Patent ID: 6304606
Filing Date: 2001-10-16
Classification: H04N

Abstract:
An image data coding apparatus for coding image data in units of blocks by dividing a frame into a plurality of blocks, comprising:a reference frame holding unit to hold image data of a reference frame;a present frame holding unit to hold image data of a present frame;a threshold value holding unit to hold a threshold value to determine whether the image data within a block of the present frame changes from corresponding image data of a corresponding block in the reference frame;a change amount calculating unit to calculate an amount of change of a value of a predetermined image element within the block of the present frame compared to a corresponding image element of the corresponding block in the reference frame;a block change determining unit to determine change in the image data between the image data within the block of the present frame and the corresponding image data of the corresponding block in the reference frame;a selecting unit to select the image data of a valid block in which change in the image data is determined by said block change determining unit, among the image data in respective blocks in the present frame held in said present frame holding unit;a coding unit, to code the image data of the valid block selected by said selecting unit to produce coded data;an invalid block calculating unit to calculate a number of continuous invalid blocks, following the valid block and containing image data determined by said block change determining unit as unchanged from corresponding blocks in the reference frame; andan outputting unit, to output a result obtained by said block change determining unit together with the coded data of the valid block generated by said coding unit and the number of continuous invalid blocks calculated by said invalid block calculating unit.