JPH07220051A - Image data conversion system - Google Patents

Abstract

(57) [Summary] [Purpose] In a system that performs data conversion and format conversion on a server so that shared data can be used by clients with different formats and resolutions,
Shorten the time from the client's request for data to the start of image display and the display end time. A storage device for storing shared data, software for converting image data in units of divided blocks, or a server having hardware, and software for performing data conversion display of image data in units of divided blocks, Or a client with hardware,
A client-server system configured with a communication line connecting these.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a display resolution, color system,
The present invention relates to an image data conversion processing system that enables compressed image data stored in a storage device of a server to be commonly used by clients even when clients having different display systems are connected by a communication line.

[0002]

2. Description of the Related Art For example, compressed image data compressed by image compression / expansion processing means in a workstation having a display resolution of 1280 × 1024 has a display resolution of 640 × 4.
When commonly used as image data in a personal computer of 80, it is necessary to convert the number of pixels of the compressed image data created by the workstation into the number of pixels according to the display resolution of the personal computer.

Conventionally, regarding the method of converting the number of pixels,
The method described in "Interface", January 1993, pages 183 to 206 is known.

[0004]

A file server having a storage device for storing compressed image data created by compression by an image compression / expansion algorithm and an image capturing device such as a scanner, a digital still camera, a video camera or the like. In a client server system in which a plurality of clients having different image resolutions / color systems / display systems are equipped with image compression / expansion processing means for compressing / expanding image data by an image compression / expansion algorithm and connected by a communication line. To make the compressed image data created by each client common to the clients,
It is extremely effective in terms of effective utilization of image material resources. Each client is equipped with image compression / expansion processing means for image compression / expansion of image data, and the color system supported by the installed image compression / expansion processing means and the display unit of the client. Compressed image data is created based on the display resolution of.

As a specific example of the color system, for example, YUV16
(Y: luminance signal, U / V: color difference signal, YUV sampling ratio = 4: 2: 2, YUV bit number = 8 bits each), YUV12 (Y:
Luminance signal, U / V: Color difference signal, YUV sampling ratio = 4: 1:
1, YUV bit number = 8 bits each, RGB24 (R: red signal, G: green signal, B: blue signal, RGB sampling ratio = 1: 1: 1, RGB bit number = 8 bits each) Etc.

Further, as a type of client display system, a CLUT (color lookup table) which is a palette of color information and a CLUT display system based on pixel data indicating CLUT allocation to each pixel and color information of each pixel are displayed as they are. There is a full color display system that does. CLUT display method is CL
There is a system where the number of UT colors is 16 or 256.

Even in the full-color display system, there are several types of display formats such as a system supporting 32,000 colors and a system supporting 16.77 million colors depending on the system.

Therefore, in order to commonly use the compressed image data compressed by the images having different display resolutions, color systems and display formats, the number of pixels of the compressed image data stored in the storage device and the color system are used. In order to adapt the display format to the display resolution, color system, and display format of the client to be used, it is necessary to perform pixel number and color system conversion and display format conversion.

However, although the prior art discloses a method of converting the number of pixels according to the display resolution, the file server communicates with a plurality of clients having different display resolutions, color systems, and display formats as described above. In a client-server system connected by a line, no consideration is given to the problem of commonly using the compressed image data stored in the storage device. For example, when the client is a personal computer having a slow processing speed, there is a problem that the processing load of the client increases and the processing time required for the pixel number conversion becomes enormous. Further, as described above, in a client / server system in which a plurality of clients having different display resolutions and color systems from the file server are connected by a communication line, in order to commonly use the compressed image data stored in the storage device, , Each client must be equipped with a means for performing pixel number conversion and color system conversion.For clients that do not have this means, other clients with different display resolutions and color systems must be created and stored in the storage device. There is a problem that the stored compressed image data cannot be used.

In order to avoid this, a server having a high processing speed has means for pixel number conversion for all clients, color system conversion, and display format conversion.
A method is conceivable in which the conversion process is performed and the data is transferred to the client. However, if the conversion processes are collectively performed and then transferred, the client cannot start displaying until the conversion process of the server is completed. Therefore, the waiting time from the user requesting the image data to the start of the display is long, and the usability for the user is not good.

An object of the present invention is to perform the pixel number conversion and color system conversion at high speed, and even if each client does not have the conversion means, the compressed image data created by each client can be transferred between all clients. It is an object of the present invention to provide a system that shortens the display start time in an image data conversion processing system that can be commonly used.

[0012]

In order to solve the above problems, the present invention provides a server with means for converting data divided in block units and means for transferring data in block units, and a client with It is characterized in that a data display means divided into blocks is provided.

[0013]

The server converts the data in the convertible unit by the means for converting the data divided into the blocks and the means for transferring the data in the block, and transfers the data. Since the client can start the display by the data display means from the time when the data in divided blocks is received, the display start time is shortened. Further, the server can perform data conversion of the next block while the client is performing display processing, and the total time for data conversion and display is shortened.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a system configuration diagram of a client / server system including an image data conversion function according to the present invention. 1 is a server including an image data conversion unit according to the present invention, 2 is a storage device for storing compressed image data, 3 is image data captured by an image capturing device such as a scanner, a still camera, a video camera, or the like, such as JPEG or MPEG. Clients equipped with image compression / expansion means for image compression / expansion by a predetermined image compression / expansion algorithm, 4, 5 and 6 have no input means described above, clients having different display resolutions, color systems, and display systems, Reference numeral 7 is a communication line that connects the server 1 and the clients 3, 4, 5, 6 to enable transfer of image data. Further, 11 to 17 are processing blocks in the server, 11 is a division reading unit that divides and reads image data, 12 is an image expansion unit that expands an image by a predetermined image expansion algorithm, 13 is the number of pixels, and , Converts data of different color system into a specified number of pixels and color system 2
Dimensional filter, 14 is an image compression unit that compresses an image with a predetermined image compression algorithm, 15 is a display format conversion unit that converts image data of different display formats into image data of a predetermined display format, and 16 is a post-conversion processing. Image data communication line
It is a transfer control unit that supplies to the client via 7.
Each processing unit can convert image data collectively or by dividing it into blocks. Reference numeral 17 denotes a processing control unit that controls each conversion processing unit when the data conversion is divided and performed.

The problem when data is commonly used will be described below with reference to FIG. In the client / server system, the data used is stored in the storage device 2. This data includes data created by a system unrelated to the system, such as a CD-ROM, and a client. There is data that has been captured and processed by the input device of the client 3 connected to the server system. Since the former data is data created by an external system, it does not always meet the specifications of each client. In addition, the latter data may be displayed on the client 3 who created the data, but may not be displayed on another client with different specifications as it is. Therefore, it is necessary to convert the data stored in the storage device 2 according to the specifications of each client. This conversion processing may be performed by each client according to the specifications of its own machine, or by the server collectively performing the conversion processing. However, if the client does not have a conversion means, or the capability is poor,
If the conversion is possible but takes a lot of time, it is more convenient for the user if the server performs the conversion all at once.

The outline of data conversion in the server will be described below.

As an example, it is assumed that the display resolution of the client 3 is 1280 × 960 and the display system is 16.77 million full color display, and the display resolution of the client 4 is 640 × 480 and the display system is 16.77 million full color display. Also, client 3
Then, although not shown, image data is captured by an image capturing device such as a scanner, a still camera, a video camera, etc., and this image data is compressed / compressed in the client 3.
The decompression means compresses the image in accordance with a predetermined image compression / decompression algorithm. The compressed image data created by the client 3 is transferred and stored in the storage device 2 connected to the server 1 via the communication line 7. The created compressed image data is data that is image-compressed with a display resolution of 1280 × 960 that the client 3 has. The compressed image data created by the client 3 and stored in the storage device 2 is used by the client 4
The common use will be explained.

The compressed image data stored in the storage device 2 is expanded by the image expansion unit 12 in the server 1 according to a predetermined expansion algorithm. The decompressed data is
The two-dimensional filter 13 converts the number of pixels according to the display resolution of the client 4. The image compression unit 14 compresses the data after conversion of the number of pixels again according to a predetermined algorithm. This compressed data is transferred to the transfer control unit.
16 is transferred to the client 4 via the communication line 7. Since the transferred image data has been converted into image data that can be expanded / displayed by the client 4, the client 4 only has to expand the compressed image data and display the expanded image data.

The outline of the function and operation of the data conversion system by the server has been described above. Next, according to the present invention in the server 1 and the clients 3, 4, 5, 6 in the client-server system shown in FIG. An example of pipeline processing will be described in detail with reference to the drawings.

The first embodiment of the present invention is 1280 in FIG.
640 × 480 JPEG compressed image data created by full color client 3 with a display resolution of × 960 dots
Data conversion in the server 1 when used in the full-color client 4 having a dot display resolution will be described as an example. The conversion processing in the server 1 includes conversion such as scaling for matching the number of pixels of image data with the display resolution of the client, color system conversion, and format conversion. However, in the present embodiment, the case of performing scaling is taken as an example. explain.

In this embodiment, the storage device 2 stores JPEG-compressed data having an image size of 1280 × 960 dots captured by an input device connected to the full-color client 3. This image data is 640 ×
In order to display with a full-color client 4 having a resolution of 480 dots, the image data must be scaled to have a resolution of 640 × 480.

First, a description will be given of the processing in the case of collectively performing data conversion without performing the pipeline processing.

FIG. 2 is a flow chart showing the processing contents of the server 1 and the full color client 4 when the shared JPEG data is collectively converted by the server 1 and is displayed collectively by the full color client 4.

Hereinafter, the server 1 and the full color client 4
The operation will be described with reference to the flowchart of FIG.

Processing of server 1 (step 200) Start of processing. Receives image transfer request from full color client 4.

(Step 201) JPEG image (1
280 × 960) is read from the storage device 2 of the server 1.

(Step 202) The read JPEG image is developed into full color data.

(Step 203) 1280 × 960 full color data is scaled to 640 × 480 full color data.

(Step 204) 640 × 480 full color data is JPEG compressed.

(Step 205) The JPEG data created in Step 204 is transferred to the full color client 4 through the communication line 7.

(Step 206) The processing of the server 1 is completed.

Processing of Client 4 (Step 210) An image transfer request is issued to the server 1.

(Step 211) Server 1 executes Step 2
Receive the 640 × 480 JPEG data for one screen transferred in 05 and decompress it.

(Step 212) The decompressed data is transferred to the display circuit and an image for one screen is displayed.

(Step 213) Display End FIG. 3 shows the processing of the server 1 and the full-color client 4 on the same time axis.

After the processing of the server 1 is completed as shown in FIG. 3, the processing of the full color client 4 is started. That is, in the flowchart of FIG. 2, after the processing step 206 of the server 1 is completed, the processing step 210 of the full-color client 4 is started. Therefore, the display start time is the time t1 after the conversion of the data for one screen in the time chart of FIG. 3 is completed.

The display end time is t2 when the display starts from time t1 and the display for one screen ends.

Next, the pipeline processing of the present invention which divides the above conversion processing will be described.

FIG. 4 is a flowchart showing the processing of the server 1 and the full color client 4 when the shared JPEG data is divided and displayed by the full color client 4 in this embodiment.

The present embodiment is characterized in that each process is divided and processed. However, when the JPEG data is divided,
There are some restrictions from that specification. In JPEG, basically
Since processing is performed in 8 × 8 block units, division processing below this unit is not possible. In this embodiment, a case will be described as an example where processing is performed by dividing the block into 60 blocks of 16 lines.

J in block units sent from the server 1
In order to actually decompress the PEG data, the JPEG
It is necessary that the full color client 4 has the data of the Huffman table and the quantization table of the data. Therefore, it is necessary to transfer the data of the Huffman table and the quantization table to the full color client 4 at the beginning of the processing.

The processing of the server 1 and the full-color client 4 in this embodiment will be described below with reference to the flowchart of FIG.

Process of server 1 (step 400) Start of process. Receives image transfer request from full color client 4.

(Step 401) The Huffman table and quantization table of the JPEG data to be transferred are read out and transferred to the full color client 4.

(Step 402) The 16-line JPEG image (1280 × 16) is read from the storage device 2 of the server 1.

(Step 403) The read JPEG image is developed into full color data.

(Step 404) 1280 × 16 full color data is scaled to 640 × 8 full color data.

(Step 405) 640 × 8 full color data is JPEG compressed.

(Step 406) The JPEG data created in Step 405 is transferred to the full color client 4 through the communication line.

(Step 407) It is checked whether the processing of the 60th block is completed. When done, step 40
Go to 8. If not completed, the process returns to step 402 and the process of the next block is repeated.

(Step 408) The processing of the server 1 is completed.

Processing of Client 4 (Step 410) An image transfer request is issued to the server 1.

(Step 411) Server 1 executes Step 4
The Huffman table and the quantization table transferred in 01 are received.

(Step 412) Server 1 executes Step 4
The 640 × 8 JPEG data transferred in 06 is received and decompressed.

(Step 413) The decompressed data is transferred to the display circuit to display an image for 8 lines.

(Step 414) It is checked whether the display processing of the 60th block is completed. Upon completion, proceed to step 415. If not, step 412
Return to and continue the expansion and display processing of the next block.

(Step 415) The display is terminated.

The flow of processing has been described above with reference to the flow chart of FIG. 4, but the relationship between the above steps of each processing and the processing section of FIG.
02, the division / expansion processing by the image expansion unit 12 is the processing of step 403, the processing of the two-dimensional filter 13 is the processing of step 404, and the division / compression processing of the image compression unit 14 is the processing of step 405. The processing of the transfer control unit 16 is step 4
Each corresponds to the processing of 06. In addition, the division processing control unit 17
Controls the size of blocks to be divided in these division conversion processes and the timing of transferring the converted data to the client.

In order to show the effect of the processing described above,
FIG. 5 shows the processing of the server 1 and the full-color client 4 on the same time axis. As shown in FIG. 5, the server 1 transfers the Huffman table and the quantization table, and then the first block of data is transferred to the full-color client.
The full-color client 3 can start the display process from the time t1 ′ after the transfer to 4. That is, in the flowchart of FIG. 4, the processing of step 412 of the full-color client 4 is started when the server 1 finishes the processing of step 406 for the first time. Therefore, in the present embodiment, the display start time is the transfer time of the table data + 1 the transfer time of one block, which is about 1/60 of t1 in the case of the batch processing. Further, as can be seen from FIG. 5, the server 1 can process the next block after transferring the block data to the full-color client 4. Therefore, since the conversion processing of the server 1 and the expansion and display processing of the full-color client 4 can be executed in parallel, the display end time is t2 'which is shorter than the display end time t2 in the case of batch conversion processing. As described above, according to the present embodiment, in a system that shares compressed data such as JPEG data, the display start time and the display end time are set when image data conversion that meets the specifications of each client is required. It can be shortened, the waiting time of the user is shortened, and the usability is improved.

In the present embodiment, the size of the block to be divided is divided into blocks of 16 lines, but the conversion processing content in the server 1, the processing time in the server 1 and the processing time in the full color client 4 are The optimal block size may change depending on the ratio. However, even in that case, the effect of the present embodiment does not change. Further, when data compressed by a compression algorithm other than JPEG is stored in the storage device 2 and this data is used by a plurality of clients having different specifications, the block size at the time of the division processing is Needs to be divided into units suitable for the compression algorithm used, but the effect of the division process remains the same.

Next, a second embodiment of the present invention will be described.

In the second embodiment of the present invention, the client 5 is a pseudo-color type client for displaying with a color map (256 colors) and pixel data.
The display resolution is 1280 x 960 dots (hereinafter referred to as CLUT client 5).

Further, it is assumed that the shared data stored in the storage device 2 is 1280 × 960 dot JPEG compressed data which is taken in by the input device of the full color client 3 and JPEG compressed.

In the second embodiment of the present invention, in addition to the difference between the data stored in the storage device 2 and the resolution of the CLUT client 5, the display method of the CLUT client 5 is the CLUT display method, so full color data is obtained. Needs to be converted to colormap and pixel data.

The conversion (hereinafter referred to as CLUT conversion) processing is roughly divided into a histogram calculation of color information, a color map creation by selecting a representative color of 256 colors based on the histogram, and a color map allocation to each pixel. There are three processes.

A flowchart of FIG. 6 shows the processing of the server 1 and the CLUT client 5 when the conversion processing is collectively performed without first performing the pipeline processing. Hereinafter, the operations of the server 1 and the CLUT client 5 will be described with reference to FIG.

Processing of Server (Step 600) The image transfer request from the CLUT client 5 is received.

(Step 601) From the storage device 2, 1280
Reads a 960x960 JPEG image.

(Step 602) The read JPEG image is developed into full color data.

(Step 603) A histogram of color information used in a full-color image is calculated.

(Step 604) 256 representative colors are selected from the histogram obtained in step 603.

(Step 605) The representative color selected in step 604 is assigned to each pixel data as a color map.

(Step 606) The color map is transferred to the CLUT client 5.

(Step 607) The pixel data for one screen (1280 × 960 dots) is transferred to the CLUT client 5.

(Step 608) The processing of the server 1 is ended.

Processing by Client (Step 610) An image transfer request is sent to the server 1.

(Step 611) The color map transferred by the server 1 and the pixel data for one screen are transferred to the display circuit to display an image.

(Step 612) The display is terminated.

FIG. 7 shows the processing of the server 1 and the CLUT client 3 on the same time axis. The color map creation process in FIG. 7 is a series of processes from steps 601 to 604 of the flowchart in FIG. 6, and the process performed by the display format conversion unit 15 in FIG. 1 corresponds to this. The process of assigning color maps to pixel data in FIG. 7 is a series of processes in steps 605 to 607 of the flowchart in FIG. From the point in time when these two processes are completed, the CLUT client 5 can perform the display process, which is the time t1 in the time chart of FIG. Then, the display processing for one screen ends at time t2 in FIG.

The amount of data in the case of CLUT conversion is only about 1/3 of the original full-color data, and the transfer time by communication is long, while the processing of the client is only display, so the processing of the server 1 is generally the client. It takes more time than processing. Therefore, if the conversion processes are collectively performed, the display start time is delayed.

Next, the processing of the server 1 and the CLUT client 5 when the data conversion to the CLUT client 3 is divided is shown in the flowchart of FIG.

Since it is necessary to create a histogram from all full-color data in order to generate a color map, a series of processes of JPEG data expansion, histogram calculation, and representative color selection cannot be performed separately. Therefore, in this embodiment, the process of assigning the color map to each pixel is divided.

The following is a description with reference to the flowchart of FIG.

Processing of Server (Step 800) The image transfer request from the CLUT client 3 is received.

(Step 801) From the storage device 2, 1280
Reads a 960x960 JPEG image.

(Step 802) The read JPEG image is developed into full color data.

(Step 803) A histogram of color information used in a full-color image is calculated.

(Step 804) 256 representative colors are selected from the histogram obtained in step 803.

(Step 805) The representative color selected in step 804 is transferred to the CLUT client 5 as a color map.

(Step 806) The representative color selected in step 804 is assigned as a color map to one block of pixel data.

(Step 807) The pixel data for one block for which the color map has been assigned is transferred to the CLUT client 5.

(Step 808) It is checked whether the color map has been assigned to all pixel data. If all the processing is completed, the process proceeds to step 809. If not completed, the process returns to step 806 to process the next block.

(Step 809) The processing of the server 1 is completed.

Processing by Client (Step 810) An image transfer request is issued to the server 1.

(Step 811) Server 1 makes Step 8
Receive the color map transferred in 05.

(Step 812) The color map and one block of pixel data transferred by the server 1 are transferred to the display circuit to display an image.

(Step 813) Check if display of all data is completed. If it is finished, the process proceeds to step 814. If it has not been completed, the process returns to step 812 to display the next block.

(Step 814) The display is ended.

The number of blocks of data in the division processing in this embodiment is not limited as in the case of JPEG data. The smaller the block size, the faster the display start time,
If it is too small, the number of times of the series of processing from step 806 to step 807 increases and the processing end time becomes late.
Generally, it is considered effective to use one block every several lines.

FIG. 9 shows the processing of the server 1 and the CLUT client 5 on the same time axis. The color map creation process is performed in steps 801 to 8 of the flowchart of FIG.
This is a series of processing of No. 05 and is the same as the case of batch processing. After that, the color map is assigned to the data of the first block and the data is transferred to the CLUT client 5, and the display is started at time t1 ′ in FIG. Then, the display is ended at the time t2 ′ when the display of the last block is ended.

As can be seen from FIG. 9, the processing of the server 1 and the CLUT client 5 for each block is processed in parallel, so the display end time t2 'is shorter than the display end time t2 in the case of batch conversion.

As described above, according to the second embodiment of the present invention, when the shared data is displayed by the CLUT client 5 which displays the color map and the pixel data, the divided data is processed. Since the display start time and the display end time can be shortened, the waiting time for the user is reduced and the usability is improved.

Next, a third embodiment of the present invention will be described. The third embodiment of the present invention is data conversion processing in a server using pipeline processing when conversion requests from a plurality of clients occur.

A process for collectively performing data conversion when data conversion requests are simultaneously issued from a plurality of clients will be described.

In the third embodiment of the present invention, as an example, 6
Full color client 4 and 320 with 40x480 resolution
A case will be described in which data conversion requests are issued from two clients having different resolutions of the full-color client 6 having a resolution of × 240 at almost the same time.

First, FIG. 10 shows a processing flowchart in the case where the data conversion processing is collectively performed by the server without performing the pipeline processing first.

The operation will be described below with reference to the flowchart of FIG.

Process of server 1 (step 1000) Start of process. Image transfer requests from the full color client 4 and the full color client 6 are received.

(Step 1001) One screen of JPEG image (1280 × 960) is read from the storage device 2 of the server 1.

(Step 1002) The read JPEG image is developed into full color data.

(Step 1003) 1280 × 960 full color data is scaled to 640 × 480 full color data.

(Step 1004) 640 × 480 full color data is JPEG compressed.

(Step 1005) The JPEG data created in Step 1004 is transferred to the full color client 4 through the communication line 7.

(Step 1006) One screen of JPEG image (1280 × 960) is read from the storage device 2 of the server 1.

(Step 1007) The read JPEG image is developed into full color data.

(Step 1008) The 1280 × 960 full color data is scaled to 320 × 240 full color data.

(Step 1009) 320 × 240 full color data is JPEG compressed.

(Step 1010) The JPEG data created in Step 1009 is transferred to the full color client 6 through the communication line 7.

(Step 1011) The processing of the server 1 is completed.

Processing of Client 4 (Step 1020) An image transfer request is issued to the server 1.

(Step 1021) The server 1 receives the 640 × 480 one-screen JPEG data transferred in Step 1005 and decompresses it.

(Step 1022) The decompressed data is transferred to the display circuit and an image for one screen is displayed.

(Step 1023) Display End Processing of Client 6 (Step 1030) An image transfer request is issued to the server 1.

(Step 1031) The server 1 receives the JPEG data of 320 × 240 for one screen transferred in step 1010 and decompresses it.

(Step 1032) The decompressed data is transferred to the display circuit and an image for one screen is displayed.

(Step 1033) Display End FIG. 11 shows the above processing on the same time axis. Figure 11
As shown in FIG. 11, the processing of the full-color client 4 starts after the conversion of the server 1 is completed, that is, from t1 in FIG. The data conversion requested by the full-color client 6 starts at time t1 in FIG. Therefore, the processing of the full-color client 6 is started at time t2 in FIG. 11, that is, when the data conversion for two screens is completed. In this case, the user of the full-color client 6 makes a request at the same time as the user of the full-color client 4, but the time until it can be actually displayed is twice as long as that of the full-color client 4, and the usability is improved. It gets very bad.

Next, the processing according to the third embodiment of the present invention will be described. The third embodiment of the present invention aims to reduce the waiting time of a user who has made a data conversion request by dividing the data requested by each client into a data conversion request from a plurality of clients and performing pipeline processing. And When the server divides the data and performs pipeline processing, the server converts one block and transfers it, and then the client performs the data conversion of the next block during the display processing of the data, but the server is fast enough In this case, the converted data cannot be transferred because the processing on the client side is not completed even after the data conversion in the server is completed. Therefore, after the data conversion is completed, the server waits until the block data display process of the client is completed. By using this wait time to perform data conversion processing for data conversion requests from other clients, even when data conversion requests from multiple clients occur, the waiting time of each client is shortened and the display start time is shortened. You can do it. Hereinafter, a specific example will be described. In the third embodiment of the present invention, as an example, the division processing is performed by dividing it into 60 blocks every 16 lines.

FIG. 12 shows a flowchart of processing in the case where shared JPEG data is divided and displayed by the full color client 4 and the full color client 6 in the third embodiment.

The third embodiment of the present invention will be described below with reference to FIG.

Server Process (Step 1200) Start of process. Image transfer requests from the full color client 4 and the full color client 6 are received.

(Step 1201) The Huffman table and quantization table of the JPEG data to be transferred are read out and transferred to the full color client 4 and the full color client 6.

(Step 1202) The 16-line JPEG image (1280 × 16) is read from the storage device 2 of the server 1.

(Step 1203) The read JPEG image is developed into full-color data.

(Step 1204) 1280 × 16 full color data is scaled to 640 × 8 full color data.

(Step 1205) 640 × 8 full color data is JPEG compressed.

(Step 1206) The JPEG data created in Step 1205 is transferred to the full color client 4 through the communication line.

(Step 1207) The JPEG image (1280 × 16) for 16 lines is read from the storage device 2 of the server 1.

(Step 1208) The read JPEG image is expanded into full color data.

(Step 1209) 1280 × 16 full color data is scaled to 320 × 4 full color data.

(Step 1210) 320 × 4 full color data is JPEG compressed.

(Step 1211) The JPEG data created in Step 1210 is transferred to the full color client 6 through the communication line.

(Step 1212) It is checked whether all conversion processing is completed. Upon completion, the process proceeds to step 1213. If not completed, the process returns to step 1202 to repeat the processing of the next block.

(Step 1213) The processing of the server 1 is completed.

Processing of Client 4 (Step 1220) An image transfer request is issued to the server 1.

(Step 1221) The server 1 receives the Huffman table and the quantization table transferred in step 1201.

(Step 1222) The server 1 receives the 640 × 8 JPEG data transferred in step 1206 and decompresses it.

(Step 1223) The decompressed data is transferred to the display circuit and the image of 8 lines is displayed.

(Step 1224) It is checked whether the display processing of the 60th block is completed. Upon completion, proceed to step 1225. If not, step 1
Returning to 222, expansion and display processing of the next block is continued.

(Step 1225) The display is ended.

Processing of Client 6 (Step 1230) An image transfer request is issued to the server 1.

(Step 1231) The server 1 receives the Huffman table and the quantization table transferred in step 1201.

(Step 1232) The server 1 receives the 640 × 4 JPEG data transferred in step 1211 and decompresses it.

(Step 1233) The decompressed data is transferred to the display circuit and the image of four lines is displayed.

(Step 1234) It is checked whether the display processing of the 60th block is completed. Upon completion, proceed to step 1235. If not, step 1
Returning to step 232, expansion and display processing of the next block is continued.

(Step 1235) The display is ended.

The figure showing the above processing on the same time axis is shown in FIG.
It is 13. As shown in FIG. 13, after the server 1 transfers the Huffman table and the quantization table, the data for one block of the full color client 4 is converted and transferred t
The display process of the full-color client 4 starts from 1 '. Further, the display processing of the full-color client 6 can be started from time t2 ′ obtained by adding the time required for the server 1 to convert the data for one block of the full-color client 6 to t1 ′.
Therefore, in this embodiment, the full color client 4
Since the display start time of is the table data transfer time + 1 block data conversion time, it is about 1/60 of the batch processing time. Also a full color client
In the case of 6, the display start time is the table data transfer time + 2
Since the data conversion time is for a block, it is about 1/60 of that of the batch processing.

In the present embodiment, the case where the data conversion process of the client 6 can be performed by the server 1 before the display process of the client 4 is finished has been described. If it is long enough, it is also possible to perform data conversion processing of two or more clients in the server while waiting for the display processing of the first client.

As described above, the pipeline processing is performed by dividing into blocks, so that even when data conversion requests are issued from a plurality of clients, the waiting time until the display start of each client is shortened. . Further, the time required to finish displaying all the blocks of the image requested by each client is shortened.

In the first embodiment and the second and third embodiments, the case where the shared data is JPEG data has been described. However, other types of compressed / non-compressed shared data can be used by various clients. The present invention is effective when data conversion is required for display.

The image data conversion for each block is
The effect can be obtained by both software and hardware. Furthermore, the present invention is not limited to the case of a still image but has moving image data as shared data, and the same effect can be obtained even when used by clients having different specifications.

[0162]

As described above, according to the present invention, the conversion processing of the shared data is divided in the server so that the time for the client to receive the data is shortened and the display start time can be shortened. Also, while the client is performing the display process, the server can perform the next block image data conversion process,
The time until the image data of all blocks is displayed is shortened. Therefore, the waiting time after the user requests the image data is shortened and usability is improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of the present invention.

FIG. 2 is a server batch data conversion processing flowchart for a full-color client.

FIG. 3 is a server batch data conversion processing time chart for a full color client.

FIG. 4 is a processing flowchart in the first embodiment of the present invention.

FIG. 5 is a processing time chart in the first embodiment of the present invention.

FIG. 6 is a flowchart of a server batch data conversion process compatible with a CLUT client.

FIG. 7 is a server batch data conversion processing time chart for a CLUT client.

FIG. 8 is a processing flowchart in the second embodiment of the present invention.

FIG. 9 is a processing time chart in the second embodiment of the present invention.

FIG. 10 is a server batch data conversion processing flowchart for a plurality of clients.

FIG. 11 is a server batch data conversion processing time chart for a plurality of clients.

FIG. 12 is a processing flowchart in the third embodiment of the present invention.

FIG. 13 is a processing time chart in the third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Server, 2 ... Storage device, 3 ... Full color client, 4 ... Full color client, 5 ... CLUT client, 6 ... Full color client, 7 ... Communication line, 11 ... Image expansion part, 12 ... Two-dimensional filter, 13 ... Image compression Section, 14 ... Display format conversion section, 15 ... Division processing control section.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical location H04N 7/14 (72) Inventor Takehiro Yamada 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. System Development Laboratory (72) Inventor Tetsuya Kawahara 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi Systems Development Laboratory (72) Inventor Taminori Tomita 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Hitachi, Ltd. In-house System Development Laboratory (72) Inventor Takero Tomokane In-house Hitachi Systems Development Laboratory, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa

Claims (8)

[Claims] 1. A plurality of clients having different specifications including an input device and an output device, a server having means for converting the specifications of image data, and a storage device storing commonly used compressed image data. In a client-server system connected by a communication line, the server divides the image data in the storage device into a plurality of blocks, and transfers the image data of arbitrary blocks converted in block units,
An image data conversion system, wherein the server converts the image data of the next block while the client is displaying the image data of the arbitrary block after the conversion. 2. The image data conversion system according to claim 1, wherein the server has means for dividing the data in the storage device into a plurality of blocks. 3. The image data conversion system according to claim 1, wherein the server has means for expanding the common compressed data divided into the block units. 4. The server has means for converting specifications such as the number of pixels of the image data expanded in the block unit in block units.
The described image data conversion system. 5. The server has means for compressing, in block units, the converted data obtained by converting the specifications in block units in block units.
The image data conversion system according to 2, 3, or 4. 6. The image data conversion system according to claim 1, wherein the server has means for transferring the image data compressed in the block unit in block units. 7. The image data conversion system according to claim 1, wherein the client has means for displaying the block data divided and converted by the server. . 8. The server comprises means for controlling each processing in the block unit.
The image data conversion system according to 2, 3, 4, 5, 6 or 7.