IMAGE PROTECTOR AND DECODER

摘要

PROBLEM TO BE SOLVED: To provide an image protector, with which protect processing is facilitated and it is not necessary to provide any device for protect processing separately from a decoder in the case of protect processing on the decode side of image information encoded while using DCT encoding, and a decoder having this image protector. SOLUTION: At a decoder A1, a protector 20 is provided between an inverse quantizer 10 and an inverse DC transformer 40. Concerning a DCT coefficient generated by inverse quantization, all the DC coefficient component values of Y signal are set at a fixed value at the macro block of picture in Intra mode or the macro block of Intra mode and the DC coefficient component value of Cb component of C signal or the DC coefficient component value of Cr component is set at a fixed value as well by the protector 20. Besides, all the AC coefficient component values of these respective components in the C signal are turned to '0'.