Patent ID: 7183950

Claim:
A data compression apparatus that applies a data compression processing to data to be compressed, the data consisting of continued numerical values represented by a predetermined number of unit bits, the data compression apparatus comprising: a difference creating section that determines a difference between adjacent numerical values on continuity of numerical values constituting the data to be compressed so as to create new data to be compressed consisting of continued numerical values representative of the difference; an offset section wherein numerical values constituting the new data to be compressed consisting of the continued numerical values, which is created by the difference creating section, is subjected to an offset by a predetermined value; a divisional section that divides every numerical value of the data to be compressed, which is subjected to the offset by the offset section, into an upper significant digit bit portion and a lower significant digit bit portion at a predetermined divisional bit number less than the predetermined number of unit bits, so that the data to compressed is divided into upper significant digit data consisting of continuity of numerical values of the upper significant digit bit portion and lower significant digit data consisting of continuity of numerical values of lower significant digit bit portion; an upper significant data compression section that applies reversal compression processing to the upper significant digit data divided by the divisional section; and a lower significant data compression section that applies reversal compression processing to the lower significant digit data divided by the divisional section.