Image data reproducing apparatus

Abstract

An apparatus for reproducing original image data from compressed image data, supplied thereto as a plurality of separate data blocks, each data block including a plurality of compressed pixel data arranged in a matrix form of rows and columns. The apparatus includes a reproducing circuit for sequentially reproducing a plurality of original pixel data, block by block, by subjecting the compressed pixel data of each data block to data expansion; and a Differential Pulse Code Modulation (DPCM) encoder, coupled to the reproducing circuit, for performing DPCM encoding on each reproduced pixel data supplied from the reproducing circuit to sequentially produce a plurality of DPCM code data. The apparatus further includes an image memory, coupled to the DPCM encoder, for storing the DPCM code data supplied from the DPCM encoder. The DPCM encoder predicts a value of reproduced pixel data to be encoded subsequent to reproduced pixel data currently being encoded, calculates a difference between the predicted value and a real value of the reproduced pixel data to be subsequently encoded, and produces DPCM code data having a code determined in accordance with the calculated difference.