Apparatus and method for data compression/expansion using block-based coding with top flag
First Claim
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1. A data compression apparatus comprising:
- a compression device compressing given data according to a block-based coding method, and generating continuation flag information expressive of a length of compressed data in block units at a top part of the compressed data; and
a storage device storing said compressed data.
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Abstract
A compression unit compresses original data in block units and encodes compressed data, and it generates continuation flag information expressive of the block length of the compressed data at the top part of the compressed data stored in a storage unit. An expansion unit determines the block length of the remaining data of the compressed data on the basis of the continuation flag information, fetches the remaining data from the storage unit and restores the original data.
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Citations
58 Claims
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1. A data compression apparatus comprising:
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a compression device compressing given data according to a block-based coding method, and generating continuation flag information expressive of a length of compressed data in block units at a top part of the compressed data; and a storage device storing said compressed data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A data compression apparatus comprising:
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a conversion device converting numerical data to use in an index for information retrieval into interim numerical data expressive of a smaller numerical value; a compression device compressing the interim numerical data by coding the interim numerical data; and a storage device storing the compressed data. - View Dependent Claims (12, 13, 14, 15)
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16. A data compression apparatus comprising:
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a compression device describing size data in block units, the size data expressing a size of an area of "occurring position of a word within a document" data for use in an index for information retrieval, and for compressing said size data; and a storage device storing the compressed size data therein.
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17. A data expansion apparatus comprising:
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a storage device storing therein data compressed in block units according to a block-based coding method; and an expansion device determining a length of the compressed data based on continuation flag information at a top part of said compressed data, and then restoring original data. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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26. A data expansion apparatus comprising:
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a storage device converting numerical data for use in an index for information retrieval into interim numerical data expressive of a smaller numerical value, compressing the interim numerical data and storing the compressed numerical data therein; and an expansion device expanding said compressed numerical data and converting the expanded numerical data into a larger numerical value.
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27. A data expansion apparatus comprising:
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a storage device compressing size data which describes in block units a size of an area of "occurring position of a word within a document" data for use in an index for information retrieval, and storing the compressed size data therein; and an expansion device restoring said size data.
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28. An information retrieval system comprising:
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a storage device compressing, according to a block-based coding method, numerical data for use in an index for information retrieval, and storing compressed data in block units therein; an expansion device determining a length of said compressed data on the basis of continuation flag information at a top part of said compressed data, and then restoring the original data; and a retrieval device retrieving a database by use of said original data restored.
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29. An information retrieval system comprising:
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a storage device converting numerical data for use in an index for information retrieval into interim numerical data expressive of a smaller numerical value, compressing the interim numerical data and storing the compressed numerical data therein; an expansion device expanding said compressed numerical data and converting the expanded numerical data into a larger numerical value; and a retrieval device retrieving a database by the use of the larger numerical value.
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30. An information retrieval system comprising:
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a storage device compressing size data which describes in block units a size of an area of "occurring position of a word within a document" data for use in an index for information retrieval, and storing the compressed size data therein; an expansion device restoring said size data; and a retrieval device retrieving a database by the use of said original data restored.
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31. A computer-readable storage medium storing a program to perform the process of compressing given data according to a block-based coding method and then generating continuation flag information expressive of a length of compressed data in block units at a top part of the compressed data.
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32. A computer-readable storage medium storing a program to perform the process of converting numerical data for use in an index for information retrieval into interim numerical data expressive of a smaller numerical value and then compressing the interim numerical data.
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33. A computer-readable storage medium storing a program to perform the process of describing size data in block units, the size data expressing a size of an area of "occurring position of a word within a document" data for use in an index for information retrieval, and then compressing said size data.
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34. A computer-readable storage medium storing a program to perform the process of determining a length of compressed in block units according to a block based coding method on the basis of continuation flag information at a top part of the compressed data and then restoring original data.
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35. A computer-readable storage medium storing a program to perform the process of expanding data compressed by converting numerical data for use in an index for information retrieval into interim numerical data expressive of a smaller numerical value, and then converting the expanded numerical data into a larger numerical value.
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36. A computer-readable storage medium storing a program to perform the process of expanding data compressed by describing in block units a size of an area of "occurring position of a word within a document" data for use in an index for information retrieval.
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37. A data compression method comprising:
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compressing given data according to a block-based coding method; and generating continuation flag information expressive of a length of compressed data in block units at a top part of the compressed data.
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38. A data compression method comprising:
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converting numerical data for use in an index for information retrieval into interim numerical data expressive of a smaller numerical value; and compressing the interim numerical data.
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39. A data compression method comprising:
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describing size data in block units, the size data expressing a size of an area of "occurring position of a word within a document" data for use in an index for information retrieval; and compressing said size data.
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40. A data expansion method comprising:
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determining a length of data compressed in block units according to a block-based coding method on the basis of continuation flag information at a top part of the compressed data; and restoring original data.
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41. A data expansion method comprising:
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expanding data compressed by converting numerical data for use in an index for information retrieval into interim numerical data expressive of a smaller numerical value; and converting the expanded numerical data into a larger numerical value.
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42. A data expansion method comprising:
expanding data compressed by describing in block units a size of an area of "occurring position of a word within a document" data for use in an index for information retrieval.
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43. A data compression apparatus comprising:
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a compression device compressing given data in block units, and generating continuation flag information expressive of a length of compressed data at a top part of the compressed data; a storage device storing said compressed data therein; and said compression device generates the continuation flag information expressive of a block length of said compressed data at the top part of said compressed data of at least one block, and generates data expressive of the given data so as to succeed said continuation flag information. - View Dependent Claims (44, 45, 46, 47, 48)
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49. A data compression apparatus comprising:
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a compression device for use in an index for information retrieval and compressing numerical data; a storage device storing the compressed data therein; and said compression device compresses the interim numerical data with 4 bits as a unit of a block, and generates continuation flag information expressive of a block length of said compressed data at a top part of said compressed data.
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50. A data compression apparatus comprising:
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a compression device for use in an index for information retrieval and compressing the numerical data; a storage device storing the compressed data therein; and said compression device expresses the interim numerical data for a numerical value of at most 2, by a block of 2 bits, and compresses the interim numerical data expressing a numerical value of at least 3, with 4 bits as a unit of a block. - View Dependent Claims (51)
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52. A data expansion apparatus comprising:
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a storage device storing therein data compressed in block units; an expansion device determining a length of the compressed data on the basis of continuation flag information at a top part of said compressed data, and then restoring original data; said expansion device derives data expressive of the original data succeeding the continuation flag information, on the basis of said continuation flag information expressive of a block length of said compressed data of at least one block, and then restores said original data; said expansion device includes a decoding device decoding a code given as said compressed data and described with 4 bits as a unit of a block.
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53. A data expansion apparatus comprising:
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a storage device storing therein data compressed in block units; an expansion device determining a length of the compressed data on the basis of continuation flag information at a top part of said compressed data, and then restoring original data; said expansion device derives data expressive of the original data succeeding the continuation flag information, on the basis of said continuation flag information expressive of a block length of said compressed data of at least one block, and then restores said original data; and said expansion device includes a decoding device decoding one block of 8 bits given as said compressed data, thereby to generate numerical data of at most 127, and decoding a top block of 8 bits and at least one succeeding block having 4 bits as a unit thereof, the blocks having been given as said compressed data, thereby to generate numerical data of at least 128. - View Dependent Claims (54)
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55. A data expansion apparatus comprising:
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a storage device storing therein data compressed in block units; an expansion device determining a length of the compressed data on the basis of continuation flag information at a top part of said compressed data, and then restoring original data; said expansion device derives data expressive of the original data succeeding the continuation flag information, on the basis of said continuation flag information expressive of a block length of said compressed data of at least one block, and then restores said original data; and said expansion device includes a decoding device decoding one block of 2 bits given as said compressed data, thereby to generate numerical data of at most 2, and decoding at least one block having 4 bits as a unit thereof and given as said compressed date, thereby to generate numerical data of at least 3. - View Dependent Claims (56)
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57. A data compression apparatus comprising:
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a compression device compressing data by generating a block of continuation flag information and compressing data into compressed data blocks using a block-based method; and a storage device storing the continuation flag information on top of the compressed data blocks.
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58. A data compression method comprising:
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generating a block of continuation flag information; compressing data using a block based method into compressed data blocks; and concatenating the continuation flag information on top of the compressed data blocks.
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Specification