JP2780664B2 - Image data transfer method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data transfer system in which a host computer transfers image data requested to be transferred to a terminal device in response to a transfer request from a terminal device connected via a communication line. .

[0002]

2. Description of the Related Art Image data is stored in a host computer, and the host computer transfers the requested image data to the terminal device in response to a transfer request from a terminal device connected via a communication line. This has been done in the past.

FIG. 10 is a block diagram for explaining a conventional technique of this type, and is composed of a host computer 50, a terminal device 70, and a communication line 60 connecting them.

[0004] The host computer 50 comprises a compression means 52 for compressing and encoding the original image data 51 as it is, and a compression means 52.
Storage means 5 for storing compressed data compressed and encoded by
3, reading means 54 for reading the compressed data stored in the storage means 53, and transmitting the compressed data read by the reading means 54 to the terminal device 70,
And a transmission / reception unit 55 for receiving a transfer request from the transmission unit 0.

[0005] The terminal device 70 includes a transmitting / receiving unit 71 for transmitting a transfer request to the host computer 50 and receiving compressed data from the host computer 50, an expanding unit 72 for expanding the compressed data received by the transmitting / receiving unit 71, An image memory 73 in which the image data expanded by the expansion means 72 is stored, and image data stored in the image memory 73 are input, and editing processing is performed on the input image data in accordance with the operation of the keyboard 76. Image data editing means 78, display control means 74 for displaying image data stored in the image memory 73 or image data being edited by the image data editing means 78 on the CRT 75, and transmitting and receiving a transfer request using the transmission / reception unit 71. Transfer request sending means 77 to send to host computer 50
And

When a user of the terminal device 70 requests the host computer 50 to transfer image data or the like to be edited, the user inputs information indicating image data to be transferred from the keyboard 76.

[0007] When the above information is input from the keyboard 76, the transfer request sending means 77 sends a transfer request including the information to the host computer 50 using the transmission / reception unit 71.

The transfer request is received by the transmission / reception unit 55 in the host computer 50. When the transmission / reception unit 55 receives the transfer request, it passes information indicating the image data included in the transfer request to the reading unit 54.

The reading means 54 stores compressed data obtained by compressing the image data indicated by the information.
And transmits the read compressed data to the terminal device 70 using the transmission / reception unit 55.

[0010] The transmission / reception unit 71 in the terminal device 70 receives the compressed data. When the transmission / reception unit 71 receives the compressed data, it passes it to the decompression means 72.

The expansion means 72 expands the compressed data passed from the transmission / reception unit 71 and stores the expanded image data in the image memory 73.

The image data stored in the image memory 73 is displayed on the CRT 75 by the display control means 74.

The user looks at the image displayed on the CRT 75 and, if it is the desired image, performs image data editing processing using the image data editing means 78. If the image is not the desired image, the user requests the host computer 50 to transfer the image data again. The user repeatedly performs such an operation until a desired image is obtained.

[0014]

By the way, when editing image data or the like, it is possible to confirm whether or not the image data transferred from the host computer is the desired one by understanding the general feeling of the image. In most cases. . However, conventionally, only compressed data obtained by directly compressing and encoding the original image data is stored in the host computer.
Even if you only need to know the general feeling of the image,
Since the compressed data obtained by directly compressing and encoding the original image data is transferred to the terminal device, there is a problem that the amount of transferred data increases, and there is a problem that the decompression process takes time.

An object of the present invention is to provide a method for transmitting compressed data corresponding to reduced image data obtained by reducing original image data when it is sufficient to understand the general feeling of the image. It is an object of the present invention to provide an image data transfer method capable of reducing the amount and shortening the time required for decompression processing.

[0016] As a related technique, "Point Illustrative Formula Latest MPEG Textbook, October 11, 1994, No. 1
The second edition, Ascii Co., Ltd., ASCII P103, discloses a technique of storing data encoded by a video encoder in a storage medium and decoding the data stored in the storage medium by a video decoder. However, there is no mention of using reduced image data obtained by reducing original image data.

[0017]

According to the present invention, in order to achieve the above object, a host computer responds to a transfer request from a terminal device connected via a communication line to the terminal device by the transfer request. In the image data transfer method for transferring the compressed image data, the host computer stores compressed data obtained by compressing and encoding reduced image data formed by thinning out some pixels from the original image data. Storage means; image quality holding data storage means for storing compressed image quality holding data obtained by compressing and encoding image quality holding data for restoring a portion of the original image data which has been subjected to thinning; If the transfer request from the device only requests the transfer of compressed data,
In the case where the transfer request compressed data stored in the compressed data storage means is transferred to the terminal device, and the transfer request from the terminal device requests the transfer of the compressed data and the compressed image quality holding data. Control means for transferring requested compressed data and compressed image quality holding data stored in the compressed data storage means and the image quality holding data storage means to the terminal device via the communication line, A terminal device, a transfer request sending unit for sending a transfer request for transferring only the compressed data or a transfer of the compressed data and the compressed image quality holding data to the host computer via the communication line; and First decompression means for decompressing the compressed data transmitted via the communication line, and a first decompression means transmitted from the host computer via the communication line And a second decompression means for decompressing the compressed image quality holding data, when the compressed data and compressed image quality holding data from said host computer is sent, the first
Integrating means for integrating the reduced image data expanded by the expansion means and the image quality holding data expanded by the second expansion means to generate image data having the same size as the original image data It is.

[0018]

When it is sufficient to understand the general feeling of the image, the user of the terminal device sends a transfer request for requesting transfer of only the compressed data to the host computer by using the transfer request sending means.

When the transfer request is sent from the terminal device, the control means in the host computer transfers the requested compressed data stored in the compressed data storage means to the terminal device.

In the terminal device, the reduced image data is restored by expanding the compressed data using the first expanding means.

When image data having the same size as the original image data is required, the user of the terminal device transmits the compressed data and the compressed image quality holding data using the transfer request transmitting means. The requested transfer request is sent to the host computer.

When the transfer request is sent from the terminal device, the control means in the host computer transmits the requested compressed data stored in the compressed data storage means and the compressed data stored in the image quality holding data storage means. The requested transfer data for compressed image quality is transferred to the terminal device.

The compressed data and the compressed image quality holding data are respectively decompressed by the first and second decompression means in the terminal device, and the data decompressed by the first and second decompression means are integrated by the integration means. , Image data having the same size as the original image data is restored.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, which comprises a host computer 1 and a terminal device 3 connected to the host computer 1 via a communication line 2.

The host computer 1 includes a reduced image data generating means 12, a first compressing means 13, a compressed data storing means 14, a reading means 15, a second compressing means 16,
Image quality holding data storage means 17 and reading means 18
And a control unit 19 and a transmission / reception unit 20.

The terminal device 3 includes a transmitting / receiving unit 31, a control unit 32, first and second decompression units 33 and 34, an integration unit 35, an image memory 36, and a display control unit 37.
, A CRT 38, a keyboard 39, an image data editing unit 40, and a transfer request sending unit 41.

The reduced image data generating means 12 in the host computer 1 has a function of generating reduced image data obtained by reducing the original image data 11. In this embodiment, as shown in FIG. 2A, the reduced image data generation means 12 converts the original image data 11 into 2 × 2 pixel blocks B11, B12,
, And thinning out the pixels other than the upper left pixel in each block B11, B12,.
It is assumed that reduced image data shown in FIG.

The first compression means 13 has a function of generating compressed data obtained by compression-encoding the reduced image data generated by the reduced image data generation means 12. In this embodiment, as shown in FIG. 3, the compression means 13 includes a DCT means 131 for performing discrete cosine transform, a quantization means 132 for quantizing the result of the DCT means 131, and a quantization means 1
And a coding unit 133 for generating compressed data by coding the 32 quantization results with a Huffman code or the like, and storing the compressed data in a compressed data storage unit 14. The reduced image data is compressed by a lossless encoding method.

The second compression means 16 stores the original image data 11
It has a function of generating compressed image quality holding data obtained by compression-encoding image quality holding data for restoring a portion that has been subjected to thinning when generating reduced image data. In this embodiment, as shown in FIG. 4, the compression unit 16 includes a difference calculation unit 161 and an encoding unit 162.
It is assumed that the image quality holding data is compressed by a reversible encoding method. FIG. 5 is a diagram for explaining the operation of the compression unit 16. The difference calculation unit 161 performs, in a predetermined order, each of the blocks in the original image data 11.
As shown in FIG. 5A, the pixels G1-G2 in the block
, G2-G3, and G3-G4 are calculated, and the calculated difference values A, B, and C are arranged as shown in FIG. The encoding unit 162 encodes the difference value passed from the difference calculation unit 161 with a Huffman code or the like.
The compressed image quality holding data is generated, and the compressed image quality holding data is stored in the image quality holding data storage unit 17.

The control means 19 comprises reading means 15 and 18
The compressed data and the compressed image quality holding data are read from the compressed data storing means 14 and the image quality holding data storing means 17 using the And the like.

The control means 32 of the terminal device 3 has a function of passing the compressed data and the compressed image quality holding data transferred from the host computer 1 to the first and second decompression means 33 and 34, respectively.

The first decompression means 33 has a function of decompressing the compressed data passed from the control means 32 and restoring the reduced image data. In this embodiment, the extension means 33 is
As shown in FIG. 6, a decoding unit 331 for decoding compressed data, an inverse quantization unit 332 for inversely quantizing the decoding result of the decoding unit 331, and an inverse quantization result of the inverse quantization unit 332 are inversed. IDCT means 333 for performing discrete cosine transform.

The second decompression means 34 has a function of decompressing the compressed image quality holding data passed from the control means 32.

When the transfer request sent to the host computer 1 requests only the transfer of the compressed data, the integration means 35 stores the reduced image data expanded by the expansion means 33 in the image memory 36, When the transfer of the compressed data and the compressed image quality holding data is requested, the original image is obtained by integrating the reduced image data expanded by the expansion unit 33 and the image quality storage data expanded by the expansion unit 34. It has a function of restoring image data of the same size as the data 11 and storing the image data in the image memory 36.

The display control means 37 converts the reduced image data stored in the image memory 36, the integrated image data or the image data being edited by the image data editing means 40 into a CR.
It has the function of displaying on T38.

The transfer request sending means 41 includes a keyboard 39
Has a function of transmitting a transfer request requesting the transfer of only the compressed data or a transfer request requesting the transfer of the compressed data and the data for maintaining the compressed image quality to the host computer 1 using the transmission / reception unit 31 in accordance with the operation of .

FIG. 7 is a flowchart showing a processing example of the control means 19, and FIG. 8 is a flowchart showing a processing example of the integration means 35.
Hereinafter, the operation of this embodiment will be described with reference to the drawings.

When the user of the terminal device 3 requests the host computer 1 to transfer image data, if it is sufficient to understand the general feeling of the image, the user of the terminal device 3 sends a request to transfer only compressed data to the host computer 1. For example, an operation for transmitting the compressed data and the transmission request for the compressed image quality holding data is performed on the keyboard 39 when complete image data is required. Do with. At this time, the user also inputs from the keyboard 39 information indicating the compressed data requested to be transferred and the compressed image quality holding data.

When an operation for sending a transfer request for only compressed data to the host computer 1 is performed, the transfer request sending means 41 outputs information indicating that the transfer request is for compressed data only, Is transmitted to the host computer 1 using the transmission / reception unit 31. When an operation for transmitting a transfer request of the compressed data and the compressed image quality holding data to the host computer 1 is performed, the transfer request sending unit 41 is a transfer request of the compressed data and the compressed image quality holding data. Information indicating that
The transmission request including the compressed data and the information indicating the compressed image quality holding data is transmitted to the host computer 1 using the transmission / reception unit 31.
To send to.

The transfer request from the terminal device 3 is transmitted to the communication line 2
Is sent to the host computer 1 via the host computer 1 and received by the transmission / reception unit 20 in the host computer 1.

When the transmission / reception unit 20 receives the transfer request from the terminal device 3, the control unit 19 requests the transfer of only the compressed data or the transfer of the compressed data and the compressed image quality holding data. (Step S1 in FIG. 7).

If it is determined that the request is a transfer request for transferring only the compressed data, the control means 19 uses the reading means 15 to request the transfer from the compressed data storage means 14 by the transfer request. The read compressed data is read, and the read compressed data is transferred to the terminal device 3 using the transmission / reception unit 20 (step S2).
S3).

If it is determined that the transfer request is to request the transfer of the compressed data and the data for holding the compressed image quality,
The control unit 19 first reads the compressed data requested to be transferred by the transfer request from the compressed data storage unit 14 using the reading unit 15 and transfers the read compressed data to the terminal device 3 (step S1). S
4, S5). Thereafter, the control unit 19 reads the reading unit 1
8 is read from the image quality holding data storage means 17 by using the transfer request, and the read compressed image quality holding data is transmitted to the terminal device by using the transmission / reception unit 20. 3 (steps S6, S7).

When the transmission / reception unit 31 receives the compressed data transferred from the host computer 1, the control unit 32 in the terminal device 3 passes it to the decompression unit 33 and receives the compressed image quality holding data. Hands it over to the expansion means 34.

The extension means 33 having the structure shown in FIG.
When the compressed data is passed from the control means 32, the compressed data is decoded by the decoding means 331, and then dequantized by the dequantizing means 332.
33, the reduced image data is restored by performing the inverse discrete cosine transform, and the restored reduced image data is passed to the integrating means 35.

When the data for holding compressed image quality is passed from the control means 32, the decompressing means 34 decodes the compressed and encoded difference value into data for holding image quality, and passes it to the integrating means 35.

When the transfer request sending means 41 sends a transfer request, the integrating means 35 determines whether the request is a transfer request of compressed data only or a transfer request of compressed data and compressed image quality holding data. (FIG. 8, step S11).

If it is determined that the request is a transfer request for compressed data only, when the reduced image data is passed from the decompression means 33, it is stored in the image memory 36 (step S12). If it is determined that the request is a transfer request of the compressed data and the compressed image quality holding data, when the reduced image data is passed from the decompression means 33, it is stored therein (step S13). When the decoded image quality holding data is passed from 34, the held reduced image data and the image quality holding data are integrated to generate image data having the same size as the original image data 11 (step S14). The generated image data is stored in the image memory 36.
(Step S15).

Here, the processing in steps S13 and S14 will be described in detail as follows.

The reduced image data held by the integrating means 35 in step S13 is the original image data shown in FIG.
Are generated by dividing the image into blocks of B2,... Of 2 × 2 pixels, and thinning out the pixels other than the upper left pixel in each of the blocks B11, B12,... And having the configuration shown in FIG. . The image quality holding data is shown in FIG.
As shown in (C), difference values A, B, C between adjacent pixels in each block B11, B12,... Are arranged in a predetermined order. In block B11, the difference value A,
B and C are respectively (G11-G12), (G12-G2
2), (G22-G21), and in the block B12, the difference values A, B, C are (G13-G1), respectively.
4), (G14-G24) and (G24-G23).

Using the reduced image data and the image quality holding data having such a relationship, the integrating means 35 generates image data having the same size as the original image data 11 as follows.

First, the upper left pixel G1 in the reduced image data
Select 1. Next, the pixel value of the selected pixel G11,
The pixel value of the pixel G12 in the block B11 is obtained by adding the difference value A for the block B11. Thereafter, by adding the pixel value of the pixel G12 and the difference value B of the block B11, the block B1 is added.
The pixel value of the pixel G22 in 1 is obtained. Further, the pixel G22
Is added to the difference value C of the block B11 to obtain the pixel value of the pixel G21. By the above processing, all pixels G11, G in the block B11
The pixel values of 12, G22, and G21 are restored. By performing the above processing for all the pixels in the reduced image data, image data having the same size as the original image data 11 can be restored.

The image data having the same size as the reduced image data or the original image data 11 stored in the image memory 36 as described above is displayed on the CRT 38 by the display control means 37.

As described above, in the present embodiment, when it is sufficient to understand the general feeling of the image, only the compressed data corresponding to the reduced image data is transferred to the terminal device 3 and the same size as the original image data 11 is transferred. When the image data is required, the amount of data to be transferred can be changed according to the request of the user of the terminal device 3 such that the compressed data and the compressed image quality holding data are transferred to the terminal device 3. For example, when the user of the terminal device 3 edits the image data, first, only the transfer of the compressed data is requested to obtain the general feeling of the image, and if the image is not the desired one, It is possible to request only the transfer of the compressed data again, and if it is desired, to request the transfer of the compressed data and the data for holding the compressed image quality. It is possible to reduce the amount of data to be transferred to 3.

[0056]

As described above, according to the present invention, when it is sufficient to understand the general feeling of an image, only compressed data corresponding to reduced image data obtained by reducing the original image data is transferred to the terminal device. When accurate image data of the same size as the original image data is required, the compressed data and the compressed image quality holding data are transferred to the terminal device. Since the amount of data can be changed, the amount of data transferred from the host computer to the terminal device can be reduced as compared with the conventional example in which the original image data and the corresponding compressed data are always transferred. The time required for the expansion process can be shortened.

Also, the present invention provides a reduced image data generating means for storing compressed data in a compressed data storage means of a host computer, a first compression means, and a compressed image quality holding data stored in an image quality holding data storage means. Since the apparatus has the second compression means for storing, it is possible to easily add compressed data corresponding to new image data and compressed image quality holding data.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram for explaining a processing example of a reduced image data generation unit 12.

FIG. 3 is a block diagram illustrating a configuration example of a compression unit 13;

FIG. 4 is a block diagram illustrating a configuration example of a compression unit 16;

FIG. 5 is a diagram for explaining an operation example of a compression unit 16;

FIG. 6 is a block diagram showing a configuration example of a decompression means 33.

FIG. 7 is a flowchart showing a processing example of a control unit 19;

FIG. 8 is a flowchart showing a processing example of the integration means 35;

FIG. 9 is a diagram for explaining a processing example of the integration unit 35;

FIG. 10 is a block diagram for explaining a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Host computer 11 ... Original image data 12 ... Reduced image data generation means 13 ... Compression means 14 ... Compressed data storage means 15 ... Reading means 16 ... Compression means 17 ... Data storage means for image quality holding 18 ... Reading means 19 ... Control means DESCRIPTION OF SYMBOLS 20 ... Transmission / reception part 2 ... Communication line 3 ... Terminal device 31 ... Transmission / reception part 32 ... Control means 33, 34 ... Decompression means 35 ... Integration means 36 ... Image memory 37 ... Display control means 38 ... CRT 39 ... Keyboard 40 ... Image data editing Means 41 ... Transfer request sending means

Claims (3)

(57) [Claims] An image data transfer system in which a host computer transfers image data requested by the transfer request to the terminal device in response to a transfer request from a terminal device connected via a communication line. The host computer includes: compressed data storage means for storing compressed data obtained by compressing and encoding reduced image data formed by thinning out some pixels from the original image data; and a thinning target in the original image data. Image quality holding data storage means for storing compressed image quality holding data obtained by compression-encoding image quality holding data for restoring a lost portion; and a transfer request from the terminal device requests only transfer of compressed data. If the compressed data is transmitted, the compressed data stored in the compressed data storage unit is transferred to the terminal device, and the transfer data from the terminal device is transferred. Is a request for transfer of compressed data and compressed image quality holding data, the transfer-requested compressed data and compressed image quality holding data stored in the compressed data storage means and the image quality holding data storage means are Control means for transferring to the terminal device via the communication line, wherein the terminal device transfers only the compressed data or the transfer of the compressed data and the compressed image quality holding data to the host computer via the communication line. Transfer request sending means for sending a transfer request for requesting, first expanding means for expanding compressed data sent from the host computer via the communication line, and transfer request sending means for sending compressed request sent from the host computer via the communication line. A second decompression means for decompressing the transmitted compressed image quality holding data, wherein the compressed data and the compressed image quality holding data are sent from the host computer. In this case, the reduced image data expanded by the first expansion unit and the image quality holding data expanded by the second expansion unit are integrated to generate image data having the same size as the original image data. An image data transfer system, comprising: an integrating unit that performs 2. Reduced image data generating means for generating reduced image data obtained by reducing the original image data by thinning out some pixels from the original image data; and generating reduced image data generated by the reduced image data generating means. First compression means for storing the compression-encoded compressed data in the compressed data storage means; and compression compression-encoding the image quality holding data for restoring the thinned target portion in the original image data. A second compression unit for storing the image quality holding data in the image quality holding data storage unit.
The described image data transfer method. 3. The image data transfer method according to claim 2, wherein said second compression means losslessly encodes a difference value between pixel values of adjacent pixels.