Image data compression

摘要

Image data compression apparatus comprises a data compressor for receiving data representing sub-areas of an input image and for generating respective blocks of compressed data representing those sub-areas, each block of compressed data comprising at least low spatial frequency image data and higher spatial frequency image data; a data formatter for formatting predetermined groups of said blocks of compressed data into output data blocks, said data formatter having a predetermined data capacity; a detector for detecting whether a current group of said blocks of compressed data contains more data than said data capacity of said data formatter; and a block truncator, responsive to a detection that a current group of said blocks of compressed data contains more data than said data capacity of said data formatter, for truncating one or more of said blocks of compressed data by discarding at least said higher spatial frequency image data.