Research Of Speech Hiding Scheme Based On Wavelet Transform

Information hiding techniques based on wavelet transform is a hot research field in last few years. This paper proposes two kinds of speech hiding algorithm based on wavelet transform. It embeds a speech as the secret message into a digital audio signal in order to transmit secret message under the camouflage of the audio signal or protect the audio product by using the speech signature as a mark.The first method described in this paper makes use of the human auditory system (HAS) characteristics and the wavelet to compress the speech signature, so it increases the capacity. A proper parameter and some wavelet coefficients of the cover audio signal are selected to embed information. The experimental results show that the algorithm can hide high capacity of date imperceptibly and it is robust to routine operations on digital signal. The second method doesn't need the original cover signal when extracts the secret dates. The even wavelet coefficients of the cover signal are substituted by the mean value of the adjacent coefficients and used to embed information. After being modified by embedded dates the substituted coefficients are closer to original coefficients. The experimental results show: when the capacity is not so large, the algorithm is robust to many operations to digital date, such as compression, filter, re-sampling, white noise etc. It is adapt to embed secret speech as a mark into audio signal in order to protect the copyright.