| 摘要 |
PROBLEM TO BE SOLVED: To embed watermark information without changing the bit string of a regular compression code and a decoder by changing the value of the parameter of control on the encoding processing of vector quantization in corresponding to watermark information. SOLUTION: An input signal from a terminal 11 is compressed/encoded by vector quantization in an encoder 12 and encoding output is outputted from a terminal 13. Watermark information is inputted to an encoding parameter control part 15, and the control parameter of encoding in the encoding processing is chanted slightly according to watermark information. A compression bit matrix (encoding bit string) outputted from the encoder 12 is changed, and the watermark information is embedded into the compression bit matrix. The weight coefficient (r) of vector quantization is used as the control parameter of encoding. Normally, a value of about r=0.7 is used. For inputting watermark information, it is set to be r=0.65 if watermark information is '0', and to be r=0.75 if it is '1'. |
