indicates that use is impossible, and the flag “0” indicates use. The determined storage address is managed as page information, the unused information in the table is updated, and a command is issued to the disk control unit 12 to start writing to the disk. When the use size of a certain page cannot be obtained due to the use state of the area, the shortage is selected from an area faster than the area Zi. In this embodiment, the worst compression ratio per page is guaranteed by the compression means of the host computer, and the hard disk is calculated from (requested transfer speed to the compressed image memory) = (data amount in worst case) / (printer output performance). The device is selected, and the required transfer speed to the compressed image memory is about the average read speed of the hard disk device.

The operation of the printer image storage device will be described below with reference to the flowchart of FIG. The image data compressed and ripped by the host computer is
From the input interface unit 19 of FIG.
The data is input to the PU memory 15 (step S5-1). Prior to input of compressed image data, output size designation and compressed image data amount information are obtained by communication from the host computer. The information may be compression rate information instead of the compressed image data size.

From the data amount M of the input compressed image and the number N of output per second from the designated output size, the requested transfer speed calculating section 141 calculates a requested speed (S = M / N) (step S5-2). ). Next, the write address determination unit 142 compares the transfer speed (s) of each of the divided disk areas with the required speed S (= M / N) to determine an area Z where s> S. That is, the disk area speed data sm (m = n) corresponding to the innermost area #Zn is extracted from the table 31 (step S5-3), and it is checked whether or not sm is greater than the required speed S (step S5-).
4) If sm is smaller than the required speed S, the disk area speed data sm (m = n-
1) is taken out (step S5-5), and it is checked again whether or not sm is greater than the required speed S (step S5-).
4). Such steps S5-4 and S5-5
When sm> S, the address of the block use status management address table 32 of the area corresponding to the sm is obtained from the area selection table 31 (step S5-6). Block use status management tables 321 to 32 specified by the obtained addresses
3, the unused flag bits are sequentially referred to, the write block is selected by M / (transfer block size) (= a), and the start address of each block is obtained from the same table (step S5-7). . The unused flag bit of each selected block in the table is updated, and the disk storage location of this page is added to the page management information on the CPU memory 15. After the write address determination processing for one page is completed, a write instruction to the address of each block is issued to the disk control unit 12 (step S5-8).

On the other hand, the compressed image memory 16 has a storage capacity for two pages (shown as 161 and 162 in FIG. 1). The compressed image data of the next page is also input,
Thereafter, the input processing to the write address determination processing are repeated until one job is completed. After completing the processing for one job,
The CPU sends the compressed image memory 1 from the disk to the disk control unit 12 one page at a time in response to an output request from the host.
6 is issued to the printer via the decompressor 18.

The write address determination section 142 calculates a seek time t = b + c (| Zj-Zk | -1) of the disk head from the disk area Zj in which the previous page is written to the current page area Zk once obtained. , T
By adding means for correcting the area where the current page is to be written in consideration of the elements described above, it is possible to read out data more efficiently during continuous output within one job. Here, b in the above formula for t is the rise time of the disk head movement, and c is the seek time required for movement per area.

According to the present embodiment, an optimal disk area is selected from the data transfer speed required for each page and stored, so that when image data with the worst compression ratio comes, the data Between the transfer speed required for the disk drive and the transfer speed of the disk area to be written. Therefore, the data read time is averaged, stable print output is possible, and the parallel processing rate of input / output to the disk within a certain time can be increased. Further, since the performance of the hard disk device can be utilized to the maximum, it is possible to cope with a high-speed printer with a hard disk device that is inexpensive compared to the related art.

In one embodiment in which the present invention is applied to a color printer, a plurality of the hard disk devices, a compressed image memory, and a decompressor are provided corresponding to the color elements, and the write address determination unit is provided for each hard disk device. , The color compressed image can be written and read efficiently.

[0021]

According to the present invention, an optimal disk area is selected from the data transfer speed required for each compressed image data and stored, so that even when image data with the worst compression ratio comes, Thus, there is no mismatch between the transfer speed required for the data and the transfer speed of the disk area to which the data is written. Therefore, the data read time is averaged, stable print output is possible, and the parallel processing rate of input / output to the disk within a certain time can be increased. Further, according to the present invention, an area having a transfer rate matching the data transfer rate required for the compressed image data can be selected and stored, so that the worst case is possible without changing the disk type storage means to be expensive. It can deal with image data with a compression ratio, and has a great cost advantage.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a functional configuration of an embodiment in which the present invention is applied to a printer image storage device;

FIG. 2 is a block diagram showing a functional configuration of a write address determining unit;

FIG. 3 is a diagram showing an example of a processing table for determining a disk write address;

FIG. 4 is a diagram showing a configuration concept inside a disk;

FIG. 5 is a schematic flowchart showing the operation of the embodiment.

[Explanation of symbols]

11: Hard disk drive, 111: Built-in buffer memory, 12: Disk control unit, 13: System bus, 14
... CPU, 141 ... Transfer request speed calculation unit, 142 ... Write address determination unit, 15 ... CPU memory, 16 ... Compressed image memory, 17 ... Memory control unit, 18 ... Decompressor, 19 ...
Input interface section.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 5/765 H04N 5/781 510C 5/781

Claims (4)

[Claims] 1. An input means for inputting compressed image data, information relating to compression of the compressed image data, and output size designation information, and a plurality of storages having different transfer speeds for storing the input compressed image data. A disk-type storage unit having an area; and a request transfer rate required to transfer the compressed data to the disk-type storage unit in real time based on the information on the compression input by the input unit and the designated output size. Request speed calculation means to be obtained, speed information storage means for holding transfer speed information of each storage area of the disk type storage means, and the requested transfer rate calculated by the request speed calculation means,
Selecting means for selecting a storage area that satisfies the required transfer rate by referring to transfer rate information of each storage area held in the speed information storage means; and storage area of the disk type storage means selected by the selection means And a writing means for writing the input compressed image data. 2. The image storage device according to claim 1, wherein the selection unit also takes into consideration a seek time required for moving the write head of the disk-type storage unit as a condition for selection. 3. The image storage device according to claim 1, wherein compression ratio information input by an input unit is used as the information on the compression. 4. The apparatus according to claim 1, wherein a plurality of disk-type storage units having the same configuration are provided corresponding to the color elements, and the selection unit is used sequentially for each hard disk to store the color compressed image data. The image storage device according to claim 1.