Patent ID: 7899262

Claim:
A data compression apparatus which performs a data compressing process on data to be compressed including a sequence of values represented by a predetermined number of unit bits, comprising: a type determination section which determines a type of the data to be compressed; a difference generation section which obtains a difference between adjacent values in the sequence of the values forming the data to be compressed, and generates new data to be compressed including a sequence of values representing the difference; an offset section which offsets each of the values forming the new data to be compressed by a predetermined value; a division section which divides the values of the data to be compressed whose values are offset by the offset section into a higher order bit portion and a lower order bit portion at a predetermined number of division bits lower than the number of unit bits, thereby dividing the data to be compressed into higher order data including a sequence of higher order bit portions of the values and lower order data including a sequence of lower order bit portions of the values; a lower order data compression section which performs a reversible compressing process on a basis of the type determined by the type determination section on the lower order data obtained through the division by the division section; and a higher order data compression section which performs a reversible compressing process on the higher order data obtained through the division by the division section.