| 摘要 |
PURPOSE: A method for concealing an information message in an audio signal is provided to prevent auditing and viewing, and to be strong for actual transmission of a digital audio signal such as filtering, re-sampling, compression, D/A(Digital-to-Analog) and A/D conversion and data format change. CONSTITUTION: A watermark parameter register(10) stores all parameters. If initial audio data are inputted from an external, a temporary calculator(20) calculates output data with fourier transform at each time internal, using data stored in the watermark parameter register(10) and the initial audio data. A watermark unit(30) changes a fourier coefficient composed of channel coefficients, namely, an information part and a correction part, and inserts a watermark signal in both channels for outputting. An output generator(40) detects the watermark signal output from the watermark unit(30), and performs inverse fourier transform for each time interval, to output an initial audio signal in which a watermark is inserted.
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