To provide an image compressing device capable of reducing the size of a signal indicating a result of area separation generated together with irreversibly compressed data (compressed image data).
A data compression section 17 uses an image expansion section 22 to expands compressed RGB data obtained through irreversible compression to thereby generate expanded RGB data and uses a 2nd area separation section 23 to generate an expanded area separation signal. Further, in the data compression section 17, a difference extraction section 25 generates a difference signal being the difference between an area separation signal and the expanded area separation signal and a 2nd signal compression section 26 generates a compressed difference signal. Then the compressed difference signal is outputted as a separation signal for storage (signal indicating information on area separation) to a data storage part 8 together with the compressed RGB data. The compressed difference signal is smaller in size than the area separation signal, so that the time for data output can be shortened to reduce necessary storage capacity.
Kenzo Hara
Ryuichi Kijima
Ichiro Kaneko