JP2006352417A5 - - Google Patents

Claims (14)

In a data compression apparatus that performs data compression processing on data to be compressed consisting of a series of numerical values represented by a predetermined number of unit bits,
By periodically decimating a numerical value from a series of numerical values constituting the compressed data, the first compressed data consisting of a series of numerical values extracted from the compressed data by the thinning and a continuation of the remaining numerical values A decimation processing unit for creating second compressed data;
A lossless compression unit that performs a lossless compression process on the first data to be compressed created by the thinning processing unit;
A data compression apparatus comprising: an irreversible compression unit that performs irreversible compression processing on the second compressed data created by the thinning processing unit. The lossy compression unit is
Whether or not the numerical value constituting the second compressed data created by the thinning processing unit has a value between the numerical values thinned out before and after the numerical value by thinning out the thinning processing unit. judgment, when it has a value between outputs a code indicating that a value of between, if not the value between the numerical values representing the numbers in the number small bits equal to or less than the number of the unit bits 2. The data compression apparatus according to claim 1, wherein the data compression apparatus outputs the data. 3. The data compression apparatus according to claim 2, wherein the irreversible compression unit truncates a lower digit of the bit value of the unit bit number when expressing a numerical value by the small bit number. When the irreversible compression unit expresses a numerical value with the small number of bits, among the numerical range expressed with the unit bit number, the remaining numerical range excluding the numerical value width of the numerical value thinned out from each predetermined place 3. The data compression apparatus according to claim 2, wherein the data is re-expressed by allocating to the small number of bits. The lossless compression unit is
Difference generation for generating new compressed data composed of a series of numerical values representing the difference by obtaining a difference between adjacent numerical values for a series of numerical values constituting the first compressed data generated by the thinning processing unit And
An offset unit for offsetting each numerical value constituting the new compressed data generated by the difference generation unit by a predetermined value;
By dividing each numerical value of the compressed data whose numerical value is offset by the offset unit into an upper bit part and a lower bit part at a predetermined number of divided bits smaller than the unit bit number, the compressed data is A dividing unit that divides the upper data consisting of a continuation of the upper bit part in each numerical value and the lower data consisting of a continuation of the lower bit part of each numerical value;
Data compression apparatus according to claim 1, wherein the for the upper data divided by said dividing unit is obtained by an upper data compression unit that performs lossless compression process.   The upper data compression unit outputs the numerical value excluding one or a plurality of predetermined compression target numerical values in the upper data as it is, and the compression target numerical value is the same as the compression target numerical value and the compression target numerical value. 6. The data compression apparatus according to claim 5, further comprising a first encoding unit that encodes and outputs a numerical value representing a continuous number of numerical values to be compressed. The upper data compression unit is
In the upper data, the numerical value excluding one or a plurality of predetermined compression target numerical values is output as it is, and for the compression target numerical value, the compression target numerical value and the number of consecutive compression target numerical values that are the same as the compression target numerical value are set. A first encoding unit that encodes and outputs a numerical value to be represented;
A second encoding unit that performs entropy encoding on data after being encoded by the first encoding unit using a table that associates codes and numerical values is provided. Item 6. The data compression device according to Item 5. The upper data compression unit is
In the upper data, the numerical value excluding one or a plurality of predetermined compression target numerical values is output as it is, and for the compression target numerical value, the compression target numerical value and the number of consecutive compression target numerical values that are the same as the compression target numerical value are set. A first encoding unit that encodes and outputs a numerical value to be represented;
6. The data according to claim 5, further comprising a second encoding unit that performs Huffman encoding on the data after being encoded by the first encoding unit using a Huffman table. Compression device. The upper data compression unit is
In the upper data, the numerical value excluding one or a plurality of predetermined compression target numerical values is output as it is, and for the compression target numerical value, the compression target numerical value and the number of consecutive compression target numerical values that are the same as the compression target numerical value are set. A first encoding unit that encodes and outputs a numerical value to be represented;
A histogram calculation unit for obtaining a histogram of numerical values appearing in the data after being encoded by the first data compression unit;
Based on the histogram obtained by the histogram calculation unit, a code allocating unit that assigns a code having a shorter code length to a table associating codes and numerical values with a higher appearance frequency,
Using a table to which a code is allocated by the code allocation unit, and a second encoding unit that performs entropy encoding on the data encoded by the first encoding unit. 6. The data compression apparatus according to claim 5, wherein 6. The data compression apparatus according to claim 5, further comprising a lower data compression unit that performs a lossless compression process on the lower data divided by the division unit. 11. The data compression apparatus according to claim 10, wherein the lower data compression unit performs entropy coding on the lower data using a table associating codes and numerical values . 11. The data compression apparatus according to claim 10, wherein the lower data compression unit performs Huffman coding on lower data using a Huffman table . The lower data compression section and the data compression apparatus according to claim 10, wherein in response to an instruction compression abbreviated characterized der Rukoto and outputs the lower data without compression. In a data compression program that is incorporated in an information processing apparatus that executes a program and causes the information processing apparatus to execute data compression processing on data to be compressed consisting of a series of numerical values represented by a predetermined number of unit bits.
  On the information processing apparatus,
  By periodically decimating a numerical value from a series of numerical values constituting the compressed data, the first compressed data consisting of a series of numerical values extracted from the compressed data by the thinning and a continuation of the remaining numerical values A decimation processing unit for creating second compressed data;
  A lossless compression unit that performs a lossless compression process on the first data to be compressed created by the thinning processing unit;
  A data compression program for constructing an irreversible compression unit that performs irreversible compression processing on the second compressed data created by the thinning processing unit.