Image encoding method using adaptive preprocessing

PURPOSE: An image encoding method with an adaptive preprocessing technique is provided to restrain an original image from being distorted by applying a filter, and to restrain compression efficiency from declining in an image compression process. CONSTITUTION: An image encoding method with an adaptive preprocessing technique includes: a step (S601) of loading an inputted image by frame; a step (S602) of distinguishing an encoding type for each frame; steps (S603,S605) of determining the size of a block which is to be encoded in each frame according to the distinguished encoding type; steps (S604,S606) of distinguishing the replicable blocks from the blocks of which the sizes are determined, and implementing a replication preprocess inside a screen or a replication preprocess between the screens; and a step (S607) of encoding the frames in which the preprocesses for the blocks are completed. [Reference numerals] (AA) Start; (BB) I frame; (CC) P/B frame; (DD) No; (EE) Yes; (FF) End; (S601) Frame load; (S602) Frame distinction; (S603) Determine the size of blocks in an I frame preprocess; (S604) Duplication preprocess in screens; (S605) Determine the size of blocks in a P/B frame preprocess; (S606) Duplication preprocess between screens; (S607) Frame encoding; (S608) Restore an encoded frame; (S609) Quality evaluation for the restored frame; (S610) Control a threshold value of a duplication preprocess; (S611) Check whether there is a final frame or not?