Additional-data embedding apparatus and additional-data embedding method

An additional-data embedding method of embedding predetermined additional data into original data, comprising:

• an adding step of summing the original data and the additional data so as to obtain summed data;
• a first amplifying step of amplifying the original data based upon a predetermined nonlinear input-output characteristic so as to obtain amplified original data;
• a second amplifying step of amplifying the summed data obtained in the adding step based on a predetermined nonlinear input-output characteristic so as to obtain amplified summed data;
• a subtracting step of taking a difference between the amplified summed data obtained in the second amplifying step and the amplified original data obtained in the first amplifying step so as to obtain modified additional data;
• and
• an embedding step of embedding the modified additional data obtained in the subtracting step into the original data.

An additional-data embedding apparatus data, comprising:

• transforming means for performing predetermined transformation of the original data;
• adding means for summing transformed data obtained from the transforming means and the additional data so as to obtain summed data;
• first amplifying means for amplifying the transformed data based on a predetermined nonlinear input-output characteristic so as to obtain amplified transformed data;
• second amplifying means for amplifying the summed data supplied from the adding means based on a predetermined nonlinear input-output characteristic so as to obtain amplified summed data;
• subtracting means for taking a difference between the amplified summed data obtained from the second amplifying means and the amplified transformed data obtained from the first amplifying means so as to obtain modified additional data;
• inverse transforming means for performing inverse transformation on the modified additional data obtained from the subtracting means, the inverse transformation being inverse to the transformation performed by the transforming means;
• and
• embedding means for embedding the modified additional data obtained from the inverse transforming means into the original data.

An additional-data embedding method of embedding predetermined additional data into original data, comprising:

• a transforming step of performing a predetermined transformation of the original data;
• an adding step of summing transformed data obtained by the predetermined transformation performed in the transforming step and the additional data so as to obtain summed data;
• a first amplifying step of amplifying the transformed data based on a predetermined nonlinear input-output characteristic so as to obtain amplified transformed data;
• a second amplifying step of amplifying the summed data obtained in the adding step based upon a predetermined nonlinear input-output characteristic so as to obtain amplified summed data;
• a subtracting step of taking a difference between the amplified summed data obtained in the second amplifying step and the amplified transformed data obtained in the first amplifying step so as to obtain modified additional data;
• an inverse transforming step of performing an inverse transformation of the modified additional data obtained in the subtracting step, the inverse transformation being inverse to the transformation performed in the transforming step;
• and
• an embedding step of embedding the modified additional data obtained in the inverse transforming step into the original data.