JPH0654290A - Data compressing and filing system - Google Patents

Abstract

PURPOSE:To record data in a prescribed file area as much as possible at the time of compressing data to record it in a recording medium. CONSTITUTION:A compression restoring program is preliminarily stored in a microcomputer, and a recognition code is imparted to the compression restoring program, and a file 10 which is provided with a recognition code recording part 13, a version number recording part 15, a compression mode code recording part 17, and a header end code recording part 19 of this program in a header part 11 and consists of the recognition code, the version number, the compression mode code, and compressed picture data is prepared and is recorded in the recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording image data handled by a computer on a recording medium such as a flexible disk or a memory card.

[0002]

2. Description of the Related Art Today, in a small computer such as a microcomputer or a personal computer, a flexible disk is often used for moving data between computers, and a recording medium such as a memory card is also used. Came. When recording data on a recording medium such as a flexible disk or a memory card, operation software often used in small computers includes a header portion 11 in a file 10 as shown in FIG. Some store compressed data in the back area.

That is, by compressing the data, as much data as possible is recorded in a predetermined memory area and transferred to another microcomputer, and the compressed data is decompressed by a decompression program corresponding to the compression program to restore the decompressed data. Utilization on other computers is widespread today. In the compression and decompression of these data, in the compression and decompression of the image data, for example, the compression is performed using a specific sequence coding table, a Huffman coding table, etc. Also record the data related to the image data in a file,
The data related to the compression method is recorded in the header part, the compressed image data is recorded after the header part to create a file that also records various conversion tables together with the image data, and the information recorded in this header part when decompressing. Data is decompressed by restoring the image data based on.

[0004]

When compressing and decompressing data, it is necessary to restore the original data from the compressed data based on the algorithm, compression mode and various encoding tables used at the time of compression. As described above, various tables and data relating to the compression program are recorded in the header part, and when the data amount of the header part becomes large, even if the image data is compressed and recorded, the image data which can be recorded in one medium such as a flexible disk is stored. In some cases, the amount cannot be increased.

That is, even if the data is compressed to record a large amount of data in a certain area, the area for recording the image data is reduced because the data related to the compression method is also recorded in the file. There is a drawback that the amount of possible image data does not increase so much.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a recognition code is added to a compression program, a mode code for identifying a stage if the compression mode has a stage is defined, and the recognition code, the compression mode code, and the compression program The version number is stored in the header part of the file, and the compression program and the decompression program are separately loaded in the computer beforehand.

[0007]

[Operation] Since the present invention records the identification code, version number, and mode code in the header part, the header part can contain about 10 bytes (hexadecimal number) including the end code. A wide recording area for image data can be obtained.

[0008]

EXAMPLES Examples of the filing method according to the present invention are as follows:
As shown in FIG. 2, a book type having a plurality of operation switches 23 around a liquid crystal display plate 21 of about 5 inches is provided, and the field of view of a CCD camera provided on the side or the back is displayed on the liquid crystal display plate 21 on the 16th floor. The image is displayed as a monotone image of tones, and this image is stopped by operating the operation switch 23,
Also, it is used in a microcomputer mainly handling image processing in which it is stored in a random access memory such as an IC card to be inserted into the IC card insertion slot 25, and further, image data can be sent to another microcomputer or printer by serial transmission. This is a method of recording the image data.

In this recording method, the compression processing program for compressing and decompressing image data and the image data are stored in different files, and the image data and the compression processing program for compressing and decompressing the image data and the data necessary for the processing are specified. The code data is recorded as one file on a recording medium such as a flexible disk via a random access memory or another interface.

As an example of a processing program for processing this image data, in the present embodiment, a fixed 16-gradation Huffman coding table is used, and the compression rate is set to 3 levels, so that the high compression rate is obtained even if the image quality is slightly deteriorated. As the above, a compression program that allows selection of recording a large amount of data or preventing compression of the image quality and keeping the compression rate low was used. That is, in this compression processing program, the number of dots in each of the vertical and horizontal directions is fixed according to the size of the liquid crystal display panel 21 as the image size, and the image data is processed by a 4-bit signal of monochromatic 16 gradations. If 100% of the image data is encoded by the sampling probability of the image data, 50%
, The image data extracted by this sampling has a fixed gradation of 8 for the first predictive value, and thereafter the value of the data of the previous pixel is the predictive value. While predicting the difference between the predicted value and the predicted value, the predictive coding is performed, the predictive coded data of each pixel is serially coded by the series conversion table, and further, the Huffman coding is performed by the Huffman coding table.

The compression program can compress the data sampled by encoding to a data amount of about 40%. Then, in the predictive coding, based on the matrix of the image data in which the row (L) and the order (N) to be newly formed by the sampled data are set, 1
The prediction value of the first pixel in the image data of the row is 8 centered on the gradation, and the data of the second and subsequent pixels in the first row is a one-dimensional predictive encoding in which the value of the data of the previous pixel is the prediction value. (L1NB-L1NB-1) is performed, and in the second and subsequent rows, only the data of the first pixel is one-dimensionally encoded by the value of the data of the first pixel in the previous row (LAN1-LA-1N1), and the same in the previous row. The two-dimensional predictive coding (LANB) that refers to the data value of the th pixel and the data value of the previous pixel in the same row
-(LA-1NB + LANB-1) ÷ 2), and
When data of 50% is sampled at the time of sampling, data of even-numbered pixels is sampled in a plurality of rows, data of pixel of an odd-numbered pixel is sampled in odd-numbered rows, and data of 25% is sampled in an odd number, for example. Image deterioration is prevented as much as possible by sampling the data of the odd-numbered pixels in the row.

As the sequence conversion table, the sequence code of 0 to 15 (decimal number) is sequentially given according to the difference from the predicted value, and 0 of the sequence encoded image data is 1 and 1 to 7 is 2 to 14. Are sequentially increased, and 8 is converted to 15, and 9 to 15 are converted to Huffman codes, which are sequentially decreased from 15 to 3. The compression processing program and the decompression processing program corresponding to the compression processing program are stored in advance in the read-only memory of the microcomputer together with each table, and the image data is compressed to IC.
When recording on a card or flexible disk,
For example, as shown in FIG. 1A, the recognition code of the program is recorded in 7 bytes in the recognition code recording unit 13, the version number of the program is recorded in 4 bytes in the version number recording unit 15, and the compression mode Is recorded in the compression mode recording unit 17 with 4 bytes, finally the header end code is recorded with 1 byte in the end code recording unit 19, and the Huffman-coded image data is recorded in the subsequent area of the file 10. The header section 11 is shortened to 16 bytes (10 hexadecimal bytes), and at the time of restoration, the image data is decompressed by the restoration program stored in the read-only memory based on this code data.

The header section also defines a character code to be inserted into an image such as a date and a code of an inset position, and this character code is followed by a character code recording section 18 (shown in FIG. 1) following the compression mode recording section 17. The size of the header portion 11 may be a variable length of 10 bytes (hexadecimal number) or 20 bytes (hexadecimal number).

In this embodiment, the data such as the compression processing program and the table necessary for the compression / decompression are separately stored in the microcomputer, and the identification code of the program for compressing the image data is stored in the header portion 1 of the file 10.
Since the method of recording in No. 1 is adopted, a large amount of image data can be easily moved when transferring image data between computers of the same type.

[0015]

According to the present invention, the compression / decompression program is stored in the microcomputer in advance, and only the recognition code, version number and compression mode code of the compression program are recorded in the header portion of the file. It is possible to reduce the occupation ratio of the header portion, efficiently record the image data on the recording medium, and transfer the data to another computer.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a header section.

FIG. 2 is an external view of a microcomputer used in an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a file structure.

[Explanation of symbols]

10 files 11 header section 13 recognition code recording section 15 version number recording section 17 compression mode recording section 19 end code recording section 18 character code recording section 21 liquid crystal display panel 23 operation switch 25 IC card insertion slot

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display area H04N 1/21 2109-5C

Claims (1)

[Claims] 1. A compression restoration program is stored in a microcomputer in advance, and a header section based on a recognition code, a version number, a compression mode code and a header end code of the compression restoration program is formed at the head of a file for recording compressed image data. A data compression filing method characterized in that the data is recorded on a recording medium.