ADDITIONAL INFORMATION SIGNAL SUPERIMPOSING AND DETECTING SYSTEM, ADDITIONAL INFORMATION SIGNAL SUPERIMPOSING AND DETECTING METHOD, AND ADDITIONAL INFORMATION SIGNAL DETECTING METHOD AND APPARATUS THEREFOR.

摘要

VIDEO SIGNALS ARE CONVERTED INTO ONE OR MORE BLOCKS FOR EACH PREDETERMINED UNIT AMOUNT OF DATA, AND A DCT PROCESS IS PERFORMED IN THIS BLOCK UNIT TO CONVERT THE VIDOE SIGNAL FROM A TIME - BASE AREA SIGNAL TO A DCT COEFFICIENT IN A FREQUENCY IN A FREQUENCY AREA FOR DATA COMPRESSION. AS REGARDS ADDITIONAL INFORMATION CONSISTING OF SPREAD SPECTRUM SIGNALS, 1 CHIP OF THE SPREAD SPECTRUM SIGNAL IS ALLOCATED TO EACH BLOCK OF THE VIDEO SIGNAL OR TO EACH PLURAL BLOCKS, AND THE ADDITIONAL INFORMATION IS SUPERIMPOSED ON THE VIDEO SIGNAL AS A CONSTANT LEVEL CORRESPONDING TO THE CHIP VALUE FOR TRANSMISSION. THE VIDEO SIGNAL ON WHICH THE ADDITIONAL INFORMATION CONSISTING OF THE SPREAD SPECTRUM SIGNAL TRANSMITTED HAS BEEN SUPERIMPOSED IS RECEIVED, AND FROM THIS RECEIVED SIGNAL, THE DC COMPONENT OF THE DCT COEFFICIENT IS EXTRACTED. INVERSE SPREAD PROCESS IS PERFORMED FOR THE DC COMPONENT OF THE DCT COEFFICIENT EXTRACTED TO DETECT THE ADDITIONAL INFORMATION.