Abstract: Watermarking is the process of embedding information into a signal (e.g. audio, video or pictures) in a way that is difficult to remove. If the signal is copied, then the information is also carried in the copy. An audio watermark is a unique electronic identifier embedded in an audio signal, typically used to identify ownership of copyright. Audio watermarking is done using Empirical Mode Decomposition (EMD) where the audio signal is divided into segments and then decomposed into different IMFs (Intrinsic Mode Functions).The watermark is then applied to the last IMF as binary bits using QIM (Quantization Index Modulation). The watermarked colour image is obtained using DCT (Discrete Cosine Transform) compression method and converted to binary bits. In the watermark extraction phase the watermark is obtained as binary bits and converted back into image using IDCT (Inverse Discrete Cosine Transform) technique. The watermark is embedded into the IMF preserving audio perceptual quality of the host signal. By varying watermarking intensity the robustness of the hidden watermark for additive noise and MP3 compression is enhanced and the payload of the watermarked audio signal is increased.
Keywords: Empirical mode decomposition, intrinsic mode function, audio watermarking, image compression, discrete cosine transform.