JP2788384B2 - Data compression device and data decompression device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data compression device for compressing image data and the like, and a data restoration device for restoring data compressed by the data compression device.

[0002]

2. Description of the Related Art Since image data has an enormous amount of information, a large capacity storage medium of, for example, megabits per screen is required to store the image data as it is. Therefore, in a device that handles image data, data is compressed using a predetermined compression method without storing the image data as it is, and by restoring the data as necessary,
It is common practice to reduce storage capacity.

FIG. 3 shows a conventional data compression apparatus of this type. In the figure, 10 is a data converter for performing data conversion processing on data to be compressed, 20 is an encoder for performing encoding on the data converted by the data converter 10 in accordance with a predetermined compression rule, 30 Is a compression table storing compression rules used in the encoder 20.

Next, the operation will be described. When data to be data-compressed is input to the input, the data converter 10 performs data conversion on the input data in preparation for encoding, and outputs the data to the encoder 20. The encoder 20 encodes the data after data conversion according to the compression rule of the compression table 30, and outputs the encoded result to a storage medium (not shown).

[0005]

The conventional data compression apparatus is constructed as described above. When data compression is performed, a considerable amount of specific data is generated. However, the encoder replaces the data in Table 3 with the data in Table 7. When the data is converted to the data, the specific data is also included in the data to be compressed, so that there is a problem that the data compression ratio is not very good.

[0006]

[Table 3]

[0007]

[Table 7]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the prior art, and a data compression apparatus and a data compression apparatus capable of further improving the compression ratio when compressing data such as images. An object of the present invention is to provide a data decompression device that can actually decompress compressed data to original data by using this data compression device.

[0009]

According to a first aspect of the present invention, there is provided a data compression apparatus comprising a plurality of blocks each including the same number of data.
Compress original data consisting of a set of locks block by block
Data compression table storing predetermined compression rules for
And the compression rules stored in the data compression table.
Using the above, the original data to be compressed
And convert each intermediate data to specific data at the end.
Data is included, delete the specific data
Encoding means for encoding and compressing the data.
More, when compressing the data for each block, remove the last specific data of the data obtained by converting the data of the data or a block of the block to another data format, obtained by the same as the compressed data is there.

Further, a data decompression device according to the invention of claim 2 of the present application provides a data decompression device by the data compression device of claim 1.
Data restoration device for restoring compressed data to original data
In, the block number of the original data before compression and the
Conversion table that stores the correspondence between data block numbers
And a set of blocks each containing the same number of data
A predetermined pressure for compressing the original data
A data compression table storing compression rules,
Compression using the compression rules stored in the data compression table.
Decode the subsequent data block by block to return to the original data before compression
When restoring, the original data in the conversion table
Block number of compressed data corresponding to block number
And the block number next to the original data block number.
Refer to the compressed data block number and
The number of data that can be restored by the reduction rule is detected, and the data
Data is less than the number of data included in the block.
If not, add the above specific data and add the original data before compression.
By providing a decoding means for restoring the over data, of the present Application
When restoring the data compressed by the data compression device according to the first aspect of the present invention to the original data, referring to a table storing the correspondence between the block numbers of the original data and the block numbers of the compressed data. First, the block number of the compressed data corresponding to the block number of the original data and the block number of the compressed data corresponding to the block number next to the block number of the original data are referred to.

[0011]

In the data compression apparatus according to the present invention, when compressing the data of each block, the block data or the last specific data of the data obtained by converting the data of the block into another data format is deleted. Is used as compressed data, so that the data compression ratio is improved.

In the data decompression device according to the present invention, when decompressing the compressed data, a table storing the correspondence between the block number of the original data before compression and the block number of the data after compression is stored. When referencing, the block number of the compressed data corresponding to the block number of the original data and the block number of the compressed data corresponding to the block number next to the block number of the original data are referred to. The number of specific data deleted at the time of compression is determined, and the data compressed by the data compression device according to the present invention can be restored to the original data.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a data compression apparatus according to an embodiment of the present invention, and its block configuration is exactly the same as that of a conventional data compression apparatus.

Next, the operation will be described. At first this figure 1
The compression procedure will be described with reference to FIG. In FIG. 1, a data converter 10 performs a data conversion process on the original image data shown in Table 1 and converts the original image data into converted data shown in Table 2. The unit of processing is each block number. In the original image data, one block is composed of n data.

[0015]

[Table 1]

[0016]

[Table 2]

Next, the encoder 20 first converts the converted data shown in Table 2 into intermediate data shown in Table 3.

Then, the data in Table 3 is converted into the data in Table 7 using the compression table shown in Table 6, and output to a storage medium (not shown). In Table 3, the block number i is composed of ni data. Ai in Table 7 is the block number of the data after compression. In the intermediate data shown in Table 3, when the b _{i ni} = B, to remove this particular data for data compression. The restoration procedure will be described later, but the deleted specific data B can be returned to the original data by referring to the conversion table 40 in FIG.

As described above, the original data is processed and compressed in block units as described above. Therefore, when this is decompressed, random access can be performed in block units and decoding can be performed.

[0020]

[Table 6]

Next, a procedure for restoring the compressed data will be described. FIG. 2 is a block diagram of a data restoration apparatus according to an embodiment of the present invention. In the figure, reference numeral 50 denotes a decoder for restoring data compressed by the data compression apparatus of FIG. 1 into converted data using the compression table 30 storing the same compression rules as in FIG. 1 and the conversion table 40; This is a data converter for converting the converted data restored by the device 50 into the original data.

Next, the operation will be described. Given the block number of the data to be restored by the data restoration device,
The data decompression device reads data necessary for the decoder 50 from a storage medium (not shown) that stores compressed data shown in Table 7. Then, the decoder 50 refers to the compression table 30 and the conversion table 40 and converts the data into intermediate data shown in Table 3.

This process will be described in detail. For example, consider a case where data of the block number i of the original image is restored.
First, the decoder 50 reads the compressed data address Ai corresponding to the original data address i and the adjacent compressed data address Ai + 1 from the conversion table shown in Table 4. By reading both addresses, the compressed data address Ai
You can see how many pieces of data there are. The data at the compressed data address Ai in Table 7 is read in order and converted into the data in Table 3 with reference to the compression table 30. Here, when the last data b _ini of the block number i in Table 3 is equal to B, this pattern is deleted at the time of encoding. Therefore,
Data has become a _{b i0 b i1 ... b in-} 1. When this data is converted into the data of Table 2, _{ai0 ai1} ... _Aim is obtained. Here, m <n. On the other hand, the data in Table 2 is composed of n data in each block. (Nm) pieces of data correspond to B in Table 3. At the time of encoding, when the data of Table 2 is converted from the data of Table 2 to the data of Table 3, since the data of Table 2 that becomes B is known in advance, this data is referred to as a _i0 a _i1 .
If it is added after a _im , it is correctly converted to the data in Table 2. This processing is continued until the data immediately before the block number of the compressed data shown in Table 7 becomes A _{i + 1} , and the intermediate data shown in Table 3 is obtained. Then, the intermediate data shown in Table 3 is converted into the conversion data shown in Table 2 in a procedure reverse to that of the encoder 20.

[0024]

[Table 4]

Next, the data converter 2 (60) converts the converted data shown in Table 2 into original image data shown in Table 1.

The conversion table may be configured as shown in Table 5. That is, the block number Ai of the compressed data and A _{i + 1} adjacent thereto are stored at the location corresponding to the block number i of the original data.

[0027]

[Table 5]

[0028]

As described above, according to the data compression apparatus of the first aspect of the present invention, the same number of data are
Source data consisting of a set of
Data compression storing predetermined compression rules for compression
Table and the compression stored in the data compression table
Using the rules, the original data to be compressed
To convert it to intermediate data, and put each intermediate data at the end.
If specific data is included, delete the specific data
Encoding means for encoding and compressing the data
As a result, when compressing the data for each block , the data of the block or the last specific data of the data obtained by converting the data of the block to another data format is deleted to be compressed data. Part of the data that had to be compressed can be deleted, and the compression ratio can be further improved compared to a normal data compression device. Moreover, when restoring the data, the original data itself
The data can be compressed so that it can be restored.

According to the data decompression device according to the second aspect of the present invention, the data compression device according to the first aspect is provided.
Data to restore the original data
In the source device, the block number and compression
A variable that stores the correspondence between the reduced data and the block number
Conversion table and a block containing the same number of data
A place to compress original data consisting of sets for each block
A data compression table that stores
Using the compression rules stored in the data compression table
To decode the compressed data block by block and
When restoring to data, the original
Blocks of compressed data corresponding to data block numbers
Block number next to the original data block number
And the block number of the compressed data corresponding to
The number of data that can be restored by the above compression rule
And the number of the data is included in the block
If the number is not enough, add the above specific data and compress
Decoding means for restoring the previous original data.
When restoring the compressed data to the original data before compression, when referring to the table storing the correspondence between the block numbers of the original data before compression and the block numbers of the compressed data, Since the block number of the compressed data corresponding to the block number of the data and the block number of the compressed data corresponding to the block number next to the block number of the original data are referred to, the above-described data compression apparatus is used. The data compressed by the actual data
Can be restored to exactly the same data .

[Brief description of the drawings]

FIG. 1 is a block diagram of a data compression device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a data restoration device according to an embodiment of the present invention.

FIG. 3 is a block diagram of a conventional data compression device.

[Explanation of symbols]

 Reference Signs List 10 data converter 20 encoder 30 compression table 40 conversion table 50 decoder 60 data converter

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tetsuo Morishige 1-12-38 Esakacho, Suita-shi, Osaka Esaka Soliton Building Megachips Co., Ltd. (56) References JP-A-3-192878 (JP, A) JP-A-3-96123 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H03M 7/30 H03M 7/44

Claims (2)

(57) [Claims] (1) A block containing a same number of data.
A place to compress original data consisting of sets for each block
A data compression table storing a fixed compression rule and a compression rule stored in the data compression table are used.
The original data to be compressed is converted to intermediate data in block units.
Data and convert each intermediate data to specific data at the end.
If it is included, delete the specific data and sign
And a coding means for compressing the data. 2. A data restoration device which restores the original data is compressed data by the data compression apparatus according to claim 1, corresponding to the block number of the data after compression and the block number of the compression before the original data a conversion table storing, from which consists of a set of blocks including the same number of data, respectively
Prescribe a specific compression rule for compressing data block by block.
Using the stored data compression table and the compression rules stored in the data compression table
To decode the compressed data block by block and
When restoring the data, the block number of the compressed data corresponding to the block number of the original data and the block number of the compressed data corresponding to the block number next to the block number of the original data in the conversion table are described. referring to
The number of data that can be restored by the above compression rule
And the number of the data is included in the block
If the number is not enough, add the above specific data and compress
A data restoring device comprising decoding means for restoring the previous original data .